            2014 Compliance Recertification Application (CRA-2014)
         Compliance Application Review Document (CARD Section 194.24)
                            Waste Characterization
24.0 Background (194.24(a))

	Section 194.24, waste characterization, generally requires DOE to identify, quantify and track the chemical, radiological, and physical components of the waste destined for disposal at WIPP that can influence disposal system performance.  Much of the waste information and waste estimates remain similar through time, but DOE may add waste and withdraw waste from the inventory.  It is a dynamic inventory and EPA expects changes through the years.  However, it is incumbent upon DOE to include the latest information on the inventory estimate in the performance assessment.  After the 2004 Compliance Recertification Application, DOE began to update the inventory on an annual basis.

      Section 194.24 (a) presents the waste inventory reporting requirements that DOE must meet to ensure that sufficient information is available for use in the WIPP performance assessment (PA).  
      
24.1 Requirement (194.24(a))
 
	(a) "Any compliance application shall describe the chemical, radiological and physical composition of all existing waste proposed for disposal in the disposal system.  To the extent practicable, any compliance application shall also describe the chemical, radiological and physical composition of to-be-generated waste proposed for disposal in the disposal system.  These descriptions shall include a list of the waste components and their approximate quantities in the waste.  This list may be derived from process knowledge, current non-destructive examination/assay, or other information and methods."
      
24.1.1   1998 Certification Decision (194.24(a))

	To meet the requirements of Section 194.24(a), EPA expected DOE's Compliance Certification Application (CCA) to provide a description of the existing waste, list approximate quantities of waste components in each description, and provide similar descriptions for to-be-generated waste, to the extent practicable.

	DOE provided the required information on existing waste (35% of the total WIPP inventory) by combining similar waste streams into waste stream profiles.  The waste stream profiles contained information in the waste material parameters, or components that could affect repository performance.  For to-be-generated waste (65% of the total WIPP inventory), DOE extrapolated (or scaled) information from the existing waste streams to determine the future amount of waste.  DOE described the waste in Volume 1 and Appendix BIR of the CCA.

	EPA reviewed the information provided and determined that DOE's waste stream profiles contained the appropriate specific information on the components and their approximate quantities in the waste.  Therefore, EPA found DOE in compliance with Section 194.24(a) (CCA CARD 24).

	A complete description of EPA's 1998 Certification Decision for Section 194.24(a) can be obtained from Docket A-93-02, Items V-A-1 and V-B-2.

24.1.2 Changes in the 2004 Compliance Recertification Applications (194.24(a))

      To meet the requirements of Section 194.24(a), DOE described and categorized the entirety of TRU waste that is currently emplaced in WIPP and the waste that exists at various DOE facilities.   Since the first emplacement of waste in 1999, DOE has tracked the waste emplaced at WIPP using the WIPP Waste Information System (WWIS).  For the waste that is stored or to-be-generated at the waste generator sites, DOE developed a descriptive methodology for grouping waste information obtained from each generator site.  For the 2004 CRA, DOE initiated a complex-wide data call in which DOE's Carlsbad Field Office (CBFO) asked every TRU waste generator site to update the CCA waste profile forms describing the physical, chemical, and radiological constituents in each waste stream that generates or generated TRU waste at that site. This data call reflected the disposal intentions of the waste generator sites as of September 30, 2002.  DOE representatives examined the information, clarified questions and then validated the waste stream profile information.  This information was synthesized across the waste generator sites and then prepared for input into performance assessment by scaling the inventory and other data reduction actions (e.g., decaying to 2033).  This process is captured in the flowchart in Figure 24-1 (Docket A-98-49, Item II-B2-60).  
      
	The details of the inventory are presented in 2004 CRA Chapter 4 Volume 1 and 2004 CRA Appendix TRU-WASTE.  Tables 2004 CRA Appendix TRU-WASTE 1-5, present the most relevant information on the important aspects of the inventory used for the 2004 CRA.  

      During EPA's review of the PA submitted in the 2004 CRA, EPA questioned aspects of the waste inventory DOE was reporting for recertification.  EPA's requests for additional information and DOE's responses can be found in EPA's E-Docket (Federal Docket Management System [FDMS] Docket ID No. EPA-HQ-OAR-2004-0025).  
      
       EPA directed DOE to conduct a new performance assessment for recertification to incorporate inventory changes as well as some other technical changes (EPA Letter, Docket A-98-49, Item II-B3-80). This new performance assessment is now called the 2004 Performance Assessment Baseline Calculations or 2004 PABC.  The new inventory component and radiological estimates for the PABC are summarized in TRU Waste Inventory for the 2004 Compliance Recertification Application Performance Assessment Baseline Calculation, Sandia National Laboratories, ERMS 541118, September, 2005, hereafter referred to as the "PABC Inventory Report" (Docket A-98-49, Item II-B2-60).  

	The chemical, physical, and radiological inventory was grouped by DOE and developed in detail from the waste stream profiles from each of the TRU waste generator and/or storage sites.  Waste groupings (other than contact handled and remote handled designations) by DOE were based on the chemical and physical aspects of the waste, not the radiological content of the waste (CCA Appendix BIR).  However, the radiological constituents were identified and quantified (in Ci/m[3] for each waste stream) on each waste profile form, and information from the forms was used by DOE to develop the radiological inventory for the WIPP.  The CCA approach was also used for the PABC.  Table 14 of the PABC Inventory Report shows the radiological constituents used for the PABC, including the inventory at the estimated time of disposal (Curie amounts of each radionuclide decayed to the year 2033), and estimated EPA units (activities normalized according to the 40 CFR 191 release limits) for each radionuclide.  
Figure 24-1 Process for Preparing the CRA-2004 TRU Waste Inventory (Source:  PABC Inventory Report, Docket A-98-49, Item II-B2-60, September 2005)



	Each WIPP Waste Profile contains information on the physical and chemical waste components (identified as Waste Material Parameters (WMP's) for DOE purposes), as well as radiological waste components, that DOE believes could affect the performance of the repository.  DOE's waste material parameters are presented as density values for use in performance assessment.  These density values are calculated by multiplying the average density of individual waste streams from a given waste form by the volume of the TWBIR waste stream and then the total volume of the final waste form.  

      The approximate maximum, average, and minimum densities for twelve (12) of DOE's waste material parameters were calculated, including iron based metals/alloys, aluminum based metals/alloys, other metal/alloys, other inorganic materials, vitrified materials, cellulosics, rubber, plastics, solidified inorganic matrix, solidified organic matrix, solidified cement, and soils (PABC Inventory Report, Table 9).  WIPP Waste Profiles contain information on the WMPs, i.e., components that DOE determined to have the potential to impact repository performance.  DOE identified the quantity of physical waste components such as cellulosic material, plastic, rubber, etc., in the 2004 PABC Inventory Report.  Tables 9 and 10 of the 2004 PABC Inventory Report show the anticipated non-radioactive TRU waste inventory for the WIPP for the CCA the CRA and the PABC.

	Also, in accordance with 40 CFR 194.24(a), DOE's waste profiles contain specific information on the species and quantities of individual radioisotopes in the waste.  

Inventory Description
	DOE indicated that to-be-generated waste will be included in those waste streams and final waste forms currently identified at DOE sites (2004 CRA Chapter 4, Section 4.1.3).  Therefore, the waste stream descriptors for existing waste also apply to to-be-generated waste.  Existing waste stream information was used by DOE in its description of to-be-generated waste.

	DOE described its contact-handled (CH) and remote-handled (RH) inventory as "stored," "emplaced," and "projected" or "anticipated."   The stored inventory is generally equivalent to existing waste at the sites, and projected waste is generally equivalent to to-be-generated waste (2004 CRA Appendix DATA, Attachment F).  Emplaced waste is waste that has been put underground at WIPP.  The anticipated inventory is the sum of the emplaced, stored and projected inventories (2004 PABC Inventory Report section 4.1.3).  Table 4 of the 2004 PABC Inventory Report lists the volumes of emplaced CH-TRU waste as of September 30, 2002 (the cutoff for inclusion in the 2004 CRA performance assessment) and August 1, 2005.  Table 5 of the same report lists the stored and projected CH-TRU waste estimates used for the CCA, 2004 CRA PA, and the 2004 PABC.  The projected inventory information was derived from each generator site from the waste stream profile forms, and reflects the site's best determination of the waste expected to be generated.  

	DOE's estimates indicate that the total expected inventory volume for CH-TRU waste will not reach the maximum disposal capacity of the WIPP for CH-TRU (approximately 168,500 m[3] or 5,950,000 ft[3]) (2004 CRA Chapter 4.1.3; 2004 PABC Inventory Report, section 4.1.4, p.27).  DOE employed a scaling approach to project the impacts of a full repository.  The CRA-2004 estimate of waste for disposal at WIPP is 145,000 m[3].  DOE developed a scaling factor based upon the approximately 23,500 m[3] of projected CH-TRU inventory it expects to be generated, as DOE believed that any new waste generated to "fill" the outstanding WIPP space would probably be more similar to the projected rather than existing waste inventory.  This scaled CH-TRU inventory was described by DOE in TRU Waste Baseline Inventory Report (TWBIR), Revision 3 and was based on the projected TRU waste inventory (e.g., waste components, quantity, types of waste, species and quantity of radionuclides).

	As reported in the 2004 PABC Inventory Report, the scaling factor calculated by DOE for CH-TRU waste is 1.48 in the 2004 PABC.  This factor is used in the following formula to project the makeup of the disposal inventory volume (m[3]) according to the LWA design limitations:  
            
Emplaced Inventory + Stored Inventory + (Projected Inventory x 1.48) = PABC Disposal Inventory

	Unlike in the CCA, the 2004 CRA used this scaling methodology on RH-TRU waste; however, the RH inventory was scaled down.  This was necessary because DOE has reported more RH-TRU inventory than there is capacity for as defined in the WIPP Land Withdrawal Act (LWA) (approximately 7,079 m3 or 250,000 ft[3]).  The scaling factor has changed considerably between the 2004 CRA and the 2004 PABC calculations due to changes in estimates in Hanford's RH-TRU inventory.  In the 2004 CRA the scaling factor was 0.172 and in the PABC it is 0.861, reflecting the lesser amount of RH-TRU expected from Hanford because of a double counting error.  The RH-TRU inventory is calculated using a similar equation for the CH-TRU disposal inventory calculation.

Number of Curies
	The total activity of radionuclides expected to be placed in WIPP has decreased from the CCA estimate of 3.44 million curies to 2.32 million curies in the 2004 PABC inventory estimate (2004 PABC Inventory Report Section 4.4, p. 36).  Table 14 of the 2004 PABC Inventory Report lists the activities by radionuclide for the CCA PA, the 2004 CRA PA, and the 2004 PABC. 
	
New Inventory Items Since 1998:  INL Buried Waste
	In the 2004 CRA documentation, DOE designated pre-1970 buried waste at INL as non-WIPP TRU waste (Annex I of CRA-2004 Appendix Data Attachment F).  As a result of an April, 2003 Federal District Court judgment against DOE on the buried waste, DOE decided to include the INL pre-1970 buried waste in the 2004 PABC calculations (2004 PABC Inventory Report section 3.2, p. 21).  The 2004 PABC inventory report estimated 17,998 m[3] of TRU waste in five waste streams from the pre-1970 buried waste.

New Inventory Items Since 1998:  Super-compacted Waste  
      In December 2002, DOE requested EPA's approval to dispose of compressed or super compacted waste from the Idaho National Laboratory's (INL) Advanced Mixed Waste Treatment Facility (AMWTF).  In DOE's waste inventory for the 2004 recertification, this super-compacted waste (waste stream IN-BN-510) accounts for approximately 20,000 m[3] of the inventory.  This waste is described as more rigid than typical waste and has a much higher content of cellulosics, plastics and rubber materials (CPR) than other waste in the CCA inventory. 
       
	DOE conducted an extensive analysis of the waste at the direction of EPA (Docket A-98-49, Item II-B3-64) and concluded that the super-compacted waste would act similarly enough to un-compacted waste that it could be considered within the existing waste envelope and performance assessment.  In March 2004, EPA determined that super-compacted waste could be disposed of at WIPP and that the characteristics of the waste were adequately reflected in the existing performance assessment (Docket A-98-49, Item II-B3-68).  Prior to the shipment of super-compacted waste, EPA conducted a waste characterization inspection to ensure that DOE was able to adequately characterize and track the super-compacted waste (Docket A-98-49, Item II-A4-53).  EPA gave its approval to dispose of super-compacted waste in May 2005.  This waste is included in the 2004 PABC waste inventory estimate (Docket A-98-49, Item II-B3-68).

New Inventory Items Since 1998:  Hanford Tank Waste
	DOE's CRA-2004 inventory included to-be-generated waste from 12 of the 177 tanks at the Hanford site.  These 12 tanks include four waste streams.  These waste streams and their corresponding tanks and waste generating process are provided in Table 24-1 of this CARD.  DOE's documentation states that although these 12 tanks have been managed as high-level waste (HLW), these tanks actually contain waste from transuranic processes (Docket A-98-49, Item II-B2-47) and are therefore eligible for disposal at WIPP.  DOE's documentation provides a technical and regulatory basis for DOE's-Office of River Protection (ORP) determination that 9 of the tanks are TRU waste due to waste origin and confirmed by radionuclide content analysis.  This waste will be contact-handled, and has yet to be removed from the tanks.  

	For the other tanks in the RH waste streams (see Table 24-1), DOE (Docket A-98-49, Item II-B2-47) discusses why they believe that this tank waste is also TRU waste and will be acceptable for disposal at WIPP after the waste is removed from the tanks and treated to meet the WIPP Waste Acceptance Criteria.  DOE states (Docket A-98-49, Item II-B2-47; Enclosure 1, p. 11) that "Two of the double-shell tanks (DSTs) identified in the CRA inventory update, tanks AW-103 and AW-105, received coating removal waste from dissolution of zirconium clad SNF [Spent Nuclear Fuel]" in the PUREX process.  DOE concludes (Ibid, p. 13) that, "the cladding removal process step did not create HLW because it only dissolved the zirconium cladding, leaving the SNF intact.  The cladding removal waste originated prior to the SNF being dissolved and reprocessed.  The NWPA defines HLW as `...the highly radioactive material resulting from the reprocessing of spent nuclear fuel...' Since SNF was intact during the cladding removal process, reprocessing had not occurred, and therefore, the cladding removal waste is excluded from the HLW definition."

	DOE states (Docket A-98-49, Item II-B2-50, p. 15) that "One of the underground storage tanks at the Hanford Site that received PFP waste was DST [double-shelled tank] SY-102.  DOE also states that the PFP [Plutonium Finishing Plant] sludge in tank SY-102 is not HLW because it is not the highly radioactive waste material from the reprocessing of spent nuclear fuel, including liquid waste produced directly in the reprocessing and any solid materials derived from such liquid waste that contains fission products in sufficient concentrations.  The PFP received plutonium materials product and converted it to forms that were used to fabricate nuclear weapons or for other purposes.  The PFP did not receive any SNF or HLW. Therefore, the waste from the PFP sludge is not HLW (Docket A-98-49, Item II-B2-50).  DOE concluded that in addition to this information, the treatment of the waste will make it suitable for disposal at WIPP.  This waste is included in the 2004 PABC waste inventory estimate.

New Inventory Items Since 1998:  Hanford Waste from K-Basin
	DOE recertification waste inventory also included two waste streams, RL-W445 and RL-W446, consisting of ~50 m[3] of sludge from the Hanford K-East and K-West Basins.  This waste was in pools of water used to store irradiated fuel prior to SNF processing (Docket A-98-49, Item II-B2-47; Enclosure 2, p. 1).  While intended to be temporary, the storage lasted for over 20 years. Furthermore, "over the lifetime of these K-West and K-East Basins, debris, silt, sand, and material from operations resulted in the formation of sludge that accumulated in the bottom of these basins.  In addition, the extended storage of the irradiated fuel resulted in corrosion of the fuel cladding and the storage canisters, especially in the K-East Basin, where the fuel was exposed directly to the storage water" (Ibid).  

	DOE concludes "that this sludge does not meet the definition of high level waste (HLW) or SNF, and if properly processed, will meet the disposal requirements for transuranic waste, and thus be eligible for disposal at WIPP" (Ibid).  This waste is included in the 2004 PABC waste inventory estimate.

Container Types
	While the waste containers are not used directly in the performance assessment, knowing the type of container is important in order estimate the amounts of CPR and metals in WIPP (2004 PABC Inventory Report, section 4.2, p. 30).  Container types new to the 2004 PABC inventory include: ten-drum overpacks (TDOPs), 5x5x8 boxes and 100-gallon drums (Ibid).  In addition, DOE used pipe overpacks within drums to contain high radioactivity salts from Rocky Flats Environmental Technology Site (RFETS).  The TDOPs are used primarily at INL and SRS, the 100 gallon drums are used at INL for the super-compacted waste, and the 5x5x8 boxes are in the SRS inventory.  Container types are considered in the 2004 PABC inventory development process.

Organic Ligands 
	A ligand is an ion or molecule that binds to a metal.  At WIPP the importance of ligands is that they could bind to the radionuclides, and potentially increase the solubility of those radionuclides. Organic ligands which attach to the cation at more than one location (by different atoms within the structure of the ligand) are called chelating groups and the complex thus formed is called a chelate.  Many synthetic compounds, such as EDTA (ethylenediaminetetraacetic acid) form chelates. Citrate is an example of a natural organic compound which forms chelates with metal ions using its three carboxylic acid groups.  

	In the CCA, DOE's analysis used low ionic strength calculations to estimate the potential effect of organic ligands because the FMT (Fracture-Matrix Transport) code thermodynamic database was not complete at the time.  Extrapolating to high ionic strength conditions, DOE identified that the EDTA would preferentially bind to transition metals (CCA Appendix SOTERM Section 5).  EPA agreed with DOE that chelating agents (organic ligands) will bind to metals other than actinides.  In addition, EPA's sensitivity analysis done at the time of the CCA indicated that chelating agents were not important to performance and that the ligands did not appear to have a strong effect on the aqueous speciation of actinides because of competition with major ions that are present at much higher concentrations (CCA CARD 24, 24.C.5, p. 24-40 and 24-41).  

	Between 1996 and the 2004 CRA, both stability constants and Pitzer parameters have been determined, allowing inclusion of the organic ligands in the FMT speciation and solubility calculations (Docket A-98-49, Item II-B2-39).  Four organic ligands were included in FMT calculations of actinide solubilities: acetate, citrate, ethylenediaminetetraacetic acid (EDTA), and oxalate. 

	DOE (2004 Attachment SOTERM (Section 5.0, p. 42)) calculated the solubilities of the +III, +IV, and +V actinides for the CRA-2004 PA using FMT, an updated thermodynamic database, and concentrations of acetate, citrate, EDTA, and oxalate updated for the CRA (Docket A-98-49, Item II-B1-3, Technical Support Document for Section 194.24).  DOE believed that "the results of the FMT calculations for the CRA-2004 PA demonstrate that acetate, citrate, EDTA, and oxalate will not form complexes with the +III and +IV actinides to a significant extent under expected WIPP conditions, and thus will not affect the +III and +IV actinide solubilities significantly" (see Docket A-98-49, Item II-B1-3 for details). 

	A complete description of EPA's 1998 Certification Decision for Section 194.24(a) can be obtained from EPA Air Docket, A-93-02, Items V-A-1 and V-B-2.

24.1.3 Evaluation of Compliance for 2004 Recertification (194.24(a))

	EPA reviewed the 2004 CRA and supplemental information to determine whether it provided a sufficiently complete description of the chemical, radiological and physical composition of the emplaced, existing and to-be-generated waste proposed for disposal in the WIPP.  EPA also reviewed DOE's description of the approximate quantities of waste components (for both existing and to-be-generated waste).  EPA considered whether DOE's waste descriptions were of sufficient detail to enable EPA to conclude that DOE did not overlook any component that is present in transuranic waste and has significant potential to influence releases of radionuclides.

Chemical, Physical, and Radiological Description of Existing Waste
	Descriptions of the chemical, radiological, and physical components of the waste were thoroughly documented in 2004 CRA and supporting documents.  This information was collected using similar methods as during the CCA and the process used was reasonable.  EPA also conducted several visits to the waste generator sites to better understand the waste estimation process (Docket A-98-49, Items II-B3-75, II-B3-86, and II-B3-87).
  
	EPA concluded on the basis of this information that the 2004 CRA and supplemental information adequately described the chemical, radiological, and physical characteristics of each waste stream proposed for disposal at the WIPP.  EPA further concluded that the information presented by DOE in the 2004 CRA provided adequate characterization of existing WIPP waste for use in PA.  

	EPA noted the following changes in the waste:  DOE listed the to-be-generated (projected) waste in waste profile tables in 2004 CRA Appendix DATA, Attachment F.  The projected waste is categorized similarly to existing waste (e.g., heterogeneous debris, filter material, soil).  The amounts are ultimately expressed in density terms (kg/m[3]) for performance assessment purposes and the projected waste is a minority of the estimated inventory.  These factors would limit the potential effects of differences in the current estimates for projected waste and future actual amounts. 

	EPA concluded that DOE's development of the disposal inventory was sufficient for PA purposes.  EPA agreed with DOE that the use of projected waste inventory for scaling the CH WIPP inventory to meet the total WIPP capacity was appropriate.  DOE's use of the inventory scaling process is similar to that used in the CCA and is adequate for projecting inventory estimates.

Waste Forms and Packaging:  Super-compacted Waste  
	EPA approved the disposal of super-compacted waste from INL at WIPP (Docket A-98-49, Item II-B3-68).  DOE's 2004 CRA adequately characterized and considered super-compacted waste in the recertification inventory.  

Waste Forms and Packaging:  Container Types
	 The important aspect of the waste containers, for inventory purposes, is the amount of metal that they contain. The amount of metal required in the repository is minimum limit.  DOE's assortment of containers was demonstrated to meet the minimum metal limit regardless of the container type, since all are metal containers. EPA did have a concern about the impact of pipe overpacks, but DOE included an analysis of the pipe overpack in the compressed waste analysis and found that the pipe overpack properties were also within that of the existing waste envelope (Docket A-98-49, Items II-B2-31, II-B2-32, and II-B3-68).  EPA found the inclusion of container types to be reasonable.
	
Waste Forms and Packaging:  Inclusion of Waste Packaging in Inventory
      During the initial review of the 2004 recertification application, EPA found that DOE did not include emplacement materials in the CRA-2004 PA calculations (Docket A-98-49, Item II-B3-73).  These materials, which consist primarily of plastics and to lesser extent cellulosics, could contribute to gas generation.  DOE stated (Docket A-98-49, Item II-B2-34) that this material accounts for only 12.7% increase in CPR if it is included in the PA and that there would be no effect on compliance if it were included in the PA.  However, DOE did include the additional emplacement material volume and mass in the 2004 PABC (2004 PABC Inventory Report section 1.3.3, p. 11), thus the emplacement materials were reflected in the release estimates.  For the 2004 PABC, the inclusion of waste packaging caused the CPR inventory to increase above DOE's stated limit.  This was discussed further in CARD 24, Section 24(c)(1) and 24(e)(1) (e)(2).  The 2004 PABC showed that WIPP still complied with the new CPR amounts, thus the use of increased CPR amounts is adequate, and the amount used in the 2004 PABC established a new limit.  

Number of Curies, Waste Streams and Volume
	DOE estimated the number of curies in the inventory on a site by site, waste stream by waste stream level using a reasonable process.  EPA requires that DOE produce a "list of the waste components and their approximate quantities."  EPA reviewed the estimate in CRA-2004 Chapter 4, Appendix TRU-WASTE, and the TRU Waste Inventory Baseline (TWIB) database and found these materials contained sufficiently specific information on the species and quantities of individual radioisotopes in the waste. This was in addition to waste that had been characterized and emplaced in WIPP.  Thus, the inventory was based on more information than was available in the CCA, which EPA approved.  	

      In addition to the radioisotope inventory information, DOE also provided sufficient information on the waste components with descriptions in the following documents:  2004 CRA Volume 1, Chapter 4, 2004 CRA Appendix DATA Attachment D, 2004 CRA Appendix DATA Attachment E, 2004 CRA Appendix DATA Attachment F Annex A-K, 2004 CRA Attachment F: Transuranic Waste Inventory Update Report, 2003, to Appendix DATA, 2004 CRA Appendix DATA Attachment H, 2004 CRA Appendix TRU WASTE, and PABC Inventory Report. 

