05000298/LER-1980-017, Forwards LER 80-017/03L-0

Forwards LER 80-017/03L-0

ML19344B329
Person / Time
Site:	Cooper
Issue date:	07/16/1980
From:	Lessor L NEBRASKA PUBLIC POWER DISTRICT
To:	Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML19344B330	List: 05000298/LER-1980-017, Forwards LER 80-017/03L-0 05000298/LER-1980-017-03, /03L-0:on 800618,during Surveillance Testing of HPCI Steam Line Low Pressure Instruments,Hpci Steam Supply Was Isolated Leaving Sys Inoperable.Probably Caused by Failure of Pressure Switch HPCI-PS-68B
References
CNSS800433, NUDOCS 8008260622
Download: ML19344B329 (2)

LER-1980-017, Forwards LER 80-017/03L-0

Event date:
Report date:
2981980017R00 - NRC Website

text

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COOPER NUCLEAR 57ATioN Nebraska Public Power District

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i CNSS800433 July 16, 1980 Mr. K. V. Seyfrit U.S. Nuclear Regulatory Commission 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 reportable occurrence that was discovered on June 18, 1980. A licensee event report form is also enclosed.

Report No.:

50-298-80-17 Report Date:

July 16, 1980 Occurrence Date: June 18,1980 Facility:

Cooper Nuclear Station Brownville, Nebraska 68321 Identification of Occurrence:

A condition occurred which resulted in operation in a degraded mode as permitted by the limiting condition for operation established in Section 3.5.C.2 of the Technical Specifications.

Conditions Prior to Occurrence:

The reactor was operating at a steady state power level of approx-imately 93% of rated thermal power.

Description of Occurrence:

During routine surveillance testing of the HPCI steam line low pressure instruments (HPCI-PS-68A, B, C, and D), HPCI isolation occurred when PS-68D was removed from service following testing PS-68A and B.

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Mr. K. V. Seyfrit July 16, 1980 Page 2.

Designation of Apparent Cause of Occurrence:

Instrument failure. The contacts cf HPCI-68E switch apparently do not fully open each time the switch is operated.

Analysis of Occurrence:

HPCI steam supply valve, HPCI-MO-16, will shut when both HPCI-PS-68B and 68D contcets are closed. Occasionally, while testing PS-68D, the isolation valve will shut isolating the steam supply.

Consequently, the contacts of ?S-68B must be cicsed or partially closed for the isolation to occur. Subsequent testing of the pressure switches produced a similar isolation signal at the same place in the procedure. With the exception of several ninutes that the isolation signal was present, the HPCI system was operable and would have performed its intended safety function, if required. At the time of the occurrence, the redundant system, Automatic De-pressurization System, as well as Reactor Core Isolation Cooling and the Low Pressure Injection Systems were operable. This occur-rence presented no adverse consequences from the standpoint of public health and safety.

Corrective Action

The switch, HPCI-PS-6SB has been replaced. The surveillance test and maintenance practices used in the test were reviewed and were found to be adequate. The maintenance history of these switches was reviewed and this does not appear to be a generic problem.

Because of the inconclusive results of the analysis, performance of the switches will be closely monitored during future testing.

Sincerely, f

L. C. Lessor Station Superintendent Cooper Nuclear Station I

LCL:cs Attach.

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