05000245/LER-1981-007, Forwards LER 81-007/03L-0.Detailed Event Analysis Encl

Forwards LER 81-007/03L-0.Detailed Event Analysis Encl

ML20037D203
Person / Time
Site:	Millstone
Issue date:	05/18/1981
From:	Mroczka E NORTHEAST NUCLEAR ENERGY CO.
To:	Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20037D204	List: 05000245/LER-1981-007, Forwards LER 81-007/03L-0.Detailed Event Analysis Encl 05000245/LER-1981-007-03, /03L-0:on 810418,one of Six Relief Valves Failed to Open.Caused by Particulate Contamination in Valve Solenoid.Solenoid Cleaned
References
MP-1-1781, NUDOCS 8105220218
Download: ML20037D203 (3)

LER-1981-007, Forwards LER 81-007/03L-0.Detailed Event Analysis Encl

Event date:
Report date:
2451981007R00 - NRC Website

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liay 18, 1981 fiP-1-1781 fir. Boyce H. Grier j &>gg91 Director, Region I 0

Office of Inspection and Enforcement U.S. Nuclear. Regulatory Commission p' 4

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631 Park Avenue g4 #'4 7p8 King of Prussia, Pennsylvania 19406 4

h Prov sional License DPR-21 i

Reference:

i Docket No. 50-245 d

Reportable Occurrence Ro-81-07/3L 4

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Dear Mr. Grier:

This letter forwards the Licensee Event Report for Reportable Occurrence R0-81-07/3L required to be submitted within 30 days pursuant to the requirements of the flillstone Unit 1 Technical Specifications, Section 6.9.1.9.

An additional three copies of the report are. enclosed.

Yours truly, it0RTHEAST NUCLEAR ENERGY COMPANY ZdC E.

. faroczka Station Superintendent EJM/t1JB:mw

Attachment:

LER R0-81-07/3L Director, Office of Inspection and Enforcement, Washington, cc:

D.C. (30)

Director, Office of Management Information and Program Control, Washington, D.C.

(3)

U. S. Nuclear Regulatory Conraission, c/o Document Management Branch, Washington, D.C.

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s ATTACilMENT TO LER Bl-07/3L NORTNEAST NUCLEAR ENERGY COMPANY

. MILLSTONE NUCLEAR POWER STATION - UNIT 1 PROVISIONAL LICENSE NUMBER OPR-21 DOCKET NUMBER 50-245 IDENTIFICATION OF OCCURRENCE Operation in a degraded mode permitted by a: limiting condition for operation occurred when one of the six main steam safety / relief valves was found'to be inoperable.

CONDITIONS PRIOR TO OCCURRENCE Prior to the occurrence, the unit was being returned to service following a planned refueling outage.

Reactor power was less than one (1) percent of rated power; reactor pressure was 67 psig.

DESCRIPTION OF OCCURRENCE On April 18,19L1, at 0445 hours0.00515 days <br />0.124 hours <br />7.357804e-4 weeks <br />1.693225e-4 months <br /> while performing routine surveillance, flanual Operation of Relief Valves When Rea tor Is At Low Pressure, one of the six valves, 1-MS-3A, failed to open (T.S. 4.D.1.b).

The test was repeated with reactor pressure at 90 psig and 110 psig, but the valve still did not operate.

At 0705 hours0.00816 days <br />0.196 hours <br />0.00117 weeks <br />2.682525e-4 months <br />, after verifying integrity of the electrical circuitry, the solenoid was exercised several times in rapid succession using the valve manual control switch, j

.and the valve operated properly.

DESIGNATION OF APPARENT CAUSE OF OCCURRENCE Failure of the valve to operate on the first initiation signal is attributable to particulate contamination in the valve solenoid resulting from work performed in the area during the refueling outage. It is felt that this material resulted in temporary blockage in the solenoid, which was loosened and freed when the solenoid was exercised.

ANALYSIS OF OCCURRENCE The relief valves of the automatic pressure relief subsystem are a back-up to the FWCI subsystem.

They enable the core spray' or LPCI to provide protection against the small pipe break in the event of FWCI failure, by depressurizing the reactor vessel rapidly enough to actuate the core sprays or LPCI.

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" f Failure of the valve in question to open on the first' actuation signal did not result in a condition that had not been previously analyzed. 'All emergency core cooling subsystems including the remaining' safety / relief-valves were operable and would have provided the required action upon receipt of the appropriate initiation signals.

The valve in question was not declared.to be inoperable, since operability was successfully demonstrated within the time frame of the surveillance being performed.

- CORRECTIVE ACTION When the valve 'did not operate initially, integrity of the electrical control circuitry was verified. The solenoid was exercised several times in rapid succession and the valve operated properly.' The valve was subsequently operated successfully on three (3) occasions, one of which was reactor manual blowdown previously reported as R0-81-04/lT.

During the shutdown resulting from this event, the solenoid was disassembled and inspected, revealing particulate con-tamination in the solenoid.

The solenoid was cleaned, reassembled and satis-factorily bench-tested. Although there were no problems encountered with the remaining safety / relief valves, their solenoids will be disassembled,. inspected anditested prior to returning the unit to service.

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