      Through the scaling process, DOE projects future waste amounts based on existing waste amounts.  EPA acknowledged that may not be entirely realistic, however, it is a rational method for predicting future unknown waste, which at the time of the 2004 CRA was projected to account for ~15% of total waste by volume.

	DOE identified a problem with the estimate of the RH waste, in which the Hanford site "double-counted" certain waste.  The result of this mistake had little effect because the RH waste volume has a small inventory limit and DOE had more RH waste inventory than legal capacity even without the mistake.  DOE caught this error and incorporated an updated scaling factor in the 2004 PABC.  EPA found that DOE adequately updated the CRA 2004 inventory.
   	
Organic Ligands 
	The Agency reviewed the updated calculations related to the effect of organic ligands on actinide solubility and determined that organic ligands are potentially important (Docket A-98-49, Item II-B1-3).  EPA found that DOE needed to provide additional information on findings from the literature since the original certification and the effect of organic ligands on the actinide +V and +VI oxidation states (Docket A-98-49, Item II-B3-74).  DOE responded (Docket A-98-49, Item II-B2-39) that while organic ligands greatly affect the solubility of +V oxidation state actinides, neptunium is the only actinide expected to be in the +V oxidation state.  EPA agreed with DOE that this was of low significance because the neptunium inventory is too low to significantly contribute to radionuclide releases.  Organic ligands had a moderate effect on the +III and +IV actinide solubilities.  DOE did include the effects of solubility of organic ligands in the 2004 PABC, and with the 2004 CRA and supplemental information, therefore, EPA found that DOE appropriately included organic ligands in the 2004 PABC (see Docket A-98-49, Item II-B1-16).

Hanford Waste
	In the 2004 CRA, DOE identified that it included waste from 12 tanks from Hanford (see Table 24-1 for a summary of the tank waste).  This included 9 tanks of CH waste and 3 tanks of RH waste.  The volume of the CH waste was estimated to be ~3,932 m[3] (~2% of the total CH inventory and ~2% of the total inventory) and the RH waste volume was estimated to be ~4,469 m[3] (~63% of total RH waste, ~2.5% of the total inventory).  The issue for this waste was whether the process by which it was created could be considered to be the reprocessing of spent nuclear fuel.  DOE stated that although all the tanks were previously managed as high-level waste (HLW), some tanks could be considered TRU waste.  HLW by law cannot be disposed of at WIPP.  DOE included the waste from the 12 tanks in the 2004 CRA PA and the 2004 PABC. EPA noted that two tanks (SY-102 and AW-103) had "non-TRU waste supernatant solutions atop" the sludges in the tanks that DOE considered to be TRU waste.  

Table 24-1 Hanford Tank Waste For Which Information was Requested in Docket A-98-49, Item II-B3-78 (Waste Stream Information From CRA Appendix DATA, Attachment F, Annex J Waste Profile Sheets and the September 2004 Hanford Meeting)
Waste Stream (Type)
Tank(s)
Volume (m[3])
Process (resulted in "solidified aqueous waste slurry")
RP-W013 (RH)
SY-102
  525
Plutonium Finishing Plant
RP-W016 (RH)
AW-103, AW-105
3944
PUREX TRU Cladding Removal
RP-W754 (CH)
B 201-204 and 
T 201-204 series tanks
1484
224 Solidified Inorganic Waste
RP-W755 (CH)
T-111 
2448
Bismuth Phosphate Process TRU Solids

(RH) = Remote Handled waste
(CH) = Contact Handled waste

	DOE provided additional information on the Hanford tank waste indicating that the waste would be treated and and would eventually meet the WIPP waste acceptance criteria (Air Docket A-98-49, Items II-B2-47 and II-B2-50).  DOE stated that tank waste that could eventually be disposed of at WIPP either was TRU waste or would be TRU waste after treatment.  DOE also stated that the tank waste had not been explicitly designated as HLW, but rather managed as HLW in accordance with their radioactive waste management procedures.  

	DOE provided information stating that the waste in question would be processed to remove any high-level waste, to the extent practical, in its preparation to meet the WIPP waste acceptance criteria.  EPA allowed this waste to be included in the performance assessment inventory for recertification.  By so including it, DOE demonstrated that with or without the Hanford tank waste, WIPP would continue to comply with EPA's disposal regulations.  The Agency believes that this is a conservative approach to the performance assessment of the WIPP repository because a broad inventory of waste is being considered.  Inclusion of a waste stream in the performance assessment of the facility does not imply or otherwise provide for EPA's approval of that waste for disposal at WIPP.  Before any waste can be shipped to WIPP, DOE must demonstrate during characterization that the waste is, in fact, TRU waste that can legally go to WIPP.  

	Public comments stated that the tank waste is high level waste, and therefore not eligible for disposal at WIPP.  Public comments requested that the tank waste be removed from the WIPP recertification inventory, or if the tanks were to remain in the inventory, that EPA conduct a rulemaking to consider the tank waste for disposal at WIPP. 

	EPA does not make waste determinations.  DOE is responsible for making waste determinations, classifications, or reclassifications.  In recognition of the public's concern about the possible future designation of the Hanford tank waste as TRU waste, DOE has proposed a process for developing or changing determinations for waste such as the Hanford tank waste.  In a February 2006 letter to EPA, DOE proposed a process (Air Docket A-98-49, Item II-B2-57) for the evaluation of tank waste that includes multiple opportunities for public input prior to the request to EPA for disposal at WIPP.  The Agency considered it appropriate for DOE to conduct a public process that would determine the designation or classification of waste prior to requesting EPA's approval for disposal at WIPP.

	The Agency's process to ensure that waste disposed of at WIPP is TRU waste may be found in the requirements listed at 40 CFR Part 194.8, 194.22, and 194.24.  The first step in this process is DOE's official request to dispose of TRU waste at WIPP from one of the waste generator sites.  Once EPA receives all required information and documentation, the Agency then inspects waste characterization activities at a waste generator site to ensure that the site has the technical ability to adequately characterize and track TRU waste.  Confirmation of waste designation is then completed through the waste characterization process at the site.  EPA believes that it currently has an adequate process in place for evaluating any DOE requests for approval of waste for disposal at WIPP.  The Agency did not find that it was necessary to conduct a rulemaking for certain waste streams.

	Waste that is not designated as TRU waste will not be considered for disposal at WIPP by EPA.  The Agency agreed with commenters that the LWA does not provide for waste determinations to be made during recertification.  Prior to disposal at WIPP, EPA will ensure that all waste meets the legal and technical requirements for disposal.  Just because waste is included in the WIPP waste inventory, does not mean that DOE will necessarily seek to ship it to WIPP or that EPA will approve it for disposal at WIPP.  Before any waste is approved to be shipped or disposed of at WIPP, EPA ensures that the waste meets the waste acceptance criteria for WIPP and that DOE can characterize and track the waste.

K-Basin Waste
	The sludges from the K-Basin storage pools consist of debris, silt, sand, and material from operations of the pools at Hanford. The 50.4 m[3] of sludges are contaminated with radionuclides associated with spent nuclear fuel that was exposed to water in the pools.  DOE believes that the radioactive contamination in the sludges is primarily from corrosion and chemical processes that could not be considered reprocessing.  DOE identified six sludges from different sections of the K-Basin. For five of the six sludges, the information provided by DOE (Docket A-98-49, Item II-B2-47; Enclosure 2, Table 2) appeared to support the contention that this waste is different from spent nuclear fuel (SNF).  SNF is prohibited by law from disposal at WIPP.  When compared to the other sludges, the sixth sludge (Knock-Out Pot Sludge) exhibits different radiological characteristics -- estimated higher radioactivity that is more similar to SNF than the other sludges.  However, its physical properties are similar to other sludges, the volume is only 0.4 m3 (with a potential to expand to 7.5 m[3]), and DOE plans to remove particles greater than (1/4) inch, eliminating the greatest radioactivity.  At the time of the 2004 CRA, DOE had performed limited measurements of the Knock-Out Pot Sludge (Docket A-98-49, Item II-B2-50), so its actual characteristics were not known with certainty.  EPA allowed this waste in the PA inventory, due to its similarity to other WIPP-bound waste, low volume, and the fact DOE must first process and characterize before it goes to WIPP, in order to demonstrate that the waste meets the technical and legal requirements for disposal.  

INL Waste
	Pre-1970 buried waste, included in the 2004 PABC, was found as waste stream IN-Z001 in Annex I of Appendix DATA 2004 Attachment F.  It was designated as non-WIPP TRU waste, but DOE decided to include it in the 2004 PABC because of a 2003 judgment against DOE related to its removal at INL.  This waste was not included in the 2004 CRA PA because the court judgment came after the September 30, 2002 cutoff date for inventory development (see the 2004 PABC Inventory Report and Inventory Data Change Addition Control Form, Docket A-98-49, Item B2-61).  This waste appeared to be similar to other WIPP waste streams, but EPA again indicated that it must still meet the WIPP waste acceptance criteria, and remained subject to EPA's inspection and approval process prior to disposal at WIPP.

Other Issues
	DOE identified and corrected one error between the 2004 CRA PA and the 2004 PABC, the LANL CH-waste stream LA-TA-55-48.  This waste stream was a low volume, high radioactive waste stream that skewed the results of the PA CCDFs upward.  Upon further review, DOE identified that this waste stream was mischaracterized; the plutonium fissile gram equivalent (FGE) was greater than shipping requirements allowed (Docket A-98-49, Item II-B2-62).  DOE re-evaluated the waste stream, and modified the waste stream radioactivity and volume for the 2004 PABC.  Since this was an estimate and the waste would be fully characterized before going to WIPP, EPA found that the waste stream correction was reasonable. 

	Commenters (Docket A-98-49, Item II-B3-77) pointed out that the radionuclide values were wrong for K-Basin sludge waste streams (RL-445 and RL-446).  DOE reviewed the information and lowered the [90]Y and [137m]Ba concentrations by about 50% for the 2004 PABC (Docket A-98-49, Item II-B2-60).  Again EPA found that this was an appropriate change and would be verified during the characterization process.

24.1.4 2004 Recertification Decision (194.24(a))

	Based on a review and evaluation of the 2004 CRA and supplemental information provided by DOE (FDMS Docket ID No. EPA-HQ-OAR-2004-0025, Air Docket A-98-49), an assessment of the changes since the 1998 Certification Decision, in this CARD and in technical support documents for this section (Docket A-98-49, Items II-B1-3 and II-B1-9, II-B1-16), and the consideration of public comments, EPA determined that DOE continued to comply with the requirements of 194.24(a).

24.1.5 Changes in the 2009 Compliance Recertification Applications (194.24(a))

      To meet the requirements of Section 194.24(a), DOE continues to describe and categorize the entirety of TRU waste that is emplaced in WIPP and exists at various DOE facilities.  Since the first emplacement of waste in 1999, DOE has tracked the waste emplaced at WIPP using the WIPP Waste Information System (WWIS).  For the waste that is stored or to-be-generated at the waste generator sites, DOE developed a descriptive methodology for grouping waste information obtained from each generator site and continues to use this approach for the 2009 CRA.  Since the 2004 CRA EPA decision, DOE initiated a yearly complex-wide data call to update the inventory annually. DOE's Carlsbad Field Office (CBFO) asks every TRU waste generator site to update the waste profile forms that describe the physical, chemical, and radiological constituents in each waste stream that generated or generates TRU waste at that site. The 2008 data call reflected the disposal intentions of the waste generator sites as of December 31, 2007.  DOE representatives examined the information, clarified questions and then validated the waste stream profile information.  This information was synthesized across the waste generator sites and then prepared for input into the performance assessment by scaling the inventory and other data reduction actions (e.g., decaying the estimated inventory to 2033).  This process is captured in the flowchart in Figure 24-2 (ATWIR-2008 Figure 2-1).  
      
	Initially DOE used the same inventory that was used in the 2004 PABC calculations for the 2009 CRA performance assessment calculations, as noted in CRA-2009 Section 24 Section 24.6.1.  EPA examined the recent inventory updates and changes, mainly the ATWIR 2007 and the ATWIR 2008, and determined that a new performance assessment, the 2009 PABC (2009 PABC), needed to be conducted in order to include the increase in chemical components, (see Table 24-2, produced from PAIR 2008 Table 5-7).  EPA directed DOE to perform the 2009 PABC using the updated inventory in its first completeness letter, dated May 21, 2009, items 1-G-3 and 1-23-1 (EPA 2009a).

Table 24-2 Chemical Component Comparisons (Source: PAIR-2008 Table 5-7)

                            Chemical Components     
                                      CCA
                                    Mass (kg)
                                  CRA-2004 PABC
                                   Mass (kg)
                                  CRA-2009 PABC
                                   Mass (kg)
Nitrate
1.62E+06
2.67E+06
1.72E+06
Sulfate
6.33E+05
4.43E+05
5.91E+05
Phosphate
                                      --
1.05E+05
1.99E+05
Acetic Acid
1.42E+02
1.42E+02
1.32E+04
Sodium acetate
1.11E+02
8.51E+03
9.70E+03
Citric Acid
1.19E+03
1.19E+03
5.68E+03
Sodium Citrate
4.00E+02
4.00E+02
2.55E+03
Oxalic Acid
1.38E+04
1.38E+04
2.66E+04
Sodium Oxalate
                                      --
3.39E+04
6.46E+02
Sodium EDTA
2.30E+01
2.56E+01
3.54E+02

      The details of the 2009 PABC inventory are presented in the Annual Transuranic Waste Inventory Report-2008, DOE/TRU-2008-3425 (ATWIR-2008), the scaled PA inventory in the Performance Assessment Inventory Report-2008, INV-PA-09 (PAIR-2008) and the Radionuclide Inventory Screening Analysis Report for the PABC-2009, ERMS 551679 (Fox et al. 2009).

	The chemical, physical, and radiological inventories continue to be grouped by DOE and developed in detail from the waste stream profiles from each of the TRU waste generator and/or storage sites.  Waste groupings (other than contact handled and remote handled designations) by DOE were based on the chemical and physical aspects of the waste, not the radiological content of the waste (CCA Appendix BIR).  However, the radiological constituents were identified and quantified (in Ci/m[3] for each waste stream) on each waste profile form, and information from the forms was used by DOE to develop the radiological inventory for the WIPP.  The CCA approach continues to be used in the 2009 CRA inventories.  Table A-1 of the 2009 SNL screening analysis for the 2009 PABC (Fox et al. 2009) shows the radiological constituents used for the 2009 PABC, including the inventory at the estimated time of disposal (year 2033), and estimated EPA units for each radionuclide.  

	Each WIPP Waste Profile continues to contain information on the physical and chemical waste components (identified as Waste Material Parameters (WMP's) for DOE purposes) and the radiological waste components that DOE believes could affect the performance of the repository.  DOE's waste material parameters are presented as density values for use in performance assessment.  These density values are calculated by multiplying the average density of individual waste streams from a given waste form by the volume of the CID waste stream and then the total volume of the final waste form.  

      The approximate average densities for waste material parameters were calculated, including iron based metals/alloys, aluminum based metals/alloys, other metal/alloys, other inorganic materials, vitrified materials, cellulosics, rubber, plastics, solidified inorganic matrix, solidified organic matrix, solidified cement, and soils (PAIR-2008 Inventory Report in Table 4-2 for CH and Table 4-3 for RH wastes).  WIPP Waste Profiles contain information on the WMPs, i.e., components that DOE determined to have the potential to impact repository performance.  DOE identified the quantity of physical waste components such as cellulosic material, plastic, rubber, etc., in the PAIR-2008 Inventory Report.  Tables 5-4 and Table 5-5 of the PAIR-2008 Inventory Report show the anticipated non-radioactive TRU waste inventory densities for the WIPP 2009 PABC calculations.
      
	Also, in accordance with 40 CFR 194.24(a), DOE's waste profiles contain specific information on the species and quantities of individual radioisotopes in the waste.  
Figure 24-2 Process for Preparing the 2009 CRA TRU Waste Inventory (Source:  ATWIR-2008 Figure 2-1)
Figure 24-2 Process for Preparing the 2009 CRA TRU Waste Inventory (Source:  ATWIR-2008 Figure 2-1)
 Inventory Description
	DOE previously indicated that to-be-generated waste will be included in those waste streams and final waste forms currently identified at DOE sites (2004 CRA Chapter 4, Section 4.1.3); this has not changed for the 2009 CRA.  Therefore, the waste stream descriptors for existing waste also apply to to-be-generated waste.  Existing waste stream information was used by DOE in its description of to-be-generated waste.

	DOE continues to describe its contact-handled (CH) and remote-handled (RH) inventory as "stored," "emplaced" and "projected" or "anticipated."   The stored inventory is generally equivalent to existing waste at the sites, and projected waste is generally equivalent to to-be-generated waste (ATWIR-2008 and PAIR-2008).  Emplaced waste is waste that has been put underground at WIPP and is recorded in the WWIS database.  The anticipated inventory is the sum of the stored and projected inventories (ATWIR-2008 Inventory Report Section 1.0).  Table ES-1 of the 2008 PAIR Inventory Report lists the volumes of emplaced CH-TRU waste and Table ES-2 of the same report lists the emplaced RH volumes as of December 31, 2007 (the cutoff for inclusion in the 2008 inventory annual update).  

	DOE's estimates indicate that the total expected inventory volume for CH-TRU and RH-TRU waste will not reach the maximum disposal capacity of the WIPP for CH-TRU or RH-TRU (approximately 168,500 m[3] (5,950,000 ft[3]) for CH-TRU and 7,079 m[3] (250,000 ft[3]) for RH-TRU) (PAIR-2008 Section 3.2.1).  DOE continues to employ a scaling factor to project the impacts of a full repository.  The current volume estimate of waste for disposal at WIPP is 130,400 m[3] for CH-TRU and 1,828 m[3] for RH-TRU.  DOE developed a scaling factor based upon the approximate CH-TRU and RH-TRU projected inventories it expects to be generated, as DOE believed that any new waste generated to "fill" the outstanding WIPP space would probably be more similar to the projected rather than existing waste inventory.  Tables 5-1 and 5-2 of the same report compare the scaled CH-TRU and RH-TRU waste volumes scaling factors used for the CCA, 2004 PABC, and the 2009 PABC.  The projected inventory information was derived from each generator site's waste stream profile forms, and reflects the sites' best determination of the waste expected to be generated.

	As reported in the PAIR-2008 Inventory Report, the scaling factor calculated by DOE in the 2009 PABC for CH-TRU waste is 5.72, and for RH-TRU waste is 4.87.  This factor is used in the following formulas to project the makeup of the CH-TRU and RH-TRU disposal inventory volume (m[3]) according to the LWA design limitations:  

For CH-TRU waste:
Emplaced Inventory + Stored Inventory + (Projected Inventory x 5.72) = 2009 PABC Disposal Inventory

For RH-TRU waste:
Emplaced Inventory + Stored Inventory + (Projected Inventory x 4.87) = 2009 PABC Disposal Inventory


Number of Curies
	The total amount of radionuclide activities expected to be placed in WIPP has decreased slightly from the 2004 PABC estimate of 3.53 million curies to 3.45 million curies in the 2009 PABC (PAIR-2008 Inventory Report Table 5-6 and EPA 2009 CARD 31 Table 31-3).  Table 5-6 of the 2009 PABC Inventory Report (PAIR-2008) lists the activities of the 29 most important radionuclides in the 2009 PABC inventory. 

	DOE documents changes to the inventory in each annual inventory report.  DOE changed a number of waste streams to the potential category; therefore they are not presently in the anticipated WIPP inventory for the 2009 PABC.  The changes documented in the two annual inventories, ATWIR-2007 page 3 and ATWIR-2008 page 14, are briefly discussed below:
	
New Inventory Items Since the 2004 CRA:
-Paducah's Gaseous Diffusion Plant TRU waste was re-categorized to WIPP bound because a waste processing method has been found (ATWIR-2008 page 14).

Inventory Items Placed in the Potential Category (*Not in Planned Inventory, Not Included in PA) Since the 2004 CRA:
-At the time the 2009 CRA was submitted, General Electric-Vallecitos Nuclear Center (GE-VNC) waste remained in potential because the site did not provide radionuclide and waste material parameters.  During the completeness review of the CRA, waste characterization activities were completed and this waste shipped to WIPP.  It is adequately represented by the scaled inventory. 

- Waste streams from Babcock and Wilcox (BL) and the Nuclear Radiation Development Site (NRD) were added to the potential inventory because their defense determination has not been completed. 

- Hanford RL and the Material Fuel Complex (MFC) waste streams that exceed the curie limit allowed in the LWA of 23,000 Ci/m[3] were changed to the potential inventory.  

-Classified wastes at all sites are categorized as potential until their documentation is properly prepared for non-classified use.

-Hanford Richland (RL) has re-categorized some of its 618-10 and 618-11 buried waste to potential waste.  Hanford RL K-Basin knock-out pot sludge has been re-categorized to potential waste.  These two changes significantly reduced the overall RH-TRU waste volume.

-Hanford Office of River Protection (RP) tank waste has been re-categorized to potential waste.

-Two INL sodium-bearing waste streams were re-categorized to potential waste.

Other Inventory Changes:
-The volume of the TRU waste stored on site at West Valley was reduced because much of the waste managed as TRU in the past has been characterized as low-level waste.

Container Types
	While the container types are not used directly in the performance assessment calculations, the type of container continues to be important in order to estimate the amount of CPR in WIPP (PAIR-2008 Section 3.2.5).  Container types for CH-TRU waste have not changed since the 2004 CRA.  They include: 7-packs of 55-gallon drums, 4-packs of 85-gallon drums, 3-packs of 100-gallon drums, standard waste boxes (SWBs), ten-drum overpacks (TDOPs), standard large boxes (5x5x8 boxes), and 100-gallon drums.  The only new container since the 2004 CRA has been the introduction of RH canisters.  EPA's approval of RH waste is discussed in Section 24.6.3.

Organic Ligands 
	At the time of the CCA, DOE's analysis used low ionic strength calculations to estimate the potential effect of organic ligands because the FMT (Fracture-Matrix Transport) code thermodynamic database was not complete at the time, and EPA's sensitivity analysis indicated that chelating agents (organic ligands) did not have a strong effect on the aqueous speciation of actinides because of competition with major ions that are present at much higher concentrations (CCA CARD 24, 24.C.5, p. 24-40 and 24-41).  For the 2004 CRA, both stability constants and Pitzer parameters had been determined, allowing inclusion of the organic ligands in the FMT speciation and solubility calculations (Docket A-98-49, Item II-B2-39).  Four organic ligands were included in the 2004 CRA FMT calculations of actinide solubilities: acetate, citrate, ethylenediaminetetraacetate (EDTA), and oxalate.  

      In the 2009 PABC, organic ligands' importance increased due to increases in their volume in the predicted inventory.  One of the most important changes was the increase in mass of EDTA from 25.6 kg in the 2004 PABC to 354 kg in the 2009 PABC updated inventory.

	EPA directed DOE to include new solubility calculations in the 2009 PABC in the first completeness letter, item 1-23-1, dated May 21, 2009 (EPA 2009a).  DOE updated the solubilities and solubility uncertainties for the 2009 PABC (see Brush et al. 2009 and Xiong etal, 2009).  DOE notes in Brush et al. 2009 that dissolved concentrations increased by factors of: 1.83 for acetate, 2.95 for citrate, 7.95 for EDTA, and 2.63 for oxalate in brine of GWB composition for the 2009 PABC calculations (Brush et al. 2009 page 17).  The ERDA-6 brine composition had similar differences.  Increased organic ligand concentrations in turn increased the actinide concentrations in the brine, and resulted in greater releases for the direct brine pathway (Clayton et al. 2009 page 45).
24.1.6 Evaluation of Compliance for 2009 Recertification (194.24(a))

	EPA reviewed the 2009 CRA and supplemental information to determine whether it provided a sufficiently complete description of the chemical, radiological and physical composition of the emplaced, existing and to-be-generated waste proposed for disposal in the WIPP.  EPA also reviewed DOE's description of the approximate quantities of waste components (for both existing and to-be-generated waste).  EPA considered whether DOE's waste descriptions were of sufficient detail to enable EPA to conclude that DOE did not overlook any component that is present in transuranic waste and has significant potential to influence releases of radionuclides.

