ML20003A134

Summarizes 801224 Telcon Rept Re Generic Deficiency in Analytical Techniques Used by Bechtel in Design of Pipe Whip Restraints Used for Std Power Block.Bechtel Reviewing Design Calculations.Final Rept Not to Be Issued Until 810228

ML20003A134
Person / Time
Site:	Wolf Creek, Callaway
Issue date:	01/23/1981
From:	Seiken S STANDARDIZED NUCLEAR UNIT POWER PLANT SYSTEM
To:	Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
10CFR-050.55E, 10CFR-50.55E, SLNRC-81-003, NUDOCS 8101290690
Download: ML20003A134 (2)

Text

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SNUPPS Standardized Nach Unit Power Plant System '?

January 23, 1981 s c m .cw,,,noa4 5'$dNo'***** SLNRC 81-003 FILE: 0491.10.2/C-202B SUBJ: Pioe Whio Restraint Design Discrecancies Mr. Boyce Grier Directer, Region I 8  %

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U.S. Nuclear Regulatory Commission ,,

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631 Park Avenue T' King of Prussia, Pennsylvania 19406 2; J AN 2 8 '.931 E3 *Q Ref: STN 50-482 "N ,-

STN 50-483 STN 50-486 ~ .v . -s e [-

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Dear Mr. Grier:

On December 24, 1980, NRC Region I (Mr..J., Mattia) was informed by the SNUPPS QA Manager (Selken) of a potential generic deficiency in the analytical techniques used by the Bechtel Power Corporation in design of pipe whip restraints used for the SNUPPS standard power block. The problem reported to Mr. Mattia involves nonconservative techniques used by Bechtel in addressing tne dynamic impaci. effects on the restraints.

As a result, the possibility exists that the energy absorbing devices (Energy Absorbing Material and upset rods) do not adequately account for the postulated impact of the pipe under all conditions. The restraints involved are mostly those for pipe diameter Size 4 inches or less.

Other conservatisms normally used in the analysis may possibly offset some portion of this problem; however, these conservatisms are difficult to quantify. As a result, it was concluded that the problem would be treated and reported to the NRC as a potential generic deficiency under 10CFR50.55(e) criteria. We are advised by Bechtel that this problem is <

unique to the SNUPPS units only.

In the Dec. 24th telecon report, it was indicated that Bechtel was proceeding to review earlier design calculations to determine speci-fic restraints which are effected by this problem. A final report indicating the scope and extent of the problem and a plan of remedial and corrective actions were anticipated within the normal 30 day re-porting period. Although these actions are well advanced, they will not be completed for another several weeks. Consesquently, a final report will not be issued until Feb. 28, 1981. Mr. Carlson, Region I, NRC, was informed on Jan. 20th of this revised schedule for issuanca l$ -

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SLNRC 81-003 Page Two of the final report and suggested a summary be provided to the NRC for use as an interim report. We trust the summary described herein will prove sufficient in this regard.

'very + rul y yours, S. J. beiken QA Manager SJS:dck:5a26 cc: Mr. J. A. Keppler, Director, Region III USNRC Mr. W. Wescott, Region III, USNRC Mr. Karl Seyfrit, Director, Region IV, USNRC

• 'Mr. Victor Stello, Jr., Director, Office of Inspection and Enforcement, USNRC, Washington, D.C.

T. Vandel, Wolf Creek Resident Inspector, USNRC W. Hansen, Callaway Resident Inspector, USNRC

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