ML19345F458

Forwards LER 80-052/03L-0.Detailed Event Analysis Submitted

ML19345F458
Person / Time
Site:	Cooper
Issue date:	01/29/1981
From:	Lessor L NEBRASKA PUBLIC POWER DISTRICT
To:	Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML19345F459	List: ML19345F458 ML19345F464
References
CNSS810058, NUDOCS 8102170515
Download: ML19345F458 (2)

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cooper NUCLEAR STATION l

Nebraska Public Power District * ' * "A*c",,ORf4;"f,'".^ii$"^""'

_J ,w CNSS810058 January 29, 1981 l

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Mr. K. V. Seyfrit. Director U.S. Nuclear Regulatory Commission J

Office of Inspection and Enforcement 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 j reportable occurrence that was discovered on December 30, 1980. In accordance with the requirements of IE Bulletin 80-17, Mr. Tom Westerman was notified by telephone on December 31, 1980. A licensee event report form is also enclosed.

Report No.: 50-298-80-52 Report Date: January 29, 1981 Occurrence Date: December 30, 1980 3 Facility: Cooper Nuclear Station i Brownville, 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 of the Technical Specifications.

Conditions Prior to Occurrence:

Steady state power operation at approximately 99% reactor power.

Description of Occurrence:

During routine surveillance testing of the RHR service water system, the Loop "A" system throttle valve, SW-MO-89A, would not respond to the remote controller after opening to the minimum flow position. The minimum flow position of the valve corresponds to

1. the minimum flow requirements of the RHR Service Water Booster Pumps.

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81021705/5 s

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• l Mr. K. V. Seyfrit l January 29, 1981 ,

l Page 2.

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I j Designation of Apparent Cause of Occurrence:

! The subject valve, SW-M0-89A, is a 18", 300# Globe valve manu-factured by Anchor / Darling Valve Company. The operator is a j

, Limitorque SMB-3. The apparent cause of the occurrence is unknown. ^

Analysis of Occurrence:

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SW-M0-89A is the service water throttle valve on the discharge of

the "A" Loop RER heat exchangar. It controls the service water j flow and maintains a minimum 20 psi differential between the ser-

, vice water and the RHR sides of the heat exchanger. Failure of this valve to operate made the "A" Loop of the RHR Service Water system inoperable. By not being able to open the valve, sufficient service water flow to heat exchanger could not be obtained. 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 subject system was initiated again in an attempt to evaluate the occurrence. During this test the system operated as designed.

Further testing is being performed on the subject valve. Recorders have been used to monitor the output of the controller, feedback from the valve positioner, and the open and close contacts on the

operator motor. These parameters will be monitored for five sub-l sequent valve operations and operability verified.

I Sincerely, l

N i L. C. Lessor Station Superintendent Cooper Nuclear Station LCL:cg Attach.

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