Chemical, Physical, and Radiological Description of Existing Waste
	Descriptions of the chemical, radiological, and physical components of the waste were thoroughly documented in 2009 CRA and supporting documents.  This information was collected using similar methods as during the CCA and the 2004 CRA, described above, thus the process used is reasonable.  EPA also conducted several visits to the waste generator sites to better understand the waste estimation process, including SRS, LANL, Hanford, and INL in 2008, and LANL and SRS in 2009.
  
	EPA concludes on the basis of this information that the 2009 CRA and supplemental information adequately describes the chemical, radiological, and physical characteristics of each waste stream proposed for disposal at the WIPP.  EPA further concludes that the information presented by DOE in the 2009 CRA provides adequate characterization of existing WIPP waste for use in PA.  

	EPA noted the following changes in the waste:  DOE listed the to-be-generated (projected) waste in waste profile tables in ATWIR 2008 Table 3-1 for CH-TRU and Table 3-2 for RH-TRU waste.  The projected waste is categorized similarly to existing waste (e.g., heterogeneous debris, filter material, soil).  The amounts are ultimately expressed in density terms (kg/m[3]) for performance assessment purposes and the projected waste is a minority of the estimated inventory.  These factors continue to limit the potential effects of differences in the current estimates for projected waste and future actual amounts for the 2009 PABC. 

	EPA concluded that DOE's development of the disposal inventory is sufficient for PA purposes.  EPA continues to agree with DOE that the use of projected waste inventory for scaling the WIPP CH-TRU and RH-TRU inventories to meet the total WIPP capacity is appropriate.  DOE's use of the inventory scaling process is similar to that used in the CCA and 2004 CRA and is adequate for projecting inventory estimates.

Waste Forms and Packaging: RH-TRU Waste  
	The only change for waste packaging since the 2004 CRA is that RH-TRU waste shipments were begun and the RH emplacement canister use was started for RH disposal operations.


Waste Forms and Packaging:  Container Types
      As stated earlier in this CARD, the most important aspect of the waste containers for inventory purposes is the amount of metal that they contain, and the amount of metal required in the repository is minimum limit.  RH-TRU emplacement containers were used for the first time since the 2004 CRA. With their introduction, the amount of metal in the repository is increased.  EPA found the inclusion of waste container types in the inventory and PA to be reasonable.	 
	
Waste Forms and Packaging:  Inclusion of Waste Packaging in Inventory
      When preparing for the 2009 CRA performance assessment calculations DOE discovered that, "the CPR contents in emplacement materials were erroneously omitted from the CRA-2004 PABC" (Clayton et al. 2009).  DOE corrected this error in the 2009 CRA PA, this correction was also used in the 2009 PABC calculations.  EPA review changes to the 2009 CRA and 2009 PABC and found this error correction to be adequate.   

Number of Curies, Waste Streams and Volume
	For the 2009 CRA, DOE continued to estimate the number of curies in the inventory on a site by site, waste stream by waste stream level using a reasonable process.  EPA requires that DOE produce a "list of the waste components and their approximate quantities."  EPA reviewed the estimates in ATWIR 2008 and PAIR 2008 reports and found these materials to contain sufficiently specific information on the species and quantities of individual radioisotopes in the waste.  In addition to the radioisotope inventory information, DOE also provided sufficient information on the chemical and physical waste components with descriptions in the ATWIR 2008 and PAIR 2008.
   	
Organic Ligands 
	The Agency reviewed the updated calculations related to the effect of organic ligands on actinide solubility and determined that organic ligands are potentially important (Brush et al. 2009, Xiong et al. 2009).  DOE properly included the impact of the increased organic ligands waste inventory in the 2009 PABC calculations.  EPA found this approach and results to be adequate. 

Hanford Waste and K-Basin Waste
	In the 2004 CRA, DOE identified that it included waste from 12 tanks from Hanford (9 tanks of CH waste and 3 tanks of RH waste - see Table 24-1 for a summary of the tank waste).  As noted in Section 24.1.5 above, these waste streams and waste streams of K-Basin sludges have been removed from the anticipated waste stream inventory in the 2009 CRA PA and the 2009 PABC performance assessment calculations.  These wastes are not presently destined for disposal at WIPP.  EPA verified that they have been removed and concluded that DOE did not include them in the performance assessment calculations for the 2009 CRA or 2009 PABC.

      Many of the public comments received from stakeholders throughout the Recertification process addressed inventory issues.  Multiple groups objected that the Comprehensive Inventory Database was not made public.  In response to these comments, DOE provided both an Excel spreadsheet and PDF file of the inventory used for the 2009 (reference DOE letter).  Other comments indicated that this was not satisfactory to all stakeholders.  EPA determined that the information provided to the public was adequate for the purposes of recertification, and commits to continue to work to provide stakeholders with the most complete information available. Other comments dealt with issues related to the accuracy of the inventory.  These were all addressed by EPA's completeness letters to DOE (reference).  During its technical review, EPA determined that all questions related to inventory information had been adequately resolved.

     A significant number of comments addressed the legality of waste for disposal at WIPP.  Commenters objected to the inclusion of potential wastes in the anticipated inventory which lacked legal determinations as either transuranic or defense waste.  These objections have been raised before, and Section 24.1.3 above describes EPA's process of verifying that no illegal waste is shipped to WIPP.  The Agency reiterates that it will not consider commercial waste, high-level waste, or spent nuclear fuel for disposal at WIPP, and that inclusion of waste in the potential inventory in no way implies approval of that waste.  The PA inventory, as described in Section 24.1.5, is scaled up in order to provide an estimate of WIPP's inventory at the time of closure.  For the same reason, EPA does not agree with commenters' demands that no waste stream be shipped to WIPP without explicit inclusion in a PA.  A compliant PA sets limits for the chemical and radiological constituents of the inventory, which are then tracked on a daily basis and may not be exceeded (see Section 24.8 below).  This ensures that the inventory remains within the bounds of the most recent PA.   Commenters' objections to the secretive nature of DOE's defense and TRU determinations fall outside the scope of recertification, however, EPA will continue to work with DOE to make waste inventory decisions as transparent as possible. 

24.1.7 2009 Recertification Decision (194.24(a))

	Based on a review and evaluation of the 2009 CRA and supplemental information provided by DOE (FDMS Docket ID No. EPA-HQ-OAR-2009-0330, Air Docket A-98-49), an assessment of the changes since the 1998 Certification Decision, in this CARD and in technical support documents for this section (EPA 2010a, EPA 2010b, EPA 2010f, and EPA 2010g) and the consideration of public comments, EPA determines that DOE continues to comply with the requirements of 194.24(a).

24.1.8 Changes in the 2014 Compliance Recertification Applications (194.24(a))

      To meet the requirements of Section 194.24(a), DOE continues to describe and categorize the entirety of TRU waste that is emplaced in WIPP and exists at various DOE facilities.  Since the first emplacement of waste in 1999, DOE has tracked the waste emplaced at WIPP using the WIPP Waste Information System (WWIS).  For the waste that is stored or to-be-generated at the waste generator sites, DOE developed a descriptive methodology for grouping waste information obtained from each generator site and continues to use this approach for the 2014 CRA.  Since the 2004 CRA EPA decision, DOE initiated a yearly complex-wide data call to update the inventory annually. DOE's Carlsbad Field Office (CBFO) asks every TRU waste generator site to update the waste profile forms that describe the physical, chemical, and radiological constituents in each waste stream that generated or generates TRU waste at that site. 
      
      DOE adopted the same approach for the 2014-CRA as was used in PABC-2009 and utilized the ATWIR 2012 inventory and 2012 PAIR reports. The details of the CRA 2012 inventory are presented in the Annual Transuranic Waste Inventory Report-2012 (ATWIR-2012), and the Performance Assessment Inventory Report (PAIR)  -  2012 (Van Soest 2012) was released on November 29, 2012. The PAIR  -  2012 contains updated estimates to the radionuclide content and waste material parameters, scaled to a full repository, based on inventory information collected through December 31, 2011.  The Inventory Technical Support Document (Docket No. EPA-HQ-OAR-2014-0609) discusses changes in the inventory since the PABC-2009, as documented in ATWIR 2012 and PAIR 2012. As appropriate, comparisons are made to the PABC-2009 inventory relative to the CRA-2014. 

	The chemical, physical, and radiological inventories continue to be grouped by DOE and developed in detail from the waste stream profiles from each of the TRU waste generator and/or storage sites.  Waste groupings (other than contact handled and remote handled designations) by DOE were based on the chemical and physical aspects of the waste, not the radiological content of the waste (CCA Appendix BIR).  However, the radiological constituents were identified and quantified (in Ci/m[3] for each waste stream) on each waste profile form, and information from the forms was used by DOE to develop the radiological inventory for the WIPP.  The CCA approach continues to be used in the 2012 CRA inventories.  Tables 5-1 and 5-2 of the PAIR 2012 shows the scaled volumes of the radiological constituents for each waste stream used for the 2012 CRA, including the inventory at the estimated time of disposal (year 2033).  

	Each WIPP Waste Profile continues to contain information on the physical and chemical waste components (identified as Waste Material Parameters (WMP's) for DOE purposes) and the radiological waste components that DOE believes could affect the performance of the repository.  DOE's waste material parameters are presented as density values for use in performance assessment.  These density values are calculated by multiplying the average density of individual waste streams from a given waste form by the volume of the CID waste stream and then the total volume of the final waste form.  

      The approximate average densities for waste material parameters were calculated, including iron based metals/alloys, aluminum based metals/alloys, other metal/alloys, other inorganic materials, vitrified materials, cellulosics, rubber, plastics, solidified inorganic matrix, solidified organic matrix, solidified cement, and soils (PAIR-2012 Inventory Report in Table 6-3).  WIPP Waste Profiles contain information on the WMPs, i.e., components that DOE determined to have the potential to impact repository performance.  
      
	Also, in accordance with 40 CFR 194.24(a), DOE's waste profiles contain specific information on the species and quantities of individual radioisotopes in the waste.  
24.1.9 Evaluation of Compliance for 2014 Recertification (194.24(a))

	EPA reviewed the 2014 CRA and supplemental information to determine whether it provided a sufficiently complete description of the chemical, radiological and physical composition of the emplaced, existing and to-be-generated waste proposed for disposal in the WIPP.  EPA also reviewed DOE's description of the approximate quantities of waste components (for both existing and to-be-generated waste).  EPA considered whether DOE's waste descriptions were of sufficient detail to enable EPA to conclude that DOE did not overlook any component that is present in transuranic waste and has significant potential to influence releases of radionuclides.

24.1.10 2014 Recertification Decision (194.24(a))

	Based on a review and evaluation of the 2012 CRA and supplemental information provided by DOE ((Docket No. EPA-HQ-OAR-2014-0609), an assessment of the changes since the 1998 Certification Decision, in this CARD and in technical support documents for this section and the consideration of public comments, EPA determines that DOE continues to comply with the requirements of 194.24(a).

24.2 Requirement (194.24(b)(1))
      
	(b) "The Department shall submit in the compliance certification application the results of an analysis which substantiates:

	(1) That all waste characteristics influencing containment of waste in the disposal system have been identified and assessed for their impact on disposal system performance.  The characteristics to be analyzed shall include, but shall not be limited to:  solubility; formation of colloidal suspensions containing radionuclides; production of gas from the waste; shear strength; compactability; and other waste-related inputs into the computer models that are used in the performance assessment."

24.2.1 1998 Certification Decision (194.24(b)(1))

	EPA expected the CCA to provide a detailed description of a waste characterization analysis that identifies a list of waste characteristics retained as a result of the analysis and explains the rationale for excluding any other waste characteristics.

	In the CCA, DOE presented the results of its waste characteristic and components analyses pursuant to 194.24(b)(1) in a number of documents.  CCA Chapter 4 and CCA Appendices MASS, WCA, SOTERM, and SA are the primary sources.  DOE indicated that the characteristics listed below were expected to have a significant effect on disposal system performance and so were used in the performance assessment (i.e., parameters were developed which account for the effects of each).

 Solubility (including redox state and redox potential).

 Formation of colloidal suspensions containing radionuclides.

 Production of gas from the waste (hydrogen, and microbial substrate/ nutrients for methane gas generation).

 Shear strength, compactability (waste compressibility), and particle diameter. 

 Radioactivity in curies of each isotope.

 TRU radioactivity at closure.

	EPA concluded in the CCA that DOE generally performed a thorough and well documented analysis, adequately identified all waste characteristics and, except for actinide solubility and shear strength, appropriately assessed them as PA input parameters.  In the case of actinide solubility, EPA believed that DOE assumed an incorrect solubility that controls the mineral phase.  However, this error led to the use of higher actinide solubilities than what EPA believed would be realistic.  EPA's review indicated that modified solubility values for actinides were required, and the Performance Assessment Verification Test (PAVT) was run using these values.  DOE subsequently performed experiments that identified hydromagnesite as a metastable mineral species.  For the shear strength (TAUFAIL) in the PAVT, EPA required the probability distribution of the shear strength parameter to be changed to a log-normal distribution with a different range and median (CCA CARDs 23 and 24).  See CCA CARD 24 for a more complete discussion.

24.2.2 Changes in the 2004 Compliance Recertification Application (194.24(b)(1))

	There were no major changes to the waste characteristics between the PAVT and the CRA-2004 PABC, but DOE did make changes to some of the parameters used in the PA.  These are summarized in Table 24-3 below.  Most of these are related to inventory changes described above in section 24 (a).  EPA was most concerned with changes affecting solubility and gas generation.  
Table 24-3 Characteristics expected to have a significant effect on disposal system performance and changes from the CCA (PAVT) to the 2004 CRA PABC
                 Waste Component or Characteristic Used in PA
                                 Significance
                             Increase or Decrease
                           From CCA to 2004 CRA PABC
Radioactivity per cubic meter
Used in calculating releases
Decrease
Solubility
Higher solubility can lead to higher releases when brine is present
Increase and Decrease, depending on oxidation state
Organic ligands -- complexing agents
Increases solubility
Similar amounts, but is now acknowledged to potentially be important
Amount of Metals
Maintains reducing environment, but also contributes to gas generation
Decrease
Amount of Cellulosics, Plastics, Rubbers
May increase gas generation from microbial processes
Increase
Oxyanions:  nitrate, sulfate, and phosphate
Nutrients for microbes, so indirectly affects gas generation
Similar, but overall increase
Cement 
Primarily a volume related component
Decrease
Shear Strength
Affects mechanical releases during Low waste shear strength
No change
Particle Diameter
Used to calculate spallings releases
The PABC used the particle diameter determination from expert panel findings during the original certification. The particle diameter used in the CCA was rejected by EPA and not used in the subsequent PAVT calculations so there is not a valid comparison between the CCA and PABC.  
Formation of colloidal suspensions
Colloids can facilitate transport of radionuclides in ground water
No change in parameterization, but DOE changed the implementation for the CRA to only include PA vectors that included microbes.  This changed again for the PABC back to the original treatment because all vectors were assumed to potentially generate microbes, and thus colloidal suspensions

Assessment of Waste Characteristics and Waste Characteristic Input Parameters
	In the CCA, DOE identified several waste characteristics as potentially important to the performance assessment (CCA Appendix WCA, Section WCA.6, pp. WCA-42 to WCA-43) based on available information, including uncertainties and WIPP system characterization.  These analyses were summarized in CCA Appendices WCA, SOTERM, and MASS, and were augmented by DOE's responses to EPA comments (CCA CARD 24).  The 2004 CRA identified the same important characteristics, although DOE now states that organic ligands can be important to solubility.

Solubility
	DOE originally stated in the CCA that solubility of actinides is among the major characteristics of the radionuclides expected to affect disposal system performance (CCA Appendix WCA, Section WCA.4, pp. WCA-30 to WCA-34).  DOE assessed the solubility of thorium, uranium, neptunium, plutonium, and americium (see below).  DOE states in the 2004 CRA's updated SOTERM (2004 CRA Appendix PA, Attachment SOTERM, p. 1):
	 "From the standpoint of their potential effects on the long-term performance of the repository, the order of importance of these actinides is Pu ≈ Am >> U > Th. Other actinides, especially neptunium (Np), have been included in the laboratory and modeling studies used to develop the actinide source term because it was not known at the outset which actinides could significantly affect the long-term performance of the repository."  
DOE assumed that cesium and strontium are inventory limited (meaning that 100% of these isotopes would be dissolved) due to their high solubilities; therefore, formal solubility values were not derived for these two radionuclides (CCA Appendix WCA p. 30).   
	DOE used the Fracture Matrix Transport (FMT) geochemical modeling code and its associated database to calculate solubilities.  No changes were made to the FMT code or conceptual models for the 2004 CRA performance assessment or 2004 PABC.  However, revisions were made to the input FMT database since the PAVT.  These changes included the addition of new aqueous actinide species to the database and revisions to existing species data because of the availability of new experimental data.

	DOE used the GWB Salado brine chemistry formulation instead of the Brine A formulation used in the CCA PA and PAVT.  The most significant differences between the brine formulations are the lower magnesium concentration and higher sulfate concentration in GWB relative to Brine A.  Comparison of geochemical modeling results using the two brine formulations indicates that GWB brines had slightly lower predicted +III actinide solubilities and higher +V actinide solubilities compared to Brine A.

2004 Performance Assessment Parameters Related to Solubility
	Solubility of actinides in the III, IV, V and VI oxidation states for both the Castile and Salado brines were calculated by DOE with the assumption that pH and f(CO2) are controlled by Mg(OH)2  -  MgCO3 equilibrium.  The solubilities (moles/liter) in Table 24-4 list the CCA and 2004 CRA PA values.  Table 24-5 lists the 2004 CRA PA values and the 2004 PABC values.

	The uncertainty ranges for the actinides in the 2004 CRA PA were the same as those used in the CCA.  DOE defined uncertainty limits for actinide concentrations calculated from solubility relationships based on the differences between measured concentrations and those predicted for the solubilities of discrete actinide solids with the FMT or NONLIN computer codes (Bynum 1996b).  These solubility differences were measured in a number of experimental studies of different actinide solids in high ionic strength solutions.

	Uncertainty limits were determined by DOE to range from 1.4 log units above to 2.0 log units below the actinide concentrations calculated from solubility expressions contained in the FMT model in the CCA.  These uncertainty ranges were used for each actinide sampled in the PA, that is for Am(III), Pu(III), Pu(IV), in Castile and Salado brines, U(IV) in Salado brine, U(VI) in both Castile and Salado brine, and Th(IV) in Salado brine.  The uncertainties in the actinide solubilities were used to define the range for Latin Hypercube Sampling of the actinide concentrations in the PA, assuming a log cumulative distribution (CCA CARD 24).  

Table 24-4.  CCA and 2004 CRA Solubilities of the Oxidation State Analogs, in moles/liter, with MgO Backfill
            Solubilities for PA Material Name and Oxidation State#
          
           PA Parameter       SOLMOD3	          SOLMOD4	SOLMOD5	SOLMOD6
Brine	         Name		     (III)		   (IV)		    (V)      	     (VI*)
Salado	CCA SOLSIM	5.82 x 10-7		4.4 x 10-6	2.3 x 10-6	8.7 x 10-6 
Salado	CRA SOLSIM	3.07 x 10-7		1.19 x 10-6	1.02 x 10-6	8.7 x 10-6

Castile	CCA SOLCIM	6.52 x 10[-8]		6.0 x 10[-9]	2.2 x 10[-6]	8.8 x 10[-6] 
Castile	CRA SOLCIM	1.69 x 10[-7]		2.47 x 10[-8]	5.08 x 10[-6]	8.8 x 10[-6]

     # Solubility values were changed for the 2004 PABC.  The solubilities were changed to changes in chemical conditions agreed to by DOE and EPA. See Table 24-5.

     * These solubilities were not calculated in the FMT model.  In addition, these solubilities were changed to 1 x 10[-3] for the 2004 PABC as required by EPA due to the failure to incorporate new data that indicated the U(VI) solubilities could be greater than those used in the CCA and CRA-2004 PA.  This is discussed more later in the Evaluation of Compliance for Recertification section.

Formation of Colloidal Suspensions Containing Radionuclides
	Colloid formation can enhance the quantity of actinides contained in brine, and was evaluated by DOE as an important group of waste characteristics.  In the CCA DOE determined that four types of colloids may be present in the WIPP repository: Intrinsic colloids, mineral fragment colloids, humic colloids, and microbe colloids (CCA Appendix WCA Section WCA.4.2, pp. WCA-34 to WCA-36).  These colloids are still modeled in the 2004 PABC and are unchanged from the CCA (see CCA CARD sections 24.B.5 and 24.B.6 for additional information).  

	DOE did, however, implement the colloidal actinide source term differently in the CRA-2004 PA than in the CCA.  In the CCA, DOE assumed all vectors would have a microbial colloid contribution to the actinide source term.  For the 2004 CRA PA, DOE assumed there would be microbial colloid transport only in vectors without significant microbial degradation.  
 
Production of Gas From the Waste (Including Microbial Substrate and Nutrients)
	Gas generation includes hydrogen gas generation, as well as carbon dioxide and methane generation by microbial degradation.  The characteristics of gas generation are linked to the waste components of waste steel, microbial substrates such as cellulosics, rubber, and plastics (CPR), as well as other microbial nutrients (nitrate, sulfate and phosphate) that could be present.  

	The same conceptual model was used for microbial gas generation in the WIPP repository for both the CCA and 2004 CRA.  In the conceptual model, it is assumed that microbial consumption of CPR may occur in the repository and produce methane (CH4) and carbon dioxide (CO2).  The major pathways for microbial degradation of 2004 CPR are predicted to include the following reactions:

		C6H10O5 + 4.8 H+ + 4.8 NO3-  7.4 H2O + 6 CO2 + 2.4 N2		(1)

		C6H10O5 + 6 H+ + 3 SO42-  5 H2O + 6 CO2 + 3 H2S		(2)

		C6H10O5 + H2O  3 CH4 + 3 CO2					(3)

where C6H10O5 is the chemical formula for cellulose.  In reactions (1) and (2), one mole of carbon dioxide is produced for each mole of organic carbon consumed.  Reaction (3), however produces only 0.5 moles of carbon dioxide per mole of organic carbon consumed.  Reactions (1) to (3) are predicted to proceed sequentially according to the energy yield of the reactions (Wang and Brush 1996).  As the denitrification and sulfate-reduction reactions (reactions 1 and 2, respectively) proceed, they are predicted to consume the limited amounts of nitrate and sulfate in the WIPP waste inventory.  In both the CCA and the 2004 CRA, it was predicted that methanogenesis (reaction 3) would be the dominant reaction pathway and consequently, that approximately half of the organic carbon consumed would be converted to carbon dioxide (CCA Appendix SOTERM Section 8.2.2; 2004 CRA Appendix PA Attachment SOTERM Section 2.2.2).  

	Microbial gas generation rates used in the average stoichiometry model were based on experimental data from microbial consumption of papers under inundated and humid conditions (Wang and Brush 1996).  A gas-generation rate is determined in BRAGFLO for the humid and inundated rates based on the effective liquid saturation (2004 CRA Section 6.4.3.3).  These gas generation rates were calculated from the initial linear part of the experimental curve of carbon dioxide as a function of time (2004 CRA Appendix PA Attachment PAR; Wang and Brush 1996).  

	For the 2004 PABC, DOE requested a change to the implementation of the gas generation, based on DOE's review of additional experimental data collected over the last several years.  The gas generation rate exhibits two rates:  an initial higher rate and a second lower rate.  DOE proposed to EPA that the long-term rate be the gas generation rate used in the PA calculations, with the initial higher rate incorporated as an initial higher pressure.  

Performance Assessment Parameters Related to Gas Generation
	DOE used Latin Hypercube Sampling (LHS) in PA for the following gas-generation-related parameters:

 Inundated steel corrosion rate 

 Probability of microbial degradation of plastics and rubbers (in the event of     microbial gas generation) 

 Biodegration rate of cellulosics, inundated and humic 

 Factor β for microbial reaction 

Performance Assessment Parameters Related to Shear Strength, Compactability (Compressibility) and Particle Diameter
	There were no changes from the PAVT.

