ML050400101
| ML050400101 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 01/20/2005 |
| From: | Douet J, Howard S Tennessee Valley Authority |
| To: | Polk E Office of Nuclear Reactor Regulation, State of TN, Dept of Environment & Conservation |
| References | |
| Download: ML050400101 (18) | |
Text
Tennessee Valley Authority, Post Office Box 2000, Soddy-Dalsy. Tennessee 37379-2000 January 20, 2005 Mr. Ed Polk, P.E., Manager Permit Section State of Tennessee Department of Environment and Conservation Division of Water Pollution Control Enforcement & Compliance Section 6th Floor, L&C Annex 401 Church Street Nashville, Tennessee 37243-1534
Dear Mr. Polk:
TENNESSEE VALLEY AUTHORITY (TVA) - SEQUOYAH NUCLEAR PLANT (SQN) -
- NPDES PERMIT NO. TN0026450 - PHASE 11316(b) RULE FOR EXISTING FACILITIES
- PROPOSAL FOR INFORMATION COLLECTION Pursuant to 40 CFR § 125.95(b)(1) of the Phase II rule for Cooling Water Intake Structures at Existing Facilities, TVA is submitting for your review this Proposal for Information Collection (PIC) for SQN. The rule, published in the Federal Register on July 9, 2004, requires the PIC to be submitted prior to start of information collection activities, but allows facilities to initiate such activities prior to receiving comment from the permitting agency. See 69 Fed. Reg. 41575, p. 41687, (July 9, 2004). The preamble to the rule encourages the Director of the permitting agency to provide comments expeditiously (i.e., within 60 days) so that the permit applicant can make responsive modifications to its information gathering activities. See 69 Fed. Reg. 41575,
- p. 41635, (July 9, 2004). Your expeditious review of the PIC is particularly important in view of an impending January 24, 2005 start date for impingement monitoring at SQN.
TVA plans to collect weekly impingement mortality samples for a minimum period of one year. A longer monitoring period may be utilized after assessing time constraints imposed by the rule for submitting the Comprehensive Demonstration Study (CDS), and after evaluating the costs of collecting additional data versus the greater uncertainties introduced by the absence of such data.
The following sections address the requirements for the PIC as spelled out in the Phase 11rule. Several of the items below refer to components of the CDS that are due at a future date. The preamble to the Phase II rule recognizes that collection and analysis of coo)
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information is an iterative process and plans for information gathering may change as information is gathered and new data needs are identified. Accordingly, TVA will periodically review the PIC in light of new information as it becomes available and provide updates as necessary.
§125.95(b)(1)(i): A description of the proposed and/or implemented technologies, operational measures, and/or restoration measures to be evaluated in the
[Comprehensive Demonstration] Study [to be provided later]:
TVA will assess the current impingement levels at SQN and determine the appropriate baseline in order to evaluate the status of compliance with EPA's national performance standards. The performance standards are for impingement mortality (IM), a reduction of 80-95% from the calculation baseline. Comparison of the current impingement mortality to the calculation baseline will provide an indication of the effectiveness of the following technologies and intake features already in use at SQN:
- Submerged plant intake Condenser Circulating Water (CCW)
- Underwater dam at approximate Tennessee River Mile 483.8 to withdraw cold water, and
- Other site-specific characteristics that may reduce IM.
TVA will conduct preliminary evaluations of the following technologies for SQN as appropriate for compliance with the rule (impingement mortality only). It may be determined that the applicable standards are already being met at SQN which would impact the technologies to be evaluated.
Impingement Standard Measures
- Restoration or protection
- Replacement or modification of existing traveling screens
- Operational modifications (e.g., intake screen operational changes)
- Barrier nets or structures
- Fish handling and return systems
- Fish avoidance technology (e.g., louvers, sound, light, etc.)
§125.95(b)(1)(ii): A list and description of any historical studies characterizing impingement mortality and entrainment and/or the physical and biological conditions in the vicinity of the cooling water intake structures and their relevance to this [Comprehensive Demonstration] Study.
The following reports describe historical levels of impingement occurring at SQN.
Baxter, D. S. and L. K. Kay. 2002. Effects of Impingement on the Aquatic Populations in Chickamuaga Reservoir. Tennessee Valley Authority, River System Operations and Environment, Aquatic Biology Lab, Norris, Tennessee 10 pp.
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Tennessee Valley Authority. 1987. Aquatic environmental conditions in Chickamauga Reservoir during operation of Sequoyah Nuclear Plant, sixth annual report (1986). Knoxville, Tennessee: Division of Air and Water Resources.
TVA/ONREDAVRF-87/7.
