ML20003H334

Final Deficiency Rept Re Potentially Defective GE Type AKR-30 & AKR-50 Circuit Breakers,Initially Reported on 810401.Bearing Assemblies Will Be Replaced by 811231

ML20003H334
Person / Time
Site:	Callaway
Issue date:	05/01/1981
From:	Bryan J UNION ELECTRIC CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
10CFR-050.55E, 10CFR-50.55E, ULNRC-439, NUDOCS 8105050600
Download: ML20003H334 (2)

Text

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.Y UNION ELECTRIC COMPANY soon uRA* LOT STREET ST. Louis. MissouR

""J.."."" May 1, 1981 .,. 7. if.%l',,* ..... h.,

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,-  ; .s " . *h Mr. James G. Keppler, Director 4 O.$ ~ 0*

US Nuclear Regulatory Commission ,,,pp.d Region III c, 799 Roosevelt Road -

Glen Ellyn, IL 60137 ULNRC- 3 sgh '

Dear Mr. Kcppler:

FINAL 10CFR50.55 (e) REPORT NO. U-30 GENERAL ELECTRIC SERVICE ADVICE 175-9.6 TYPE AKR CIRCUIT BREAKERS CALLAWAY PLANT UNIT 1 On April 1, 1981 we provided NRC Region III verbal notification of a 10CFR50.55 (e) Report regarding potentially defec-tive General Electric Type AKR-30 and AKR-50 circuit breakers.

Our final report, which indicates corrective action will be completed by December 31, 1981, is enclosed, Ve 'truly yours, k()

Iol,n d /%fM

. Bryag i V

RPW/jds Enclosure cc: J. E. Konklin, Region III Victor Stello, Jr., Director I&E /

W. A. Hansen, NRC Resident Inspection, Callaway Plant Missouri Public Service Commission Bo/'l s

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10CFR50. 55 (e) FINAL REPORT NO. U-30 GENERAL ELECTRIC CO. SERVICE ADVICE 175-9.6 TYPE AKR CIRCUIT BREAKERS CALLAWAY PLANT UNIT 1 INTRODUCTION By letter dated March 20, 1981 General Electric Company advised the SNUPPS A/E, Bechtel Power Corporation, of a potential problem with Type AKR-30 and AKR-50 circuit breakers. Bechtel sub-sequently advised SNUPPS and Union Electric that suspect breakers had been furnished in load centers shipped to callaway under Bechtel PO 10466-E-017-2, and on April 1, 1981 Union Electric provided notification to NRC Region III headquarters in accordance with 10CFR50. 55 (e) . It is our understanding that General Electric directly notified the NRC of this reportable defect in a January 13, 1981 letter to the Office of Inspection and Enforcement in Washington, DC.

DESCRIPTION OF DEFICIENCY General Electric advised that they have encountered a limited number of instances where electrically operated AKR-50 low voltage power circuit breaker manufactured before December 19, 1980 failed to close on command after the breaker had been left in the charged position for-several hours. The cause of this failure has been traced to deformation of a lead Teflon sleeve serving as a bearing in the breaker. The same lead Teflon sleeve bearing design was used on the AKR-30 breaker although no failures have been reported.

ANALYSIS OF SAFETY IMPLICATIONS Safety systems fed by Class lE load centers containing AKR-30 and AKR-50 breakers would be degraded if the breakers failed to'close when required.

CORRECTIVE ACTION The suspect bearing assemblies of AKR-30 and AKR-50 breakers will be replaced with ones of an improved design furnished by General Electric Company. Replacement of bearing assemblies in safety-related load centers at Callaway is controlled by Deficiency Report 2SD-3398-E.

Hold tags will remain on the load centers until all bearings are replaced. This corrective action will be completed by December 31, 1981.

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