Site Visit Report

Ginna Station

	1503 Lake Road

	Ontario, NY 14519

April 3, 2008

Background and Objectives

The Environmental Protection Agency (EPA) is in the process of
developing 316(b) cooling water intake structure requirements that
reflect the best technology available (BTA) for minimizing adverse
environmental impact for all existing power plants and manufacturing
facilities. As part of this process, EPA staff is visiting electric
generators and manufacturers to better understand the cooling water
intake structure (CWIS) technologies in use at facilities, including the
site-specific characteristics of each facility and how these affect the
selection and performance of CWIS technologies.  EPA is also visiting
facilities to better understand cooling water use and specific issues or
technologies that can affect 316(b) compliance.  Ginna Station (Ginna)
was selected for a site visit due to its use of an offshore intake
location (with a velocity cap) and its large intake flows.

Facility Description

The R.E. Ginna nuclear facility is operated by Constellation Energy and
consists of one pressurized water reactor (PWR) located in Ontario, NY,
20 miles east of Rochester. The existing facility is on a large
industrially-zoned site approximately 500 acres in total size on the
southern shore of Lake Ontario. Approximately 25 percent of the site is
dedicated to buildings, roads and other improvements associated with
facility operations; the remaining portion is undeveloped with large
portions leased to agricultural operations. New housing developments
have been constructed near the property border to the southwest (see
Attachment B).

Cooling water withdrawals from and discharges to Lake Ontario for Unit 1
are permitted under SPDES Permit No. NY000493.

Electricity Generation and Transmission

Ginna Unit 1, a PWR nuclear unit, came online in 1970 and has a rated
capacity of 490 MW. The unit is a baseload facility providing
electricity to the Niagara-Mohawk grid. As a baseload facility,
Ginna’s capacity utilization rate is high with recent years averaging
more than 90 percent. 

Refueling outages occur every 18 to 24 months and last approximately 30
days. Because outages are routine, facility-wide maintenance activities,
including those related to the intake structure, are scheduled to occur
at the same time.

Cooling Water Intake Structure

The intake structure for Unit 1 is located approximately 3,000 ft
offshore in Lake Ontario.  The terminal end of the intake conduit is
fitted with an octagonally-shaped concrete velocity cap, the top of
which rises 11 feet off the lakebed and is approximately 15 feet below
the lake surface.  The velocity cap measures 50 feet in total diameter.
Each of the eight sides has three water inlet slots totaling 3 feet high
by 17 feet wide. Galvanized steel bars spaced 10 inches apart prevent
large objects from entering the system. Intake velocity at the velocity
cap is approximately 0.6 feet per second (fps) (see Attachment A). 

Two circulating water pumps draw water through a 120-inch concrete
tunnel to the onshore pump house at a maximum velocity of 7 feet per
second. Trash racks remove larger debris from the instream flow. The
intake divides into four channels in the screen house, each fitted a
vertical traveling screen with 3/8-inch mesh panels. The approach
velocity to the screens is 0.8 fps. Screens are rotated periodically
based on a pressure differential between the upstream and downstream
faces and washed with a high-pressure spray. Screen washings, including
impinged fish, are discharged to a separate debris trough that empties
into the discharge canal. 

The maximum design flow rate is 510 million gallons per day (mgd). As a
baseload facility, Ginna Unit 1 withdraws water at its maximum capacity
during normal operations and does not moderate flows based on climate or
operating conditions. The facility does moderate intake water
temperatures during winter months by recirculating a portion of the
heated discharge water to the intake to maintain the desired condenser
water temperature (approximately 41-44º F). This reduces the total
volume of water withdrawn from Lake Ontario by as much as 10 percent
depending on water temperatures. 

Water passing through the surface condenser is discharged into the
discharge canal, a surface outfall located at the shoreline. The normal
temperature increase over the ambient water temperature at the point of
discharge is about 44º with a distinct thermal plume approximately 175
acres in total area.

The auxiliary cooling system includes service water, fire protection,
and other uses, and draws water from the main cooling water intake in
the screen house. These systems use approximately 14,600 gpm, or 21 mgd.
The service water system circulates lake water from the screen house to
various heat exchangers and systems inside the containment building as
well as the auxiliary, intermediate, turbine, and diesel generator
buildings. 

