ML19344E570
| ML19344E570 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 08/25/1980 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, NCR-27P, NUDOCS 8009020281 | |
| Download: ML19344E570 (2) | |
Text
t 400 Chestnut Street Tower II August 25, 1980 hr. James P.
Reilly, Director Office of Insp. icn and Enforcement U.S. huclear Regu tory Conmissicn Region II - Suite 3 0 101 Marietta Street Atlanta, Georgia 3030-
Dear Mr. O'Reilly:
SEQUOYAH I;UCLEAR PLANT UNIT 1 - SAFETY INJECTION PUMP BREAKER LOCKOUT -
NCR 27P - FI?!AL REPORT The cubject deficiency uas initially reported to NRC-CIE Inspector
- h. Thomas on June 19, 1980, in accordance with 10 CFR 50.55(e). An interim report tas submitted on July 18, 1980. Enclosed is our final report.
If you have any questions, please get in touch with D. L. Lc=bert at FTS 857-2581.
Very truly yours, IEM4ESSEE VALLEY AUTHORITY L. M. Mills, Manager Nuclear Regulation and Safety Enclosure cc:
Mr. Victer Stello, Director (Enclosure)
Office of Inspecticn and Enforcenent U.S. hucicar Regulatory Cocznission Washington, DC 20555
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ENCLOSURE SEQUOYAH NUCLEAR PLANT UNIT 2 SAFETY INJECTION PUMP BREAKER LOCK 0tfr NCR 27P 10 CFR 50.55(e)
Final Report Description of Deficiency During preoperational tasting of Sequoyah unit 2 safety injection pumps (2A-A.and 2B-B), it was found that if the pumps were given a closed (start) signal for greater than 0 32 seconds while a pump trip condition existed, the 6900V breakers would lock out', preventing pump start. There is no visual or audio indication to operations personnel when this lockout condition exists. The breakers appear to be available for service when they actually are not.
Safety Implication The lack of an indication of the locked-out condition of the circuit breakers could result in a failure of the safety injection pumps to start autocatically under emergency conditions. This could result in less core cooling capability than was assumed in the plant safety analysis, jeopardizing the safe operation of the plant.
Corrective Action TVA has investigated this problem and has found it to be common only to Sequoyah and Watts Bar Nuclear Plants. To alleviate the problem, the seal-in contact of the 1% relays will be removed from the circuit breakers in the 6900V shutdown boards. This will prevent any recurrence of this problem. This work will be completed by November 3, 1980.
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