Radioactivity in Curies of Each Isotope
	In the CCA, DOE indicated (Sections 3.1 and 3.2 of CCA Appendix WCA) that the radioactivity of each isotope is important to the performance assessment because it directly affects the waste unit factor (number of million curies of TRU isotopes in the WIPP inventory), which is the normalization factor used to calculate allowable releases for each radionuclide (see Table WCA-1 in CCA Appendix WCA).   Since the same approach is used in the 2004 CRA, the CCA approach is summarized.

  The following radionuclides were determined important by DOE (CCA Figure WCA-4): 

 Cuttings/cavings/spallings release:  [238]Pu, 239Pu, 240Pu, 241Pu, [241]Am, [233]U, 234U, [90]Sr, [137]Cs, [244]Cm.

 Direct Release in Brine:  [238]Pu, [239]Pu, [240]Pu, [241]Pu, [242]Pu, [241]Am, [243]Am, [233]U, [234]U, [235]U, [236]U, [238]U, [229]Th, 230Th, [232]Th, [237]Np, [243]Cm, [244]Cm, [245]Cm.

 Long-term groundwater release:  [239]Pu, [240]Pu, [242]Pu, [241]Am, [233]U, [234]U, [229]Th, [230Th].

	DOE indicated that U and Th isotopes are required in direct brine release assessments because, although they comprise negligible fractions of the total EPA unit, they do influence the total quantity of dissolved radionuclides (p. WCA-22).  In addition, DOE indicated that although EPA units for [90]Sr and [137]Cs at the time of the WIPP's closure are significant, they are not included in direct release of brine because they rapidly decay and result in "negligible impact on the PA from those two isotopes" (p. WCA-26).  If a direct brine release occurred early after closure, the total brine released would be minimal and the [90]Sr and [137]Cs would still, therefore, play a minor role in compliance (p.WCA-26).  

	DOE justified the radionuclide list for the long-term groundwater pathway (releases to the Culebra) based upon the following (CCA Appendix WCA, Section WCA.3.2.3, pp. WCA-26 to WCA-27):

 [233]U can be combined with [234]U for transport because their half-lives are similar.

 [229]Th can also be combined with [230]Th because they are in a fixed ratio to each other.

 [232]Th can be dropped because it is a constant small fraction of normalized releases throughout the 10,000-year regulatory period.

 [240]Pu and [242]Pu can be combined with [239]Pu. Long half-lives also indicate a fixed ratio between them.

 [238]Pu will have decayed to about 0.5% of its initial inventory after 700 years, and its contribution to releases will be negligible because of the long (>700 year) travel time in the Culebra; it was therefore dropped from consideration.

Performance Assessment Parameters Related to Radioactivity in Curies of Each Isotope
	DOE used the information from the update of the CCA inventory to define the isotope inventory for the 2004 CRA PA, which was modified for the 2004 PABC.  Refer to Section 194.24(a) of this CARD for a discussion regarding the description of this inventory.  The 2004 PABC Inventory Report (Docket A-98-49, Item II-B2-60) provides the radioactivity in curies of each isotope used in the 2004 PABC (See Table 14, p. 37).

TRU Radioactivity at Closure
	Table 14 of the 2004 PABC Inventory Report lists the DOE inventory at closure, based upon the September 2002 cutoff and updates described in Section 194.24(a) above.  The 2004 PABC Inventory Report indicates that the inventory activity estimate for the year 2033 (the planned date for closure) is 2.32 x 106 Ci, resulting in a waste unit factor of 2.32.

Performance Assessment Parameters Related to TRU Radioactivity at Closure
	The 2.32 waste unit factor is the number of millions of curies of alpha-emitting TRU radionuclides with half-lives longer than 20 years used in the calculation of the EPA normalized unit.  DOE discusses this in 2004 CRA Chapter 4 and Appendix TRU Waste Section TRU Waste-2 and in the 2004 PABC Inventory Report page 36.  

	A complete description of EPA's 1998 Certification Decision for Section 194.24 can be obtained from EPA Air Docket, A-93-02, Items V-A-1 and V-B-2.

24.2.3 Evaluation of Compliance for 2004 Recertification (194.24(b)(1))

	For the CCA, EPA reviewed information on waste characteristics and components in a number of technical documents.  This review encompassed references, experimental programs, logical arguments, and modeling.  EPA determined all relevant waste characteristics and components were identified and evaluated.  For the 2004 CRA, EPA focused on changes and new information that could affect DOE's analyses and findings.

	EPA concluded that, with the combination of the 2004 CRA, supplemental information, and the PABC, DOE performed an adequate update to the CCA.

Solubility
	EPA's review identified two areas in which DOE failed to adequately address solubility.  First, DOE did not update the uranium (+VI) solubility to incorporate new data that had become available since the certification decision.  The data indicated that the +VI solubility should be higher than that used by DOE in the CRA-2004 PA.  Second, DOE failed to update the solubility uncertainty ranges used for actinide solubility oxidation states based on new data.

	For the 2004 PABC, EPA stated that the solubility of U(+VI) needed to be changed to a fixed value of 1 x 10[-3] M because of experimental data that became available since the CCA.  In addition, EPA required that new solubility uncertainty ranges, based on the FMT database and currently available experimental solubility data, be incorporated into the 2004 PABC.  DOE made additional changes to the calculation of the +III, +IV, and +V actinide solubilities based on revised thermodynamic data for the +IV actinides, a different Salado brine formulation, and revised concentrations of organic ligands.  These changes were properly implemented as discussed in Section 7 of the Technical Support Document for Section 194.24:  Evaluation of the Compliance Recertification Actinide Source Term and Culebra Dolomite Distribution Coefficient Values (A-98-49, Item II-B1-3).  Table 24-5 lists the actinide solubility values for the 2004 PABC and the 2004 CRA PA.

	Other changes and improvements incorporated into the calculation of actinide solubilities for the 2004 PABC that have been implemented since the PAVT include:

 Incorporation of organic ligand complexation data into the FMT thermodynamic database so the effects of organic ligands on +III, +IV, and +V actinide solubilities can be calculated directly.  The organic ligand concentration changes were the result of corrections to the masses of organic ligands and the minimum estimated brine volume required for a release from the repository.

 Refinement of the thermodynamic database using new +III, +IV, and +V actinide data

 Use of GWB instead of Brine A as the Salado Brine formulation for actinide solubility calculations

 Correction of the minimum brine volume necessary for direct brine release

 Revision of the estimated uranium(VI) solubility to account for new data

 Recalculation of actinide solubility uncertainties based on a much larger number of solubility measurements, with separate distributions developed for the +III, +IV, and +V actinide solubilities instead of the single distribution used for the PAVT.  The new ranges are provided in Table 24-6. 

Table 24-5 2004 CRA PA and 2004 PABC Solubilities of the Oxidation State Analogs, in moles/liter, with MgO Backfill
                                        
            Solubilities for PA Material Name and Oxidation States
          
       PA Parameter	        SOLMOD3	         SOLMOD4	SOLMOD5	SOLMOD6
Brine	    Name		             (III)		   (IV)		    (V)      	     (VI*)
Salado   PABC SOLSIM	3.87 x 10-7		5.64 x 10-8	3.55 x 10-7	1 x 10-3 
Salado   CRA04 SOLSIM	3.07 x 10-7		1.19 x 10-6	1.02 x 10-6	8.7 x 10-6

Castile   PABC SOLCIM	2.88 x 10[-7]		6.79 x 10[-8]	8.24 x 10[-7]	1 x 10[-3] 
Castile   CRA04 SOLCIM	1.69 x 10[-7]		2.47 x 10[-8]	5.08 x 10[-6]	8.8 x 10[-6]
Table 24-6 Cumulative Distribution Function (CDF) Ranges Established by the Revised Actinide Solubility Uncertainty Analysis for the 2004 PABC.  The CDF Ranges Vary by Oxidation State.  No Range Was Used for the +VI Oxidation State Since EPA Required DOE to Use an Upper Bound for the Uranium Solubility.
                           Actinide Oxidation State
                                   CDF Range
                                      III
                                 -3.00 to 2.85
                                      IV
                                 -1.80 to 2.40
                                       V
                                 -1.95 to 1.95

Colloids
	The PAVT included microbial colloid transport of actinides for all vectors.  The 2004 CRA PA included different assumptions about the colloidal source term concentrations for microbial and non-microbial vectors, with no microbial colloid transport of actinides assumed for non-microbial vectors.  However, for the 2004 PABC, it was assumed that all vectors included microbial activity.  Therefore, DOE included microbial colloid transport of actinides for all 2004 PABC vectors (Brush 2005).  This approach, therefore, was the same for the PAVT and 2004 PABC, and was consistent with the Agency's direction that all vectors include microbial activity.

Production of Gas from the Waste
	Microbial degradation of CPR may influence WIPP repository performance because of its effects on repository chemistry and gas generation.  The Agency reviewed the approach and assumptions used by DOE to model microbial degradation for the 2004 CRA PA.  The Agency's review comments to DOE focused on the probability of significant microbial degradation, the nature of the microbial degradation reactions likely to occur in the repository, and microbial gas generation rates.  As a result of the Agency's review and comments, DOE changed the modeling of microbial degradation processes for the 2004 PABC.

	During the review of the 2004 CRA PA, the Agency noted that additional information related to the probability of significant microbial degradation in the WIPP repository had become available since the time of the CCA PA and PAVT.  EPA reviewed the information presented by DOE and other available information and concluded that new data regarding the potential existence and survival of microbes had increased the probability of significant microbial degradation of cellulosics.  On the other hand, the Agency did not find significant information supporting an increase in the probability of microbial degradation of plastics and rubbers in the repository.  Therefore, the Agency instructed DOE to assume that microbial degradation of CPR would occur in all 2004 PABC vectors.  
	Based on the inventories of nitrate and sulfate in the waste, DOE assumed in the 2004 CRA PA that these constituents would be quickly consumed during microbial degradation of CPR in the waste, and that methanogenesis would therefore be the dominant microbial degradation reaction.  However, adequate sulfate anions are likely to be available in the Salado anhydrite interbeds and will insure that methanogenesis does not occur regardless of the quantity of sulfate in the waste. Because DOE had not conclusively demonstrated that methanogenesis would be the dominant pathway for microbial degradation reactions, the model required revision.  This pathway was eliminated by DOE in the 2004 PABC and only denitrification and sulfate reduction reactions were included in the microbial gas generation model.  Based on the revised 2004 PABC inventory values, 4% of the microbial gas generation is from denitrification and 96% is from sulfate reduction.  These reactions will produce one mole of carbon dioxide for each mole of CPR carbon consumed by microbial degradation.  DOE has adequately revised the microbial gas generation reactions and evaluated the effects on PA.

	During the review of the 2004 CRA PA, DOE informed the Agency that the microbial gas generation experiments had continued and additional information related to microbial gas generation rates in the WIPP repository had become available since the time of the CCA PA and the PAVT.  In the letter directing DOE to perform the 2004 PABC, the Agency allowed DOE to propose a new gas generation rate scheme based on the new experimental data.  

	Because of the shape of the curve formed by carbon dioxide generated as a function of time, the degradation rates were modeled by obtaining a least-squares fit of two linear functions to the reported mean values for the carbon dioxide gas generation data.  In this manner, both a short-term and a long-term rate were determined for each experimental data set.  A minimum of three data points were included in each short-term or long-term fit to the data.  

	The revised microbial gas generation rates were based on long-term experimental data.  Therefore, gas generation during the early stages of the repository was accounted for in BRAGFLO by assuming a fixed amount of gas was present in the repository at the beginning of the calculations.  The amount of gas in the repository was assumed to be equal to the amount of gas generated per gram of cellulose at the point where the relatively rapid short-term rate changed to the slower long-term rate in the nutrient and nitrate-amended inundated experiments; these experiments were used to evaluate the maximum long-term rate.  This amount of gas initially present in the repository was converted to a pressure value of 26.714 kPa using the ideal gas equation and the volume and temperature of the repository.  This additional pressure was assumed to be generated immediately upon closure, resulting in an initial total repository pressure of 128,039 kPa.  
	At the Agency's direction, DOE changed the probability of microbial degradation to account for new evidence regarding the presence and viability of microbes capable of degrading CPR in the WIPP repository.  The revised probability parameters resulted in microbial degradation in all vectors for the 2004 PABC.  However, DOE asserted that uncertainties remained regarding the viability of microbes in the repository because of different conditions in the repository compared to the conditions in the experiments.  DOE therefore introduced an additional sampled parameter, BIOGENFC.  This parameter, which had a uniform distribution from 0 to 1, was multiplied by the microbial gas generation rates to effectively reduce the humid and inundated microbial gas generation rates from the experimentally determined long-term rates.  

	EPA did not receive any public comments on DOE's continued compliance with the requirements of Section 194.24(b)(1).
24.2.4 2004 Recertification Decision (194.24(b)(1))

	After a modification of the actinide solubility, solubility uncertainty ranges, methanogenesis assumption, and microbial gas generation rate and probability and based on a review and evaluation of the 2004 CRA and supplemental information provided by DOE (FDMS Docket ID No. EPA-HQ-OAR-2004-0025, Air Docket A-98-49), EPA determined that DOE continues to comply with the requirements for Section 194.24(b)(1).
24.2.5 Changes in the 2009 Compliance Recertification Application (194.24(b)(1))

	There were important changes made to the waste characteristics between the CRA-2004 PABC and the CRA-2009 PABC.  DOE also made changes to some of the parameters used in the PA, in particular increasing the quantity of certain chemical components.  These are summarized in Table 24-7, below.  Most of these are related to inventory changes described above in Section 24.1.5.  EPA continued to be most concerned with changes affecting actinide solubility and gas generation for the 2009 recertification.  
Table 24-7 Characteristics expected to have a significant effect on disposal system performance and changes from the 2004 CRA PABC to the 2009 CRA PABC
                 Waste Component or Characteristic Used in PA
                                 Significance
                             Increase or Decrease
                           From CCA to 2009 CRA PABC
Radioactivity per cubic meter
Used in calculating releases
Slight decrease
Solubility
Higher solubility can lead to higher releases when brine is present
Increase 
Organic ligands -- complexing agents
Increases solubility
Significant increase in acetic acid, sodium citrate, and EDTA.  
Amount of Metals
Maintains reducing environment, but also contributes to gas generation
Decrease for CH-TRU, increase for RH-TRU
Amount of Cellulosics, Plastics, Rubbers
May increase gas generation from microbial processes
Slight increase
Oxyanions:  nitrate, sulfate, and phosphate
Nutrients for microbes, so indirectly affects gas generation
Similar, but overall slight increase
Cement 
Primarily a volume related component
Increase
Shear Strength
Affects mechanical releases during Low waste shear strength
No change
Particle Diameter
Used to calculate spallings releases
No change  
Formation of colloidal suspensions
Colloids can facilitate transport of radionuclides in ground water
No change

Assessment of 2009 CRA Waste Characteristics and Waste Characteristic Input Parameters
	In the original CCA, DOE identified several waste characteristics as potentially important to the performance assessment (CCA Appendix WCA, Section WCA.6, pp. WCA-42 to WCA-43) based on available information, including uncertainties and WIPP system characterization.  These analyses were summarized in CCA Appendices WCA, SOTERM, and MASS, and were augmented by DOE's responses to EPA comments (CCA CARD 24).  The 2004 CRA identified the same important characteristics and DOE added organic ligands as important waste components that may increase waste solubility.  The most significant change since the 2004 CRA is that the EDTA mass increased by more than 10 times (Table 24-2, PAIR-2008 Table 5-7). 

2009 CRA Solubility Discussion
	DOE continued to use the Fracture Matrix Transport (FMT) geochemical modeling code and its associated database to calculate solubilities.  No changes were made to the FMT code, FMT database, or dissolved actinide solubility conceptual models for the 2009 PABC solubility calculations.  However, revisions were made to the input FMT database since the 2004 PABC (EPA 2010a Section 6.5).  The major differences in the input data are the increased organic ligand inventory and minimum brine volume used in the new 2009 PABC calculations.  The actinide solubility uncertainties used for the 2004 PABC calculations were also revised for the 2009 calculations.

2009 CRA Performance Assessment Parameters Related to Solubility
	Solubilities of actinides in the III, IV, V and VI oxidation states for both the Castile and Salado brines continue to be calculated by DOE with the assumption that pH and f(CO2) are controlled by Mg(OH)2  -  MgCO3 equilibrium.  The solubilities (moles/liter) in Table 24-8 list the CCA, 2004 CRA PA, 2004 PABC, and the new 2009 PABC solubility values (Clayton et al. 2009 Section 2.2).  The uncertainty ranges for the actinides in the 2009 CRA PABC were also changed for the 2009 PABC (Table 24-9).  

Table 24-8 Solubilities of the Oxidation State Analogs, in moles/liter, with MgO Backfill
             Solubilities for PA Material Name and Oxidation State
          
           PA Parameter       SOLMOD3	          SOLMOD4	SOLMOD5	SOLMOD6
Brine	         Name		     (III)		   (IV)		    (V)      	     (VI*)
Salado	CCA SOLSIM	5.82 x 10-7		4.40 x 10-6	2.30 x 10-6	8.7 x 10-6 
Salado     CRA04 SOLSIM	3.07 x 10-7		1.19 x 10-6	1.02 x 10-6	8.7 x 10-6
Salado    PABC04 SOLSIM   3.87 x 10-7             5.64 x 10-8       3.55 x 10-7         1.0 x 10-3
Salado    PABC09 SOLSIM   1.66 x 10-6             5.63 x 10-8       3.90 x 10-7         1.0 x 10-3
Castile	CCA SOLCIM	6.52 x 10[-8]		6.00 x 10[-9]	2.20 x 10[-6]	8.8 x 10[-6] 
Castile     CRA04 SOLCIM	1.69 x 10[-7]		2.47 x 10[-8]	5.08 x 10[-6]	8.8 x 10[-6]
Castile   PABC04 SOLCIM   2.88 x 10[-7]             6.79 x 10[-8]       8.24 x 10[-7]         1.0 x 10[-3]
Castile   PABC09 SOLCIM   1.51 x 10[-6]             6.79 x 10[-8]       8.75 x 10[-7]         1.0 x 10[-3]
* See Section 24.2.3 of this CARD.

2009 CRA Formation of Colloidal Suspensions Containing Radionuclides
	Colloid formation can enhance the quantity of actinides contained in brine, and continues to be evaluated as an important group of waste characteristics.  In the CCA DOE determined that four types of colloids may be present in the WIPP repository: Intrinsic colloids, mineral fragment colloids, humic colloids, and microbe colloid.  These colloids are still modeled in the 2009 PABC and are unchanged from the CCA.  

	DOE did not change the implementation of the colloidal actinide source term approach from the CRA-2004 PABC in the 2009 PABC.  In the 2004 CRA PA, DOE assumed there would be microbial colloid transport only in vectors without significant microbial degradation.  The 2004 PABC included microbial degradation in all vectors.  This assumption did not change in the 2009 CRA PAs. 

2009 CRA Production of Gas From the Waste (Including Microbial Substrate and Nutrients)
	The same conceptual model was used for microbial gas generation in the WIPP repository for the CCA, the 2004 CRA and the 2009 CRA.  The model implementation was changed in the 2004 CRA (Section 24.2.2 of this CARD). The 2009 CRA used the same implementation (2009 CRA Section 24.5.2.3).

2009 CRA Performance Assessment Parameters Related to Gas Generation
	DOE used Latin Hypercube Sampling (LHS) in PA for the following gas-generation-related parameters:

 Inundated steel corrosion rate 

 Probability of microbial degradation of plastics and rubbers (in the event of     microbial gas generation) 

 Biodegradation rate of cellulosics, inundated and humic 

 Factor β for microbial reaction 

	This continues to be DOE's approach in the 2009 CRA PAs.

2009 CRA Performance Assessment Parameters Related to Shear Strength, Compactability (Compressibility) and Particle Diameter
	There have been no changes to these parameters since the PAVT.

2009 CRA Radioactivity in Curies of Each Isotope
	In the CCA, DOE indicated (Sections 3.1 and 3.2 of CCA Appendix WCA) that the radioactivity of each isotope is important to the performance assessment because it directly affects the waste unit factor (number of million curies of TRU isotopes in the WIPP inventory), which is the normalization factor used to calculate allowable releases for each radionuclide (see Table WCA-1 in CCA Appendix WCA).   DOE used the same approach in the 2004 CRA and the 2009 PABC.  See Section 24.2.2 of this CARD for a more complete discussion.

2009 CRA Performance Assessment Parameters Related to Radioactivity in Curies of Each Isotope
	DOE used the information from the update of the PAIR-2008 inventory to define the isotope inventory for the 2009 PABC.  Refer to Section 24.1.5 of this CARD for a discussion regarding the description of this inventory.  The PAIR-2008 provides the radioactivity in curies of each isotope used in the 2009 PABC.

2009 CRA TRU Radioactivity at Closure
	PAIR-2008 Table A-1 lists the DOE inventory at closure, based upon the December 31, 2007 cutoff date and updates described in Section 24.1.5 of this CARD.  Fox, Clayton and Kirchner(2009), Table B-2 indicates that the inventory estimate for the year 2033, which is the planned date for closure, is 2.60 x 106 Ci.  Thus the waste unit factor (WUF) - the number of millions of curies of alpha-emitting TRU radionuclides with half-lives longer than 20 years used in the calculation of the EPA normalized unit - is 2.60 (Fox, Clayton and Kirchner 2009, page 6).   Out of the 145 radionuclides reported in the present inventory, 17 transuranic waste radionuclides contribute to the unit of waste used to calculate the WUF.

24.2.6 Evaluation of Compliance for 2009 Recertification (194.24(b)(1))

	For the 2009 CRA, EPA focused on changes and new information in DOE's analyses that could impact disposal system performance based on changes in waste characteristics, such as solubility and gas generation.  EPA concluded that, with the combination of the 2009 CRA, supplemental information, and the 2009 PABC, DOE performed an adequate update to the CCA and the 2004 recertification.

2009 CRA Solubility
	DOE used the 2004 CRA inventory in the 2009 CRA PA calculations.  Comparison of the most recent 2008 inventory data on organic ligands (Crawford et al. 2009) with the quantities used to calculate actinide solubilities for the CRA-2004 PABC shows that organic ligand quantities have increased dramatically for acetic acid, citric acid, sodium citrate, and sodium EDTA (Table 24.2).  Because of the potential effects of organic ligands on actinide solubilities, EPA instructed DOE to include the revised inventory of organic ligands in the CRA-2009 PABC actinide solubility calculations (Cotsworth 2009a, Comments 1-23-1 and 1-23-4).  In addition, EPA requested that DOE consider the updated inventory of organic ligands and the extent to which ligands are likely to affect actinide solubilities (Cotsworth 2009a, Comments 1-C-6 and 1-C-14).  Moody (2009a) responded that DOE would perform a new PA that includes an updated EDTA, acetate, citrate, and oxalate concentration, based on the information provided in Crawford et al. (2009) and provide documentation of this PA to EPA.
	Other changes and improvements incorporated into the calculation of actinide solubilities for the 2009 PABC include: changes to the MgO excess factor and MgO reactivity test procedure (EPA 2010i Section 4.0) and re-evaluation of the actinide distribution coefficients used in the 2009 PABC to account for the effects of higher organic ligand concentrations (EPA 2010a Section 10.0).
Table 24-9  Cumulative Distribution Function (CDF) Ranges Established by the Revised Actinide Solubility Uncertainty Analysis for the 2009 PABC.   
                           Actinide Oxidation State
                                   CDF Range
                                      III
                                 -4.20 to 2.70
                                      IV
                                 -2.25 to 3.30
Source: Xiong et al. 2009, Table 7 and Table 11

2009 CRA Colloids
	DOE included microbial colloid transport of actinides for all 2004 PABC vectors (Brush 2005).  This approach was the same approach applied in the 2009 CRA PAs.  No changes have been made to the Colloidal Actinide Source Term conceptual model or its implementation since the CCA PAVT.  Data developed since the CCA PAVT, most notably the evidence from Wall and Mathews (2005), indicate that the current model is likely to conservatively overestimate colloidal associated actinides in the source term.

