ML20207J126
| ML20207J126 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah, 05003288  |
| Issue date: | 08/25/1988 |
| From: | Gridley R TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| NUDOCS 8808300243 | |
| Download: ML20207J126 (3) | |
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e TENNESSEE VALLEY AUTHORITY CHATTANOOGA, TENNESSEE 37401 5H 157B Lookout Place AUG 251988 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C.
20555 Centlemen:
In the Mattar of
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Docket Nos. 50-327 Tennessee Valley Authority
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50-328 SEQUOYAH NUCLEAR PLANT (SQN) UNITS 1 AND 2 - APPENDIX B, ENVIRONMENTAL TECHNICAL SPECIFICATION - FISHKILL Enclosed is TVA's report of the August 1, 1988 fishkill in accordance with the requirements in Appendix B, Environmental Technical Specifications, subsections 4.1.1 and 5.4.2.
If you have any questions concerning this matter, please telephone M. A. Cooper at (615) 870-6549.
Very truly yours, TENNESSEE VALLEY AUTHORITY R.
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er Nuclear Licens og and Regulatory Affairs Enclosure
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An Equal Opportunity Employer
1 U.S. Nuclear Regulatory Commission ec (Enclosure):
Ms. S. C. Black, Assistant Director for Projects TVA Projects Division U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852 Mr. F. R. McCoy, Assistant Director for Inspection Programs TVA Projects Division U.S. Nuclear Regulatory Commission Region 11 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 Mr. Philip L. Stewart, Manager Chattanooga Field Office Office of Water Pollution Control 2501,Milne Avenue Chattanooga, Tennessee 37406-3399 Mr. David Young, Fish Habitat Biologist Tennessee Wildlife Resources Agency 216 East Penfield Street Crossville, Tennessee 38555 Sequoyah Resident Inspector Sequoyah Nuclear Plant 2600 Igou Ferry Road Soddy Daisy, Tennesseo 37379 l
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ENCLOSURE
' On Monday, August 1,1988, SQN personnel reported dead fish in the plant intake forebay. They requested that the situation be investigated and i
documented. A crew led by fishery biologist Wayne Wilson arrived at the intake forebay at approximately 11 a.m.
They' surveyed the entire shoreline of the forobay and found the largest concentration of dead fish at the end of the intake channel near the pump screens.
A few, including two large, flathead catfish, were found in the area near the end of the cooling tower return canal. No dead fish were noted in the open-water area of the forebay, but a number (perhaps 200) of small (approximately 2 inches) gizzard shad appeared to be breaking the surface in a possibly stressed condition in the area i
inmediately behind the skluner wall.
The sof t parts of many dead corbicula were floating throughout the forebay and were concentrated by the thousands at the end of the intake channel.
There were no fish observed floating in the Tennessee River.
The water in the forebay was dark in color, with dissolved oxygen (DO) readings ranging from 0.5 milligrams per liter (mg/1) at the surface to 0.2 mg/l at the bottom and temperature readings ranging from 25.2 degrees centigrade (C) at the surface to 24.4 degrees C at the bottom.
Approximately 450 dead fish were observed, of which 268 were concentrated at the end of the intake channel. Approximately 400 were gizzard shad (2-12 inches), 57 were freshwater drum (6-10 inches), 3 were channel catfish (12-18 inches), 2 were flathead catfish (20-24 inches), and oae was a blue catfish (15 inches).
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The fishkill was undoubtedly related to the extremely low DO levels in the intake forebay. The water in the forebay is drawn under the skimmer wall from the deepest strata of the reservoir where essentially anoxic conditions prevail.
Data collected as part of the Chickamauga DO study on July 26, 1988, at Tennessee River Marker 484.5, just outside the skimmer wall, show DO readings cf 0.1 to 0.2 mg/l in the bottom five meters of the reservoir.
lt was evident from the condition of the dead fish that they did not all die at the same time.
Apparently they enter under the skiemer wall into the forebay, become trapped, and cannot survive the critically low Do levels.
The floating bodies of the fish are then drawn into the intake canal where they concentrate near the pump screens. This pattern will undoubtedly continue until higher Do levels are restored in the lower strata of Chickamauga Reservoir.
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