ML18353B268

06/09/1975 Letter Submitting Abnormal Occurrence Report AO-11-75 Which Involves Safety Setting on Linear Power Channel of Reactor Protective System

ML18353B268
Person / Time
Site:	Palisades
Issue date:	06/09/1975
From:	Sewell R Consumers Power Co
To:	Office of Nuclear Reactor Regulation
References
LER 1975-011-00
Download: ML18353B268 (2)

Text

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• H 1 egulatory Dodtet File consumers Power company General Offices: 212 West Michigan Avenue, Jackson, Michigan 49201

• Area Code 517 788-0550 Directorate of Licensing US Nuclear Regulatory Commission Washington, DC 20555 Gentlemen:

Re: Docket License DPR-20 Palisades Plant -A0-11-75 Attached is Abnormal Occurrence Report A0-11-75 which volves a safety setting on the linear power channel of the reactor protective system. The analysis of the occurrence concluded that there was no significant effect on safety . DAB/ds CC: JGKeppler, USNRC Yours very truly, Ralph B. Sewell Nuclear Licensing Administrator

• *

• I . ** ABNORMAL OCCURRENCE REPORT Palisades Plant

• 1. Report No: A0-11-75, Docket 50-255 2a. Report Date: May 30, 1975 2b. Occurrence Date: May 29, 1975 3. Facility:

Palisades Plant, Covert, Michigan 4. Identification of Occurrence:

Linear power channel reactor protective system setting above technical specifications set point. 5. Conditions Prior to Occurrence:

Plant operating at steady-state 80 percent thermal power. 6. 7. 8. 9. 10. Description of Occurrence:

While performing monthly surveillance cedure MD-1, it was found that Channel NI-005 trip point was above the Technical Specifications limit, Table 2.3.1, of less than or equal to 106.5 percent by 0.3 percent. The set point was corrected . The linear power channel drawer was replaced with a spare. Designation of Apparent Cause of Occurrence:

Component Failure -Channel, Internal Positive 15-Volt Power Supply. Analysis of Occurrence:

The reactor protection system is a 2 out of 4 system. Inasmuch as only one channel was affected, the system remained functional.

In addition, the set point was at plus 106.8 percent whereas the safety analysis, FSAR Section 14.1, assumed a power level of 112 percent. We have concluded that this occurrence had no cant effect on plant safety. Corrective Action: Repair failed component.

Our records indicate that this is only the second failure out of 13 units in 6 years; thus, we have concluded no further action is required.

Failure Data: a. Previous Failure -Similiar Unit 10/5/72. b. Equipment Identification

-Technipower Power Supply Model 227-4170 .