ML20137U178
| ML20137U178 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 01/31/1986 |
| From: | Mangan C NIAGARA MOHAWK POWER CORP. |
| To: | Starostecki R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| (55(E)-84-42), (NMP2L-0601), (NMP2L-601), NMP2L-601), NUDOCS 8602190080 | |
| Download: ML20137U178 (3) | |
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M V NIAGARA nUMOHAWK NIAGARA MOHAWK POWER CORPORATION /300 ERIE BOULEVARD WEST, SYRACUSE, N.Y.13202/ TELEPHONE (315) 474-1511 January 31, 1986 (NMP2L 0601)
Mr. R. W. Starostecki, Director U.S. Nuclear Regulatory Commission Region I Division of Reactor Projects 631 Park Avenue King of Prussia, PA 19406 Re: Nine Mile Point - Unit 2 Docket No. 50-410
Dear Mr. Starostecki:
Enclosed is a final report, in accordance with 10CFR50.55(e), for the problen concerning the failure of containment purge systen isolation valves to close under loss of coolant accident condi ti on.
This problen was reported vi a tel-con to S. Collins of your staff on Septenber 25, 1984.
Very truly yours, DJYO W
C. V. Mangan Senior Vice President CVM/GG/cla (1409H) xc: Director of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, DC 20555 R. A. Granun, NRC Senior Resident Inspector gDR602190oe0 860131 ADOCK 03000410 S
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I f, NIAGARA M0 HAWK POWER CORPORATION NINE MILE POINT - UNIT 2 DOCKET NO. 50-410 Final Report For a Problem Concerning Failure of Containment Purge Systen Isolation Valve To Close Under Loss of Coolant Accident Condition (55(e)-84-42)
Description of the Problem The problem pertains to containment purge system i solation valves.
The original application of these valves stipulated that the valves will remain closed during nomal plant operations and will serve the containment purge system only.
However, system design changes implemented due to NUREG-0660, Task II.B.8 resulted in the subject valves serving both the containment purge systen and nitrogen inerting system. These system changes required the valves to be open during certain nonnal operational modes.
As a result, these valves are required to close within 5 seconds in the event of a Loss of Coolant Accident.
At our request, the valve vendor, Posi-Seal International Incor-porated, perfonned an analysis which indicated that during Loss of Coolant Accident blowdown valves 2 CPS *A0V104, 105, 110 and 111 will not meet the requirement to close wi thin 5 seconds without being in the preferred ori entation.
Analysis of Safety Implications Since the subject valves were called on to service an additional system, (ni trogen inerting system) their design criteria changed.
The failure of these valves to initially meet the new criteria is a result of a design change, not the result of a design error or deficiency.
Therefore, the above problem does not represent a reportable deficiency under 10CFR50.55(e).
It should be noted that closure time of the subject valves is being considered under an open item covered in SER section 3.10.2.