ML19248C920
| ML19248C920 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 04/30/1979 |
| From: | Head J SOUTH CAROLINA ELECTRIC & GAS CO. |
| To: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| NUDOCS 7907050442 | |
| Download: ML19248C920 (7) | |
Text
GW Southern California Edison Company
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P. O DOX 8 0 o 2244 WALN UT GROVE AVENUE J. T. HEAO JR.
RO S E M E AD, C ALIFO R N I A 91770 T E t t PHON E April 30, 1979
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U. S. Nuclear Regulatory Commission
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Region V D
Suite 202, Walnut Creek Plaza M
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.TV 1990 N. California Boulevard Walnut Creek, California 94596 Attention:
Mr. R. II. Engelken, Director Docket No. 50-206 San Onofre Unit l_
References:
(1)
IE Bulletin No. 79-07 dated April 14, 1979
" Seismic Stress Analysis of Safety-Related Piping" (2)
Southern California Edison Company letter dated April 24, 1979; J. T. Head, Jr. (Vice President) to R. H. Engelken (Director, Region V)
Reference (1) requested that we submit information in order to permit a determination of whether piping systems important to safety have been designed using piping analysis corputer codes which contain algebraic summation errors.
Reference (2) indicat d that we did not believe that any computer codes contain-ing algebraic summation errors have been used in the design and for analyses of San Onofre Unit 1, and that we would confirm this as well as provide additional information concerning benchmark problems and verification analyses by April 30, 1979.
Accordingly, our response to each item of Reference (1) is contained in the enclosed report entitled " Responses to IE Bulletin No. 79-07, San Onofre Nuclear Generating Station, Unit 1, April, 1979".
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Should you require additional information concerning the enclosed materir1, please let ne know.
Very truly yours, f ^ fj/of 1, Enclosures cc:
Director, Office of Inspection and Enforcement 5
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RESPONSES TO IE Bl'LLETIN NO. 79-07 SAN ONOFRE NUCLEAR GENERATING STATION UNIT 1 k-April, 1979 201 270
INFORMATION REQUEST ITEM (1)
Identify which, if any, of the methods specified below were enployed or were used in computer codes for the seismic analysis of safety related pining in your plant and provide a list of saf ety sys c:as (er portions thereof) r affected:
Response Spectrum Model Analysis:
a.
Algebraic (considering signs) summation of the codirectional spatial components (i.e.,
algebraic summation of the maximum values of the codirectional responses caused by each of the components of earthquake motion at a particular point in the mathematical model).
b.
Algebraic (considering signs) summation of the codirectional inter-modal responses (i.e.,
for the number of modes considered, the maximum values of response for each mode summed algebraically).
Time History Analysis:
Algebraic summation of the codirectional maximum a.
responses or the time dependent responses due to each of the components of earthquake motion acting simultaneously when the earthquake directional motions are not statistically independent.
RESPONSE
A revicw of computer codes utilized in the seismic analysis of safety related piping, including modifications and additions to such piping at San Onofre Unit 1 has concluded that none of the methods specified above have been utilized.
A review of seismic analyses not utilizing computer codes is being completed to verify the same conclusion for such analyses.
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INFOIGIATION REQUEST TTEM (2)
Provide complete computer program listings for the dynamic response analysis portions for the codes which employed the techniques identified in Item 1 above.
RESPONSE
Not applicable.
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INFORMATION REQUEST ITEM (3)
Verify that all piping computer prograns were checked against either piping benchmark problems or compared to other piping computer programs.
You are requested to identify the benchmark problems and/or the computer programs that were used for such verifications or describe in detail how it was determined that these programs yielded appropriate results (i.e., gave results which corresponded to the correct performance of their intended methodology).
RESPONSE
The computer codes which have been utilized in the seismic analysis of safety related piping, including modifications and additions to such piping at San Onofre Unit 1 are as follows:
WECAN - Westinghouse Electric Corporation Proprietary Program ME 632-Seismic Analysis of Piping Systems, Bechtei Power Corporation ME 101-LEAP:
Linear Elastic Analysis of Pipe, Bechtel Power Corporation SAP IV-A Structural Analysis Program for Static and Dynamic Response of Linear Systems Verification of the WECAN computer code is documented in the Westinghouse report " Benchmark Problem Solutions Employed for Verification of the WECAN Computer Program", WCAP-8929, April 1977, which has been submitted to the NRC.
ME 632 has been verified using PISOL, PIPESD and TPIPE.
ME 101 has been verified using ME 632, TPIPE and SUPERPIPE.
SAP IV was originally benchmarked by its author (E.
L. Wilson, et. al.).
Sample problems were compared with results obtained from ADLPIPE for static analysis of a pipe network and PIPDYN for dynamic response spectrum analysis of a pipe network.
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INFORMI. TION REQUEST ITdM (4)
If any of the methods listed in item 1 are identified, submit a plan of action and an estimated schedule for the re-evaluation of the safety related piping, supports, and equipment affected by these analysis techniques.
Also provide an estimate of the degree to which the capability of the plant to safely withstand a seismic event in the interim is impacted.
RESPONSE
Not applicable.
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