ML17334B133

Part 21 Rept Re Defective Torque Switches for in Valve Motor Operator Supplied to Plant by Limitorque Corp. Initially Reported on 870821.Caused by Inadequate Design of Double Torque Switch.Defective Switches Replaced

ML17334B133
Person / Time
Site:	Cook
Issue date:	08/26/1987
From:	Alexich M INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG
To:	Murley T NRC, NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
REF-PT21-87, REF-PT21-87-054-000 AEP:NRC:0971D, AEP:NRC:971D, PT21-87-054-000, PT21-87-54, NUDOCS 8709020271
Download: ML17334B133 (6)

Text

REQULATO INFORMATION DISTRIBUTION ~TEM (RIDS)

ACCESSION NBR: 8709020271 DOC. DATE: 87/08/26 NOTARIZED: NO DOCKET FACIL: 50-315 Donald C. Cook Nuclear Power Planti Unit ii Indiana 5 05000315 50-316 Donald C. Cook Nuclear Power Planti Unit 2i Indiana 5 05000316 AUTH. NAME AUTHOR AFFILIATION Al EXICHi M. P. Indiana 5 Michigan Electric Co.

RECIP. NAME RECIPIENT AFFILIATION MURLEYi T. E. Document Control Branch (Document Control Desk)

SUBJECT:

Part 21 rept re defective torque switches for SMB-000 valve motor operator supplied to plant bg Limitorque Corp.

Initially reported on 870821. Caused bg inadequate design of double torque switch. Defective switches replaced.

DISTRIBUTION CODE: *OPED COPIES RECEIVED: LTR TITLE: OR/Licensing Submittal: Equipment i ENCL Qualification 0 SIZE:

NOTES:

RECIPIENT COP IES REC IP I ENT COP IES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD3-3 LA PD3-3 PD WIGQINGTONe D INTERNAL: ARM/DAF/LFMB QC NRR/DEST/*DE NRR/DEST/MEB 1 NRR/ ESTHER OQC/HDS1 1 1 01 RES/DE/EIB 1 1 EXTERNAL: LPDR NRC PDR NSIC TOTAL NUMBER OF COPIES REQUIRED: LTTR 14 ENCL

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INDIANA 8 MICHIGAN ELECTRIC COMPANY P.O. BOX 16631 COLUMBUS, OHIO 43216 August 26, 1987 AEP:NRC:0971D Donald C. Cook Nuclear Plant Units 1 and 2 Docket Nos. 50-315 and 50-316 License Nos. DPR-58 and DPR-74 10 CFR 21 NOTIFICATION: INADEQUATELY DESIGNED TORQUE SWITCHES IN VALVE MOTOR OPERATORS U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555 Attn: T. E. Murley

Dear Dr. Murley:

Pursuant to 10 CFR 21, this letter is being submitted to provide written notification of the existence of a defect associated with torque switches for the SMB-000 operator supplied to the D. C. Cook Nuclear Plant by the Limitorque Corporation via Hammel-Dahl & Jamesbury Controls Company. Initial notification was made in a telephone conversation between representatives of the American Electric Power Service Corporation and Mr. D. C. DiIanni of the NRC Office of Nuclear Reactor Regulation on August 21, 1987.

On August 13, 1987, a Limitorque torque switch on one of the DC auxiliary feedwater regulating valve operators (SMB-000) shorted during MOVATS (motor-operated valve analysis and tesLing system) testing.

After the torque switch failed, the failure was analyzed by American Electric Power personnel, and on August 21, 1987, it was concluded that the switch failure was sufficient to cause a potential safety hazard.

This was based on the fact that failure of the switch could leave the safety-related valve incapable of remotely changing position (electrically). During procurement of the torque switches for the auxiliary feedwater regulating valves, we requested a double pole, double torque switch for the SMB-000 operator; therefore, the supplied torque switch was not of standard Limitorque design.

The standard SMB-OOO, double torque switch, breaks one set of series connected contacts in the opening rotation and a second set in the closing rotation. The double break, single pole switches were modified at Limitorque by removing the jumper straps between the series connected contacts. Removal of the jumper straps provides four separate terminations for each torque rotation, thus producing a double pole, double torque switch design.

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Dr. T. E. Murley 8Q-getup~

We have procured negfopqge switches of the standard design in order to replace the defective 4wi/tchee.tpgontrol

~y f8 circuitry for the motor operators involved have been revxsee to allow the standard SMB-000 torque switch design.

-We are not aware of other facilities or activities subject to 10 CFR 21 to which these switches have been supplied.

This document has been prepared following Corporate procedures which incorporate a reasonable set of control@ to insure its accuracy and completeness prior to signature by the undersigned.

Very truly yours, M. Alexi Vice President cm cc: John E ~ Dolan W.'. Smith, Jr. - Bridgman R. C. Callen G. Bruchmann G. Charnoff NRC Resident Inspector - Bridgman A. B. Davis - Region III

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