ML19289C391

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Forwards LER 78-037/03L-0
ML19289C391
Person / Time
Site: Cooper Entergy icon.png
Issue date: 12/27/1978
From: Lessor L
NEBRASKA PUBLIC POWER DISTRICT
To: Seyfrit K
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
791227, NUDOCS 7901120130
Download: ML19289C391 (2)


Text

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0 COOPER NUCLEAR STATION

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Nebraska Public Power District

"' ~ " "A"e" *o"7EEls""^'i December 27, 1978 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 Specifications for Cooper Nuclear Station and discusses a reportable occurrence that was discovered on December 1, 1978. A licensee event report form is also enclosed.

Report No.: 50-298-78-37 Report Date: December 27, 1978 Occurrence Date: December 1, 1978 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 Table 3.2.F of the ".chnical Specifications.

Conditions Prior to Occurrence:

The reactor was at steady state power level of approximately 94% of rated thermal power.

Description of Occurrence:

During performance of an instrument check as required by Technical Specifications Table 4.2.F, pressure recorder (PC-PR-512A) was found to be indicating full scale and determined to be inoperable.

Designation of Apparent Cause of Occurrence:

The cause of the occurrence was a failed servo amplifier circuit board.

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Mr. K. V. Seyfrit December 27, 1978 Page 2.

Analysis of Occurrence:

Pressure recorder PC-PR-512A is one half of a two pen recorder.

The other half being used for suppression chamber level indication (PC-LR-ll), was operating satisfactory. PC-PR-512A and pressure indicator PC-PR-512B indicate drywell pressure. These two instru-ments have no alarm or protective functions. Pressure indicator PC-PI-512B was operable. The exact cause of the failure of the servo amplifier board could not be determined. This occurrence presented no adverse consequences from the standpoint of public health and safety.

Corrective Action:

The servo amplifier board was replaced and after satisfactory alignment the instrument was returned to service. There have been no other failures of this recorder and this failure is considered random.

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