ML19353A223

Forwards LER 80-042/03L-0

ML19353A223
Person / Time
Site:	Cooper
Issue date:	11/18/1980
From:	Lessor L NEBRASKA PUBLIC POWER DISTRICT
To:	Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML19353A224	List: ML19353A223 ML19353A226
References
CNSS800638, NUDOCS 8101070507
Download: ML19353A223 (2)

Text

s COOPER NUCLEAR STATION

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CNSS800638 November 18, 1980 --

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Mr. K. t'. Seyfrit, Director  !

U.S. Nuclear Regulatory Coc: mission h .

Office of Inspection and Enforcement M Region IV [

611 Ryan Plaza Drive Suite 1000 Arlington, Texas 76011

Dear Sir:

This report is submitted in accordance with Section 6.7.2.B.2 of the Technical Specifications for Cooper Nuclear Station and discusses a report.able occurrence that was discovered on October 20, 1980. 'A li-censee event report form is also enclosed.

Report No.: 50-298-80-42 Report Date: November 18, 1980 Occurrence Date: October 20, 1980 Facility: Cooper Nuclear Station Brownv111e, Nebraska 68321 Identification of Occurrence:

Conditions leading to operation in a degraded mode permitted by a limiting condition for operation as delineated in Section 3.5.B.3 of the Technical Specifications.

Conditions Prior to Occurrence:

Steady state power operation at approximately 100% reactor power.

Description of Occurrence:

During routine surveillance testing of the RHR containment cooling system, SW-MO-89A failed to close completely.

Designation of Apparent Cause of Occurrence:

The subject valve, SW-MO-89A, is a 18", 300# Globe valve manu-factured by Anchor / Darling Valve Company. Due to a worn key groove, the valve stem clamp slipped out of position allowing the valve stem to rotate causing the motor operator limit switches to indicate that the valve was fully closed when it'actually was not.

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4 Mr. K. V. Seyfrit November 18, 1980 Page 2.

Analysis of Occurrence:

SW-MO-89A is the throttle valve on the discharge of the "A" Loop RHR heat exchanger for the service water side. It controls the service water flow and maintains a minimum 20 psi differential between the service water and the RER sides of the heat exchanger.

Failure of this valve to operate made the "A" loop of the RHR system inoperable. In the event of an emergency, the "B" loop was operable as well as both diesel generators. This event presented no adverse consequences from the standpoint of public health and safety.

Corrective Action:

The stem clamp was returned to it's proper position and the stem clamp was temporarily tack welded to it's key. This was done to

, compensate for a worn kcy groove in the stem clamp. The limit switches were reset and valve operability verified. The valve was returned to service af ter performance of the appropriate surveil-l lance procedures. SW-MO-89A was inoperable for seven hours.

On November 6, 1980, SW-MO-89A was scheduled out of service and the stem clamp and key were replaced.

i Sincerely, l

k /t h j L. C. Lessor

Station Superintendent l Cooper Nuclear Station I

LCL:cg Attach.

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