§125.95(b)(1)(ii): ... If you propose to use existing data, you must demonstrate the extent to which the data are representative of current conditions and that the data were collected using appropriate quality assurancelquality control procedures; TVA will be evaluating data collected in accordance with this PIC and comparing the results with previously collected data to ascertain if historic data are still representative of current levels of impingement. TVA is assessing historic data and records to verify that data were collected in accordance with a valid Quality Assurance Procedure for impingement mortality; it is believed that is the case. Additional information may be provided later, as appropriate, in support of using historic data.
§125.95(b)(1)(iii): A summary of any past or ongoing consultations with appropriate Federal, State, and Tribal fish and wildlife agencies that are relevant to this [Comprehensive Demonstration] Study and a copy of written comments received as a result of such consultations None known.
§125.95(b)(1)(iv): A sampling plan for any new field studies you propose to conduct in order to ensure that you have sufficient data to develop a scientifically valid estimate of impingement mortality and entrainment at your site. The sampling plan must document all methods and quality assurance/quality control procedures for sampling and data analysis. Proposed methods must be appropriate for a quantitative survey including consideration of methods used in other studies performed in the source water body. The sampling plan must include a description of the study area including the area of influence of the cooling water intake structure(s), and provide a taxonomic identification of the sampled biological assemblages (including all life stages of fish and shellfish).
Plant Description SQN is located on the west shore of Chickamauga Reservoir at Tennessee River Mile (TRM) 484.5. The two identical units (Pressurized Water Reactor) are each rated at 3,455 megawatts thermal (MWt). Two natural draft cooling towers enable SQN to operate in any of three modes: open, helper, or closed mode. In open mode operation with both units at maximum power, total water demand is 2502 cfs. CCW is drawn from Chickamauga Reservoir into the intake channel through an opening approximately 550 feet in length and 10 feet in height located at the bottom of the skimmer wall. The skimmer wall is situated near the river channel enabling SQN to withdraw cooler water from the lower stratum. From the intake channel, water passes through six, 14 feet wide traveling screens to the intake pumps. Mesh openings on the screens are 3/8 inch.
Physical Data
- 1. Condenser Circulating Water (CCW) Pumping Station The CCW intake pumping station, located at the end of the intake channel, houses the CCW pumps, traveling screens, and screen wash pumps. For each unit, three CCW pumps pump condenser circulating water through the condensers. Each pump 3
has a capacity of 187,000 gpm at a design head of 30 feet. Each pump is installed in a separate suction well with entering water strained by trash racks and a traveling screen. Three CCW pumps can operate in parallel for each unit. However, if one pump is out of service, the two remaining pumps will deliver sufficient flow for full-load operation but with a higher turbine backpressure. Differential pressure across each traveling screen is monitored. When a preset differential pressure of water is reached across the screen, the screen wash pump is started. When a preset pressure is established at the screen wash nozzles, the screen motors are automatically started and the screens are washed until the pump is manually stopped.
- 2. Essential Raw Cooling Water (ERCW) Pumping Station The maximum velocity (adjusted for mesh) is below the 0.50 fps; therefore the ERCW pumping station meets the IM standard and no IM monitoring is planned for this intake.
- 3. Intake Channel The intake channel extends approximately 1,800 feet from the skimmer wall to the CCW pumping station.
- 4. Skimmer Wall A 550 foot long concrete skimmer wall which extends approximately 34 feet below the minimum water surface is positioned across the entrance of the intake channel.
Water depth varies based on reservoir elevations: the bottom of the skimmer wall is 641 feet msl, the riverbed elevation is 631 feet msl, and the minimum pool elevation is 675 feet msl.
Impingement Sampling Methods Samples will be collected according to TVA's Quality Assurance Procedure (NR OPS-FO-OBR-23.1 1) for Impingement Counts (TVA 1983a or later). A copy of this procedure is enclosed. Weekly counts of fish impinged during a 24-hour period on the CCW intake traveling screens at SQN will be collected beginning January 24, 2005 and continue for at least one year. Prior to conducting the sampling, Operations personnel will be notified in time to ensure that all available traveling screens for units in operation are washed 24-hours prior to the scheduled sampling event. These washings, occurring 24-hours in advance of the sampling, will be conducted concurrently if possible. At the time of the scheduled sample collection, available screens will be rotated and back-washed individually or in groups. During periods of heavy debris load, it may become necessary for Operations personnel to wash more frequently than once per 24-hours; if this proves to be true, daily counts of fish impinged will be adjusted to account for the actual time between screen backwash operations.
After each available screen (or groups of available screens) is washed, all fish (and debris) will be removed from the collection baskets. The baskets installed to collect the fish and debris may be pressure washed with relatively small amounts of potable water or raw water (approximately 50 gallons). The wash water from the baskets will drain to the CCW trash sluice to Outfall 116 and is expected to have no discemable impact. The zone of influence for impingement monitoring is being defined in front of and at the intake structure.
