ML19257C607

Forwards LER 79-042/03L-0

ML19257C607
Person / Time
Site:	Cooper
Issue date:	01/16/1980
From:	Lessor L NEBRASKA PUBLIC POWER DISTRICT
To:	Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML19257C608	List: ML19257C607 ML19257C615
References
CNSS800030, NUDOCS 8001290485
Download: ML19257C607 (2)

Text

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COOPER NUCLEAR STATION Nebraska Public Power District "'A"E,"o *"J'Mj;"Z",^if" 5

CNSS800030 January 16, 1980 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 Tec'cnical Specifications for Cooper Nuclear Station and discusses a reportable occurrence that was discovered on December 23, 1979. A licensee event report form is also enclosed.

Report No.: 50-298-79-42 Report Date: January 16, 1980 Occurrence Date: December 23, 1979 Facility: Cooper Nuclear Station Brownville, Nebraska 68321 Identification of Occurrence:

A condition w..ich 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 state power level of approximately 89%

of rated thermal power.

Description of Occurrence:

During a routine plant tour an operator noticed that RRR pump "lD" breaker was not charged.

Designation of Apparent Cause of Occurrence:

A screw which fastens an electrical lead to the latch monitoring switch was loose. This prevented operation of the charging motor.

Analysis of Occurrence:

The RER System provides core cooling and containment cooling as required during abnormal operational transients and postulated accidents. RHR Pump "lD" was operated on December 23, 1979 and MP9+-Me A2 1821 001 s --

8001290

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

secured at about 1420 hours0.0164 days <br />0.394 hours <br />0.00235 weeks <br />5.4031e-4 months <br /> on the same day. At about 1630 hours0.0189 days <br />0.453 hours <br />0.0027 weeks <br />6.20215e-4 months <br />, it was noticed that RHR Pump "1D" breaker was not charged. The breaker for RHR Pump "lD" could not close. Loss of RHR Pump "lD" did not affect public health and safety because the three other RHR pumps remained operable. All other Emergency Core Cooling Systems were also operable.

Corrective Action:

The RHR Pump "lD" breaker was immediately charged. After com-pleting necessary surveillance tests the breaker was removed from its cubicle and inspected. The screw on the latch monitoring switch was retightened, the continuity of the circuit was verified and the correct operation of the breaker was checked. The re-maining breakers of the same type were checked and found charged.

The latch =onitoring switch leads will be checked on all similar breakers during the next periodic inspection.

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

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