ML20092P424

Submits Westinghouse Recommendations Re Insp of Rod Cluster Control Assemblies.Insp Revealed 21 Rods W/Wear Possibly Exceeding Allowable Limits & 12 Rods Acceptable for Reuse

ML20092P424
Person / Time
Site:	Point Beach
Issue date:	06/27/1984
From:	Fay C WISCONSIN ELECTRIC POWER CO.
To:	Harold Denton, John Miller Office of Nuclear Reactor Regulation
References
TAC-55330, TAC-55331, NUDOCS 8407060280
Download: ML20092P424 (2)

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i 11 $W PonTR COMPANY l 231 W. MICHIGAN, P.O. BOX 2046, MILWAUKEE, WI 53201 June 27, 1984 Mr. H. R. Denton, Director Office of Nuclear Reactor Regulation U. S. NUCLEAR REGULATORY COMMISSION Washington, D. C. 20555 Attention: Mr. J. R. Miller, Chief Operating Reactors, Branch'3 Gentlemen:

DOCKET NO. 50-266 CONTROL ROD WEAR POINT BEACH NUCLEAR PLANT, UNIT 1 In an August 18, 1983 letter on Unit 2 control rod wear, we informed you that we would be inspecting Unit 1 control rods during the fall 1983, outage and that we would report the results of the inspection.

Westinghouse, the NSSS vendor, examined all 33 Unit 1 rod cluster control assemblies (RCCAs) in October, 1983 during a refueling / steam generator replacement outage. Westinghouse subsequently determined that 21 RCCAs may have wear exceeding allowable operational limits. The remaining 12 RCCAs were found acceptable for reuse.

The wear is similar to that found on Unit 2 RCCAs and  ;

is postulated to be a combination of two types. One is wear occurring as a result of RCCA stepping and trip insertion. The other is wear occurring as a result of vibratory interaction between rodlets and control rod guide tube cards and sheaths during long periods of steady-state power operation with the rods essentially fully withdrawn from the core.

Based on these findings, the Westinghouse recommendations included the following: .

1. The 21 RCCAs with wear possibly exceeding allowable limits be replaced prior to continued operation.

2. The other 12 RCCAs be positioned in a neu axial position as prescribed for Unit 2 to change the wear points.

MO7060280 840627 PDR ADOCM 05000266 G pg .

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• s Mr. H. R. Denton June 27, 1984 The 21 RCCAs with wear possibly exceeding allowable limits were replaced with new RCCAs before continued operation of Unit 1. The 12 reinserted RCCAs were initially positioned in the new axial position as prescribed and will be repositioned as soon as Technical Specification Change Request No. 99 is approved. The 12 reinserted RCCAs will be reexamined during the next refueling outage. Additional Westinghouse recommendations are being studied.

If you have any questions concerning this matter, please contact us.

Very truly yours, i/

l[h I Vice President-Nuclear Power C. W. Fay Copy to NRC Resident Inspector 1

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