At the May 2010 public stakeholder meeting related to EPA's completeness decision, and later in written comments, Citizens for Alternatives to Radioactive Dumping (CARD) requested that the Agency verify that experimental results from Argonne National Laboratory related to the structure of plutonium nanocolloids which possess enhanced transport capabilities.  EPA issued a completeness letter asking whether DOE has incorporated these results into the 2009 PABC.  In its letter dated September, 2010, DOE indicated that it was aware of the results.  The ANL experiments were carried out in a low-pH environment, making the formation of these colloids unlikely in WIPP-relevant conditions.  However, the inclusion of intrinsic colloids in the PA conservatively takes into consideration the formation and transport of these colloids (DOE 2010g).  EPA concurs with DOE.

2009 CRA Production of Gas from the Waste
	As noted earlier, the gas generation conceptual model and model implementation were not changed in the 2009 CRA PAs (see Section 24.2.2 of this CARDS for details).  EPA verified that microbial degradation of CPR occurs in all 2009 PABC vectors, that both a short-term and long-term gas generation rates based on experimental results are used, and that methanogenesis does not occur regardless of the quantity of sulfate in the waste (2009 CRA Appendix PA-2009 Section PA 4.2.5).  EPA finds DOE's approach to be adequate.

	EPA did not receive any additional public comments on DOE's continued compliance with the requirements of Section 194.24(b)(1).

24.2.7 2009 Recertification Decision (194.24(b)(1))

	After a modification of the actinide solubility, solubility uncertainty ranges, methanogenesis assumption, and microbial gas generation rate and probability and based on a review and evaluation of the 2009 CRA and supplemental information provided by DOE (FDMS Docket ID No. EPA-HQ-OAR-2004-0025, Air Docket A-98-49), EPA determines that DOE continues to comply with the requirements for Section 194.24(b)(1).

24.2.8 Changes in the 2014 Compliance Recertification Application (194.24(b)(1))

	There were important changes made to the waste characteristics since the CRA-2009 PABC, for example, waste component information was updated and added waste inventory parameters were used in the WIPP PA.  DOE also updated some of the waste related parameters used in the PA.  Additional parameters include the mass of waste and packaging materials, the solubilities calculated using multiples of the minimum brine volume necessary for a DBR to occur, and those to describe the additional biodegradation reactions implemented within the repository chemistry model. These are summarized in Table 24-8, below (2014 CRA DOE Section 24.8.2).  Most of these are related to inventory changes described above in Section 24.1.5.  

Table 24-8 Characteristics expected to have a significant effect on disposal system performance and changes from the 2009 CRA PABC to the 2014 CRA PA 
                 Waste Component or Characteristic Used in PA
                                 Significance
                             Increase or Decrease
                        From 2009 PABC to 2014 CRA PA 
Radioactivity per cubic meter
Used in calculating releases
Decrease
Solubility
Higher solubility can lead to higher releases when brine is present
Increase and decrease, depending on oxidation state 
Organic ligands -- complexing agents
Increases solubility
Decrease  
Amount of Metals
Maintains reducing environment, but also contributes to gas generation
Decrease
Amount of Cellulosics, Plastics, Rubbers
May increase gas generation from microbial processes
Decrease
Oxyanions: nitrate, sulfate, and phosphate
Nutrients for microbes, so indirectly affects gas generation
Increase and decrease
Cement 
Primarily a volume related component
Decrease
Shear Strength
Affects mechanical releases during Low waste shear strength
Increase
Particle Diameter
Used to calculate spallings releases
No change  
Formation of colloidal suspensions
Colloids can facilitate transport of radionuclides in ground water
Increase and decrease

Assessment of 2014 CRA Waste Characteristics and Waste Characteristic Input Parameters
	In the original CCA, DOE identified several waste characteristics as potentially important to the performance assessment (CCA Appendix WCA, Section WCA.6, pp. WCA-42 to WCA-43) based on available information, including uncertainties and WIPP system characterization.  These analyses were summarized in CCA Appendices WCA, SOTERM, and MASS, and were augmented by DOE's responses to EPA comments (CCA CARD 24). DOE noted that organic ligands were important waste components that may increase waste solubility, therefore organic ligands continue to be included in the solubility calculations (Brush and Domski 2013a).  These changes are refinements to the implementation of the PA conceptual models; no changes were made to these models for the 2014 CRA PA.

2014 CRA Solubility 
      DOE notes that the CRA-2014 includes new solubility values for Th(IV), Np(V) and Am(III) (Brush and Domski 2013a), and new solubility uncertainty distributions (Brush and Domski 2013b). The DOE also implemented a new method for calculating the organic ligand concentrations for the minimum brine volumes necessary for a DBR by adding additional parameters (Camphouse 2013). The DOE replaced FMT with EQ3/6, Version 8.0, and the thermodynamic database DATA0.FMT.R2, also known as DATA0.FM1, for the analyses performed in support of the CRA-2014. The CRA-2014 continues to include the effects of organic ligands in the solubility calculations, as was first done in the CRA-2004.
	
2014 CRA Performance Assessment Parameters Related to Solubility
	Solubilities of actinides in the III, IV, V and VI oxidation states for both the Castile and Salado brines continue to be calculated by DOE with the assumption that pH and f(CO2) are controlled by Mg(OH)2  -  MgCO3 equilibrium.  The Agency had some questions and concerns related to DOE's updated uncertainty distribution used in the CRA 2014 PA. The Agency identified some inconsistencies DOE had adopted in selecting the references used in that distribution. As a result of these concerns, the Agency requested DOE revise the references to be used in developing the actinide solubility uncertainty distributions and resulted in a different actinide uncertainty distribution. The resulting actinide uncertainty distribution was used in the SEN4 sensitivity study. The revised criteria and references to be used in developing the actinide uncertainty in the SEN4 study are listed in (Table 24-10) discussed in Technical Support Document in Support of Section 194.24 Evaluation of the Compliance Recertification Actinide Source Term, Gas Generation, Backfill Efficacy, Water Balance, and Culebra Dolomite Distribution Coefficient Values. (Docket ID No. EPA-HQ-OAR-2014-0609).
Table 24-9 Solubilities of the Oxidation State Analogs, in moles/liter, with MgO Backfill
             Solubilities for PA Material Name and Oxidation State
          
           PA Parameter       SOLMOD3	          SOLMOD4	SOLMOD5	SOLMOD6
Brine	         Name		     (III)		   (IV)		    (V)      	     (VI*)
Salado	CCA SOLSIM	5.82 x 10-7		4.40 x 10-6	2.30 x 10-6	8.7 x 10-6 
Salado     CRA04 SOLSIM	3.07 x 10-7		1.19 x 10-6	1.02 x 10-6	8.7 x 10-6
Salado    PABC04 SOLSIM   3.87 x 10-7             5.64 x 10-8       3.55 x 10-7         1.0 x 10-3
Salado    PABC09 SOLSIM   1.66 x 10-6             5.63 x 10-8       3.90 x 10-7         1.0 x 10-3
Salado     CRA14 SOLSOH   2.59 x 10[-6]             6.05 x 10[-8]       2.77 x 10[-7]         1.0 x 10[-3]

Castile	CCA SOLCIM	6.52 x 10[-8]		6.00 x 10[-9]	2.20 x 10[-6]	8.8 x 10[-6] 
Castile     CRA04 SOLCIM	1.69 x 10[-7]		2.47 x 10[-8]	5.08 x 10[-6]	8.8 x 10[-6]
Castile   PABC04 SOLCIM   2.88 x 10[-7]             6.79 x 10[-8]       8.24 x 10[-7]         1.0 x 10[-3]
Castile   PABC09 SOLCIM   1.51 x 10[-6]             6.79 x 10[-8]       8.75 x 10[-7]         1.0 x 10[-3]
Castile    CRA14 SOLCOH   1.48 x 10[-6]              7.02 x 10[-8]      8.76 x 10[-7]          1.0 x 10[-3]

* See Section 24.2.3 of this CARD.


2014 CRA Formation of Colloidal Suspensions Containing Radionuclides
	Colloid formation can enhance the quantity of actinides contained in brine, and continues to be evaluated as an important group of waste characteristics.  In the CCA, DOE determined that four types of colloids may be present in the WIPP repository: Intrinsic, mineral fragment, humic colloids, and microbial.  These colloids are still modeled in the 2014 CRA.  

      The colloid parameters were re-examined for the 2014 CRA (Appendix PA-2014, Section PA-1.1.11). Based on the recommendations of Reed et al. (Reed et al. 2013), the DOE updated the PA parameter properties CONCINT, PROPMIC and CAPMIC. More details are provided in 2014 CRA Appendix SOTERM-2014, Section SOTERM-4.6.

2014 CRA Waste Shear Strength Parameter Revised
      The parameter related to the waste shear strength was revised for the CRA-2014. DOE did experiments to directly measure waste shear strength. Herrick and Kirchner (Herrick and Kirchner 2013) recommended that the DOE included a modified distribution for the parameter BOREHOLE:TAUFAIL in the CRA-2014 PA calculations (Appendix PA-2014, Section PA-1.1.5). The DOE updated the parameter for the CRA-2014 from a log uniform distribution with a range of 0.05 - 77.0 Pa, to a uniform distribution with a range of 2.22 - 77.0 Pa. 

2014 CRA Performance Assessment Parameters Related to Gas Generation
	Two changes related to the gas generation from the waste were implemented in the CRA-2014 PA: the refinement of the repository water balance (see 2014 CRA DOE Section 24.8.2.5.1) and the update to the anoxic steel corrosion rate (see 2014 CRA DOE Section 24.8.2.5.2).

	DOE continued to use used Latin Hypercube Sampling (LHS) in PA for the following gas-generation-related parameters:

 Inundated steel corrosion rate 

 Probability of microbial degradation of plastics and rubbers (in the event of     microbial gas generation) 

 Biodegradation rate of cellulosics, inundated and humid 

2014 CRA Radioactivity in Curies of Each Isotope
	In the CCA, DOE indicated (Sections 3.1 and 3.2 of CCA Appendix WCA) that the radioactivity of each isotope is important to the performance assessment because it directly affects the waste unit factor (number of million curies of TRU isotopes in the WIPP inventory), which is the normalization factor used to calculate allowable releases for each radionuclide (see Table WCA-1 in CCA Appendix WCA).   DOE used the same approach in the 2014 PA as in previous CRAs (see 2014 CRA PAIR Tables 5-1 (CH) and 5-2 (RH).

2014 CRA TRU Radioactivity at Closure
	PAIR-2012 lists the DOE inventory at closure used in the 2014 CRA, based upon the December 31, 2011 cutoff date and waste inventory updates.  Kicker and Zeitler 2013, Table 1 indicates that the inventory estimate for the year 2033, which is the planned date for closure, is 2.06 x 106 Ci.  Thus, the waste unit factor (WUF) - the number of millions of curies of alpha-emitting TRU radionuclides with half-lives longer than 20 years used in the calculation of the EPA normalized unit  is 2.06 (Kicker and Zeitler 2013, page 8).   Out of the 179 radionuclides reported in the present inventory, 17 transuranic waste radionuclides contribute to the unit of waste used to calculate the WUF.

24.2.9 Evaluation of Compliance for 2014 Recertification (194.24(b)(1))

	For the 2014 CRA, EPA continued to focus on changes and new information in DOE's analyses that could impact disposal system performance based on changes in waste characteristics, such as solubility and gas generation.  Please refer to Technical Support Document in Support of Section 194.24 Evaluation of the Compliance Recertification Actinide Source Term, Gas Generation, Backfill Efficacy, Water Balance, and Culebra Dolomite Distribution Coefficient Values. (Docket ID No. EPA-HQ-OAR-2014-0609) for details on EPA's analyses of the topics below.

2014 CRA Solubility  
	EPA finds the update to calculating solubility using variable brine volumes acceptable and addresses the issue of changes in organic ligand concentrations that occur with different volumes of brine. EPA also accepts the migration to the EQ3/6 code to calculate actinide solubility, which we believe is far more robust than the previous FMT code. Because the geochemical database used to calculate solubility had not been updated since 2002, EPA requested DOE use the latest data to update the database. However, The Agency has identified multiple flaws in the update DOE produced, including insufficient information regarding carbonate, borate, and organic complexation as well as hydromagnesite and Nd solubility. As such, EPA continues to accept the original database and urges DOE to continue its update of the geochemical database in consultation with the Agency.
	
	EPA has identified multiple problems with the uncertainty distribution DOE has provided, largely in DOE's inconsistent application of the criteria used to choose studies for this distribution. For example, the studies span a time frame with an arbitrary cutoff date, thereby decreasing the number of studies utilized in the analysis. Furthermore, DOE screened studies using only a limited range of pcH conditions, as well as borate and carbonate concentrations. Additionally, DOE included studies that overestimate +IV concentrations (e.g., Altmaeier et al 2004) and underestimated +III concentrations (e.g., Borkowski et al. 2009). After reviewing the uncertainty distribution for the 2014 CRA, EPA revised the uncertainty by providing a new set of criteria to search for solubility data used in the SEN4 sensitivity study, including considerations of both borate and carbonate as these have been found to be important in the WIPP. This resulted in a new uncertainty distribution that highlights DOE overpredicting +IV actinide solubility and underpredicting +III actinides. EPA will accept the revised uncertainty distribution because, even though releases increased with the Agency's modifications, releases still remained within compliance limits. This uncertainty is represented as a cumulative distribution function, with values shown in Table 24-10 below.

	The Agency has also identified deficiencies in DOE's assessment of solubility, particularly on the topic of plutonium oxidation state. We find this topic especially important as actinide oxidation state is a fundamental concept in plutonium solubility, with the +III state being more soluble than the +IV. DOE addresses uncertainty in which plutonium oxidation state will dominate the WIPP by including the +III oxidation state in 50% of PA realizations and +IV in the other 50%. Recent data compels EPA to believe that the +III state will dominate in repository conditions. In order to fully address this topic, we believe DOE should conduct an independent technical review prior to CRA-2019 and implement the recommendations provided by this review for the next PA.	

Table 24-10.  Cumulative Distribution Function (CDF) Ranges Established by the Revised Actinide Solubility Uncertainty Analysis for the 2009 PABC.   
                           Actinide Oxidation State
                              2009 PABC CDF Range
                               2014 PA CDF Range
                                      III
                                 -4.20 to 2.70
                                 -3.55 to 2.97
                                      IV
                                 -2.25 to 3.30
                                 -1.52 to 3.19
Source: Xiong et al. 2009, Table 7 and Table 11

2014 CRA Colloids 
	DOE has performed multiple investigations on Nd(III), Pu(III), Am(III), Th(IV), and U(IV) intrinsic colloids and these results have been incorporated into the 2014 PA and the intrinsic colloid concentration parameter (CONCINT) (Reed et al. 2013). Many of the updates to the parameter, such as Th(IV) colloids, are based on an arithmetic mean to measured values in experiments over a narrow range of repository pcH values. EPA disagrees with this limited approach and believes that an upper-bounding value should be used from a wider range of pcH values in order to include more data and to represent the maximum intrinsic colloid concentrations.  Other colloid values, such as Pu(III), also appear to use an arithmetic mean when they should be utilizing an upper bound value.

      The Department has also conducted microbial colloid investigations on WIPP-indigenous microorganisms. From these investigations, DOE has redone how microbial colloids are calculated, which is a significant change to the previous model. In addition, updated sorption experiments were conducted for 2 hours in comparison to previous WIPP microbial adsorption tests over a period of 11 to 21 days. This time period may not adequately account for steady state and may underestimate colloids as it only accounts for biosorption without including bioaccumulation and biomineralization. 

      EPA has identified major issues with the experiments performed to calculate intrinsic and microbial colloids and believes that these result in an underestimation on colloidal concentrations. While EPA continues to welcome updates to these parameters, in light of these major experimental and calculation issues, EPA rejects DOE's updates to the colloid model for the 2014 CRA and continues to accept the approach used in the 2009 CRA. For the 2019 CRA, DOE should continue to use the approach applied in the 2009 CRA until it provides an update EPA finds acceptable.

2014 CRA Production of Gas 
      In the new values used for the updated corrosion rates, the minimum rates do not account for the atmospheric concentrations of CO2 in the repository while the maximum rates do not account for increases in repository pressure concomitant with CO2 increase. The latter in particular, can result in increased corrosion rates that can subsequently lead to higher repository pressure conducive to releases. In addition, EPA believes that H2S induced steel passivation will occur, causing a significant decrease in corrosion once it occurs. 
      
      The model also ignores lead in the waste containers and do not account for their maximum potential of future containers which may be significant. The corrosion and gas generation model also ignores the putative effects of radiolysis on gas generation as this rate was negligible in comparison to other potential sources of gas generation. However, because lower microbial gas generation rates were used in the 2014 PA, radiolysis may now provide a bigger contribution to gas generation.

      To address EPA's concerns about corrosion, part of DOE's sensitivity study involved simulating passivation by turning off the corrosion reaction. These changes resulted in a slight increase in gas pressures as well a decrease in the saturation of the waste area because both H2 gas and H2O were eliminated from the end products. Results from this study included an adequate margin of safety allowing for EPA to accept the updates to corrosion. However, the EPA expects the DOE to account for steel passivation and corrosion issues addressed above in the CRA-2019. EPA also expects DOE to develop upper bound estimates for lead corrosion and methods to account for radiolysis.

      For the 2014-PA, DOE has also chosen to calculate repository water balance, which is the culmination of multiple chemical reactions like corrosion. Although changes to each of the chemical reactions are minor, these reactions will all have a cumulative effect and increase repository saturation or change repository pressure and subsequent releases. Based on previous exchanges with DOE as well as the SEN4 sensitivity study, EPA can accept the current water balance as it does not appear to significantly affect the PA. However, by continuing to refine this calculation, DOE can provide a realistic and defensible calculation for the WIPP PA.

	EPA did not receive any additional public comments on DOE's continued compliance with the requirements of Section 194.24(b)(1).

24.2.10 2014 Recertification Decision (194.24(b)(1))

	After discussions with DOE, the sensitivity study, and based on a review and evaluation of the 2014 CRA and supplemental information provided by DOE (Docket No. EPA-HQ-OAR-2014-0609), EPA determines that DOE continues to comply with the requirements for Section 194.24(b)(1).

24.3 Requirement (194.24(b)(2))

	(b) "The Department shall submit in the compliance certification application the results of an analysis which substantiates:
(2) That all waste components influencing the waste characteristics identified in 		paragraph (b)(1) of this section have been identified and assessed for their impact on disposal system performance.  The components to be analyzed shall include, but shall not be limited to: metals; cellulosics; chelating agents; water and other liquids; and activity in curies of each isotope of the radionuclides present."

24.3.1 1998 Certification Decision (194.24(b)(2))

	To demonstrate compliance with Section 194.24(b)(2), EPA expected DOE to present rationales, logical arguments, applications of screening procedures, results of bounding or sensitivity analyses, etc., beginning from the description required by 194.24(a) and leading to the selection of the important or significant waste components to be limited and controlled to assure compliance with the disposal regulations.  DOE identified a number of waste components and characteristics that would be important to performance and EPA reviewed them.  EPA identified several issues with DOE's treatment of the waste components and characteristics in the CCA PA, but through independent analysis and changes to the PA in the PAVT, these issues were resolved and EPA determined that DOE complied with this section (CCA CARD 24).

	A complete description of EPA's 1998 Certification Decision for Section 194.24(b)(2) can be obtained from EPA Air Docket, A-93-02, Items V-A-1 and V-B-2.

24.3.2 Changes in the 2004 Compliance Recertification Application (194.24(b)(2))

	DOE indicated that the components identified below were expected to have a significant effect on disposal system performance and so were used in the CCA PA, 2004 CRA PA and the 2004 PABC:

 Ferrous metals

 Cellulose and other chelating agents (i.e., organic ligands) as they pertain to enhanced actinide mobility

 Radioactivity in curies of each isotope

 -emitting TRU radionuclides, t1/2 > 20 years (t1/2 is the half-life)

 Radionuclides

 Solid waste components (e.g., soils and cementitious materials)

 Sulfates

 Nitrates

	Most of the inventory amounts of the listed components have changed and are discussed in the PABC Inventory Report and EPA's Technical Support Document for Section 194.24:  Review of the Baseline Inventory Used in the Compliance Recertification Application and the Performance Assessment Baseline Calculation (A-98-49, Item II-B1-9).  The important items have not changed from the CCA, and EPA agreed that DOE's information was adequate and reported this in CCA CARD 24.  

	The only change of significance is the incorporation of organic ligands in the actinide solubility PA calculations.  DOE updated the FMT thermodynamic databases with information related to organics to account for the organic ligands' effect on actinide solubility (2004 CRA Appendix SOTERM 5.0).

	DOE had reported in CCA Appendix SOTERM that organic ligands are not expected to affect the aqueous speciation of actinides, given anticipated repository conditions, because of competition for the ligands with major solutes in the brine and metal ions derived from corrosion of waste materials.  In addition, DOE's thermodynamic database did not have the parameters to analyze the effect of organic ligands under the high ionic strength solutions expected at WIPP. EPA conducted an independent evaluation of the effects of organic ligands by conducting modeling runs at lower ionic strengths to examine the effects of the organic ligand EDTA on the aqueous speciation of Th(IV) and the solubility of ThO2(am).  EDTA was considered because it has the greatest affinity for forming aqueous complexes with the actinides compared to acetate, citrate, and oxalate.

	The modeling runs indicated that the EDTA concentration would have to increase by at least 1,000 times the maximum concentrations expected for the repository to produce an appreciable change in the aqueous speciation of Th(IV) and solubility of ThO2(am), and this range was limited primarily to acidic pH conditions.  At the pH conditions of 9 to 10 that are relevant to the repository with MgO backfill, the EDTA was complexed predominantly by Ca and Mg ions.  These results implied that the organic ligands are unlikely to affect the mobilities of the actinides.  

	Reported inventories of the four ligands changed between the CCA and 2004 CRA, including increased concentrations of acetate, changes in oxalate and citrate inventories that appear to have been caused by transposing the data during the CCA, and a decrease in the estimated inventory of EDTA (2004 CRA Appendix PA Attachment SOTERM Table SOTERM-4).  In addition, new estimates of the available brine necessary for a release have decreased, thus effectively increasing concentrations (from ~30,000 m[3] to ~10,000 m[3]).	
	DOE stated that acetate, citrate, EDTA, and oxalate will not significantly affect the +III and +IV actinide solubilities (CRA Appendix PA Attachment SOTERM Section 5.0).  Comparison of FMT calculations with and without organic ligands indicates that this is true for the +IV actinides.  However, comparisons of FMT output files for calculations with and without organic ligands indicate that higher +III actinide solubilities are observed in runs with organic ligands than in runs without organic ligands.  These higher concentrations occurred because AmEDTA[-] constituted approximately one-quarter to one-half of the aqueous americium(III) species in FMT runs with organic ligands.  These comparisons also indicated that oxalate complexation significantly increased neptunium(V) solubilities, however, since the neptunium will be present in such low concentrations, there is little effect on releases.
24.3.3 Evaluation of Compliance for 2004 Recertification (194.24(b)(2))
	
	The concentrations of organic ligands were re-evaluated for the PABC actinide solubility calculations based on a revised estimate of the minimum amount of brine that could lead to a release from the repository.  In addition, new data regarding the possible complexation of +IV actinides by EDTA were identified; these data were evaluated to determine its potential significance to the actinide solubility calculations for WIPP repository conditions.

	In the PA vectors, the volume of brine used to dissolve the ligands may not be the minimum value that could be released from a single panel.  It is also possible that the majority of ligands will be placed in a single panel because most ligands are in a limited number of waste streams.  The assumption that all ligands are in the same panel and that these ligands would be mobilized by the minimum brine volume released from a single panel would be the most-conservative scenario for calculating ligands concentrations.  However, the probability of a randomly located borehole encountering such a panel, if it existed in the repository, would be correspondingly reduced.  The individual PA vectors would be influenced if modeling could be done on a panel-by-panel basis, but the influence on the mean concentrations would probably be small.  Therefore, the use of the minimum amount of brine that could be released from the entire repository and assuming that all ligands are dissolved in this amount of brine is likely to be a reasonable approximation for calculating ligands concentrations and the resulting actinide solubilities.

