ML19253B400

Interim Deficiency Rept Re Possible Failure of William Powell Co Supplied Valves to Meet Seismic Requirements.Data Still Being Gathered to Determine Natural Frequencies of Valves W/Extended Topworks.Final Rept by 791230

ML19253B400
Person / Time
Site:	Grand Gulf
Issue date:	10/04/1979
From:	Dale L MISSISSIPPI POWER & LIGHT CO.
To:
References
AECM-79-112, NUDOCS 7910150501
Download: ML19253B400 (3)

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• MISSISSIPPI POWER & LIGHT COMPANY

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Helping Build Mississippi

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..o overie ~ ocn aru es t October 4, 1979 Otfice of Inspection and Cnforce=ent U. S. Nuclear Regulatory Co==ission Region II - Suite 1217 230 Peachtree Street, N.W.

Atlanta, Georgia 30303 Attention: Mr. J. P. O' Reil _y, Director Gentlemen:

SUBJE.T: Grand Gulf Nuclear 5tation Interim Report of PRD 79/13 as Defined - 10 CFR 50.55(e) .

File 0260/0498/15525/15526 AECM-79/il2 On September 4, 1979, Mr. V. Brownlee of your office was notified of a potential reportable deficiency regarding Willia = Powell supplied valves which =ay not =eet the seismic require =ents of the original purchase specifi-cation. Data is still being gathered and analyzed preparatory to determining reportability within the =eaning of 10 CFR 50.55(e).

The following is the present status of the engineering activity:

Part of the New Loads requalification for valves includes deter-

=1 nation of natural frequencies of valves having extended topworks (i.e. , motor, sir and gear operators) . Equip =ent which was previously qualified to be rigid thru 33 H: for seismic loads must now be either requalified thru 100 H: or its natural f requency cust be determined and other fixes utilized. Natural f requency reports in house for William Powell valves indicated frequencies f ro= approximately 150 H: to 1400 Hz. To ascertain the accuracy of these reports; three valves were selected and finite element analysis was perfor=ed by Acton Lab. The results of Acton Lab analysis should have been within 10-20% of the original valves, obtained by Powell using the lumped

= ass =ethod with 13 degrees of freedom. But the differences ranged fro = 200-2000% with some frequencies falling below 33 H:. Since this was not a vslid co=parison, the data f ce the Powell reports were input into Bechtel Power Corporation's ME-101 c2=puter progra=.

Again the resultant frequencies were low. Willia = Powell was contacted and requested to recalculate the natural frequencies and asked to review Acton's work for errors. Powell identified some =inor =odeling errors and perfor=ed some calculations. The methodology used by Powell is acceptable. The original analysis were performed by Mid-West Technical for Powell. Por these types of calculations the supplier q or his sub vendor is responsible for the accuracy of the analysis. p 'g 8 013 792o13nsof Member Middle South Utilities System

MISSISSIPPI i30WER & LIGHT COMPANY

, Office of Inspecticn & Enforcement U. S. Nuclear Regulatory Cecm. AECI-79 /112 Bechtel only reviews the methodology and assures that specificatien parameters are met. Therefore, Powell was requested to e:cplain the apparent discrepancies. Powell then requested Mid4'est to recalcu-late the frequencies and an outside consultant has been called ia.

_ The results of the above actions are expected to be available for analysis, the analysis completed, and the determinatien 7f reportability within the meaning of 10 CFR 50.55(e) be made by Decencer 30, 1979. A final repor: will be cubmitted at that time.

Ve ry truly yours ,

L. F. Dale Nuclear Project Manager JRS/JDR:dwe cc: Mr. T. 3. Conner bec: Dr. D. C. Gibbs Mr. R. 3. McGehee Mr. Adrian Zaccaria Mr. N. L. Sta=pley Mr. J. . Ward Mr. Victor Stello, Jr. , Din (cIB16 COPY F4R Mr. R. L. Scott Mr. D. M. Lake Mr. W. L. Nail Mr. T. E. Reaves Mr. J. P. NicCaughy Mr. C. K. McCoy Mr. J. C. Fuller File 1'"7 A I I s J. i,