TXX-6764, Final Deficiency Rept CP-86-62 Re Misinterpretation of Polar Crane Load Cases.Initially Reported on 861003.Installation of Addl Rail Clips Scheduled for Completion by 871009

Final Deficiency Rept CP-86-62 Re Misinterpretation of Polar Crane Load Cases.Initially Reported on 861003.Installation of Addl Rail Clips Scheduled for Completion by 871009

ML20235G991
Person / Time
Site:	Comanche Peak
Issue date:	09/25/1987
From:	Counsil W TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
CP-86-62, TXX-6764, NUDOCS 8709300324
Download: ML20235G991 (2)

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== Log # TXX-6764

' ::- File # 10110

-Z E 903.8 Ref # 10CFR50.55(e)

Wmiam G. Counsil n=riv, vie w&"'

September 25, 1987  !

U. S. Nuclear Regulatory Commission Atto: Document Control Desk Washington, D. C. 20555.

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SUBJECT:

COMANCHE PEAK STEAM ELECTRIC STATION (CPSES) ,

DOCKET NOS. 50-445 AND 50-446 POLAR CRANE SUPPORT STRUCTURE SDAR: CP-86-62 (FINAL REPORT)

Gentlemen:

On' 0ctober 3,1986, we notified you by our letter logged TXX-6011 of a j deficiency involving a misinterpretation of the polar crane load cases which we deemed reportable under the provisions of 10CFR50.55(e). Our latest interim report logged was TXX-6493 dated June 8, 1987. This report provides an. update to the corrective action taken to date.

In previous reports, we concluded that the actual load cases recognized by the polar crane support structure were less than specified in the original design.

An analysis of the acceptability of the crane rail. structure for these reduced loads and with the conservative assumption that all loads were imposed on one end of the crane'has been completed with the following conclusions.

o The seismic event will not cause crane uplift, s o The crane rail is adequate for horizontal loads, and o The worst case for rail stability occurred for an SSE without lifted load since the addition of lifted load created an additional righting moment to counter rail overturning from the horizontal seismic load.

Using reduced loading, a finite element analysis was performed to determine I the adequacy of the rail and clips and to determine the degree of modification  ;

l or stiffening that will be required to achieve the stress allowables noted in 1 l the FSAR. Our analysis concludes that the stability of the crane rail was L maintained for seismic loads, but that the rail hold down clips were overstressed (relative to FSAR rec uirements). As a result, we have determined the weld modifications to the gircer seat, described in TXX-6011, are not required. However, DCA-31296 has been issued to provide modification details that assure the rail hold clips remain within allowable stresses for specified loads. The modification consists of installing additional rail clips.

8709300324 87092 PDR ADOCK 0500 n S P, a n ,,a ou n s, , ta si a n . w . m os

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,- l TXX-6764-September 25, 1987 f' Page 2 of 2 The installation of additional rail clips has been completed on Unit 1 and is in progress on Unit 2. . The installation of the additional Unit 2 rail clips is scheduled to be. completed by October 9, 1987. l Supporting documentation will be available at the CPSES site for your inspector's review after December 31, 1987. This extended period is necessary to allow com)letion of work, unrelated to this issue, that is necessary.for closure of tie associated work documents.

Very truly yours, SWfl W. G. Counsil CBC/gj c - Mr. R. D. Martin, Region IV Resident Inspectors, CPSES (3) l 1

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