ML20153H262
| ML20153H262 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 05/05/1988 |
| From: | Gridley R TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| NUDOCS 8805120197 | |
| Download: ML20153H262 (3) | |
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YU.NN*d' % '.',. LEY AUTHORITY n
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',N ls/B Lookout Place MAY 051988 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C.
20555 Gentlemen:
In the Matter 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 SPECIFICATIONS - FISHKILL Enclosed is my follow-up report to the April 12, 1988 fishkill in accordance with the requirements in Appendix B, Environmental Technical Specifications, subsections 4.1.1 and 5.4.2.
The initial notification required by sut,section 5.4.2.a was made by telecopy to the Document Control Desk on April 12, 1988.
If you have any questions, please telephone M. R. Harding at (615) 870-6422, Very truly yours, TENNESSEE VA EY AUTHORITY A' -
R. Gridley,iirector Nuclear Licensing and Regulatory Affairs Enclosure cc:
See page 2 i
6905120197 890505 PDR ADOCK 05000327 S
DCD An Equal Opportunity Ernployer
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' U.S. Nuclear Regulatory Commission MAY 051988 cc (Enclosure):
Mr. K. P. Barr, Acting Assistant Olrector for Inspection Programs TVA Projects Division U.S. Nuclear Regulatory Commission Region II 101 Harletta 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 Mr. G. G. Zech, Assistant Director for Projects TVA Projects Division U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852 Sequoyah Resident Inspector Sequoyah Nuclear Plant 2600 Igou Ferry Road Soddy Daisy, Tennessee 37379
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Enclosure i
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.On April 12, 1988, the Sequoyah Nuclear Plant (SQN) Environmental Section 1
l supervisor discovered a fishkill in the yard drainage pond. This event was l
1 reported to the State of Tennessee, Division of Water Pollution Control, and i
NRC as required by SQN Environmental Technical Specifications.
Upon the discovery, the supervisor requested that chemistry personnel collect samples j
of pond effluents.
Additionally, TVA biologists were contacted to initiate an i
j investigation of the fishkill.
Preliminary analysis results yielded a hydrazint concentration of 52 parts per billion (ppb), potential hydrogen-ion activity (pH) 8.21, ammonia 843 ppb, dissolved oxygen 6.8 parts per million t
l (ppm), and total residual chlorine less than 0.1 ppm.
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On April 13, 1988 TVA biologists began an investigation of the fishkill.
The biologist estimated that 3,000 to 4,000 green sunfish were killed--most were l
between one to three inches in length. Most of the fish were thought to have been dead for approximately one to three days (April 11-13, 1988).
The most i
probable cause of the fishkill is considered to have been toxic concentrations of hydrazine and ammonta in the yard drainage pond inlet channel and pipe.
The toxic concentration of hydrazine and ammonia in the inlet channel and pipe i
j resulted from its limited volume.
The long, narrow channel routes from the Turbine Building sump discharge to the east inlet of the yard drainage pond.
I Fish frequently congregate in this channel and at the inlet pipe to the yard i
drainage pond.
l Normally, the drainage of effluents from the Turbine Building sump would have been discharged to the SQN low-volume waste pond; however, the sump was routed to the yard dratnage pond to ameliorate a high pH problem caused by algal photm ynthesis in the yard drainage pond.
The yard drainage pond normally i
pros Nes collection, blending, and monitoring for yard and station drainage.
l The National Pollutant Discharge Elimination System (NPDES) permit allows the yard dratnage pond or low-volume waste pond to receive effluents from the
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Turbine Building sump.
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l During the preliminary investigation, it was suspected that effluents from a steam generator and/or aux 111ary boiler drain to the yard drainage pond possibly attributed to the fishkill.
Daily journais were reviewed to determine if these systems were drained before and during the fishkill.
It has been determined that 3,800 gallons of waste was drained from auxiliary i
boilers A and B on April 11, 1988.
Hydrazine concentrations measured 224 ppm
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and 136 ppm respectively in boilers A and B.
The No. 3 steam generator for I
unit 2 was intermittently drained (approximately 35,000 gallons) to the l
Turbine Building sump in the April 8-9, 1988 period.
The hydrazine j
concentration in the steam generator on April 8, 1988, was 0.88 ppm.
i TVA has concluded that the steam generator and boiler drains, coupled with low flows of the yard drainage systems and limited inlet channel volume, created i
j localized concentrations (predominantly hydrazine and ammonia) that were l
probably toxic to fish.
Also, the high hydrazine concentration probably I
l created low or nonexistent dissolved oxygen content at the yard drainage pond
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inlet pipe and channel areas resulting in asphyxiation of the fish. During l
this event, no NPOES limits were exceeded.
The State has concurred with TVA's
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results. The State has informed TVA that they consider this incident closed.
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There is no further corrective action required for this incident.
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