ML19274F043

Forwards LER 79-011/03L-0

ML19274F043
Person / Time
Site:	Cooper
Issue date:	05/23/1979
From:	Lessor L NEBRASKA PUBLIC POWER DISTRICT
To:	Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML19274F044	List: ML19274F043 ML19274F045
References
CNSS790250, NUDOCS 7906080253
Download: ML19274F043 (2)

Text

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) COOPER NUCLEAR STATtoN

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CNSS790250 May 23, 1979 Mr. K. V. Seyfrit U.S. Nuclear Regulatory Commission Office of Inspection and Enforcement Region IV 611 Ryan Plaza Suite 1000 Arlington, Texas 76011

Dear Sir:

This report is submitted in accordance with Section 6.7.2.B.2 of the Technical Specificat. ions for Cooper Nuclear Static,c. and discusses a reportable occurrence that was discovered on April 24, 1979. A licensee event report form is also enclosed.

Report No.: 50-298-79-11 Report Date: Shy 23, 1979 Occurrence Date: April 24, 1979 Facility: Cooper Nuclear Station Brownville, Nebraska 68321 Identification of Occurrence:

This report describes a condition which may have resulted in the limiting condition for operation established in Section 3.7.D.1 of the Technical Specifications if the condition had occurred during reactor power operation.

Conditions Prior to Occurrence:

The reactor was in cold shutdown.

Description of Occurrence:

RWCU MO-18 failed to close when manually actuated during cold shutdown. -

Designation of Apparent Cause of Occurrence:

Failure of the auxiliary contact mechanism in the GE Model CR105X contactor.

Y 7906080 463 vW

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Mr. K. V. Seyfrit May 23, 1979 Page 2.

Analysis of Occurrence:

A Group III isolation signal as defined in Table 3.2.A of the Radiological Technical Specifications actuates the CR105X contactor and if this isolation had been initiated, RWCU MO-18 may not have closed. Surveillance Procedure 6.2.1.5.2 had been performed April 6, 1979 approximately one day prior to shutdown and the automatic operation of RWCU MO-18 and the CR105X contactor was verified. 'RWCU MO-15 is the redundant inboard isolation valve for RWCU MO-18 and was operable. The failure mode of the GE Model CR105X contactor was identical to the failure mode addressed in IE Bulletin Nc. 78-05.

This occurrence presented no adverse consequences from the stand-point of public health and safety, j Corrective Action:

An approved Minor Design Change to retrofit all GE Model CR105X auxiliary conta'ctors as per IE Bulletin No. 78-05 was in progress when the subject failure occurred. However, the subject CR105X contactor had not been worked on. This Minor Design Change was completed during the April 1979 refueling outage.

Sincerely, L. C. Lessor Station Superintendent Cooper Nuclear Station LCL:cg Attach.

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