ML20055F147

Discusses Generic Implications & Resolution of Control Element Assemblies Failure at Plant.Requests Description of Analyses Planned & Schedule for Completion of Analysis within 60 Days of Ltr Receipt

ML20055F147
Person / Time
Site:	Maine Yankee
Issue date:	07/06/1990
From:	Nerses V Office of Nuclear Reactor Regulation
To:	Frizzle C Maine Yankee
References
NUDOCS 9007130350
Download: ML20055F147 (4)

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July 6,1990 Docket No. 50-309 L

Mr. C. D. Frizzle, President U

Maine Yankee Atomic Power Company 83~ Edison Drive Augusta, Maine 04336

SUBJECT:

GENERIC IMPLICATIONS AND RESOLUTION OF CEA FAILURE AT MAINE YANKEE On June 7,-1990, while conducting cold functional testing of the control element assemblies (CEAs) following the cycle 12 refueling cutage at Maine 9

Yankee, one CEA could not be fully inserted in the core.

Subsequent inspection of the CEA revealed that the end cap was missing from the center CEA finger, the lower stainless steel spacer and boron carbide pellets had fallen out of the center finger and an axial crack existed at the lower end. The upper t

stainless steel spacer was cocked in the bottom of the CEA finger and was causing the center CEA finger to bind against the guide tube. The CEA could-not be fully inserted in the core during cold functional testing due to interference from boron carbide pellets that had fallen into the center'CEA guide tube.

On June 25,-1990, the NRC staff met with the Combustion Engineering Regulatory _

Response Group (CERRG) to-discuss the generic implications and proposed resolution of the CEA failure that occurred at Maine Yankee. The CERRG concluded;that the CEA failure was rost likely due to irradiation assisted stress corrosion cracking (IASCC). The-CERRG also concluded that the failure mechanism was only applicable to the older Corbustion Engineering'(CE) CEA design which did not have an absorber plug (other than boron carbide pellets) at-the bottom of the center CEA finger.

In order to resolve this issue, the CERRG proposed specific Action Programs for each affected licensee. The CERRG submitted its report to the NRC addressing this issue by letter dated June 26, H

1990.

It is our understanding that Maine Yankee currently has one old style CEA installed in the reactor core, and that this CEA has had no previous exposure and is located in a non-trippable_ location. -You are requested to confirm our understanding 'regarding this matter and to describe your plans for 'oture use of old style CEAs.

It is also our understanding that additional analyses are being performed to determine the Maine Yankee CEA failure mechanism. You are requested to provide a description of the analyses that you plan to complete and'your schedule for completing these analyses. Additionally, upon completion of your analyses, you are requested to submit the results to the NRC for our information.

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July 6,1990 t

Please provide your resaonse within 60 days of the date of this letter. - The.

reporting and/or record (eeping requirements contained in this-letter affect fewer.than ten respondents; therefore, OMB clearance is not required under

-Pub. L.96-511'.

Sincerely,

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Qriginal' signed by' V1ctor Herses, Acting Project Director

,t Project Directorate I-3 Division of Reactor Project - I/II Office of Nuclear Reactor Regulation r

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-OFFICIAL RECORD COPY I

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Mr. C. D. Frizzle Maine Yankee Cc:

Mr. Charles B. Brinkman tir. G. D. Whittier, Manager Manager - Washington Nuclear fluclear Engineering and Licensing Operations Maine Yankee Atomic Power Company Combustion Engineering, Inc.

83 Edison Drive 12300 Twirbrook Parkway, Suite 330 Augusta, Maine 04336 Rockville, Maryland 20852 Mr. Robert W. Blacknore, John A. Ritsber Esquire Plant Manager Ropes & Gray Maine Yankee Atomic Power Company 225 Franklin Street P.O. Box 408 Boston, Massachusetts 02110 Wiscasset Maine 04578 State Planning Officer Executive Department 189 State Street Augusta, Maine 04330 Dr. E. 1. Boulette, Vice President Operations Maine Yankee Atomic Power Company P. O. Box 408 Wiseasset,tiaine 04578 Regional Administrator, Regien 1 U.S. Nuclear Regulatory Commission 475 Allendale Read King of Prussia, Pennsylvania 19406 First $6.uien of Wiscasset Municipal Buildwo U.S. Route 1 Wiscasset, Maine 04578 Mr. Charles S. Marschall Resid.+nt Inspector Maine Yankee Atomic Power Station U.S. Nuclear Regulatory Comission P. O. Box E Wiscasset, Maine 04578 Nr. P. L. Anderson, Project Manager Mnkee Atcmic Electric Company 580 Main Street Bolton, Massachusetts 017A0-1398 l

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DISTRIBUTION,

N 50-309 NRC PDR Local PDR 1

PDI-3 Reading I

J. Partlow

. J S. Varga R. Wessman M. Rushbrook E. Leeds I

V. Nerses l

0GC(Info.only)

E. Jordan s

L. Phillips R. Hermann t

J. Tatum

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ACRS (10)

J. Johnson, Region I i

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