ML20034B468
| ML20034B468 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 04/20/1990 |
| From: | Grimes B Office of Nuclear Reactor Regulation |
| To: | Recasha Mitchell GENERAL ELECTRIC CO. |
| References | |
| NUDOCS 9004270211 | |
| Download: ML20034B468 (2) | |
Text
.
April 20. 1990 i
s Mr. Robert C. Mitchell, Manager l
Nuclear Products Licensing t
GE Nuclear Energy i
175 Curtner Avenue San Jose, California 95125
Dear Mr. Mitchell:
(
On March 20 1990, a GE Model AK A 50 480 volt circuit breaker failed to automatically trip at the Pilgrim Nuclear Power Station during an auto-transfer
.i from one safety-related bus to another in preparation for surveillance activi.
i ties. The root cause of the breaker f ailure has been detemined to be a missing 4
retaining clip on one end of the trip / latch pivot pin. This missing retaining clip allowed nevenent of the pivot pin out of its support which ap?arently then led to failure of the breaker to tri). This breaker as well as otier 480 volt AK brealtrs were overhauled /refurbisied in 1987 by the GE Breaker Plant Operations Service Center, Philadelphia, Pennsylvania.
The licensee examined other 480 volt circuit breakers and identified additional instances of misaligned and niissing parts, such as washers and lock nuts.
Most of these breakers had also been overhauled / refurbished by the GE Philadelphia Service Center in 1987 While the licensee's and our review of i
this matter is not complete, the initial infomation does raise questions on.
your control of circuit breakers during manufacture and subsequent control of overhaul / refurbishing activities.
+
The staff is interested in actions planned by GE Nuclear Energy to address' the apparent generic implications of these GE breaker failures. We would appreciate your keeping us apprised of your findings, conclusions, and any follow-up actions you plan to take regarding this issue.
Should you have any questions concerning this letter, please call se or
^
Bill Brach of nty staff, phone (301) 492-0961.
Sincerely, OrigirirdshrlodW l
Brian K. Grines, Director l
Division of Reactor Inspection and Safeguards j
Office of Nuclear Reactor Regul6 tion DISTRIBUTION:
see page 2
- Previously concurred.
i l
^ (8 lFC- :VIB:DRl5:hhR:VIB:DRI5;NRR:C:VI :DRIS :D:pR5:pRr e
W----:
W -------:f.Kfd me t....:rt \\ tA
- c -- --:------------:------ -----:---------
- LWrach*
AME : At c n re
- UPot povs*
p....:.. 1........)...........::............:............::.........
ATE 14/09/90:mkm :4/
90
- 4/11/90&4/16:4// 4 90 i
0FFICIAL RECORD COPY Docunent Name: LETTER TO STRAMBACK 3
p 9004270211 900420 i
PDR ADOCK 05000293 S
FDC
l J
9 l
t Mr. Robert C. Mitchell 2-April 20. 1990-I DISTRIBUTION
- centrai nies PDR
{
DRIS R/T i
VIB R/F i
TEMurley FJMiraglia JPartlow WTRussell l
CERossi BKGrines EWBrach Thovak, AEOD PBaranowsky CBerlireger JRamsey VPotapovs i
RMcIntyre
,