ML20207Q357

Forwards Safety Evaluation Re MSIV Logic Mods Resulting from 861203 Full Scram,Per 861218 & 870106 Meetings.Mods Do Not Meet Requirements of 10CFR50,App A,Gdc 21 or IEEE Std 279.Issue Must Be Resolved Before Initial Criticality

ML20207Q357
Person / Time
Site:	Nine Mile Point
Issue date:	01/14/1987
From:	Bernero R Office of Nuclear Reactor Regulation
To:	Mangan C NIAGARA MOHAWK POWER CORP.
Shared Package
ML17055C788	List: ML20207Q357
References
NUDOCS 8701270209
Download: ML20207Q357 (2)

Text

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January 1.4, 1987 Docket No. 50-410 DdRIBUTION: l Eocket No. 50-410 NRC PDR Local PDR Mr. C. V. Mangan, Senior Vice President BWD-3 r/f RStevens Niagara Mohawk Power Corporation EAdensam JPartlow 301 Plainfield Road MHaughey Attorney,(0GC)

Syracuse, New York 13212 EHylton BGrimes RBernero EJordan

Dear Mr. Mangan:

AMarinos ACRS (10)

Subject:

Main Steam Isolation Valve Logic Modifications at Nine Mile Point, Unit 2 l On December 3, 1986, a full scram occurred at Nine Mile Point Unit 2 (NMP-2) as a result of a loss of power to both reactor protection system (RPS) scram sensor buses. This event was caused by an overcurrent resulting from the crossing of loads in the MSIV logic circuit.

Alerted by this event, the NRC requested NMPC to' meet with them on December 18, 1986, to discuss the details of the logic modifications to the main steam isola-tion valves (MSIVs). After reviewing the modifications performed on the MSIVs, I and the additional proposed changes as a result of the December 3,1986, event, i at~ this meeting, the staff stated that the MSIV logic scheme was una::ceptable l and NMPC should propose additional changes. In a conference call on December 22, i 1986, the staff further clarified its concern stating that because of the

- modified MSIV logic design, a fault could propagate back to both buses of the RPS. Therefore, the modified design does not meet the requirements of 10 CFR 50, Appendix A, General Design Criterion 21 and of IEEE Standard 279. At your re-quest, the staff again met with NMPC on January 6, 1987 to discuss the MSIV logic design. After extensive discussion, the staff advised NMPC that it still

' could not conclude that NMPC's proposed design was acceptable. Additional details relating to the staff's review of the MSIV logic modifications discussed

December 19, 1986, and January 6,1987, are provided in the enclosed safety evaluation.

The issue of the MSIV logic must be resolved before initial criticality. Please contact the License Pro.iect Manager, Mary Haughey, at (301) 492-9422, if you have any questions concerning the enclosed safety evaluation or to discuss any proposed alternate MSIV logic arrangements. ,

Sincerely, 8701270209 870114 l PDR ADDCK 05000410 /

S PDR l

.obert M. Bernero. Director Division of BWR Licensing

Enclosure:

As stated I l

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4 Mr. C. V. Mangan Nine Mile Point Nuclear Station Niagara Mohawk Power Corporation Unit 2 CC*

Mr. Troy B. Conner, Jr. , Esq. Regional Administrator, Region I Conner & Wetterhahn U.S. Nuclear Regulatory Connission Suite 1050 631 Park Avenue 1747 Pennsylvania Avenue, N.W. King of Prussia, Pennsylvania 19406 Washington, D.C. 20006 Mr. Paul D. Eddy Richard Goldsmith New York State Public Serice Syracuse University Commission College of Law Nine Mile Point Nuclear Station -

E. I. White Hall Campus Unit II Syracuse, New York 12223 P.O. Box 63 Lycoming, New York 13093 Ezra I. Bialik Assistant Attorney General Mr. Richard M. Kessel Environmental Protection Bureau Chair and Executive Director New York State Department of Law State Consumer Protection Board 2 World Trade Center 99 Washington Avenue New York, New York 10047 Albany, New York 12210 Pesident Inspector Nine Mile Point Nuclear Power Station P. O. Box 99 Lycoming, New York 13093 Mr. John W. Keib, Esq.

Niagara Mohawk Power Corporation 300 Erie Boulevard West Syracuse, New York 13202 Mr. James Linville U. S. Nuclear Regulatory Comission Region I 631 Park Avenue King of Prussia, Pennsylvania 19406 Mr. Peter E. Francisco, Licensing

, Niagara Mohawk Power Corporation l 301 Plainfield Road i

Syracuse, New York 13212 Don Hill Niagara Mohawk Power Corporation Suite 550 4520 East West Highway Bethesda, Maryland 20814 l

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