ML19290B820

Responds to ASLAP 791108 Request.Forwards Rept on Effect of Outdated Amplified Response Spectrum Curves on Svc Water Pumphouse Settlement, Which Details Errors in Stress Analysis

ML19290B820
Person / Time
Site:	North Anna
Issue date:	12/05/1979
From:	Christman J HUNTON & WILLIAMS
To:	Buck J, Mike Farrar, Rosenthal A NRC ATOMIC SAFETY & LICENSING APPEAL PANEL (ASLAP)
References
NUDOCS 7912140172
Download: ML19290B820 (4)

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Huwrow & WILLI AMS 707 EAST MAIN s7RcCT P. o. Box 1535 Rxcnxown.VanorxtA 20212 Tc Lc PN o N c so4 7sa-saoo CABLc HU NrWA ND WASJIINGTON D. C . Orric a 1919 PENNSYLVANIA AvC.N.W. 20036 P. o. Box 19230 TE L t p M o N E 2o2 223-8650 December 5, 1979 ,,,, , , ,

cancer o AL No ao4 7s.3368 Alan S. Rosenthal, Esquire Atomic Safety and Licensing Appeal Board U.S. Nuclear Regulatory Commission ;m Washington, D.C. 20555 L-- Q ,

Dr. John H. Buck .i Atomic Safety and Licensing Appeal J' Board y

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Y- l f Washington, D.C. 20555 ' k c4U/JN gy/

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Michael C. Farrar, Esquire Atomic Safety and Licensing Appeal Ng,';g+Nf6 g Board U.S. Nuclear Regulatory Commission Washington, D.C. 20555 In the Matter of Virginia Electric and Power Company (North Anna Power Station, Units 1 and 2)

Docket Nos. 50-339 OL and 50-339 OL Gentlemen:

Enclosed is the report, entitled " Report on Ef-fect of Outdated Amplified Response Spectrum Curves on Ser-vice Water Pumphouse Settlement, North Anna 1 and 2," that Ms. Bishop requested me to send you in her letter of Novem-ber 8, 1979. It details the errors that were discovered in certain stress analyses of piping in the Service Water Pump House, Auxiliary Building, Safeguards Buildings, Fuel Build-ing, Auxiliary Feedwater Pump Houses, and Main Steam Valve Houses at North Anna 1 and 2. 1574 189 h 7912140

HuwTow & WILLIAxs Alan S. Rosenthal, Esquire Dr. John H. Buck Michael C. Farrar, Esquire December 5, 1979 Page Two I believe the report is responsive to your request for a report on the nature and scope of the errors and on why Vepco believes they have no bearing on the pumphouse settlement issue. If it does not supply enough detail for your purposes, Vepco will be happy to provide more.

I am sending this letter and the attached report to the Appeal Board members and NRC Staff counsel by hand today. I will submit an affidavit verifying that the re-port is true as soon as I can get one executed by the Stone & Webster people in Boston. If you need anything more frcm Vepco or me, please let me know.

urs very truly, W

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,JamesN. Christman 126/586 Attachment cc: Richard M. Foster, Esq.

Anthony J. Gambardella, Esq.

Daniel T. Swanson, Esq.

Chief, Docketing and Service Section 1574 190

REPORT ON EFFECT OF OUTDATED AMPLIFIED RESPONSE SPECTRUM CURVES ON SERVICE WATER PUMPHOUSE SETTLEMENT NORTH ANNA UNITS 1 AND 2 During the review of the seismic analysis of Category I piping, as required by Inspection and Enforcement Bulletin No. 79-14, an inconsistency was discovered in the way in which certain of the seismic amplified response spectrum (ARS) curves were used as input data to the stress analysis.

(Information about amplified response spectra can be found in section 3.7.2 of the North Anna 1 & 2 FSAR.) An investigation showed there to be three types of inconsistencies in the ARS data. The first inconsistency was that certain curves had two or more values of acceleration for the same period (i.e.,

multiple periods). The second was that the peak-spreading (the technique used to develop a conservative envelope) of some curves was not exactly 115 percent of the peak's period as described in FSAR Section 3.7.3. The third discrepancy was that a few of the ARS curves were not the most current. It has been determined, by a complete review of the ARS input to pipe stress calculations, that there are no inconsistencies other than those described above.

The piping systems affected by the above findings are located in the Service Water Pump House, the Auxiliary Building, the Safeguards Buildings, the Fuel Building, the Auxiliary Feedwater Pump Houses, and the Main Steam Valve Houses. Curves having multiple periods were used in the Main Steam Valve Houses, the Fuel Building, and the Safeguards Buildings. The peak spreading problem affects only those analyses using the ARS data for the Main Steam Valve Houses. Outdated curves were used for analyses in the Service Water Pump House, the Auxiliary Building and the Auxiliary Feedwater Pump Houses.

These discrepancies affect only the dynamic analysis of piping systems.

The static analysis involving seismic building movements is not affected. In addition, the ARS inconsistencies apply only to analyses using the SH0CK III program and not those using the NUPIPE program.

The only portion of the piping in the Service Water Pump House (SWPH) that is affected by the use of outdated ARS curves is that which extends from the point at which the two 36-inch discharge headers are embedded in the north wall of the SWPH to the pumps inside the structure. The two 36-inch return headers and the service water spray piping to the south of the SWPH are not affected. The stress analysis of the affected piping is not related to the pump house settlement, nor is it related to the motion of the short section of pipe that extends from the north f ace of the SWPH to the expansion joints.

The motion of that short section of pipe is a direct result of pump house seismic motion. The seismic input information used to calculate the SWPH motion has been reviewed and is current.

The analysis of the buried piping and the expansion joint outside of the SWPH is completely unaffected by SH0CK III because that analysis was conducted using the NUPIPE program. Since NUPIPE requires input data in a format that is different from the data for the SH0CK III program, a separate file of digitized ARS curves is maintained for NUPIPE analyses. The ARS curves that were used with NUPIPE for the SWPH buried piping and expansion joint analysis are current, as has been verified by a recent detailed check. Therefore, the existing analysis is valid and not affected by the SHOCK III format inconsistencies described above.

1574 191

In order to verify our piping seismic design, we are revising all computerized analyses which had inconsistencies in the SH0CK III format ARS input. As explained above, however, the analyses performed on the expansion joints and the buried lines north of the SWPH and on the service water spray piping south of the SWPH are not affected by the inconsistencies. Therefore, our design analysis and, consequently, our testimony before the Appeal Board

• remain valid.

• Hearing of June 18-20, 1979.

1574 192 C2082