Impingement and Entrainment Information

Constellation Energy has conducted weekly impingement and entrainment
sampling at the Unit 1 intake and surrounding locations as part of its
Comprehensive Demonstration Study to meet Phase II and SPDES
re-application requirements. The sampling will also allow Constellation
Energy to evaluate the relative effectiveness of its current intake
configuration (offshore with velocity cap) to an estimated baseline
configuration that would be representative of a nearshore, unprotected
intake structure. 

The in-plant portion of impingement sampling involves collection and
identification of fish and macroinvertebrates impinged on the traveling
screens on a weekly basis over a two-year period. To establish a
calculation baseline, gill nets are set at several locations in the
nearshore area and at offshore locations near the velocity cap (at
sufficient depth in the water column). Gill nets are set for a 24-hour
period and compared to the in-plant impingement rates.

Entrainment sampling is conducted in a similar manner as impingement
sampling on the same weekly schedule. In-plant samples are collected in
the screen house prior to the traveling screens using 4-foot diameter
bongo nets. To establish a calculation baseline, entrainment is
simulated at a nearshore location using the same equipment.

A final analysis of all collected data has not been completed, but
preliminary findings show a significant difference in the number and
relative species abundance between the actual intake and the offshore
location (see Attachment E). 

	

Facility representatives indicated that Lake Ontario’s aquatic
biology, specifically the number and relative abundance of various fish
species, has changed dramatically over the last 10-15 years.
Biologically-productive areas have moved further offshore from their
historical settings, with invasive and introduced species playing a
significant role in these shifts. 

In the mid-1970s, a salmonid introduction program, designed to increase
recreational fishing in the lake, contributed to a precipitous drop in
the impingement rates of many target species at Ginna, particularly
alewife. Pre-introduction impingement rates ranged as high as 950,000
individuals per year (total) dropping to less than 200,000 in years
immediately following introduction (see Attachment C).

Cooling Tower Feasibility

Facility representatives stated that retrofitting to closed-cycle would
be difficult given the available space and additional aesthetic impacts.
 They noted that the Ginna facility is located in an area where
aesthetic impacts are a significant consideration; over the years, the
facility has taken steps to minimize its visual impact by maintaining a
low profile with all buildings and a large buffer zone around the active
site. 

Facility representatives also noted that the existing condenser may not
have sufficient capacity to handle the water volume necessary to reject
the required thermal load.  The placement of the Unit 1 condenser
(directly below the turbine in the main building) and the confined area
would likely require substantial modifications to the condenser itself
and the surrounding superstructure.

Facility representatives stated that impacts to the unit’s thermal
performance would increase the operating heat rate.  Any generating
shortfall would have to be obtained from other sources, potentially
increasing air emissions if fossil fuel plants are used.

Facility representatives also stated that a nuclear plant retrofit would
involve significant downtime. 

Attachments

Attachment A		List of Attendees

Attachment B		Aerial Photo

Attachment C		CWIS Schematic

Attachment D		Facility Layout 

Attachment E		Impingement Rates 1973-2004

Attachment F		Site Photo

Attachment G		Impingement Comparison

Attachment A--List of Attendees

Paul Shriner, EPA

Jan Matuszko, EPA

Tim Havey, Tetra Tech

Mary Ellen Dangler, Constellation Energy

Michael Bodine, Constellation Energy

E. John Fischer, Constellation Energy

John Walden, Constellation Energy

Dean Discenza, Constellation Energy

Mary Burgess, Constellation Energy

Tom Harding, Constellation Energy

Paul Miller, Constellation Energy

Attachment B—Aerial Photo

Please see DCN 10-6508A accompanying this document.

Attachment F—Site Photo

Please see DCN 10-6508B accompanying this document.

Attachment C--CWIS Schematic

 

Attachment D--Ginna Site Layout

Attachment E--Impingement Rates 1973-2004

Attachment G--Impingement Comparison

 PAGE   

 PAGE   2 