	EPA did not receive any public comments on DOE's continued compliance with the requirements of Section 194.24(b)(2).

24.3.4 2004 Recertification Decision (194.24(b)(2))

	During EPA's review of the important waste components, EPA identified that only organic ligands were addressed differently than in the CCA.  Organic ligands could increase actinide solubility, but EPA has determined that DOE has adequately included their effects in the PABC.

	Based on a review and evaluation of the 2004 CRA and supplemental information provided by DOE (FDMS Docket ID No. EPA-HQ-OAR-2004-0025, Air Docket A-98-49), EPA determined that DOE continued to comply with the requirements for Section 194.24(b)(2).

24.3.5 Changes in the 2009 Compliance Recertification Application (194.24(b)(2))

	DOE continues to indicate that the components identified Section 24.3.2 of this CARD are expected to have a significant impact on disposal system performance and continue to be used in the 2009 CRA PABC calculations.  These components are: ferrous metals, cellulose and other chelating agents (i.e., organic ligands) as they pertain to enhanced actinide mobility, radioactivity in curies of each isotope, -emitting TRU radionuclides, t1/2 > 20 years (t1/2 is the half-life), radionuclides, solid waste components (e.g., soils and cementitious materials), sulfates, nitrates, and organic ligands used in the actinide solubility PA calculations.  The most significant change in the 2009 PABC is the increase in some waste materials' chemical components, noted in Table 24-2 of this CARD.

24.3.6 Evaluation of Compliance for 2009 Recertification (194.24(b)(2))

	DOE calculated new solubility values for the 2009 PABC based on the most recent inventory (ATWIR-2008, PAIR-2008).  EPA reviewed DOE's development of solubilities and solubility uncertainty for the 2009 PABC and evaluated the impact of the increased inventory items on WIPP performance predictions.  EPA found that DOE continues to identify waste characteristics that are important to repository performance and assess their impact as required by 194.24(b)(2).

	EPA did not receive any public comments on DOE's continued compliance with the requirements of Section 194.24(b)(2).

24.3.7 2009 Recertification Decision (194.24(b)(2))

	EPA's reviewed of the important waste components determined that DOE has adequately included their effects in the 2009 PABC calculations.

	Based on a review and evaluation of the 2009 CRA and supplemental information provided by DOE (FDMS Docket ID No. EPA-HQ-OAR-2004-0025, Air Docket A-98-49), EPA determines that DOE continues to comply with the requirements for Section 194.24(b)(2).

24.3.8 Changes in the 2014 Compliance Recertification Application (194.24(b)(2))

	DOE continues to indicate that the components identified Section 24.3.2 of this CARD are expected to have a significant impact on disposal system performance and continue to be used in the 2014 CRA calculations.  These components for the 2014 CRA continue to be: ferrous metals, cellulose and other chelating agents (i.e., organic ligands) as they pertain to enhanced actinide mobility, radioactivity in curies of each isotope, -emitting TRU radionuclides, t1/2 > 20 years (t1/2 is the half-life), radionuclides, solid waste components (e.g., soils and cementitious materials), sulfates, nitrates, and organic ligands used in the actinide solubility PA calculations.  The most significant change in the 2014 PA is the increase in some waste materials' chemical components, noted in Table 24-2 of this CARD.

24.3.9 Evaluation of Compliance for 2014 Recertification (194.24(b)(2))

	DOE calculated new solubility values for the 2014 PA based on the most recent inventory (ATWIR-2012, PAIR-2012).  EPA reviewed DOE's development of solubilities and solubility uncertainty for the 2014 PA and evaluated the impact of the increased inventory items on WIPP performance predictions.  EPA found that DOE continues to identify waste characteristics that are important to repository performance and assess their impact as required by 194.24(b)(2).

	EPA did not receive any public comments on DOE's continued compliance with the requirements of Section 194.24(b)(2).

24.3.10 2014 Recertification Decision (194.24(b)(2))

	EPA's reviewed of the important waste components determined that DOE has adequately included their effects in the 2014 PA calculations.

	Based on a review and evaluation of the 2014 CRA and supplemental information provided by DOE (FDMS Docket ID No. EPA-HQ-OAR-2014 -0609), EPA determines that DOE continues to comply with the requirements for Section 194.24(b)(2).

24.4 Requirement (194.24(b)(3))

	(b) "The Department shall submit in the compliance certification application the results of an analysis which substantiates:

		(3) Any decision to exclude consideration of any waste characteristic or waste 				component because such characteristic or component is not expected to significantly 			influence the containment of the waste in the disposal system."

24.4.1 1998 Certification Decision (194.24(b)(3))

	To demonstrate compliance with 194.24(b)(3), EPA expected DOE to present rationales, logical arguments, applications of screening procedures, results of bounding or sensitivity analyses, etc., beginning from the description required by 194.24(a) and leading to the selection of the important or significant waste components to be limited and controlled to assure compliance with the disposal regulations.

	DOE provided a list of those waste characteristics and components that were excluded from consideration in the PA for various reasons, such as negligible impact.  EPA examined DOE's exclusion of the specified waste characteristics and components to determine whether DOE excluded them appropriately.

	EPA evaluated DOE's assumptions, calculations and experimental results and posed questions pertaining to assumptions and conclusions made by DOE.  EPA's concerns centered around DOE's exclusion of the effects of organic ligands (in particular EDTA) on repository performance, because EPA found DOE's justification to be weak.  EPA's investigation found that the mechanisms that DOE postulated concerning organic ligands' behavior came from well-established fundamental principals existing in relevant literature.  EPA performed a bounding analysis assuming EDTA volumes up to approximately 1000 times that used by DOE.  This analysis showed that the solubility of the modeled actinide was unaffected by EDTA quantity at repository pH and pCO2 .  EPA therefore concluded that DOE's treatment of organic ligands was adequate (CCA CARD 24).  

	A complete description of EPA's 1998 Certification Decision for Section 194.24(b)(3) can be obtained from EPA Air Docket, A-93-02, Items V-A-1 and V-B-2.

24.4.2 Changes in the 2004 Compliance Recertification Application (194.24(b)(3))

	DOE provided a list of those waste characteristics and components that were excluded from consideration in the PA for various reasons, such as negligible impact (CCA Appendix WCA, Table WCA-4 and CRA Appendix TRU WASTE-6).  The effect of organic ligands, however, is incorporated into the PABC.  These characteristics and components included the following changes from the CCA noted in bold):


                                                   Characteristic				Component			Reason Excluded
                                             cellulosics radiolysis			radionuclides			negligible effect on total CO2
explosivity					other organic compounds	no effect
                                                   brine radiolysis				radionuclides			negligible effect on actinide valence
galvanic action				nonferrous metals		negligible effect on PA
complexation with actinides	soil/humic material		actinide mobility
                                                   buffering action				cement				negligible; reacts w/CO2 and MgCl2
heat of solution				cement				negligible effect on PA
                                                   Ca[2+] binding-organic ligands	cement				negligible compared to other metals
buffering action				ferrous metals			would reduce actinide mobility
galvanic action				ferrous metals			negligible effect on PA
binding to organic ligands		ferrous alloy components	can reduce actinide mobility	
redox reactions				nonferrous metals		negligible compared to iron
binding to organic ligands		nonferrous metals		can reduce actinide mobility	
complexation with actinides	organic ligands		negligible effect (in 2004 PABC) 
gas generation				Al, other non-ferrous metals	negligible effect relative to steels
microbial nutrients, 
                                                   CO2 generation 				phosphates			negligible due to MgO-CO2 reaction
microbial nutrients		
CH4 generation				phosphates			negligible
heat generation				RH-TRU			negligible
electrochemical	processes		sulfate, nitrate, phosphate	negligible

	A complete description of EPA's 1998 Certification Decision for Section 194.24(b)(2) can be obtained from EPA Air Docket, A-93-02, Items V-A-1 and V-B-2.

24.4.3 Evaluation of Compliance for 2004 Recertification (194.24(b)(3))

	There were no changes in the important waste components and characteristics, with the exception that DOE did analyze the effect of organic ligands in the CRA performance assessment calculations as discussed for section 194.24(b)(3).  

	EPA did not receive any public comments on DOE's continued compliance with the requirements of Section 194.24(b)(3).

24.4.4 2004 Recertification Decision (194.24(b)(3))

	Since there were no additional exclusions of waste components or characteristics since the CCA and DOE adequately incorporated organic ligands as discussed in Section 194(b)(2),
based on a review and evaluation of the 2004 CRA and supplemental information provided by DOE (FDMS Docket ID No. EPA-HQ-OAR-2004-0025, Air Docket A-98-49), EPA determined that DOE continued to comply with the requirements for Section 194.24(b)(3). 



24.4.5 Changes in the 2009 Compliance Recertification Application (194.24(b)(3))

	DOE's list of waste characteristics and components that were excluded from consideration in the PA has not changed since the 2004 CRA, as noted in section 24.4.2 above (DOE 2009 CRA Section 24.6.4)). 

24.4.6 Evaluation of Compliance for 2009 Recertification (194.24(b)(3))

	EPA verified that the excluded waste characteristics and components have not changed since the 2004 CRA. 

	EPA did not receive any public comments on DOE's continued compliance with the requirements of Section 194.24(b)(3).

24.4.7 2009 Recertification Decision (194.24(b)(3))

	There were no additional exclusions of waste components or characteristics since the 2004 CRA, and DOE continues to adequately incorporate organic ligands as discussed in Section 194(b)(2).  Based on a review and evaluation of the 2009 CRA and supplemental information provided by DOE (FDMS Docket ID No. EPA-HQ-OAR-2009-0330, Air Docket A-98-49), EPA determines that DOE continues to comply with the requirements for Section 194.24(b)(3). 

24.4.8 Changes in the 2014 Compliance Recertification Application (194.24(b)(3))

	DOE's list of waste characteristics and components that were excluded from consideration in the PA has not changed since the 2009 CRA, as noted in Section 24.4.2 above (see 2014 CRA DOE CRA Section 24.8.3). 

24.4.9 Evaluation of Compliance for 2014 Recertification (194.24(b)(3))

	EPA verified that the excluded waste characteristics and components have not changed since the 2009 CRA. 

	EPA did not receive any public comments on DOE's continued compliance with the requirements of Section 194.24(b)(3).

24.4.10 2014 Recertification Decision (194.24(b)(3))

	There were no additional exclusions of waste components or characteristics since the 2009 CRA, and DOE continues to adequately incorporate organic ligands as discussed in Section 194(b)(2).  Based on a review and evaluation of the 2014 CRA and supplemental information provided by DOE (FDMS Docket ID No. EPA-HQ-OAR-2014), EPA determines that DOE continues to comply with the requirements for Section 194.24(b)(3). 
24.5 Requirements (194.24(c)(1) and 194.24(e)(1, 2))

	(c) "For each waste component identified and assessed pursuant to paragraph (b) of this section, the Department shall specify the limiting value (expressed as an upper or lower limit of mass, volume, curies, concentration, etc.), and the associated uncertainty (i.e., margin of error) for each limiting value, of the total inventory of such waste proposed for disposal in the disposal system.  Any compliance application shall:

	(1) Demonstrate that, for the total inventory of waste proposed for disposal in the disposal system, WIPP complies with the numeric requirements of §194.34 and §194.55 for the upper or lower limits (including the associated uncertainties), as appropriate, for each waste component identified in paragraph (b)(2) of this section, and for the plausible combinations of upper and lower limits of such waste components that would result in the greatest estimated release."
	
	(e) "Waste may be emplaced in the disposal system only if the emplaced components of such waste will not cause:

	(1) The total quantity of waste in the disposal system to exceed the upper limiting 		value, including the associated uncertainty, described in the introductory text to 			paragraph (c) of this section; or

	 (2)  The total quantity of waste that will have been emplaced in the disposal 			system, prior to closure, to fall below the lower limiting value, including the 			associated uncertainty, described in the introductory text to paragraph (c) of this 			section."

24.5.1 1998 Certification  Decision (194.24(c)(1) and 194.24(e)(1, 2))

	EPA expected the CCA to specify the limiting value of a given waste component, note whether it is an upper or lower limiting value, and provide the uncertainty associated with each value.  EPA also expected DOE to provide:  plausible combinations of upper and lower limits and a rationale for these limits; the results of modeling code runs; the demonstration of numeric compliance; and the greatest release estimates.

	DOE identified four waste component groupings that require limitations. These waste components groupings and their limiting values are:

     	Ferrous metals (iron) -- minimum of 2x10[7] kilograms
	
		Cellulosics, rubber, and plastic (CPR) -- maximum of 2x10[7] kilograms total

		Free water emplaced with waste -- maximum of 1684 cubic meters and

		Nonferrous metals (metals other than iron) -- minimum of 2x10[3] kilograms

	EPA evaluated the waste limits provided by DOE and determined that the appropriate components requiring limitation were identified and that the applied waste limits were sufficient.  EPA found that the CCA adequately described model code runs, maximum calculated releases, and release estimates.  EPA also agreed that the PA appropriately accounted for the upper and lower limits because fixed values were used.

	EPA reviewed DOE's description of system controls, chain of custody information, controls in place to track WIPP waste, waste record keeping and accountability systems, and WIPP WAC requirements and controls.  EPA reviewed the CCA and determined that DOE adequately referenced and summarized the WIPP WAC in the CCA (CCA CARD 24).

	A complete description of EPA's 1998 Certification Decision for Sections 194.24(c)(1) and 194.24(e)(1, 2)) can be obtained from EPA Air Docket, A-93-02, Items V-A-1 and V-B-2.

24.5.2 Changes in the 2004 Compliance Recertification Application (194.24(c)(1)) and 194.24(e)(1,2))

	For the 2004 CRA PA, DOE did not make any changes to the limits identified in the CCA or their implementation into the 2004 CRA PA.  In reviewing the 2004 CRA PA, EPA identified that the packaging materials for the INL supercompacted were omitted from the CPR total.  For the PABC, DOE included the packaging material as part of the inventory estimate, although it was above DOE's previously stated CPR limit.  The limited additional packaging CPR did not significantly affect the results of the 2004 PABC.

24.5.3 Evaluation of Compliance for 2004 Recertification (194.24(c)(1) and 194.24(e)(1, 2))

	In the CCA, EPA found that DOE identified those waste components that required limits, and that the limits were reasonable and quantifiable.  EPA's main concern was that the waste components being emplaced were maintained at levels necessary to keep the repository in compliance with the disposal standards.  The waste components of special concern are the amounts of CPR and their potential to generate gas that contributed increased pressure in the repository.  

	At the rate iron was being placed in the repository, DOE would easily exceed the lower limit necessary.  Other (upper) limits would not be reached until later in the operations at WIPP.  Given this and that PA uses projected values of inventory in the PA, the issue of inventory uncertainty did not impact compliance with the release limits.  However, it could in the future, as the repository approaches disposal capacity.  DOE may change these limits in the future, provided the changes are supported by a compliant performance assessment.

 	This section requires that DOE identify the associated uncertainty for each limiting value.  As with the CCA, DOE did not provide the associated uncertainty for the waste component limits in the 2004 CRA, stating that the waste component limits are fixed values with no associated uncertainties.  EPA identified two issues with this claim of no uncertainty: ensuring that the inventory remains within the limits established by DOE, and that the performance of the repository is not compromised by the uncertainty in the inventory.    

	EPA requested that DOE review the issue of uncertainty (Docket A-98-49, Item II-B3-89).  DOE states (ERMS 542308, p. 6, Docket A-98-49, Item II-B2-63) that the "sum of the weights of individual components in a container can at most differ from the total weight of the container by 5 percent."  Thus, DOE now acknowledges that there is a measure of uncertainty, but it appears low.  For the CCA, EPA agreed with this approach since the limiting value could be used to represent the "upper end" of an uncertainty value. However, the lack of information on the waste component inventory is of concern for the future, especially with the CPR materials, since they have the most potential to affect performance. 

	While there is no limit on radionuclides, DOE establishes the radionuclide inventory amounts for use in PA.  As stated in the CCA (see CCA CARD 24), EPA considers the radionuclide inventory used in the PA to be a de facto upper bound.  DOE may not place more radionuclide inventory in the repository than what is considered in the most recent compliance performance assessment.  Responding to EPA's query about the quality of the waste estimates used in PA versus waste actually emplaced (Docket A-98-49, Item II-B2-63), DOE addresses a comparison of emplaced waste at three closed TRU waste sites (RFETS, LBL, and MURR).  The comparison indicated a relatively good agreement between the 2004 PABC inventory and the actual radionuclide inventory identified in the WIPP Waste Inventory System. Table 24-10 lists the radionuclides with the greatest inventory at RFETS.

Table 24-10 Comparison of Estimated and Emplaced Inventory of Three Radionuclide at RFETS (Source ERMS 542225 in Docket A-98-49, Item II-B2-63)

Site

Am-241
(Curies)
Pu-239
(Curies)
Pu-240
(Curies)
Total 
Curies
RFETS -- WWIS
1.03E+05
2.04E+05
4.63E+04
3.61E+05

RFETS -- PABC estimated inventory
1.15E+05
2.09E+05
4.72E+04
3.79E+05

	In ERMS 542308 (in Docket A-98-49, Item II-B2-63), DOE identifies extremely small errors in the total measured activity for the RFETS inventory, and EPA found the uncertainty characterization as provided to be suspect.  For example, the uncertainty for the total Am-241 is stated to be 127 curies for 103,000 total curies or an uncertainty of 0.12%.  However, for an individual container report, the uncertainty is 1 curie for a 2.8 total curie measurement.  This is an uncertainty of ~35%.  EPA disagreed with DOE's characterization that this is unimportant. While it did not pose and compliance during the 2004 CRA because of the limited emplaced waste, it will be potentially impactful as the WIPP repository approaches capacity, and was identified as an issue that DOE will need to address for the next recertification.  

	EPA did not receive any public comments on DOE's continued compliance with the requirements of Sections194.24(c)(1) and 194.24(e)(1, 2)).

24.5.4  2004 Recertification Decision (194.24(c)(1) and 194.24(e)(1, 2))

	EPA found that DOE identified the limits of important waste components, and that the PA implementation was adequate.  Although DOE increased the modeled CPR inventory above its stated limit to include the packaging material, the PABC demonstrated that the effect on performance is limited.  Thus, the 2004 PABC CPR inventory establishes a new CPR limit. 

	Since the inventory emplaced in WIPP was at a fraction of the total expected inventory, and since a significant fraction of the inventory was composed of estimated future waste, EPA found that the use of point estimates was acceptable for the waste components and radionuclides for the 2004 recertification and that the inventory and its associated uncertainty fell below the respective limiting values.   The Agency indicated, however, that DOE must demonstrate better knowledge of the measurement uncertainty during the next recertification and include these uncertainties into the PA process.

	Based on a review and evaluation of the 2004 CRA, and supplemental information provided by DOE (FDMS Docket ID No. EPA-HQ-OAR-2004-0025, Air Docket A-98-49), EPA determines that DOE continues to comply with the requirements for Sections 194.24(c)(1) and 194.24(e)(1, 2)).

24.5.5  Changes in the 2009 Compliance Recertification Application (194.24(c)(1)) and 194.24(e)(1,2))

	The only changes related to these requirements for the 2009 CRA are related to changes in the estimated inventory.  As noted in Section 24.5.3 of this CARD, "EPA considers the radionuclide inventory used in the PA as de facto upper limits."  Therefore, the inventory that is used in performance assessment calculations to determine compliance with release standards re-sets the limits on radionuclide emplacement at WIPP.  Also, EPA believes that estimates of waste components set limits on waste emplacement.  CPR that is estimated for each PA inventory establishes the maximum amount of CPR that can be emplaced in the repository."  EPA also emphasized in Section 24.5.4 of this CARD, "Thus, the [2004] PABC CPR inventory establishes a new CPR limit."  When these values are used in a compliant performance assessment, DOE verifies that these waste characteristics, upper and lower limits, still comply with release standards.

	EPA also noted in Section 24.5.3 of this CARD, "EPA's main concern is that the waste components are kept to levels that keep the repository in compliance with the disposal standards," and stated that "DOE needs to better demonstrate knowledge of measurement uncertainty, for the next recertification and include these uncertainties into the PA process."  Between the 2004 CRA and 2009 CRA DOE requested a reduction in the quantity of MgO emplaced with the waste to control repository chemical conditions.  EPA required DOE to perform uncertainty analysis on critical waste components (CPR) to evaluate the potential impact of errors (or uncertainty) in waste estimation on the predicted performance of the repository.  DOE performed this analysis (DOE Appendix MgO-2009 Section MgO-6.2.4.4) and showed that the uncertainty in the estimation of these waste components is low, and does not have a detrimental impact on repository performance.

24.5.6  Evaluation of Compliance for 2009 Recertification (194.24(c)(1) and 194.24(e)(1, 2))

	EPA verified that DOE appropriately continued to identify waste components that require limits, and that these limits continue to be reasonable.  As in the 2004 CRA, upper limits of iron, CPR, etc. are measured at the time waste characterization is performed to prepare waste for shipment to WIPP and the accumulated information is captured in the WIPP waste information system (WWIS).  EPA verified that the WWIS system is adequate for verifying waste emplaced in EPA's annual emplacement inspections (see 2009 CRA CARD 21).  EPA will continue to ensure that the WWIS data is evaluated to assure that waste components emplaced are within the limits established by DOE.

	EPA required DOE to consider the uncertainty of critical waste components when DOE submitted a planned change request to decrease the amount of MgO from 1.67 to 1.2 times the emplaced CPR waste components.  EPA directed DOE to perform an uncertainty analysis to verify that, even with the uncertainty of these waste components included in the performance prediction, a decreased amount of MgO would still ensure control of repository chemistry and safe operation of the WIPP for the long-term.  DOE's analysis (DOE Appendix MgO-2009, Section 6.2.4.4) showed and verified that even with uncertainty considered, compliance with the release standards is demonstrated.  EPA ultimately concurred with DOE's uncertainty analysis and conclusions.

	EPA did not receive any public comments on DOE's continued compliance with the requirements of Sections194.24(c)(1) and 194.24(e)(1, 2)).

24.5.7  2009 Recertification Decision (194.24(c)(1) and 194.24(e)(1, 2))

	EPA finds that DOE continues to identify the limits of important waste components and that the PA implementation is adequate.  Based on a review and evaluation of the 2004 CRA, and supplemental information provided by DOE (FDMS Docket ID No. EPA-HQ-OAR-2009-0330, Air Docket A-98-49), EPA determines that DOE continues to comply with the requirements for Sections 194.24(c)(1) and 194.24(e)(1, 2)).

24.5.8  Changes in the 2014 Compliance Recertification Application (194.24(c)(1)) and 194.24(e)(1,2))

	DOE noted (2014 CRA DOE Section 24.8.5) that all others limits remain the same except the nonferrous metals limit has been removed. At the time of the CCA DOE introduced the nonferrous metal limit to reduce the impact of organic ligands on the solubility of radionuclides.  Since the 2004 CRA, the effect of organic ligands on actinide solubility has been included in the PA, therefore the nonferrous metal limit is no longer needed.  

	Once again, as noted in Section 24.5.3 of this CARD, "EPA considers the radionuclide inventory used in the PA as de facto upper limits."  Therefore, the inventory that is used in performance assessment calculations to determine compliance with release standards re-sets the limits on radionuclide emplacement at WIPP at each recertification.  Also, EPA believes that estimates of waste components set limits on waste emplacement.  For example; CPR that is estimated for each PA inventory establishes the maximum amount of CPR that can be emplaced in the repository."  Thus, the 2014 CRA CPR inventory establishes a new CPR limit.  When these values are used in a compliant performance assessment, DOE verifies that these waste characteristics, upper and lower limits, still comply with release standards. 

24.5.9  Evaluation of Compliance for 2014 Recertification (194.24(c)(1) and 194.24(e)(1, 2))

	EPA verified that DOE appropriately continued to identify waste components that require limits, and that these limits continue to be reasonable.  As in the 2009 CRA, upper limits of iron, CPR, etc. are measured at the time waste characterization is performed to prepare waste for shipment to WIPP and the accumulated information is captured in the WIPP WDS and the WIPP inventory database. EPA verified that the WDS system and inventory database are adequate for verifying waste emplaced in EPA's annual emplacement inspections (see 2014 CRA CARD 21).  EPA will continue to ensure that the WDS data is evaluated to assure that waste components emplaced are within the limits established by DOE.

