ML20213E889
| ML20213E889 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 12/31/1984 |
| From: | Mangan C NIAGARA MOHAWK POWER CORP. |
| To: | Starostecki R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| REF-PT21-87-018-000 (55(E)-84-20), (NMP2L-0313), (NMP2L-313), PT21-87-018-000, PT21-87-18, NUDOCS 8611130340 | |
| Download: ML20213E889 (2) | |
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M Y NIAGARA g.za RUMOHAWK N
NIAGARA MOHAWK POWER CORPORATION /300 ER!E BOULEVARD WEST SYRACUSE N Y.13202/ TELEPHONE (315) 474-1511 i
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December 31, 1984 (NMP2L C313)
Mr. R. W. Starostecki, Director U. S. Nuclear Regulatory Comission Region I Division of Project and Resident Programs 631 Park Avenue King of Prussia, PA 19406 Re: Nine Mile Point - Unit 2 Docket No. 50-410
Dear Mr. Starostecki:
rm Enclosed is a final report, in accordance with 10CFR50.55(e), for the problem
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concerning silicon. controlled rectiff ars in the ITE Brown-Boveri trip x.d devices.
This problem was reported to S. Collins of your staff on June 8, 1984.
An interim report was submitted via our letter dated July 6,1984.
Very truly yours, OAWOApg C. V. Mangah Vice President Nuclear Engineering and Licensing CVM/GG:csb (0623H) xc: Director of Inspection and Enforcement U. S. Nuclear Regulatory Commission Washington, DC 2G555 R. A. Gram, NRC Resident Inspector Project File (2)
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NIAGARA M0 HAWK POWER CORPORATION NINE MILE POINT - UNIT 2 DOCKET NO. 50-410 Final Report for a Problem Concerning Silicon Controlled Rectifiers (55(e) 84-20)
Description of the Problem The problem concerns silicon controlled rectifiers in the ITE (Brown-Boveri) trip devices used in 600-V type K-line circuit breakers at Nine Mile Point -
r Unit 2.
Breakers were found to have silicon controlled rectifier trip devices with the potential for excessive leakage which could result in spurious tripping of the breaker.
The problem was reported by Brown-Boveri, Inc. to the Nuclear Regulatory Commission under 10CFR21 via letter dated April 16, 1984.
At Nine Mile Point - Unit 2 only one Category I breaker has been found to have a silicon controlled rectifier trip device with excessive leakage which could have caused spurious tripping of the breaker.
This breaker is located in compartment 7C of the load center 2EJS*US3 and supplies power to battery charger and uninterrupted power supply in addition to other
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safety-related distribution panels of Division II.
Analysis of Safety Implications The spurious tripping of the subject circuit breaker could have resulted in the icss of safety-related components when needed.
Therefore, the problem could have adversely affected the safety of operations of the plant.
Corrective Action The subject silicon controlled rectifiers trip device will be repl aced in accordance with Nonconfomance and Disposition Report No. 9748.