ML20215M737

Final Deficiency Rept (55(e)-86-21) Re Inadvertent Closure of Automatic Fire Suppression Control Valve.Initially Reported on 860918.Drawing Fsk 23-6c Revised to Change Isolation Valve 2DFR-V128 to Open Position

ML20215M737
Person / Time
Site:	Nine Mile Point
Issue date:	10/23/1986
From:	Mangan C NIAGARA MOHAWK POWER CORP.
To:	Kane W NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
(55(E)-86-21), (NMP2L-0923), (NMP2L-923), NUDOCS 8611030237
Download: ML20215M737 (2)

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as" T NIAGARA RuMOHAWK NIAGARA RIONAWK POWER CORPORATION /300 ERIE BOULEVARD WEST, SYRACUSE, N.Y.13202/ TELEPHONE (315) 474-1511 October 23, 1986 (NMP2L 0923)

Mr. H. Kane, Director U.S. Nuclear Regulatory Commission Region I Division of Reactor Projects 631 Park Avenue King of Prussia, PA 19406 Re: Nine Mlle Point Unit 2 Docket No. 50-410

Dear Mr. Kane:

Enclosed is a final report, in accordance with 10CFR50.55(e), for the problem concerning inadvertent closure of automatic fire suppression control valve.

This problem was reported via tel-con to G. Meyer of your staff on September 18, 1986.

Very truly yours, C. V. Mangan Senior Vice President CVM/AZP/cla -

(1879H)

Enclosure xc: J. M. Taylor, Director of Inspection and Enforcement U.S. Nuclear Regulatory Commission ,

Washington, DC 20555 , ,

H. A. Cook, NRC Resident Inspector 8611030237 861023 O PDR ADOCK 0S00 S

II Ti: 21

NIAGARA M0 HAWK POWER CORPORATION NINE MILE POINT - UNIT 2 DOCKET N0. 50-410 Final Report for a Problem Concerning Inadvertent Closure of Automatic Fire Suppression Control Valve (55(e)-86-21)

Description of the Problem On August 23, 1986, Reactor Building sprinkler system W56 (operational and in service) was tripped by a fire detection signal. A system Motor Operator Valve (MOV) opened allowing the top chamber of the deluge valve to vent creating a differential pressure across the valve enabling the deluge valve to open as designed. The MOV discharged into a common drain header isolated by normally closed valve 2DFR-V128. The M0V continued to drain after actuation (as designed) until the drain header became pressurized (due to valve V128 being closed), ultimately closing the deluge valve. This condition rendered auto- matic fire suppression to all divisions in the Reactor Buf1 ding inoperable.

Analysis of Safety Implications The described problem violates the requirements of 10CFR50, Appendix R which requires that fire protection be provided so that a fire in one safe shutdown train does not damage the redundant train. Both safe shutdown trains could have been degraded by a common fire within the Reactor Building secondary containment due to the non-availability of the 20 foot non-combustible zone within the Reactor Building. If this condition had remained uncorrected and a fire occurred, it could have adversely affected the safety of operations of the plant.

Corrective Action Engineering Change Notice DFR-605 has revised Drawing FSK 23-6c to change isolation valve 2DFR-V128 from a normally closed position to normally open (locked open). Engineering & Design Coordination Report F13650A revises the M0V discharge from drain to permit discharge directly to the floor. MOV discharge drain paths for all remaining NMP2 fire protection systems have been reviewed and confirmed to be unobstructed. The work on the M0V drain lines is now complete.

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