	EPA closely examined DOE's removal of the nonferrous metal limit and found that this change is reasonable and appropriate.

	EPA did not receive any public comments on DOE's continued compliance with the requirements of Sections194.24(c)(1) and 194.24(e)(1) and, (2).

24.5.10  2014 Recertification Decision (194.24(c)(1) and 194.24(e)(1, 2))

	EPA continues to find that DOE continues to identify the limits of important waste components and that the PA implementation is adequate.  Based on a review and evaluation of the 2014 CRA, and supplemental information provided by DOE (FDMS Docket ID No. EPA-HQ-OAR-2014), EPA determines that DOE continues to comply with the requirements for Sections 194.24(c)(1) and 194.24(e)(1, 2)).

24.6 Requirement (194.24 (c)(2))  

      (c)   For each waste component identified and assessed pursuant to paragraph (b) of this section, the Department shall specify the limiting value (expressed as an upper or lower limit of mass, volume, curies, concentration, etc.), and the associated uncertainty (i.e., margin of error) for each limiting value, of the total inventory of such waste proposed for disposal in the disposal system.  Any compliance application shall:

      	(2)  Identify and describe the method(s) used to quantify the limits of waste 			components identified in paragraph (b)(2) of this section.

24.6.1 1998 Certification Decision (194.24 (c)(2))

      To meet this requirement, EPA expected the Compliance Certification Application (CCA) to specify the waste characterization methods used to quantify the limits of certain waste components.  EPA expected the CCA to specify how each method will be used to quantify the amounts of listed waste components, the scale to which the method is applied (e.g., individual waste container, batch, statistical sample of drums, etc.), the instrumentation used and its sensitivity, and the parameter measured and its relationship to the regulated waste component in question.

      EPA also expected the CCA to describe how the data obtained by each method meet or exceed quality assurance indicators or data quality indicators that were assumed or derived relative to waste-related inputs to the PA.  Finally, EPA expected the CCA to demonstrate DOE's ability to quantify each of the listed waste components (for purposes of control, at the precision and accuracy adequate to assure that limiting values will not be exceeded in the inventory shipped to WIPP).  [See additional requirements at Section 194.24(c)(5) of this CARD].  In other words, DOE had to show that the proposed methods can be performed, using the available technology, at the precision and accuracy necessary to quantify the waste components.  The quantification results are then to be summed and tracked against the limiting values to ensure that the limits will not be exceeded.

      To quantify TRU waste components of concern, DOE proposed to use non-destructive assay (NDA), non-destructive examination (NDE) consisting of radiography (RTR) and visual examination (VE).  DOE described numerous NDA instrument systems and described the equipment and instrumentation for RTR and VE found in facilities.  DOE also provided information about performance demonstration programs intended to show that data obtained by each NDA method could meet data quality objectives established by DOE.  
      
	EPA found that these methods, when implemented appropriately, would be adequate to characterize the important waste components.  EPA found DOE to be in compliance with the requirements of Section 194.24 (c)(2).  

	A complete description of EPA's 1998 Certification Decision for Section 194.24(c)(2) can be obtained from EPA Air Docket, A-93-02, Items V-A-1 and V-B-2.

24.6.2 Changes in the 2004 Compliance Recertification Application (194.24(c)(2))

      As noted in Section 194.24(b), DOE did not modify the list of CCA components and characteristics requiring quantification.  Therefore, the 2004 CRA did not identify any significant changes to the measurement techniques used in the waste characterization program (i.e., VE, RTR, AK, NDA).  Also, the 2004 CRA did not propose changes to the current waste characterization program through the use of different NDA and NDE characterization methodologies.  The 2004 CRA indicated that the location of NDA and NDE methodology documentation had changed since the CCA, with both the Quality Assurance Program Plan (QAPP) and Methods Manual supplanted by the CH-Waste Acceptance Criteria (WAC) and the Waste Analysis Plan (WAP).  EPA was aware of this shift in source information location.  The 2004 CRA revised some of the information presented in the CCA with respect to quality assurance objectives (QAOs).  The 2004 CRA, however, included the following changes to the characterization program as presented in the CCA.    

      With respect to Waste Characterization (2004 CRA Chapter 4), DOE removed references to specific characterization methodologies, including statements that measurements shall be obtained on a waste container basis.  DOE also modified a diagram that previously described the waste characterization program hierarchy, and replaced it with the QA document hierarchy@; previously this diagram showed 40 CFR 191/194 CCA requirements as being represented in the WAC, but the 2004 CRA shows the requirements of 40 CFR 194 as ultimately feeding to the Quality Assurance Program Document (QAPD).  DOE also revised the 2004 CRA to include a description of the 194.8 approval process (Sections 4.1.2 and 4.4 of the 2004 CRA).  

      The 2004 CRA mentioned the then-pending RH waste characterization program.  The 2004 CRA provided no description of the proposed RH Waste Characterization Program, stating only on page 4-54 that ANo RH-TRU waste had been shipped to the WIPP at the time of 2004 CRA.  EPA approval of DOE=s proposed RH-TRU characterization procedure is pending. 
24.6.3 Evaluation of Compliance for 2004 Recertification (194.24(c)(2))  
      
      Since the 1998 Certification Decision, the waste characterization program has been implemented at several DOE waste generator sites.  This represents a change in activities since approval of the CCA, since only LANL was approved at that time.  Between the CCA and 2004 CRA, EPA approved waste characterization activities at the larger generator sites namely, the Advanced Mixed Waste Treatment Plant, Hanford, Idaho National Laboratory, and the Savannah River Site, and the small generator sites namely, Lawrence Livermore National Laboratory, and the Nevada Test Site. These sites continue to characterize CH-TRU waste for disposal at WIPP.  Three DOE sites - Rocky Flats Environmental Technology Site, Argonne National Laboratory  -  East and Lawrence Livermore National Laboratory, have completed CH-TRU waste characterization and no longer ship CH-TRU waste to WIPP for disposal.  The CRA summarized DOE site audit and inspection information in Chapters 5 and Appendix QAPD.  Table 8-1 of CARD 8, includes a summary of EPA waste characterization inspections completed at different sites as of December 2005.  On July 16, 2004, EPA modified their 194.8 inspection process to streamline inspection activities and allow site-specific flexibility.  This change, however, did not modify the fundamentals or contents of the inspection process.  
      
      EPA approved several changes to DOE's waste characterization program since the 1998 Certification Decision.  The changes did not significantly alter the CH-TRU waste characterization program contained in the CCA and related documents and references.  These include:  

      	Modification of Appendix A of the CH-WAC to include AK and NDA measurement requirements.   (EPA Docket A98-49, II-B3-22) 

      	Allowance of RTR and no VE of newly-generated/packaged waste (EPA Docket A98-49, II-B3-49) 

      	Addition of new Appendix (Appendix E) to the CH-WAC implementing payload management (i.e., inclusion of <100 nCi/g drummed waste with >100 nCi/g drummed waste from the same waste stream in a payload container, ten-drum overpack). (EPA Docket A98-49, II-B3-58)

      	Submission of the RH waste characterization program implementation plan (WCPIP).  EPA approved the RH framework in WCPIP and identified pre-requisite steps. (EPA Docket A98-49, II-B2-21)
      
	EPA did not receive any public comments on DOE's continued compliance with the requirements of Section 194.24(c)(2). 

24.6.4 2004 Recertification decision (194.24(c)(2))

      Based on a review of the 2004 CRA, including the new information and references presented therein, EPA agreed that the methods used to quantify the limits of waste components had not changed substantially since the 1998 Certification Decision.  The Agency kept abreast of all the changes to the program, including information source document changes that transpired after EPA's 1998 Certification Decision.  Changes implemented up to the 2002 CH-WAC and WAP referenced in the CCA have not affected the sites' abilities to adequately quantify waste components in individual containers.  DOE, therefore, will continue to require each waste site to characterize radiological contents of every container of CH waste streams destined for WIPP disposal using the EPA-approved NDA systems.  Similarly, each site will continue to examine each TRU waste container to ensure absence of prohibited items using the EPA-approved RTR and/or VE procedures.
      
	Based on a review and evaluation of the 2004 CRA and supplemental information provided by DOE (FDMS Docket ID No. EPA-HQ-OAR-2004-0025, Air Docket A-98-49), EPA determines that DOE continues to comply with the requirements for Section 194.24(c)(2).

24.6.5 Changes in the 2009 Compliance Recertification Application (194.24(c)(2))

      Since the 2004 recertification decision, DOE continues to implement the CH waste characterization program at the TRU sites.  The AK process and waste characterization measurement techniques (that is, VE, RTR, and NDA) have not significantly changed.  Since the 2004 Recertification decision, TRU sites have disposed of RH waste at the WIPP which were characterized using RH-specific AK process measurement techniques approved by EPA. 
      
24.6.6 Evaluation of Compliance for 2009 Recertification (194.24(c)(2))  
      
      Following the July 16, 2004, promulgation of the modifications to the 40 CFR 194.8-prescribed inspection process, EPA conducted baseline inspections and Tier 1 (T1) evaluations of the CH-TRU waste characterization activities at the previously approved TRU generator sites.  In addition, EPA performed baseline inspections and T1 evaluations of the RH-TRU waste characterization activities.  Table 8-1 of 2009 CRA CARD 8, includes a summary of EPA waste characterization inspections completed at different sites (EPA 2010i).
      
      Based on a review of the 2009 CRA, including the new information and references presented therein, EPA agrees that the methods used to quantify the limits of waste components have not changed substantially for CH and RH wastes since the 1998 Certification Decision.
      
      The RH waste characterization processes implemented by the Central Characterization Project (CCP) and approved by EPA are different than those discussed in the RH Waste Characterization Program Implementation Plan (WCPIP).  EPA and DOE HQ staff agreed that the current WCPIP did not reflect characterization activities occurring at the sites therefore it was necessary to revise the WCPIP before it is implemented at new RH sites.  EPA, therefore, asked DOE to revise the WCPIP and seek EPA concurrence before its implementation.  With one specific exception (baseline waste characterization at the Bettis Atomic Power Laboratory), DOE may not characterize waste at any new RH TRU site until these revisions are finalized Using the revised processes, RH TRU sites would quantify the radiological and physical contents of the waste to demonstrate compliance.
      
      EPA did not receive any public comments on DOE's continued compliance with the requirements of Section 194.24(c)(2). 

24.6.7 2009 Recertification decision (194.24(c)(2))

	Based on a review and evaluation of the 2009 CRA and supplemental information provided by DOE (FDMS Docket ID No. EPA-HQ-OAR-2009, Air Docket A-98-49), EPA determines that DOE continues to comply with the requirements for Section 194.24(c)(2).

24.6.8 Changes in the 2014 Compliance Recertification Application (194.24(c)(2))

      Since the 2009 recertification decision, DOE continues to implement the CH waste characterization program at the TRU sites.  The AK process and waste characterization measurement techniques (that is, VE, RTR, and NDA) have not significantly changed.  DOE continued to dispose of RH waste at the WIPP which were characterized using RH-specific AK process measurement techniques approved by EPA. See 2014 CRA DOE Section 24.8.5 for container changes and document revisions. 
      
24.6.9 Evaluation of Compliance for 2014 Recertification (194.24(c)(2))  
      
      Based on a review of the 2014 CRA, including the new information and references presented therein, EPA agrees that the methods used to quantify the limits of waste components have not changed substantially for CH and RH wastes since the 1998 Certification Decision.
      
      EPA did not receive any public comments on DOE's continued compliance with the requirements of Section 194.24(c)(2). 

24.6.10 2014 Recertification decision (194.24(c)(2))

	Based on a review and evaluation of the 2014 CRA and supplemental information provided by DOE (FDMS Docket ID No. EPA-HQ-OAR-2014), EPA determines that DOE continues to comply with the requirements for Section 194.24(c)(2).

24.7 Background (194.24(c)(3))
      
      Section 194.24(c)(3) requires DOE to demonstrate that the use of process knowledge to quantify components in the waste conforms with the QA requirements found in '194.22.  
      
24.7.1 Requirement (194.24(c)(3))

      (c)  For each waste component identified and assessed pursuant to paragraph (b) of this section, the Department shall specify the limiting value (expressed as an upper or lower limit of mass, volume, curies, concentration, etc.), and the associated uncertainty (i.e., margin of error) for each limiting value, of the total inventory of such waste proposed for disposal in the disposal system.  Any compliance application shall:

      	(3)  Provide information which demonstrates that the use of process knowledge to 		quantify components in waste for disposal conforms with the quality assurance 			requirements found in Section 194.22.
      
24.7.2   1998 Certification Decision (194.24(c)(3))

       EPA expected the compliance application to: provide information used in connection with control of the use of process knowledge; cite objective evidence substantiating the degree of implementation of quality assurance for each generator site that is approved to use process knowledge for characterization; and provide an implementation plan for application of quality assurance requirements to process knowledge at remaining sites.  
      
      At the time of the 1998 Certification Decision, EPA determined that DOE adequately described the use of acceptable knowledge only for legacy debris waste at the Los Alamos National Laboratory (LANL).  DOE did not demonstrate compliance with Section 194.24 (c)(3) for any other waste streams at LANL or for waste at any other waste generator site.  EPA instituted Condition 3 of the 1998 Certification Decision which requires EPA to determine that for any other LANL waste streams and any other site, DOE has provided information on how acceptable knowledge (AK) will be used for waste characterization of the waste stream(s) proposed for disposal at WIPP.
      
	A complete description of EPA's 1998 Certification Decision for Section 194.24(c)(3) can be obtained from EPA Air Docket, A-93-02, Items V-A-1 and V-B-2.

24.7.3 Changes in the 2004 Compliance Recertification Application (194.24(c)(3))

The 2004 CRA was revised to indicate that the AK process is now presented in the CH-WAC.  The CH-WAC has been revised to include more discussion of AK with respect to radionuclides (Appendix A).  Modifications made to the CH-WAC since the CCA that are pertinent to AK include, but are not limited to, are the following:

      Use of existing (i.e., AK) information describing radiological and physical contents of the waste collected prior to the implementation of a quality assurance (QA) program under 40 CFR 194.22(a) may be qualified in accordance with an alternative methodology and employs one or more of the following methods: peer review, corroborating data, confirmatory testing, and collection of data under an equivalent QA program.

 Methods for confirming isotopic ratios using AK (i.e., methods pertinent to sites generating weapons grade plutonium vs. heat grade).

 Required and supplemental AK documentation

 Discrepancy resolution and data limitation identification

 AK- radioassay data measurement comparisons as a means to assess comparability

      These modifications effectively focused the CH-WAC to address specific allowances and requirements with respect to AK applicable to radionuclide data, but the overall AK process is still contained in the Hazardous Waste Facility Permit (HWFP) Waste Assessment Plan (WAP).  The revised WAP has retained most of the AK requirements of data assembly, compilation, etc. included in the CCA documentation.  Also, it is structured differently to include several provisions either not originally included in the CCA Appendix WAP or worded differently than what was presented in the CCA documents.  These include but are not limited to the following:

 proceduralization of requirements

 modifications with respect to visual verification

 sealed source characterization based on AK

24.7.4 Evaluation of Compliance for 2004 Recertification (194.24(c)(3)) 

      The EPA WIPP regulations require DOE to provide information which demonstrates that the use of process knowledge to quantify components in waste for disposal conforms with the quality assurance requirements found in 194.22.  For example, 194.22(b) requires that the use of data collected prior to implementation of a QA program as described in section (a) must be qualified by an alternative methodology such as corroborating data, confirmatory testing, peer review, or demonstration that an equivalent QA program was place at the time of data acquisition.  At TRU waste sites, process knowledge/acceptable knowledge (PK/AK) data for all legacy waste was obtained prior to the establishment of an EPA-approved QA program; therefore, confirmation of PK/AK data by analyzing TRU waste containers using the EPA-approved assay equipment is necessary.  EPA found that the information presented in the CRA for 194.24(c)(3) was adequate, and that adherence by TRU waste sites to the CRA-based AK process would allow them to meet their regulatory obligation. 

      Some of the changes to the AK program were made to better define the use of AK (i.e., CH-WAC Appendix A), and EPA was kept abreast of these modifications to ensure that they do not compromise compliance with EPA regulations.  Most of the changes presented in the 2004 CRA, however, are to recognize DOE=s election to move requirements demonstrating compliance between various documents, and eliminate text within the 2004 CRA that may be repeated in these documents.  For example, the quality assurance objectives (QAOs) are included in the HWFP WAP and CH WAC (Appendix A), and were therefore removed from the body of the 2004 CRA text.  
      
	EPA did not receive any public comments on DOE's continued compliance with the requirements of Section 194.24(c)(3).

24.7.5 2004 Recertification Decision (194.24(c)(3))

	Based on a review and evaluation of the 2004 CRA and supplemental information provided by DOE (FDMS Docket ID No. EPA-HQ-OAR-2004-0025, Air Docket A-98-49), EPA determines that DOE continues to comply with the requirements for Section 194.24(c)(3).  

24.7.6 Changes in the 2009 Compliance Recertification Application (194.24(c)(3))
      
      Between 2004 CRA and 2009 CRA no changes were made to the WAC to address AK-related issues.

24.7.7 Evaluation of Compliance for 2009 Recertification (194.24(c)(3)) 

      EPA is requiring TRU waste generator sites to prepare a detailed AK Summary (AKS) document containing all waste-specific information in one place with properly cited references.  The site-specific AK Summary document is widely used in the field by site personnel identifying and measuring radiological contents and estimating weights of individual waste material parameters.  EPA has suggested that information not necessarily needed by the above site personnel could be included in appendices and adequately referenced.  The AKS document prepared in this manner will facilitate EPA review.  Also, it can be a useful source document for Site Program Manager, (NDA) Expert, non-destructive evaluation (NDE) Expert, if they find a need for additional background information, explanation, justification, rationale, etc.   
      
	EPA did not receive any public comments on DOE's continued compliance with the requirements of Section 194.24(c)(3).

24.7.7 2009 Recertification Decision (194.24(c)(3))

	Based on a review and evaluation of the 2009 CRA and supplemental information provided by DOE (FDMS Docket ID No. EPA-HQ-OAR-2009-0330, Air Docket A-98-49), EPA determines that DOE continues to comply with the requirements for Section 194.24(c)(3). 

24.7.8 Changes in the 2014 Compliance Recertification Application (194.24(c)(3))
      
      Since the CRA-2009, the AK process has not changed for CH and RH waste (2104 CRA DOE Section 24.8.6 and 24.6.7). The DOE has added a gravimetric or dimensional analysis for RH unique waste streams where the activity on or within a waste stream is identified as discreet pieces of irradiated materials to estimate the activity content of the waste container or to confirm AK information for the same measurements.

24.7.9 Evaluation of Compliance for 2014 Recertification (194.24(c)(3)) 

      EPA is requiring TRU waste generator sites to prepare a detailed AK Summary (AKS) document containing all waste-specific information in one place with properly cited references.  The site-specific AK Summary document is widely used in the field by site personnel identifying and measuring radiological contents and estimating weights of individual waste material parameters.  EPA has suggested that information not necessarily needed by the above site personnel could be included in appendices and adequately referenced.  The AKS document prepared in this manner will facilitate EPA review.  Also, it can be a useful source document for Site Program Manager, (NDA) Expert, Non-destructive Evaluation (NDE) Expert, if they find a need for additional background information, explanation, justification, rationale, etc.   
      
	EPA did not receive any public comments on DOE's continued compliance with the requirements of Section 194.24(c)(3).

24.7.10 2014 Recertification Decision (194.24(c)(3))

	Based on a review and evaluation of the 2014 CRA and supplemental information provided by DOE (FDMS Docket ID No. EPA-HQ-OAR-2014-0609), EPA determines that DOE continues to comply with the requirements for Section 194.24(c)(3). 


24.8 Requirement (194.24(c)(4)) 

      (c)  For each waste component identified and assessed pursuant to paragraph (b) of this section, the Department shall specify the limiting value (expressed as an upper or lower limit of mass, volume, curies, concentration, etc.), and the associated uncertainty (i.e., margin of error) for each limiting value, of the total inventory of such waste proposed for disposal in the disposal system.  Any compliance application shall:

      (4)  Provide information which demonstrates that a system of controls has been 			and will continue to be implemented to confirm that the total amount of each 			waste component that will be emplaced in the disposal system will not exceed the 			upper limiting value or fall below the lower limiting value described in the 			introductory text paragraph (c) of this section.  The system of controls shall 			include, but shall not be limited to: Measurement; sampling; chain of custody 			records; record keeping systems; waste loading schemes used; and other 				documentation.
      
24.8.1 1998 Certification Decision (194.24(c)(4))

      EPA expected the compliance application to describe:  (1) a system for maintaining centralized control over the waste characterization activities; (2) a mechanism for maintaining chain of custody over waste and waste records; (3) controls in place for receipt of waste at the WIPP; (4) a record keeping/accounting/tracking system for controlling limited waste components for verification of emplaced waste; and (5) describe all requirements or controls (i.e., waste acceptance criteria) that are relevant to compliance with 40 CFR Part 194.  EPA expected the CCA to discuss evidence (auditable records) necessary for inspection substantiating compliance with WAC limits set under '194.24, showing that waste components for which inventory limits were set are monitored, controlled, and accounted for in a systematic and traceable manner.

      DOE described the system of controls for waste characterization activities and required that these be conducted in accordance with approved documentation that describes the management, operations and QA aspects of the program.  DOE also indicated that conformance with applicable regulatory (Federal and State), programmatic and operational requirements is monitored by the DOE/CBFO audit and surveillance program. 

      DOE provided descriptions of the documentation, data fields, and features of the WIPP Waste Information System (WWIS).  The WWIS is DOE's record keeping and accounting system for tracking waste components and associated uncertainties, controlling limited waste components for verification of placement of the waste in WIPP, and providing notification before the waste component limits are exceeded, in accordance with 40 CFR 194.24(e)(1) and (2).  In addition, in the WWIS, DOE identified a sample of 17 waste material parameters fields relevant to compliance that are included in the more than 130 parameters tracked in the WWIS. 
      
      DOE described the controls in place to determine completeness and accuracy of the waste container-specific information and a process to identify and resolve discrepancies before receipt of waste at the WIPP.  DOE described the type of records for each waste container managed at WIPP that must be maintained for waste characterization purposes as part of the WIPP operating record which to be backed up, secured, and archived.  The audit process in the CCA provided on-site verification of characterization procedures, data package preparation and record keeping. 
      
      EPA determined that DOE provided an adequate description of the system (controls and processes) for maintaining centralized command and control over waste characterization activities.  At the time of the 1998 Certification Decision, EPA was able to inspect and verify that LANL had demonstrated an adequate system of controls.  Conditions 2 and 3 of the 1998 Certification Decision specified that DOE was prohibited from shipping waste for disposal at WIPP until EPA approved site-specific waste characterization programs and controls.  
      
	A complete description of EPA's 1998 Certification Decision for Section 194.24(c)(4) can be obtained from EPA Air Docket, A-93-02, Items V-A-1 and V-B-2.

24.8.2 Changes in the 2004 Compliance Recertification Application (194.24(c)(4)) 

	According to the 2004 CRA, while the WWIS used the Oracle (Version 7) database management system at the time of the CCA, the current computing system used Oracle (Version 9) but otherwise remained unchanged.  DOE also inserted a statement in the 2004 CRA that [a]dditional computing system upgrades may be implemented in the future."

      CCA and 2004 CRA Section 4.3.2 included a sample of the more than 130 important parameters tracked in the WWIS at the time of the 2004 CRA.  The data fields listed in 2004 CRA were a subset of the total list included in the WWIS data tracking system.  EPA examined the WAP and WWIS users manual and verified that DOE is tracking more than 130 data fields in the WWIS.  EPA was able to verify that the parameters listed in 2004 CRA Section 4.3.2 were included in the WWIS tracking system, plus many more parameters.

      Section 5.0 of the 2004 CRA Appendix TRU WASTE (Page 52) briefly describes the WWIS as part of a system of controls that address the requirements of 40 CFR '194.24(c)(4) and (5), requirements for computer software for nuclear facility applications.

