United States Nuclear Regulatory Commission - Protecting People and the Environment


ACCESSION #: 9705120023



                                         Manufacturers of

Automatic Switch Co.                    DEPENDABLE CONTROL

                                             Since 1888



FLORHAM PARK, NEW JERSEY 07932 o NJ-(201) 966-2000 / NY-(212) 344-3765

FAX: (201) 966-2628



                                   April 29, 1997



U.S.  Nuclear Regulatory Commission

Washington, DC 20555



ATTN: Document Control Desk



Dear Sir:



We are writing to notify you of a potential safety-related problem with

ASCO HV 266000-007/J Scram Solenoid Pilot Valves (SSPV's) possibly

supplied to several BWR Nuclear Plants through our customer, General

Electric Company.



During performance maintenance testing of SSPV's at GPU Nuclear's Oyster

Creek Nuclear Plant, some thirteen out of thirty-six SSPV's installed in

the plant exhibited excessive air leakage.  An investigation by the

utility, General Electric, and ASCO concluded that the leakage was the

result of hardening of the core disc in the SSPV pilot head.



Subsequent investigation by ASCO indicates that some SSPV's installed in

the Oyster Creek Plant may have been shipped with core discs fabricated

from commercial grade Buna-N (Nitrile) material rather than the required

nuclear grade Fluorocarbon material.



We are continuing our investigation in cooperation with the utility and

General Electric to determine the root cause of this problem and

population of suspect SSPV's.  At the present time, the evidence suggests

that the substitution of the Buna-N material occurred in a portion of the

first lot of SSPV's manufactured after a 1994 design change that changed

the core discs to the Fluorocarbon material.



We will keep you informed of the progress of our investigation.  Please

feel free to contact me at 201-966-2100 for additional information.



                                   Sincerely,

                                   AUTOMATIC SWITCH COMPANY



                                   Randy P. Smith

                                   President



RPS/ja



CC:  General Electric

     GPU Nuclear - Oyster Creek



                                                  NUC-REG DOC





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