ML18348A636

Unusual Event Report 75-6 Covering a Control Switch Failure Associated with the Safety Injection System

ML18348A636
Person / Time
Site:	Palisades
Issue date:	08/22/1975
From:	Bixel D Consumers Power Co
To:	Office of Nuclear Reactor Regulation
References
UE-75-6
Download: ML18348A636 (2)

Text

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Power company General Offices: 212 West Michigan Avenue, Jackson, Michigan 49201

• Area Code 517 788-0550 August 22, 1975 Division of Reactor Licensing US Nuclear Regulatory Commission Washington, DC 20555 DOCKET 50-255, LICENSE DPR-20, PALISADES PLANT, UE-75-6 Attached is Unusual Event Report 75-6 covering a control switch failure associ-ated with the Safety Injection System. This event was determined to be non-reportable because the inoperable time period fell within that allowed by the pl~nt Technical Specifications 3.3.2(c) and (e). The report is provided for your information.

David A. Bixel Assist~~t Licensing Administrator CC: JGKeppler, USNRC File

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• 1. Report Number:

UNUSUAL EVENT REPORT Palisades Nuclear Plant UE 75-6, Docket 50-255.

2. a. Report Date: August 22, 1975

b. Occurrence Date: July 18, 1975.

3. Facility: Palisades Nuclear Plant, Covert, Michigan.

4. Identification of Occurrence: Failure of a high-pressure Safety Injection motor-operated valve to open during a Technical Specifications test of the Safety Injection System.

5. Conditions Prior to Occurrence: Plant was operating at 535 MWe (80% power).

6. Description of Occurrence: On July 18, 1975 the Quarterly Technical Specifications Test of the Safety Injection System "with standby power" was conducted. This test was completed satisfactorily. Subsequent to this, the Quarterly Technical Specifications Test of the Safety Injection System, "without standby power;" was conducted. During this test the operator ob-served that high-pressure Safety Injection motor-operated Valve MOV-3011

• 7.

did not open. An operator was dispatched to the redundant Safety Injec-tion ~anel (C-33) to attempt to operate MOV-3011, using control switch 42-237. This resulted in the valve cycling between the open and closed p8§ftions.

• Apparent Cause of Occurrence: Investigation revealed that even though con-trol switch 42-237 for MOV-3011 located in the control room {Panel C0-3) was in the pr8~~r position (midposition), the closed contacts of the switch were stuck shut.

8. Analysis of Occurrence: The valve had operated properly during the test "with standby power." Consequently, the valve was in a malfunctioning state for only approximately one hour. *This condition is permitted by the plant Technical Specifications (3.3.2).

9. Corrective Action:

a. The switch was removed from service, repaired and returned to service.

The system was then retested satisfactorily.

b. A replac~ent switch has been ordered and its installation will be com-pleted as soon as practical. Further examination of the failed switch will be conducted at that time.

10. Failure Date: Failed Switch.

• .42-237 Control Switch CSI GE Type CR2940, US200BE Spring Return Bat Lever Operator