Part 21 Report - 1997-171

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 *** END OF DOCUMENT ***

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