ML17261B078

Part 21 Rept Re Potential Common Mode Failure of OT-2 Type Reset Switches Supplied by Westinghouse.Plungers for Listed OT-2 Type Reset Switches Verified to Be in Proper Position. Separate Independent Switches for Each Train Will Be Added

ML17261B078
Person / Time
Site:	Ginna
Issue date:	06/15/1990
From:	Rich Smith ROCHESTER GAS & ELECTRIC CORP.
To:	Murley T NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation
References
REF-PT21-90 NUDOCS 9006270227
Download: ML17261B078 (9)

Text

ACCELERATED D7 TIUBUTION DEMONST1WTION SYSTEM REGULATORY INFORMATION DXSTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9006270227 DOC.DATE: 90/06/15 NOTARIZED: NO DOCKET FACIL:50-244 Robert Emmet Ginna Nuclear Plant, Unit 1, Rochester G 05000244 AUTH. NAME AUTHOR AFFILIATION SMITH,R.E. Rochester Gas & Electric Corp.

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

SUBJECT:

Part 21 rept re potential common mode failure of OT-2 type R.

reset switches supplied by Westinghouse.

DXSTRIBUTION 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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RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL A';

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TOTAL NUMBER OF COPIES REQUIRED: LTTR 23 ENCL 22

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ROCHESTER GAS AND ELECTRIC CORPORATION o 89 EAST AVENUE; ROCHESTER, N.Y. 14649.0001 TCLCQHONE ARKA cooK Tld 546.2700 June 15, 1990 U.S. Nuclear Regulatory Commission Document Control Desk Attention: Dr. Thomas E. Murley Of fice of Nuclear Reactor Regulation Washington, 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, updated 10CFR, Part 21, Evaluation and Notification. The notifica-tion concerns a potential common mode failure of OT-2 type reset switches supplied by Westinghouse during the late 1960's.

As part of corrective action taken for LER 89-016 (Due to a Design Deficiency the Failure of the SI Block/Unblock Switch Could Render Some Automatic Actuation Features of Both Trains of SI Inoperable), an evaluation of eighteen (18) main control board OT-2 type switches that are common to both trains of safeguard functions was performed'- to determine potentially disable safeguard functions. The results of this if a single failure could evaluation identified six (6) manual reset switches that could result in disabling both trains of their safeguard function if the switch failed in the reset position.

These switches are as follows: (1) Safety Injection Reset, (2)

Containment Isolation Reset, (3) Containment Spray Reset, (4)

Containment Vent Isolation Reset, (5) Feedwater Isolation Loop A Reset, (6) Feedwater Isolation Loop B Reset.

The above listed OT-2 type reset switches are used very infre-quently. These reset switches are only used following safeguards testing during the annual outage or for reset of an actual event.

))6'/5 9006270227 900+15 PDR ADOCK 05000240 PDC (

Page 2 Dr. Thomas E. Murley June 15, 1990 The plungers for all of the above listed OT-2 type reset switches have been verified to be in the proper position (i.e., plungers recessed). This ensures that contacts are in the proper position and the switches are functioning properly.

Specific information regarding failure identification and correc-tive action taken are. detailed on the enclosed Attachment I.

Should further information be required, please contact Mr., Steve Adams, Ginna Station Technical Manager, at (315)524-4446.

Very truly your ,

obert E. Smith Senior Vice President Production Engineering xco Mr. Thomas T. Martin Regional Administrator U.S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406 xco Ginna Station USNRC Senior Resident Inspector

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Attachment I Name: Robert E. Smith

Title:

Senior Vice President, Production & Engineering Facility: R.E. Ginna Nuclear Power Plant Docket No.: 50-244 Basic Component: OT-2 Type Switches Supplier: Westinghouse Electric Corporation Nature of Defect: Eighteen (18) main control board OT-2 type switches that are common to both trains of safeguard functions were evaluated to determine if a single failure could potentially disable safeguard functions. This evaluaiton identified six (6) manual reset switches that could result in disabling both trains of their safeguards function failed in the reset position.

if the switch Date Obtained: This information was developed May 29, 1990, following the completion of an Engineering evaluation of the 18 main control board OT-2 type switches.

Basic Component Affected:

Six (6) safety related main control board OT-2 type reset. switches.

Corrective Action: Immediate corrective action was to verify that the switches were in the proper position and functioning properly. This was accom-plished by verifying that the plungers were in the proper position. Further corrective action being evaluated to eliminate the single failure concern via design changes are: (1) the addition of separate independent switches for each train, or (2) rewiring and/or reconfiguring existing switches to provide adequate separation between trains A and B.

Responsible Individual for Action:

Steven T. Adams, Technical Manager, Ginna Station

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Time to Complete Action:

All reset switches affected were verified functioning properly. Corrective action to eliminate the single failure concern is planned for the 1991 annual refueling and maintenance outage.

Advice Related to Defect:

Westinghouse stipulates that the OT-2 type switches are highly reliable and have a low probability of failure. There have been no reported OT-2 type switch failures which have resulted in a common mode failure when used for manual actuation, manual block, or manual reset of safety related functions.

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