ML20029B506

Ack Receipt of 900907 Response to NRC 900712 Request for Addl Info Re Plan for Replacement of Two Control Element Assemblies.Commitment to Replace Assemblies Prior to Reaching Accumulated Exposure of 2,500 EFPDs Acceptable

ML20029B506
Person / Time
Site:	Fort Calhoun
Issue date:	03/07/1991
From:	Quay T Office of Nuclear Reactor Regulation
To:	Gates W OMAHA PUBLIC POWER DISTRICT
References
NUDOCS 9103110283
Download: ML20029B506 (3)

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6 March 7, 1991 Docket No. 50-285 Mr. W. Gary Gates Division Manager -~ Nuclear Operations Omaha Public Power District 444 South 16th Street Mall Mail Stop 8E/EP 4 Omaha, Nebraska 68102-2247

Dear Mr. Gates:

Thank you for your letter of September 7,1990, in response to our letter dated July 12,1990, requesting you to submit within 60 days a response regarding the plan for replacement of two Control-Element Assemblies (i.e. number 47 and 48).

We have reviewea your reply and fin.d it responsive to the concerns raised in our letter.

Your commitment to replace these CEAs before rear;hing an accumulated exposure of 2500 effective full power days is acceptable. However, you should follow the results of the Combustion Engineering Owner's Group Task 666 for the examination of selected Maine Yankee CEA fingers at a hot cell in order to develop an understandit;g of the mechanism leading to the CEA failures-(Letter, S.E. Nichols to USNRC, Maine Yankee CEA Failure Mechanism Investigation,-dated December 12,1990). When the examinaticn report becomes available (scheduled for July 1991), your replacement plan should be revisited to confirm that it remains appropriate. The staff will also continue to monitor the performance of this CEA-design as it is being phased out at other plants, end will inform you of any adverse experience which could ' impact the continued acceptabi_lity 'of your replacement plan.

Sincerely, original signed by v.

Theodore R. Quay, Director Project Directorate 11V'l Division of Reactor! Projects 111, IV,-and Y Office of Nuclear Reactor Regulation cc: See next page CO DISTRIBUTION

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March 7,1991 Docket No. 50-285 Mr, W. Gary Gates Division Mon 69er-- Nuclear Operotion.s Omabo Public Power District 444 South 16th Street Mall Moil Stop 8E/EP 4 0 moho, Nebraske 68102-2247

Dear Mr. Gates:

Thank you for your letter of September 7,1990, in response to our letter dated July 12,1990, requesting you to submit within 60 days e response regarding the plan for replacement of two Control Element Assemblies (i.e. nuinber 47 and 48),

We have reviewed your reply and find it responsive to the concerns raised in our letter.

Your commitment to replace these CEAs before reaching an accumulated exposure of 2500 effective full power days is acceptable. However, you should follow the results of the Combustion Engineering Owner's Group Task 666 for the exe:ninetion of selected Maine Yankee.CEA fingers at a hot cell in order to i

develop an understanding of the mechanism leading to the CEA failurus (letter, S.E. Nichols to USNRC, Maine Yonkee CEA feilure Mechanism Investigo!1on, dated December 12,1990). When the examination report becomes aveilable (sci,eduled

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for July 1991), your replacement plun should be revisited to confirm that it remains-appropriate. The staff will also continue to monitor the_ performance of this CEA design as it is being phased out at other plants, and will inform you of any adverse experience which could impact-the continued; acceptability of your replacement plan, Sincerely, l,f}a vcLw

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Theodore R.. Quay, Director-i'roject Olrectorate'IV-1 Division of. Reactor Projects III, IV, and Y Office of Nuclear Reactor Regulation cc:

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Mr. W. Cut ty Q (e s Omahu tablic Power 01strkt Fort Calhoun Station, Unit No. 1 cc:

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1333 New Hampshire Avenue, NW Washington, D.C.

20036 Mr. Jack Jensen, Chairman hshington County Board 1

of St.pervisc rs Blair, Nebrosta 68008 Mr. Raymond P. Mullikin, Fm ident inspector U.S. Nuclear Regulatory CutMssion Post Of fice Bo: 303

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Mr. Chorles B, Brinkman, Manager i

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12300 Twiatroak Parkway, Suite 330 Rockyil1e, ND 208S2 Regional Adminu2rator, Region IV U.S. Nuclear Regulatory Commission Of fict c' Encutive Directov-i for Opa ations 611 Ryer. Plaza Drive, Suite 1000 Arlington, Texas 76011 Harold Borchert, Director Divisien of Radiological Health Nebroska C&pirtment of Herilth 301 Centennial Mall, South Post Office Box 95007 Lincoln, Nebrasko 68509 Mr. T. L. Patterson, Nonager Fort Calhoun Station Fett Office Box 399 Fo"t Calhour, Nebreska 68023 m.,

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