05000311/LER-1981-023, Forwards LER 81-023/01T-0.Detailed Event Analysis Encl

Forwards LER 81-023/01T-0.Detailed Event Analysis Encl

ML20004E736
Person / Time
Site:	Salem
Issue date:	06/02/1981
From:	Uderitz R Public Service Enterprise Group
To:	Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20004E737	List: 05000311/LER-1981-023, Forwards LER 81-023/01T-0.Detailed Event Analysis Encl 05000311/LER-1981-023-01, /01T-0:on 810522,main Steam Isolation Valves Failed to Close within Required 5-s During Startup Test. Caused by Design Error.Design Change Developed to Allow for Proper Interaction of Hydraulic & Steam Closing Subsys
References
NUDOCS 8106150140
Download: ML20004E736 (3)

LER-1981-023, Forwards LER 81-023/01T-0.Detailed Event Analysis Encl

Event date:
Report date:
3111981023R00 - NRC Website

text

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PSEG Pebut Sercce Electr,c anJ Gas Comca'1y 80 Park Plaza Ne.sark N.J 07101 Pho.e 201/430 7000 e_7Ti JN

'3). # " % y a June 2, 1981 N

Mr. Boyce H. Grier J'

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Director of USNRC b:

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Office of Inspection and Enforcement d,jp, I 2 I$3j s 6f Region 1

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631 Park Avenue 4

s King of Prussia, Pennsylvania 19406

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Dear Mr. Grier:

'N'i' LICENSE NO. DPR-75 DOCKET NO. 50-311 REPORTABLE OCCURRENCE 81-23/0lT Purusant to the requirements of Salem Generating Station Unit No. 2 Technical Specifications, Section 6.9.1, we are submitting Licensee Event Report for Reportable Occurrence 81-23/0lT.

This report is required within fourteen (14) days of the occurrence.

Sincerely yours, s

~

R. A. Uderitz General Manager -

Nuclear Production CC:

Director, Office of Inspection and Enforcement (40 copies)

Director, Office of Management Information and Program Control (3 copies) 8106150 NO S

O Report Number:

81-23/OlT Report Date:

June 2, 1981 Occurrence Date:

5/22/81 Facility:

Salem Generating Station, Unit 2 Pub'.ic Service Electric & Gas Company Hancocks Bridge, New Jersey 08038 IDENTIFICATION OF OCCURRENCE:

Main Steam Isolation Valves - Closure Time Failure CONDITIONS PRIOR TO OCCURRENCE:

Mode 2 - Rx Power 0% - Unit Load OMWe DESCRIPTION OF OCCURRENCE:

Startup Procedure Sup-53 was specially developed to verify the time response of the Main Steam Isolation Valves (MS167) during hydraulic operation of the valves in coincidence with an emergency close signal.

The time response for the valves under the best conditions was 8.63 seconds.

The test results were, therefore, in excess of the allowable Technical Specification (i.e. 3.7.1.5) limit of 5 seconds.

Furthermore, in preparing a design modification to correct the above mentioned problem, an additional problem with the control cir;uit was fourd.

Specifically, a potential for an inadvertant reopening of the valves after a steam closure with a hydraulic operation in progress exists.

As specified in Technical Specification 6.9.1.81, this occurrence constituted discovery during plant life of conditions not specifically considered in the safety analysis report or technical specifications that require remedial action or corrective measures to prevent the existence or development of an unsafe condition.

DESIGNATION OF APPARENT CAUSE OF OCCURRENCE:

The designation of the apparent cause of this occurrence is design error in that the design of the valve positioning subsystem and control circuitry did not allow the hydraulic system to properly reset before the steam close circuitry actuates to close the valve.

ANALYSIS OF OCCURRENCE:

Technical Specification Surveillance Requirement 4.7.1.5 states that each main steam line isolation valve shall be demonstrated operable by verifying full closure within 5 seconds when tested pursuanc to Technical Specification Surveillance Requirement 4.0.5.

6/2/81 LER 81-23/0lT.

CORRECTIVE ACTION

A design change whic14 provides for circuitry changes (i.e. time delays, etc.) to allow for proper interactive operation of the hydraulic and steam closing subsystems has been developed.

For Unit 2, this design change (DCR-2EC-1229) was incorporated.

Subsequent to the incorporation of the DCR, the valves were retested satisfactorily with a response time of 3.9 seconds.

For Unit 1, this design change (DCR-lEC-1230) will be incorporated prior to the next startup of the unit.

This condition, for Unit 1, is not a problem during normal power operation since the Main Steam Isolation Valves are not tested.

FAILURE DATA:

Not Applicable Prepared By J. J.

Espey

/i Manager - Salem / Generating Station SORC Meeting No.

81-45 I

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