ML20058M232

Forwards Rept of 900709 Fishkill,Per Requirements in App B, Environ Tech Spec,Subsections 4.1.1 & 5.4.2.Sudden Water Temp Increase Killed Approximately 150 Fish in Plant Diffuser Pond

ML20058M232
Person / Time
Site:	Sequoyah
Issue date:	08/07/1990
From:	Wallace E TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9008100020
Download: ML20058M232 (3)

Text

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. TENNESSEE VALLEY AUTHORITY

- CH ATTANOOGA, TENNESSEE 374o1 -

5N 157B Lookout Place AUS 07:1990-m.

LU.S. Nuclear Regulatory Commission ATTN: Document Control Desk

-Washington, D.C. 20555 Centlemen:

In the Matter of ) Docket Nos. 50-327

Tennessee Valley Authority- ) 50-328 .

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SEQUOYAH NUCLEAR PLANT (SQN) UNITS 1 AND 2 - APPENDIX B ENVIRONMENTAL TECHNICAL SPECIFICATION - FISHKILL ,

Enclosed is TVA's report of the July 9, 1990, fIshkill in accordance with the j requirements-in Appendix B Environmental Technical Specification, Subsections 4.1.1 and 5.4.2.

If you have any questions concerning this submittal, please telephone EM.'A. Cooper:at (615) 843-6422.

Very truly yours, TENNESSEE VALLEY AUTHORITY

/ $<A.L.--

E. G. Wallace, Manager 1

' Nuclear Licensing and Regulatory Affairs

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! Enclosure -]

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9006100020 900807 7

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'PDR: ADOCK 05000327 g PDC

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An Equal Opportunity Employer C00/ \

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U.S.- Nuclear- Regulatory Comission M 0720 N

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cc (Enclosure)*~ I Ms. S. C. Black, Deputy Director j

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' Project Directorate II-4

- U' S. Nuclear Regulatory Comission One White Flint, North 11555 Rockville Pike.

ic Rockville, Maryland- 20852 Mr. J. N.-Donohew, Project Manager U.S. ' Nuclear Regulatory Comission One White Flint, North 9 11555 Rockville Pike Rockville, Maryland 20852

-NRC Resident, Inspector .

Sequoyah Nuclear Plant  :

2600 Igou-Ferry Road

-Soddy Daisy,-Tennessee 37379 Mr. Phillip L. Stewart, Manager.

Chattanooga Field' Office

' Division of Water Pollution Control i 2501 Milne Street  :- l Chattanooga, Tennessee 37406 Mr. B. A. Wilson, Project Chief' 1 U.S. Nuclear Regulatory Comission~- 1 Region II l 101 Marietta Street, NW, Suite 2900' Atlanta, Georgia 30323 1 Mr. David Young. Fish Habitat Biologist- 1 Tennessee Wildlife Resources Agency. -j

.216 East Penfield Street Crossville, Tennessee 38555 ,

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dp ENCLOSURE On Monday, July 9-,1990, SQN personnel reported approxiniately 150 dead fish'in the plant diffuser pond. This event was reported to the State of Tennessee Division.of Water. Pollution: Control and to NRC as required by SQN environmental technical specifications. At the time of the discovery. the .

. plant _was operating with~both units at approximately 100 percent power and in full. compliance with the. National Pollutant Discharge Elimination System's permit.

A field' crew from TVA's Aquatic Biology group was dispatched to investigate at i 1723 Eastern daylight time (EDT) on July 9, 1990. The field crew determined

,, .the water surface temperature at the boat ramp on the diffuser pond to be ,?

106 degrees Fahrenheit (F); and at midwater, the surface temperature was  !

-109 degrees F. No odor was detectable that might indicate a chemical cause for the observed dead fish and other aquatic life-(one dead frog). _

i Approximately 257 dead fish were observed of the following species and-sizes: i

. Species 'l- to-6-Inch Class 6- to 12-Inch Class 12- to 18-Inch Class Largemouth bass 0 0 1  :

Channel catfish 73 77 14 Carp 1 13 28 Bluegill. 37 7 0 Freshwater drum 1 5 0 .t Most of the fish appeared to have been dead for only a few hours. Fewer than a dozen appeared to have been dead for more than'24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, and there were no bug-eyed specimens. No live fish were seen in a stre.ssful condition.

nThe root cause of'the fishkill was hot water. Investigation of operating conditions preceding the fishkill indicates that it resulted from operation of the planticooling towers. The cooling towers were placed in service on July 8 .i at 2245 EDT and operated for three hours. The towers were needed because the indicated river temperature was approaching the state discharge-permit limit  ;

of 112.5 degrees F. The cooling tower return channel that discharges intolthe-  !

diffuser pond in the " helper" mode of operation was filled with essential raw-cooling water flow, which has probably not exceeded 90 degreca F for a number. ,

of months. Fish had grown in the return channel and.had become accustomed to the relatively cool water. During the cooling tower start-up process, hot

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water was flushed into the return channel and increased =its water temperature approximately 20-25 degrees F in a few minutes. The sudden water temperature increase killed the fish in the channel, which were then washed into the diffuser pond where they were observed the following morning. SQN Operations' personnel confirmed that they could see a few dead fish durine the night while the towers were operating.

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