ML17250B249

Forwards 10CFR21 Evaluation & Notification Re Design Defect of Solid State Switch Printed Circuit Cards for 480 Volt Safeguards Undervoltage Monitoring/Protection Sys

ML17250B249
Person / Time
Site:	Ginna
Issue date:	09/04/1991
From:	Mecredy R ROCHESTER GAS & ELECTRIC CORP.
To:	Murley T NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation
References
REF-PT21-91 NUDOCS 9109160088
Download: ML17250B249 (9)

Text

ACCELERATED DISQUBUTION DEMONST1TION SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9109160088 DOC.DATE: 91/09/04 NOTARIZED: NO DOCKET FACIL:50-244 Robert Emmet Ginna Nuclear Plant, Unit 1, Rochester G 05000244 AUTH. NAME AUTHOR AFFILIATION MECREDY,R.C. Rochester Gas & Electric Corp.

RECIP.NAME RECIPIENT AFFILIATION MURLEY,T.E. Office of Nuclear Reactor Regulation, Director (Post 870411

SUBJECT:

Forwards 10CFR21 evaluation 6 notification re design defect of solid state switch printed circuit cards for 480 volt safeguards undervoltage monitoring/protection sys.

DISTRIBUTION CODE IE19D COPIES RECEIVED:LTR ENCL SIZE:

TITLE: Part 21 Rept (50 DKT) S NOTES:License Exp date in accordance with 10CFR2,2.109(9/19/72). 05000244 /

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TOTAL NUMBER OF COPIES REQUIRED: LTTR 17 ENCL 16

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ROCHESTER GAS AND ELECTRIC CORPORATION o 89 EAST AVENUE, ROCHESTER, N.Y. 14649-0001 1CLEPHONC AREA coDK 7ld 546-2700 September 4, 1991 U.S. Nuclear Regulatory Commission Document Control Desk Attention: Dr. Thomas E. Murley Office of Nuclear Reactor Regulation Nashington, DC 20555

Subject:

Notification of 10CFR, Part 21 R. E. Ginna Nuclear Power Plant Docket No. 50.244 License No. DPR-18

Dear Dr. Murley:

Rochester Gas and Electric Corporation is submitting the attached 10CFR, Part 21, Evaluation and Notification. The notification concerns a design defect of solid state switch printed circuit cards for the 480 Volt Safeguards Undervoltage Monitoring/Protection System, which has reduced the useful life of the electronic components and causes premature failures. The solid state switch printed circuit cards were supplied by ABB Electro-Mechanics, Inc., which were custom designed for our Undervoltage Monitoring/Protection System.

Extensive corrective actions have been taken to assure continued operability of the 480 Volt Safeguards Undervoltage Monitoring/Protection System. The periodic test procedure for the undervoltage relay testing has been enhanced to provide complete end-to-end testing on a monthly basis. (End-to-end testing had previously been performed on an annual basis.) In addition, all solid state switch cards will be replaced with qualified spare components in the near future. Further evaluations will be conducted to completely alleviate the potential failure mechanism.

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Page 2 Dr. Thomas E. Murley August 30, 1991 Specific information regarding failure identification and corrective actions taken are detailed on the enclosed Attachment I. Should further information be required, please contact Mr. Steven Adams, Ginna Station Technical Manager, at (315) 524-4446.

Very truly yours, Robert C. Mec edy Vice President Ginna Nuclear Production xc'r. Thomas T.

Regional Martin Administrator U.S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406 xc: Ginna Station USNRC Senior Resident Inspector

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Attachment I Name: Robert C. Mecredy

Title:

Vice President, Ginna Nuclear Production Facility: R. E. Ginna Nuclear Power Plant Docket No.: 50-244 Basic Component: Solid State Switch Printed Circuit Cards Supplier: ABB Electro-Mechanics, Inc.

Nature of Defect: Eight (8) Undervoltage Monitoring/Protection System solid state switch printed circuit cards have been degraded due to excessive heat generation. The present circuit design results in fairly high temperatures at the circuit card. This high temperature reduces the useful life of electronic components and causes them to fail prematurely. As identified in LER 91-008 (During Maintenance, A Failure of One of Two Trains of Undervoltage Protection, Was Discovered on Safeguards 480 Volt Bus 14), the card failure may result in a loss of protective functions requiring a 1 out of 2 plus 1 out of 2 coincidence, which includes stripping of the safeguards bus on an underyoltage condition.

Date Obtained: This information was developed August 30, 1991, during the evaluation in support of drafting and reviewing LER 91-008.

Basic Component Affected:

The solid state switch printed circuit cards are used in the Safeguards 480 Volt Bus Undervoltage Monitoring/Protection Systems providing protection for safeguard buses 14, 16, 17, and 18. There are two (2) cards used for each bus.,

Corrective Action: Immediate corrective actions included replacement of the Bus 14 solid state switch printed circuit cards and enhancing the periodic test procedure to detect card failures. The enhanced periodic test procedure ensures that complete end-to-end testing, of the undervoltage system, is performed on a monthly basis.

All safeguards buses solid state switch printed circuit cards will be changed out.

Safeguards Buses 14 and 16 have been completed and safeguards Buses 17 and 18 will be done as soon as replacement cards become available.

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Attachment I (continued)

Rochester Gas and Electric Engineering Department will be. evaluating the design of the Safeguards 480 Volt Buses Undervoltage Monitoring/Protection System and will make recommendations for improvement to prevent recurrence of the problems experienced.

Responsible Individual for Action:

Steven T. Adams, Technical Manager, Ginna Station Time to Complete Action:

All safeguards buses solid state switch printed circuit cards will be changed out as soon as qualified spare components become available, which is currently estimated for September, 1991. Enhanced periodic testing has been initiated, and will continue to be performed on a monthly basis. The Engineering evaluation and implementation of any design changes will be completed by the end of the 1993 annual refueling and maintenance outage.

Advice Related to Defect:

The solid state switch card design for the Ginna 480 Volt Undervoltage Monitoring/Protection System was a custom design for Rochester Gas and Electric. The design defect has reduced the expected useful life of the solid state switch card. See LER 91-008, Docket No. 50-244 for additional details.

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