United States Nuclear Regulatory Commission - Protecting People and the Environment


ACCESSION #: 9708070153



SOR

14685 W. 105th Street o Lenexa,

Kansas 66215-5964 USA

Tel. 913.888.2630 - Fax 913.888.0767

                                                            9001

                                             REGISTERED



Mr. Anil S. Gautam, NRC



Subject:  10CFR21 dated October 14, 1994



Dear Mr. Gautam:



In July of 1993 SOR began to manufacture pressure, vacuum, and

temperature switches that were qualified by SOR test report 9058-102.  In

September of 1994 SOR was notified of a manufacturing defect by Nebraska

Public Power (Ref. RGA 2125, seven defective units) and Connecticut

Yankee (Ref. RGA 2117, one defective unit).  In addition SOR assembly

personnel had identified the same defect (Ref. MRR 1479, one defective

unit).  The defect was identified as a crack in the lead wire insulation.

This prompted SOR to issue a 10CFR21 and investigate the cause of the

defect.  The cause of the cracked insulation was a heavy coating of epoxy

on the wires outside of the potted area and was due to poor workmanship.

This condition went undetected because SOR quality inspectors did not

notice the coating of epoxy on the wires.



As noted in the Part 21 Notification, the following corrective action was

taken in October 1994:



1.   The Work Order formats for the conduit seals were revised to include

     specific instructions not to allow epoxy on the wires.  In addition,

     there is an inspection step at the end of the Work Order that

     instructs the inspector to examine the wire and reject any that have

     epoxy on the wire.  Each of these steps must be signed off on the

     Work Order by Manufacturing and QA personnel for each order of

     conduit seals.

2.   Shrink tubing was added to the lead wires where they exit the

     conduit seal.  The purpose of this tubing is to protect the wire

     insulation during shipping and handling.  This step is signed off on

     the assembly procedure by Manufacturing and it is reviewed by QA

     personnel for every switch.

3.   The wire manufacturers recommended minimum bend radius was added to

     the SOR General Instructions that are provided to the customer with

     each switch.



The conduit seals are manufactured as a sub-assembly in a separate

environmentally controlled room.  Therefore, there is no danger of epoxy

contamination on any other parts of the switches.



Reference Corrective Action Report 0357.



Regards,



Colbert Turnev, V. P. Quality                Joseph G. Modig, Engineer



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