      The WWIS was only used for the CH-TRU program, and did not include all data fields required for the disposal of RH-TRU waste.  According to Section 9.4.19.1 of the 2004 CRA (Page 9-148), WWIS would be modified by the addition of data fields to meet additional tracking and control requirements imposed on RH-TRU waste by the LWA.

24.8.3 Evaluation of Compliance for 2004 Recertification (194.24(c)(4))  

      EPA determined that the general description of the WWIS in the CRA was adequate.  Hardware modifications and software upgrades described in the CRA were necessary to maintain system reliability, security, and performance.  EPA reviewed the WWIS during its inspections of the WIPP and TRU waste generator sites and was aware of the changes made to the WWIS since the CCA.  EPA determined that the WWIS adequately gathers, stores, and processes information pertaining to TRU waste destined for or disposed of at the WIPP.

      DOE stated that a majority of the 130 WWIS data fields were pertinent to demonstrate compliance with TRU waste transportation and disposal requirements.  EPA verified that DOE has adequately tracked more than these 130 data fields in the WWIS and that DOE had not changed its tracking methodology and in fact has added parameters to be tracked in the WWIS. 
      
	EPA did not receive any public comments on DOE's continued compliance with the requirements of Section 194.24(c)(4).

24.8.4 2004 Recertification Decision (194.24(c)(4))

	Based on a review and evaluation of the 2004 CRA and supplemental information provided by DOE (FDMS Docket ID No. EPA-HQ-OAR-2004-0025, Air Docket A-98-49), EPA determined that DOE continued to comply with the requirements for Section 194.24(c)(4).

24.8.5 Changes in the 2009 Compliance Recertification Application (194.24(c)(4)) 

	Since 2004 CRA, DOE revised WWIS to add the ability to track RH TRU waste as required by the LWA.  Also, DOE updated the WWIS and renamed it the Waste Data System (WDS).  The WDS is a web-based software system used by the Waste Isolation Pilot Plant (WIPP) to gather, store, and process information pertaining to contact-handled (CH) and remote-handled (RH) transuranic (TRU) waste. The WDS is used to create and store documentation about waste containers, shipments, and emplacement information at WIPP. The WDS includes all of the elements that were implemented in the WIPP Waste Information System (WWIS) to meet regulatory requirements for the operation of WIPP. 

24.8.6 Evaluation of Compliance for 2009 Recertification (194.24(c)(4))  

      EPA reviewed the WWIS modification to track RH waste content information from generators to the repository and found this change is acceptable.
      
	EPA did not receive any public comments on DOE's continued compliance with the requirements of Section 194.24(c)(4).

24.8.7 2009 Recertification Decision (194.24(c)(4))

	Based on a review and evaluation of the 2009 CRA and supplemental information provided by DOE (FDMS Docket ID No. EPA-HQ-OAR-2009-0330, Air Docket A-98-49), EPA determines that DOE continues to comply with the waste data tracking requirements for Section 194.24(c)(4).

24.8.8 Changes in the 2014 Compliance Recertification Application (194.24(c)(4)) 

	The WWIS was retired in December 2009, and replaced with the WDS to provide DOE with a modern approach to process controls and data sharing. The WDS uses Oracle
DB 11g.  The WDS is used by DOE to comply with the 194.24(c)(4) requirements.

24.8.9 Evaluation of Compliance for 2014 Recertification (194.24(c)(4))  

      EPA reviewed the WDS by annual inspections to determine its ability to track waste content information from generators to the repository and found this change is acceptable.
      
      EPA performed baseline, Tier 1 change and continued compliance inspections at all operational sites listed in Table 8-1 of CARD 8. Continued compliance inspections are shown in italic, some of which were unannounced type. EPA concluded that waste characterization of WIPP bound waste is according to the requirements of this section and using the EPA approved systems of controls  -  processes, procedures and equipment.
      
	EPA did not receive any public comments on DOE's continued compliance with the requirements of Section 194.24(c)(4).

24.8.10 2014 Recertification Decision (194.24(c)(4))

	Based on a review and evaluation of the 2014 CRA and supplemental information provided by DOE (FDMS Docket ID No. EPA-HQ-OAR-2014 -0609), EPA determines that DOE continues to comply with the waste data tracking requirements for Section 194.24(c)(4).

24.9 Requirement (194.24(c)(5)) 
      
      (c)  For each waste component identified and assessed pursuant to paragraph (b) of this section, the Department shall specify the limiting value (expressed as an upper or lower limit of mass, volume, curies, concentration, etc.), and the associated uncertainty (i.e., margin of error) of each limiting value, of the total inventory of such waste proposed for disposal in the disposal system.  Any compliance application shall:

      	(5) Identify and describe such controls delineated in paragraph (c)(4) of this 			section and confirm that they are applied in accordance with the quality assurance 			requirements found in 194.22.

24.9.1 1998 Certification Decision (194.24(c)(5))

      EPA expected DOE to provide a description of all Performance Demonstration Programs (PDPs) used to certify the capability and comparability of radiological measurements at waste generator sites, and to provide standardized waste characterization methodologies, if not provided under '194.24(c)(2).  EPA also expected DOE to cite objective evidence of the status of current implementation methods or procedures.  Finally, EPA expected the CCA to include documentation of QA for waste characterization activities from the point of generation (for to-be-generated waste) to the point of disposal at the WIPP.
      
      See Section 194.22(a)(2)(I) in CARD 22, Quality Assurance for additional discussion of quality assurance for waste characterization activities. 

	DOE described the Performance Demonstration Program (PDP) for NDA designed to ensure compliance with the Quality Assurance Objectives identified in the QAPP by providing a test program that each generator site must pass prior to waste shipment.  The PDP was crucial because it was the only means of qualifying some of the NDA equipment (which was state-of-the-art and first-of-a-kind in most cases).  The PDP was a multiple (approximately 12)-cycle program for a site's NDA system(s) to test their ability to detect radionuclides from various source standards in different waste matrices.  Each site must demonstrate its measurement performance on a semiannual basis.  CBFO was the reviewing and approving authority for the PDP and used the PDP to assess, evaluate, and approve DOE facilities for waste measurement and characterization before the waste was shipped to the WIPP.  The PDP standards addressed activity ranges relative to WAC limits, quality assurance program plan (QAPP) QAOs, and NDA method detection limits.  The isotopes analyzed under this program included, but were not limited to, [238]Pu, [239]Pu, [240]Pu and [241]Am.  When a site passed a particular PDP cycle, the site demonstrated its ability to accurately assay waste contained in a matrix for which the PDP test matrix was representative. 

	EPA reviewed the updated PDP Plan for NDA and concluded that DOE provided adequate information regarding the PDP for NDA.  However, in its CCA, DOE did not provide the status of the current implementation of PDPs at the generator sites in the application.  This information was only available for LANL and RFETS at the time of inspections.

      The QAPP did not contain specific radiological waste characterization (i.e., NDA) procedures, but did provide VE and RTR procedures that can be found in QAPP Chapter 10.  Each generator site, when performing radiological characterization using NDA methods, is responsible for meeting the data quality requirements outlined in the QAPP.  

      EPA confirmed through inspections at LANL that the system of controls and in particular, the measurement techniques were adequate to characterize waste and ensure compliance with the limits of waste components, and also that a QA program had been established and executed in conformance with NQA requirements.  Moreover, DOE demonstrated that the WWIS was a functional system at LANL.  During the CCA review process, DOE had not demonstrated compliance with these requirements for any other waste generator site.

      DOE did not provide documentation of QA for waste characterization activities from the point of generation (for to-be-generated waste) to the point of emplacement and disposal at the WIPP.  Instead, DOE implemented a QA program by preparing several QA procedural documents and conducting audits.  These QA documents were described further in CARD 22, Quality Assurance. 

	A complete description of EPA's 1998 Certification Decision for Section 194.24(c)(5) can be obtained from EPA Air Docket, A-93-02, Items V-A-1 and V-B-2.

24.9.2 Changes in the 2004 Compliance Recertification Application (194.24(c)(5)) 

      DOE described the changes to the PDP program in Section 4.3.3.1 PDP (pg 4-49) of the 2004 CRA.  There were three significant changes in this section relative to the CCA; a) the QAPP was no longer referenced as the document defining the PDP QAO requirements, b) the PDP Plan had been removed as a reference and replaced by the statement that the PDP NDA plans are revised as required, and c) the section no longer contained a detailed description of the isotopes to be analyzed and the configuration of the PDP tests.  Additionally, the PDP tests had been changed from a semi-annual to an annual schedule, a change of which EPA was previously notified.  DOE also changed the item that was approved by the PDP test.  The CCA stated that waste analysis can only be performed by measurement facilities that have demonstrated acceptable performance in the PDP.  In the 2004 CRA, this was changed to NDA analysis of drums or boxes is performed by measurement systems that have demonstrated acceptable PDP performance.  This wording change applied the PDP results to equipment rather than a facility.

      DOE also revised the Quality Document hierarchy for waste characterization activities by making the CBFO quality assurance program document (QAPD) a higher tier document, and the QAPP of lesser importance.   This new document hierarchy was shown in 2004 CRA Figure 4-3, which replaced CCA Figure 4-6.

24.9.3 Evaluation of Compliance for 2004 Recertification (194.24(c)(5))
      
      The QAPP and the Methods Manual were replaced by the WAC, as noted in previous sections of this document.  EPA was aware of these changes to the program requirements documents.  The wording changes regarding the description of the PDP test and the removal of the PDP plan did not affect EPA's ability to ensure that DOE had implemented a series of intercomparability tests for NDA equipment that developed similar results.  The elimination of the PDP test description from the 2004 CRA required that DOE makes available to EPA the PDP plans and test descriptions so that EPA could ensure that the program was indeed acting as a true blind sample program.  The change in PDP certification from the facility to the equipment is acceptable, since facilities often used multiple sets of NDA equipment to meet the expedited waste shipment schedule.  

	EPA did not receive any public comments on DOE's continued compliance with the requirements of Section 194.25(c)(5).

24.9.4 2004 Recertification Decision (194.24(c)(5))

      EPA continued to ensure, through audits and inspections, that the waste characterization program meets QA controls sufficiently.  The inspection program was the primary method by which EPA determined the implementation of QA controls to the waste characterization program. 
       
      DOE's changes to the PDP program did not affect EPA's ability to assess the implementation of quality controls to the waste characterization program.  The wording changes allow DOE more flexibility in developing PDP test now that the initial series of test have been completed since the CCA.  The changes to the QA document hierarchy did not lessen the implementation of quality controls to the waste characterization program.

	Based on a review and evaluation of the 2004 CRA and supplemental information provided by DOE (FDMS Docket ID No. EPA-HQ-OAR-2004-0025, Air Docket A-98-49), EPA determined that DOE continued to comply with the requirements for Section 194.24(c)(5).

24.9.5 Changes in the 2009 Compliance Recertification Application (194.24(c)(5)) 

      Since 2004, DOE made the following changes to the PDP: (1) the QAPP is no longer referenced as the document defining the PDP QAO requirements, (2) the PDP Plan was removed as a reference and replaced by the statement that "the NDA PDP plans are revised as required," and (3) the section no longer contains a detailed description of the isotopes to be analyzed and the configuration of the PDP tests.  These are acceptable.

24.9.6 Evaluation of Compliance for 2009 Recertification (194.24(c)(5))
      
	These changes do not affect compliance with 40 CFR 194.24(c)(5)

	EPA did not receive any public comments on DOE's continued compliance with the requirements of Section 194.25(c)(5).

24.9.7 2009 Recertification Decision (194.24(c)(5))

	Based on a review and evaluation of the 2009 CRA and supplemental information provided by DOE (FDMS Docket ID No. EPA-HQ-OAR-2009-0330, Air Docket A-98-49), EPA determines that DOE continues to comply with the requirements for Section 194.24(c)(5).


24.9.8 Changes in the 2014 Compliance Recertification Application (194.24(c)(5)) 

      Since the 2009 CRA, DOE made the following changes to the PDP:  
      
To "...both the Performance Demonstration Program Plan for Nondestructive Assay of Boxed Wastes for the TRU Waste Characterization Program, Revision 3 (U.S. DOE 2011c) and the Performance Demonstration Program Plan for Nondestructive Assay of Drummed Wastes for the TRU Waste Characterization Program, Revision 3 (U.S. DOE 2011d) have been revised. The most important changes to these documents were implemented to simplify sample preparation team requirements and instructions, better define the process to address failures of the tested NDA systems to meet NDA PDP criteria, single out the non-interfering matrix standard waste box and non-interfering matrix drum as distinct from other matrices tested and define their use for specialized circumstances, and to improve the descriptions of NDA PDP components and inventory of materials. The Performance Demonstration Program Plan for Analysis of
Simulated Headspace Gases, Revision 7 (U.S. DOE 2010d) has also been revised since CRA-2009 to implement a change removing the compound cis-1,2-dichloroethylene from the target compound list." (2014 CRA DOE Section 24.8.8). These are acceptable.

24.9.9 Evaluation of Compliance for 2014 Recertification (194.24(c)(5))
      
	These changes updates to PDP documents and do not affect compliance with 40 CFR 194.24(c)(5)

	EPA did not receive any public comments on DOE's continued compliance with the requirements of Section 194.25(c)(5).

24.9.10 2014 Recertification Decision (194.24(c)(5))

	Based on a review and evaluation of the 2014 CRA and supplemental information provided by DOE (FDMS Docket ID No. EPA-HQ-OAR-2014-0609), EPA determines that DOE continues to comply with the requirements for Section 194.24(c)(5).
24.10  Requirements (194.24(d) and 194.24(f))

	(d) "The Department shall include a waste loading scheme in any compliance application, or else performance assessments conducted pursuant to § 194.32 and compliance assessments conducted pursuant to § 194.54 shall assume random placement of waste in the disposal system."

	(f) "Waste emplacement shall conform to the assumed waste loading conditions, if any, used in performance assessments conducted pursuant to §194.32 and compliance assessments conducted pursuant to §194.54."

24.10.1 1998 Certification Decision (194.24(d) and 194.24(f))

	EPA examined the CCA to determine whether DOE provided a final plan for waste loading that addresses the emplacement of radioactive waste and implements any assumptions about the distribution of the waste that were used in the performance assessment.  EPA expected DOE to cross-reference the waste distribution assumptions from the waste loading plan with the waste distribution assumptions used in the PA.  Finally, EPA examined DOE's description of how the planned distribution of waste (as assumed in the PA) would be achieved.  This discussion should identify both the acceptance criteria for implementation and the controls that will be in place to assure proper implementation of the plan.

	EPA determined that, because DOE had (1) assumed random waste loading and (2) evaluated the potential consequences resulting from the non-random loading of the highest-activity waste stream containing at least 810 drums, a final waste loading plan was in fact unnecessary.  EPA determined that DOE was therefore not required to describe how the planned distribution of radioactive waste (as assumed in the PAs) would be achieved because the random distribution of waste containers in the WIPP resulted in compliance (i.e., it did not matter to compliance how the drums were placed in the WIPP).  EPA therefore concluded that DOE adequately cross-referenced the resultant waste distribution assumptions from the waste loading plan with the waste distribution assumptions used in the PA (CCA CARD 24).  

	A complete description of EPA's 1998 Certification Decision for Sections 194.24(d) and 194.24(f) can be obtained from EPA Air Docket, A-93-02, Items V-A-1 and V-B-2.

24.10.2 Changes in the 2004 Compliance Recertification Application (194.24(d) and 194.24(f))

	DOE did not use a performance based waste loading scheme for waste emplacement and DOE assumed random waste loading in its performance and compliance assessments.  Prior to the 2004 CRA, EPA requested that DOE analyze waste loading with respect to supercompacted waste, and DOE identified that clustering of waste would not affect performance (Docket A-98-49, Item II-B3-64; Item B-2-31; also see Docket A-98-49, Item II-B3-68). 

24.10.3 Evaluation of Compliance for 2004 Recertification (194.24(d) and 194.24(f))

	In performance assessments to date, DOE has assumed random waste emplacement.  In the CCA, EPA asked for additional analysis assuming clustering of waste.  DOE did an analysis and showed that clustering of even higher than average waste streams would not significantly affect results.  Indeed, RFETS waste was eventually clustered in the WIPP, (Docket A-98-49, Item II-B2-31).  In addition, EPA required DOE to conduct another analysis assuming non-random waste emplacement as part of the review of supercompacted waste from INL.  The results again showed that non-random placement of waste was not significant (e.g., CRA Appendix PA Attachment MASS 21.0).  Thus, no waste loading assumptions are necessary in performance assessment calculations.

	EPA did not receive any public comments on DOE's continued compliance with the requirements of Sections 194.24(d) and 194.24(f).

24.10.4 2004 Recertification Decision (194.24(d) and 194.24(f))

	Based on a review and evaluation of the 2004 CRA and supplemental information provided by DOE (FDMS Docket ID No. EPA-HQ-OAR-2004-0025, Air Docket A-98-49), and because DOE has shown that waste loading assumptions are not necessary for use in PA, EPA determines that DOE continues to comply with the requirements for Sections 194.24(d) and 194.24(f). 

24.10.5 Changes in the 2009 Compliance Recertification Application (194.24(d) and 194.24(f))

	In the 2009 CRA DOE continues to not use a performance based waste loading scheme for waste emplacement and DOE assumed random waste loading in its performance and compliance assessments

24.10.6 Evaluation of Compliance for 2009 Recertification (194.24(d) and 194.24(f))

	In performance assessments to date, DOE continues to assume random waste emplacement.  In the CCA and in the 2004 CRA, EPA asked for additional analysis assuming clustering of waste.  DOE did an analysis and showed that clustering of even higher than average waste streams would not significantly affect results.  The results of these analyses showed that non-random placement of waste was not significant.  Thus, no waste loading assumptions continue to be necessary in performance assessment calculations.

      Commenters noted the additional ten-drum overpacks (TDOPs) which will be used to ship wastes that are high in carbon tetrachloride, and questioned whether a waste loading study was needed in order to determine their impact.  Significant numbers of TDOPs are already emplaced in the underground, and any additional packaging and emplacement materials are adequately tracked by the Waste Data System (WDS).  For these reasons, EPA determines that no further consideration of waste-loading is necessary.

	EPA did not receive any additional public comments on DOE's continued compliance with the requirements of Sections 194.24(d) and 194.24(f).

24.10.7 2009 Recertification Decision (194.24(d) and 194.24(f))

	Based on a review and evaluation of the 2009 CRA and supplemental information provided by DOE (FDMS Docket ID No. EPA-HQ-OAR-2009-0330, Air Docket A-98-49), and because DOE has shown that waste loading assumptions are not necessary for use in PA, EPA determines that DOE continues to comply with the requirements for Sections 194.24(d) and 194.24(f) for the 2007 recertification. 

24.10.8 Changes in the 2014 Compliance Recertification Application (194.24(d) and 194.24(f))

	In the 2014 CRA DOE continues to not use a performance based waste loading scheme for waste emplacement (194.24(d) and DOE assumed random waste loading in its performance and compliance assessments (194.24(f) (2014 CRA DOE Section 24.8.9).

24.10.9 Evaluation of Compliance for 2014 Recertification (194.24(d) and 194.24(f))

	In performance assessments to date, DOE continues to assume random waste emplacement and does not assume a waste loading scheme (2014 CRA Appendix MASS-2014, Section MASS-19.0).  

	EPA did not receive any additional public comments on DOE's continued compliance with the requirements of Sections 194.24(d) and 194.24(f).

24.10.10 2014 Recertification Decision (194.24(d) and 194.24(f))

	Based on a review and evaluation of the 2014 CRA and supplemental information provided by DOE (FDMS Docket ID No. EPA-HQ-OAR-2014-0609), and because DOE has shown that waste loading assumptions are not necessary for use in PA, EPA determines that DOE continues to comply with the requirements for Sections 194.24(d) and 194.24(f) for the 2007 recertification. 

24.11 Requirement (194.24 (g))

	(g) "The Department shall demonstrate in any compliance application that the total inventory of waste emplaced in the disposal system complies with the limitations on transuranic waste disposal described in the WIPP LWA."
24.11.1 1998 Certification Decision (194.24 (g))

	EPA expected the compliance application to describe the WIPP waste inventory in terms of the units specified in the limitations of the LWA and to describe how these limitations will be assured through implementation of the required system of controls.  DOE identified the following limits:

     	Curie limits for RH-TRU waste: 5.1 million curies (app. 19.8 x 10[16] Becquerels). 

		Total capacity of RH and CH-TRU waste that may be disposed:  6.2 million cubic feet (175,564 cubic meters).

     	Waste will not exceed 1,000 rem per hour, no more than 5 percent by volume of RH will exceed 100 rem per hour, and RH will not exceed 23 curies per liter.

	DOE provided numerous tables that presented the WIPP waste inventory in terms of curies and total volumes.  In addition, DOE presented information pertaining to the WIPP WWIS, which tracks and controls waste emplaced in WIPP.  EPA reviewed this information, which included the process DOE outlined for controlling the waste and the use of the WWIS, and determined that DOE had an adequate program for tracking and controlling the waste (CCA CARD 24). 

	A complete description of EPA's 1998 Certification Decision for Section 194.24(g) can be obtained from EPA Air Docket, A-93-02, Items V-A-1 and V-B-2.

24.11.2 Evaluation of Compliance for 2004 Recertification (194.24 (g))

	DOE had several years of experience with the WWIS and, through EPA's inspections, DOE has shown the WWIS to be effective in tracking and controlling waste disposed of at WIPP. Results of EPA inspections related to the WWIS can be found in Docket A-98-49, Category II-A1, Category II-A4, and Category II-B3.  DOE had not characterized or shipped any RH-TRU waste at this time, but it would have to meet WIPP waste acceptance criteria in a process similar to CH-TRU waste.  

	EPA did not receive any public comments on DOE's continued compliance with the requirements of Section 194.24(g).

24.11.3 2004 Recertification Decision (194.24 (g))

	Based on a review and evaluation of the 2004 CRA and supplemental information provided by DOE (FDMS Docket ID No. EPA-HQ-OAR-2004-0025, Air Docket A-98-49), EPA determined that DOE continued to comply with the requirements for Section 194.24(g).

24.11.4 Changes in the 2009 Compliance Recertification Application (194.24(g)

	The limits specified in the WIPP LWA have not changed and DOE's use of the WWIS has not changed.

24.11.5 Evaluation of Compliance for 2009 Recertification (194.24 (g))

	EPA continued to verify that DOE is using the WWIS to keep track of waste emplaced at the WIPP repository in its annual emplacement inspections (see 2009 CRA CARD 21, Table 21-3).  These annual inspections confirm that DOE continues the ability to comply with Section 194.24 (g)

	EPA did not receive any public comments on DOE's continued compliance with the requirements of Section 194.24(g).

24.11.6 2009 Recertification Decision (194.24 (g))

	Based on a review and evaluation of the 2009 CRA and supplemental information provided by DOE (FDMS Docket ID No. EPA-HQ-OAR-2009-0330, Air Docket A-98-49), EPA determines that DOE continues to comply with the requirements for Section 194.24(g).


24.11.7 Changes in the 2014 Compliance Recertification Application (194.24(g)

	The limits specified in the WIPP LWA have not changed.  The WWIS was replaced by the WDS in December of 2009 which includes all of the elements of the WWIS (see 2014 CRA DOE Section 24.8.7 and 2014 CRA Appendix MON-2014, Section MON-3.6).  DOE's use of the WDS is the same as the WWIS, therefore DOE continues to monitor and calculate the limits on waste disposal as required by 194.24(g).

24.11.8 Evaluation of Compliance for 2014 Recertification (194.24 (g))

	EPA continued to verify that DOE is using the WDS to keep track of waste emplaced at the WIPP repository in its annual emplacement inspections (see 2014 CRA CARD 21, Table 21-5).  These annual inspections confirm that DOE continues the ability to comply with Section 194.24 (g)

	EPA did not receive any public comments on DOE's continued compliance with the requirements of Section 194.24(g).

24.11.9 2014 Recertification Decision (194.24 (g))

	Based on a review and evaluation of the 2014 CRA and supplemental information provided by DOE (FDMS Docket ID No. EPA-HQ-OAR-2014-0609), EPA determines that DOE continues to comply with the requirements for Section 194.24(g).
