05000298/LER-1980-034, Forwards LER 80-034/03L-0

Forwards LER 80-034/03L-0

ML19340B187
Person / Time
Site:	Cooper
Issue date:	10/01/1980
From:	Lessor L NEBRASKA PUBLIC POWER DISTRICT
To:	Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML19340B188	List: 05000298/LER-1980-034, Forwards LER 80-034/03L-0 05000298/LER-1980-034-03, /03L-0:on 800908,during Routine insp,4160-volt Breaker RHR Id Found Not Capable of Closing Automatically. Caused by Failure of GE Magna Blast 4160 Vac Breaker to Charge Rendering Pump Inoperable.Switch Replaced
References
CNSS800581, NUDOCS 8010210633
Download: ML19340B187 (2)

LER-1980-034, Forwards LER 80-034/03L-0

Event date:
Report date:
2981980034R00 - NRC Website

text

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1 COOPER NUCLEAR STATION P.o. Box 98, SRoWNVILLE. NEBR ASKA 68321 Nebraska Public Power D. tr. t is ic TEtEP~o~E son.2s.3.n 1

CNSS800581 October 1, 1980 Mr. K. V. Seyfrit, Director U.S. Nuclear Regulatory Commission Offica of Inspection and Enforcement Region IV 611 Ryan Plaza Drive.

Suite 1000 3

Arlington, Texas 76011

Dear Sir:

This report is submitted in accordance with Section 6.7.2.B.2 cf the Technical Specifications for Cooper Nuclear Station and discusses a reportable occurrence that was discovered on September 8, 1980.

Mr.

Spangler wil notified on September 8,- 1980 in accordance with the re-quirements of IE Bulletin No. 80-17.

A licensee event report form is also enclosed.

Report No.:

50-298-80-34 Report Date:

October 1, 1980 Occurrence Date: September 8, 1980 Facility:

Cooper Nuclear Station Brownville, Nebraska 68321 Identification of Occurrence:

A condition which lead to operation in a degraded mode permitted by a limiting _ condition for operation established in Section 3.5:A.4 of the Technical Specifications.

Conditions Prior to Occurrence:

The reactor was at a steady stat, power level of approximately 100%

of rated thermal power.

Description of Occurrence:

During routine plant inspection, an operator observed the 4160V breaker for RHR pump 1D was not capable of automatically closing and starting the subject pump.

Designation of Apparent Cause of Occurrence:

The breaker's ' closing spring was not compressed (charged). The failure to. charge was caused by the latch menitoring switch which did not close. The latch monitoring switch is operated by the closing latch stop. This stop failed to return to its normal position 'af ter-the breaker tripped because of friction inside the spring release solenoid.

1. ,,(,

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f e-u-

o Mr. K. V. Seyfrit October 1, 1980 Page 2.

Analysis of Occurrence:

The inability of RHR 1D breaker to close automatically made RHR 13 pump inoperable for approximately 20 hours2.314815e-4 days <br />0.00556 hours <br />3.306878e-5 weeks <br />7.61e-6 months <br />. The remaining three RHR pumps, both core spray pumps, and both diesel generators were operable.

This occurrence presented no adverse consequences from the stand-point of public health and safety.

Corrective Action

Breaker RHR 1D was immediately removed and replaced with an id-entical spare. The breaker which failed to charge was disassembled and thoroughly inspected. The bracket holding the spring release solenoid was adjusted and the latch monitoring switch was replaced.

Free travel of the closing latch stop assembly and correct oper-ation of the latch monitoring switch were verified.

Sincerely, f

m L. C. Lessor Station Superintendent Cooper Nuclear Station L

LCL:cg l

Attach.

1 l