ML20041G451

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Requests Amend to 810814 Record Re IE Circular 80-04, Securing of Threaded Locking Devices on Safety-Related Equipment, Due to Safety Injection Pump Failure.All Safety Injection Pumps Will Be Inspected & Action Implemented
ML20041G451
Person / Time
Site: Diablo Canyon  Pacific Gas & Electric icon.png
Issue date: 02/11/1982
From: Crane P
PACIFIC GAS & ELECTRIC CO.
To: Engelken R
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
REF-SSINS-6830 IEC-80-04, IEC-80-4, NUDOCS 8203220318
Download: ML20041G451 (2)


Text

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fir. R. H. Engelken, Director Office of Inspection and Enforcement RECENED -pj Region V g: ,

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EI Walnut Creek, CA 94596 ** E78 8 j 3'g s  :; 2 to Re: Docket No. 50-275 m .--

Docket No. 50-323 N

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IE Circular 80-04

Dear fir. Engelken:

IE Circular 80-04 (" Securing Of Threaded I ocking Devices On Safety-Related Equipment") was closed in the NRC Inspection Report 50-275/81-19 dated August 14, 1981. We wish to amend the record regarding this Circular because we have since experienced a Safety Injection Pump failure similar to that reported in IE Circular 80-04.

During routine surveillance testing on October 14, 1981 the motor for a safety injection pump exhibited current fluctuations. The pump was shut down, vented and restarted. The pump tripped on overcurrent and could not be rotated by hand. Upon disassembly, the sixth stage impeller was found fused to the sixth stage wear ring. The impeller locknuts were loose, apparently allowing the impeller to move into contact with the wear ring. The shaft bowed approximately 0.016 inches.

8203220318 820211 IEL PDR ADOCK 05000275 $( 0 G PDR i

Mr. R. H. Engelken February 11, 1982 In our earlier investigation of Circular 80-04, we had contacted the manufacturer regarding the torque requirements for the impeller l ocknuts. We were told that it was normal manufacturing practice to only hand tighten the locknuts to prevent shaft bowing caused by misalignaent of the impeller and spacer faces. He trued-up the faces of the impellers and spacers to decrease the tendency for the shaft bow and we increased the locknuts torque. The locknuts still came loose leading to the failure described.

We are working with both the manufacturer (Pacific Pump) and the NSSS supplier (Westinghouse) to resolve the problea. Use of a thread-locking compound is under investigation.

All safety injection pumps will be inspected and necessary action implemented.

Very truly yours, 2 ~

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