TXX-6363, Interim Deficiency Rept CP-86-79 Re Possible Overtightening of Contact Cartridge Terminal Screws on Westinghouse AR Relays.Initially Reported on 861107.Review of Contact Operability for Wrenches Continues.Next Rept by 870622

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Interim Deficiency Rept CP-86-79 Re Possible Overtightening of Contact Cartridge Terminal Screws on Westinghouse AR Relays.Initially Reported on 861107.Review of Contact Operability for Wrenches Continues.Next Rept by 870622
ML20205Q857
Person / Time
Site: Comanche Peak  Luminant icon.png
Issue date: 03/30/1987
From: Counsil W, Keeley G
TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
CP-86-79, TXX-6363, NUDOCS 8704060092
Download: ML20205Q857 (2)


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P9 Log # TXX-6363 File # 10110

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= = Ref # 10CFR50.55(e) nlELECTRIC DENa.,,, March 30, 1987 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555

SUBJECT:

COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)

DOCKET NOS. 50-445 AND 50-446 OVER-TORQUED WESTaGH0VSE AR RELAYS SDAR: CP-86-79 (INTERIM REPORT)

Gentlemen:

On November 7,1986, we verbally notified your Mr. T. Westerman of a deficiency involving the possible overtightening of the contact cartridge terminal screws on the Westinghouse AR Relays. This is an interim report of a potentially reportable item under the provisions of 10CFR50.55(e). We have submitted interim reports, logged TXX-6141 and TXX-6253 dated December 5, 1986, and January 27, 1987, respectively.

Conceivably, overtightening of the terminal screws could have deformed the stationary contact assembly, reduced contact overtravel, and resulted in a loss of contact continuity. These terminal screws have a specified torque requirement of 9.5 0.5 inch-pounds. The accuracy of the torque wrench used at CPSES may have allowed an.overtorqued or undertorqued condition on the terminal screws. The accuracy of the torque wrench, when set for 9.5 inch-pounds, allowed a range of 9.5 1.5 inch-pounds.

Preliminary review results have indicated that no material deformation would occur (at 11.0 inch-pounds) which would cause the relay contact to malfunction. Additionally, it was previously thought that some torque wrenches used for this application had a calibration range which did not encompass-the Westinghouse specified range. Our evaluation has determined that all torque wrenches used had a calibration range which encompassed the Westinghouse specified range (9 to 10 inch-pounds). However, review of contact operability for their qualified life is continuing.

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TXX-6363 March 30, 1987 Page 2 of 2 We are continuing our evaluation and anticipate submitting our next report by June 22, 1987.

Very truly yours, W. G. Counsil G. S. Keeley Manager, Nuclear Lic sing RDD/dl c - Mr. E. H. Johnson - Region IV Mr. D. L. Kelley, RI - Region IV Mr. H. S. Phillips, RI - Region IV

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