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Fish will be sorted by species in 25-mm total length (TL) groups, then counted, weighed and recorded. Any fish that cannot be positively field-identified will be preserved in 10%
formalin and taken to the TVA Aquatic Biology Laboratory in Norris, Tennessee, for identification or verification.
At times when it is determined that a complete count of all fish impinged during the sample cannot be made during the working day with the available field personnel, the crew leader may elect to subsample as described below:
- All fish of a species over 300-mm TL will be sorted into size classes, weighed and recorded.
- Only size classes containing large numbers of individuals will be subsampled by mixing them and scooping approximately 2.5 kg as a subsample from the pile.
- Fish from the subsample will then be separated into length classes and the number and weight for each size class recorded.
- All remaining fish from which the subsample was taken are then weighed and that total weight recorded.
Moribund/Dead Fish Fish collected from a 24-hour screen wash will usually all be dead when processed.
Incidental numbers of fish which appear to have been dead for more than 24-hours will not be included in the sample. Determinations of previously dead fish will be made using Best Professional Judgment based on observations of condition of fish. Also, during winter, species of fish such as shad occasionally suffer die-offs and could be impinged after death or in a moribund state. In that case, field personnel would document that due to ambient temperatures, either all, or a portion of impinged species of fish were due to cold-shock and would not have been impinged otherwise.
Additionally, if species of fish were observed dying in the reservoir from cold-shock, this would be documented and presented in the records and report to indicate cold-shock as the primary cause of unusually high impingement of this species.
Records and RecordkeepinQ Data collection forms will be completed with the counts and weights of species. These forms will include the date, time, facility name and location of the sample (i.e., at intake screen backwash), and the person collecting data.
For quality control and assurance, voucher specimens will be sent to the TVA Aquatic Biology Laboratory for verification. Completed data forms will be submitted to the project leader for technical review and signoff. Once the data have been verified and the project leader has signed the forms, copies of all forms will be provided to Site Environmental.
Site Environmental may replace the draft form with the signed official record. Records will be maintained on site per requirements of TVA's Environmental Records Management Process (currently 10 years). Data will then be entered by a TVA Resource Stewardship employee into the TVA Dazzler database (or equivalent) for subsequent analysis and reporting. In addition, during the sample year, a minimum of two sampling audits will be conducted to ensure proper standard procedures are followed.
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A list of species identified from historical impingement monitoring at SQN is in Table 1 below.
Table 1. List of species impinged on the intake screen at Sequoyah Nuclear Plant in ten samples collected between December 18, 2001 and February 25, 2002.
Fish Clupeidae Alewife Alosa pseudoherengus Gizzard shad Dorosomacepedianwn Threadfm shad Dorosomapetenense Cyprinidae Bluntnose minnow Pimephalesnotatus Ictaluridae Channel catfish Ictaluruspunctatus Flathead catfish Pylodictis olivaris Poeciliidae Mosquitofish Gambusiaaffinis Percichthyidae Striped bass Morone saxatilis Centrarchidae Redbreast sunfish Lepomis auritus Bluegill Lepomis macrochirus Redear sunfish Lepomis microlophus Largemouth bass Micropterussalmoides White crappie Pomoxis annularis Percidae Logperch Percinacaprodes Sciaenidae Freshwater drum Aplodinotus grunniens Mussels Zebra mussels Dreissenapolymorpha Extrapolation of Impingement, Losses to Equivalent Adult and Production Foregone.
To facilitate the implementation of and compliance with EPA's regulations for Section 316(b) of the Clean Water Act (Federal Register Vol. 69, No. 131; July 9, 2004),
impingement losses of juvenile and adult stages of fish will be evaluated by extrapolating the losses to equivalent reductions of adult fish, or of biomass production available to predators. EPRI (formerly the Electric Power Research Institute) has identified two models for extrapolating losses of juvenile and adult stages at intake structures to numbers or production of older fish. Equivalent Adult (EA) models quantify impingement losses in terms of the number of fish that would have survived to a given future age.
Production Foregone (PF) models are applied to forage fish species and quantify the loss from impingement in terms of potential available forage for consumption by 6
predators. Requirements of the models are site-specific data on the distribution and abundance of fish populations vulnerable to impingement. TVA will be using these models to determine the "biological liability" of the intake structure.
TVA sincerely appreciates your expeditious review of this PIC so that your comments may be appropriately incorporated into the impingement sampling methods.
If you need additional information, or would like to schedule a meeting to discuss this document please contact me at (423) 843-6700.
Sincerely, Stephanie A. Howard Principal Environmental Engineer Signatory Authority for J. Randy Douet Site Vice President Sequoyah Nuclear Plant Enclosure cc (Enclosure):
Chattanooga Environmental Assistance Center Division of Water Pollution Control State Office Building, Suite 550 540 McCallie Avenue Chattanooga, Tennessee 37402-2013 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 7
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