ML19242A236
| ML19242A236 | |
| Person / Time | |
|---|---|
| Site: | Fort Saint Vrain  |
| Issue date: | 05/15/1979 |
| From: | Swart F PUBLIC SERVICE CO. OF COLORADO |
| To: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| NUDOCS 7908010066 | |
| Download: ML19242A236 (2) | |
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J May 15, 1979 Fort St. Vrain Unit No. 1 P-79104 Mr. Karl V. Seyfrii Director, Nuclear Re_,ulatory Comnission Region IV 611 Ryan Drive, Suite 1000 Arlington, Texas 7601' Docket F50-267 Subjcct:
IE Bulletin 79-07 Seismic Stress Analysis of Safety-Related Piping Gentlemen:
The following is in response to the various items called out in IE Bulle-tin 79-07, dated April 14, 1979:
Item 1 -- Determine method of algebraic summation of component responses due to seismic event.
None t the sum.natica methods listed for Item 1 in tho bulletin were used in our comoiter design programs for the design of Class I piping systems.
The programs used extensively for design work were Dynapipe and Dynaflex. Both of these prograns use the square rcot of the sum of the squares (SRSS) method to combine force components.
Therefore, Item 1 in IE Bulletin 79-07 does not apply.
Item 2 -- Provide computer listings for the portions of the codes or programs wnich used the direct algebraic method described in Item 1, This does not aoply since we used the SRSS method.
Item 3 -- Veri fy tha piping computer programs were checked against benchmark problems.
The Dynapipe program was checked out on a hot reheat piping system and the results were check d against Dynal, a McDonnell-Douglas Automation Company program.
Dynapipe was further checked out against MEL-21, a Los Alcmos Scien-ti fic Laboratory program using various sample problems.
In all cases the re-sults were in close agreement.
Additional references ccn be supplied upon request to further valiocte the Dynapipe program.
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Sey f ri t "ay 15,19 79 Page 2 The Dynaflex program was checked out oa a sample problem and compared against other computer piping programs, namely PIPEsD and ADLPIPE.
The sample problems were called DlPl and Dl A2 and involved complex three-dimensional runs of pipe.
In all cases the results from Dynaflex checked out to within a few percent of the results of these other programs.
Iterd -- If any of the algebraic reth:ds listed in item 1 were used, submit ~
a plan of action to correct them.
This item does not apply since we used a SRSS method of combining model response components, as opposed to adding them algebraicly.
Therefore, we feel that Fort St. Vrain is not affected by any of the problens noted in IE Bulletins 79-06 and 79-07 concerr.ing computer piping design criteria.
Should you have any questions regarding this letter, please contact re.
Very truly yours,
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Frederic E. Swart fluclear Pro.iect flanager FES/ PAG:ler E R;j i
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