ML20085F576

AO AO-23-74:on 740906,three Primary Coolant Pump Mode of Operation Used W/O Min Thermal Margin/Low Pressure Trip Setpoint Raised to Tech Spec Limit.Caused by Failure of Procedures to Specify That Setpoint Should Be Changed

ML20085F576
Person / Time
Site:	Palisades
Issue date:	10/25/1974
From:	Sewell R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:	US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20085F577	List: ML20085F576 ML20085F579
References
AO-23-74, NUDOCS 8308230014
Download: ML20085F576 (2)

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Directorate of Licensing Re: Docket 50-255 US Atomic Energy Commission License DPR-20 Washington, DC 20545 Palisades Plant - AO-23-74 Gentlemen:

Attached is Abnormal Occurrence Report A0-23-Th which covers our finding of improper setting of the thermal margin / low-pressure trip set point. This abnormal occurrence was discovered during a review of these set points. The plant was in the hot standby condi-tion during this occurrence. No limits were exceeded.

Yours very truly, Ralph B. Sewell (Signed)

DAB /mel Ralph B. Sewell Nuclear Licensing Administrator CC: JGKeppler, USAEC g& D. 3'S' , ,

8308230014 741025 s,<c< h uf' PDR ADOCK 05000255 S PDR

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. . r's ('s ABNORMAL OCCURRENCE REPORT Palisades Plant

1. Report Number: A0-74-23, Docket 50-255

2. a. Report Date: October 25, 1974

b. Occurrence Date: September 6, 1974 (discovered October 16,1974).

3. Facility: Palisades Plant, Covert, Michigan.

h. Identification of Occurrence: The three-primary coolant pump (PCP) mode of operation was used without having the minimum thermal margin /

low-pressure trip set point raised to the Technical Specifications limit.

5. Conditions Prior to Occurrence: The reactor was critical in the hot standby condition.

6. Description of Occurrence: On September 6, 1974 at Ih51 the PCP operating configuration was changed from four-pump to three-pump without raising the minimum thermal margin / low-pressure trip set point to above 1750 psia as specified in the Technical Specifica-tions.

7 Apparent Cause: At the ti=e of the occurrence, the operators had no obvious mechanism to remind them that the thermal margin / low-pressure trip set point should be changed. Some such mechanism should have been provided so that, especially at such times as plant start-up, an obvious reminder is present to prevent this oversight from occurring.

8. Analysis of Occurrence: The operation of the plant in this mode -

three-PCP - was limited to the hot standty condition. Since the thermal margin / low-pressure trip is used to prevent DNB, no safety significance can be attributed to this particular incident as there was no power operation in the three-pump mode.

9. Corrective Action: Corrective action recommended by the Plant Review Committee follows:

a. Provide a tag near the flow trip point selector switch stating that thermal margin / low-pressure trip set point must be changed prior to going to the three-PCP or two-PCP mode of operation.

b. Initiate a change to Procedure Bl.0 to incorporate the same caution as above.

10. Failure Data: Not applicable.