ML20083Q704

Final Deficiency Rept U-65 & Part 21 Rept Re Gould Containment Cooling Fan Starter Interlock Failure.Initially Reported on 831123.Interlocks Cleaned & Operated Properly. Four Replacement Interlock Mechanisms Installed

ML20083Q704
Person / Time
Site:	Callaway
Issue date:	04/10/1984
From:	Schnell D UNION ELECTRIC CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
REF-PT21-84-254-000 PT21-84-254, PT21-84-254-000, U-65, ULNRC-796, NUDOCS 8404230197
Download: ML20083Q704 (2)

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UNION ELECTRIC COM PANY 1908 GRATIOT STREET ST. Louis, MISSOURI

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Mr. James G. Keppler Reaional Administrator US Nuclear Regulatory Commission Region III ULNRC- 79 6 799 Roosevelt Road Glen Ellyn, IL 60137

Dear Mr. Keppler:

FINAL 10CFR50.55 (e) /PART 21 REPORT NO. U-65 CONTAINMENT COOLING FAN STARTER INTERLOCK FAILURE CALLAWAY PLANT On November 23, 1983, Union Electric informed the NRC Region III Office of a potential 10CFR50.55 (e)/PNE 21~ deficiency concerning failure during initial testing of a mechanical interlock on Gould Motor Control Center size 5 two speed starters for Containment Cooling Fan Motors. On January 6, 1984, Union Electric filed Interim 10CFR50.55(e)/PART 21 Report No. U-65 with the NRC Region III office. A verbal extension was obtained from Mr. F. J. Jablonski, Region III on April 4, 1984, extending the due date for this response until April 19, 1984. On April 6, 1984, Union Electric confirmed that this item was reportable under the criteria of 10CFR50.55 (e) /PART 21.

Gould has been contacted by our A/E, Bechtel Power Corporation, and has stated that they are not aware of a generic deficiency with the interlock mechanism. Initial inspection by Gould determined that the failure was due to weak interlock springs. However, subsequent to that determination, the interlocks were thoroughly cleaned by Union Electric and operated properly. Gould presently attributes the failure to possible dirt contamination during shipping or storage.

Since Gould's final determination of the cause of the failure can not be substantiated by analysis, Union Electric has received and installed four replacement interlock mechanisms on the two-speed starters for the Containment Cooling Fan Motors.

Subsequently, we have not experienced sticking or unreliable operation of the new interlocks.

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+ s Regarding 10CFR50.55 (e) reportability, Union Electric believes that the failure of the interlock mechanism could have prevented the Containment Cooling Fans from transferring from high speed (normal operation) to low speed (LOCA condition).

Therefore, this item is reportable under the guidelines of 10CFR50.55(e). This is our final report on this subject.

Very truly yours,

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( Don'A5$1 F Schnell f v MAC/glp V cc: B. L. Forney, NRC Region III Richard DeYoung, Director I & E NRC Resident Inspectors, Callaway Plant (2)

Missouri Public Service Commission