LIC-90-0741, Submits Plan for Replacement of Remaining Two Control Element Assemblies Which Contain All B4C Pellets

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Submits Plan for Replacement of Remaining Two Control Element Assemblies Which Contain All B4C Pellets
ML20059G051
Person / Time
Site: Fort Calhoun Omaha Public Power District icon.png
Issue date: 09/07/1990
From: Gates W
OMAHA PUBLIC POWER DISTRICT
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LIC-90-0741, LIC-90-741, NUDOCS 9009120106
Download: ML20059G051 (2)


Text

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Omaha PubBc Power District P.O. Box 399 Hwy. 75. North of Pt. Calhoun Fort Calhoun, NE 680234399

. 402/636-2000 1

September 7,.1990-l LIC-90-0741 U. S. Nuclear Regulatory Commission Attn: Document' Control Desk M:il Station P1-137 Washington, DC.20555 1 .

References:

- 1. Docket 50-285

2. Lettei'fromNRC-(R.F.Dudley)toOPPD(W.G. Gates) dated, July 12, 1990 Gentlemen:

SUBJECT:

Fort Calhoun Station Unit No. 1 CEA Replacement Plan l InReference2,OmahaPublicPowerDistrict(OPPD)wasrequestedtosubmit within 60 days a response regarding the plan for replacement of the' remaining  ;

twoControlElementAssemblies(CEAs)oftheoriginaldesignwhi.:hcontain i all-B 4C pellets in each CEA finger. .

1 The two CEAs in question (i.e. Numbers 47 and'48), which were inserted into the 1

core effectiveat the fullbeg,nn4.pg pevcc days of Cy(EFPD) through August 5, 1990.cle:10, have each accu Based on extensiva measurements and test data taken at Fort Calhoun Station-(FCS) for CEA strain and integrity at the end of Cycle 9 (2889 EFPD), the Maine i Yankee CEA failure data, and discussions with ABB Combustion Engineering,_OPPD  ;

plans on replacing CEA. Numbers 47 and 48 before reaching 2500 EFPD. Present ,

estimate for replacement of the CEAs is the end of Cycle 15, assuming there are no changes to the_ planned fuel cycle lengths or outage durations. If there is l any change to the planned fuel cycle lengths or outage durations, OPPD will '

adjust tae replacement dates a :ordingly to stay within 2500 EFPD.. The basis for the proposed-2500 EFPD lim.t is that forty-t.ive FCS full length CEAs of the original design were c)erated up to 2889 EFPD with no loss of integrity and no i signs of cladding cracting. As indicated in Reference 2, early signs _of degradation (e.g. cracking)wereobservedatMaineYankeeforanexposureas .

low as 2732 EFPD. The proposed 2500 EFPD limit for FCS is considerably less 1

()tji@'px'posure values to which FCS CEAs (of identical design) have been oper ited with no degradation, and it allows significant margin to the minimum exposure  ;

where CEA degradation at Maine Yankee has been observed. (

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DR ADoCK 0500o205 PDC ,

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3 U. S. Nacleae Regulatory _Cammission 11C-90-0741 l

Page 2 If you have .any questions or concerns regarding this response do not hesitate to contact us. ' >

i Sincerely,.

1 see-ab${-sbbept3V W. G. Gates-

  • Division Manager I*

Nuclear Operations.

WGG/sel.

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c: LeBoeuf, Lamb, Leiby & MacRae -

A. Bournia .NRC Project Manager- >

R. D. Martin,'NRC Regional Administrator, Region IV i R. P. Mullikin, NRC Senior' Resident Inspector- i 1

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