United States Nuclear Regulatory Commission - Protecting People and the Environment


ACCESSION #: 9712300219



                              Douglas R.  Gipson

                              Senior Vice President, Nuclear Generation



                    Fermi 2

                    6400 North Dixie Hwy., Newport, Michigan 48166

                    Tel: 313.586.5201 Fax: 313.586.4172



                              Detroit Edison



10 CFR 21.21



December 23, 1997

NRC-97-0141



U.  S.  Nuclear Regulatory Commission

Attn.: Document Control Desk

Washington, D.  C.  20555



References:    1)   Fermi 2

                    NRC Docket No.  50-341

                    NRC License No.  NPF-43



               2)   Detroit Edison Letter to NRC, "10CFR21 Interim Report

                    for Emergency Diesel Generator Automatic Voltage

                    Regulator Printed Circuit Board," NRC-97-0005, dated

                    February 6, 1997



Subject:       10 CFR 21 Final Report for Emergency Diesel Generator

               Automatic Voltage Regulator Printed Circuit Board



Reference 2 submitted an interim report for notification of a potential

10 CFR 21 reportability issue related to a malfunction of the Emergency

Diesel Generator No. 11 Automatic Voltage Regulator (AVR) Printed Circuit

Board Revision B.  An analysis of the AVR board revision B determined

that malfunction of the AVR board was due to failure of the operational

amplifier U8 chip.  As part of the continuing evaluation of this failure

and to determine the root cause, the AVR board revision B was sent

offsite to an independent engineering test facility.



Detroit Edison has received the test report from the testing facility on

the U8 chip and the report has determined that failure of the U8 chip was

probably caused by a voltage spike that exceeded the maximum specified

rating of the device.  This voltage spike most likely occurred due to

arcing to ground at the Current Potential Transformer CPT2 which provides

current and voltage feedback to the AVR control circuitry.



                                        A DTE Energy Company





USNRC

NRC-97-0141

Page 2



The test report did not indicate that failure of the U8 chip was due to a

defect or deviation in the component as defined by or subject to 10 CFR

21.  Therefore, Detroit Edison has concluded that malfunction of the

Emergency Diesel Generator No. 11 Automatic Voltage Regulator (AVR)

Printed Circuit Board Revision B due to failure of the U8 chip is not

reportable under 10 CFR 21.



If you have any questions, please contact Mr.  Norman K.  Peterson,

Director, Nuclear Licensing at (313) 586-4258.



                                        Sincerely,



Enclosure



cc:  A.  B.  Beach

     B.  L.  Burgess

     G.  A.  Harris

     A.  J.  Kugler





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