ML19246B852
| ML19246B852 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 07/02/1979 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Boyer V PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| References | |
| NUDOCS 7907180802 | |
| Download: ML19246B852 (1) | |
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UNITED STATES S f ;,',y/ (',j d
NUCLEAP REGULATORY COMMISSION
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KING OF PRUSSIA, PENNSYLVANIA 1940G
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Docket Nos. 50-352 yg ; ' g 50-353 Philadelphia Electric Company ATTN:
Mr. V. S. Boyer Vice President Engineering and Research 2301 Market Street Philadelphia, Pennsylvania 19101 Gentlemen:
The enclosed Bulletin 79-14 is forwarded to you for action. Written responses are required.
If you desire additional information regarding this matter, please contact this office.
Sincerely,
,l oyce
. Grier
- Director
Enclosures:
1.
List of IE Bulletins Issued in Last 12 Months 79071808o1 t /SC3?-
ENCLOSURE 1 UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C.
20555 IE Bulletin No. 79-14 Date:
July 2, 1979 Page 1 of 3 SEISMIC ANALYSES FOR AS-BUILT SAFETY-RELATED PIPING SYSTEMS Description of Circumstances:
Recently two issues were identified which can cause seismic analysis of safety-related piping systems to yield nonconservative results.
One issue involved algebraic summation of loads in some seismic analyses.
This was addressed in show cause orders for Beaver Valley, Fitzpatrick, Maine Yankee and Surry.
It was also addressed in IE Bulletin 79-07 which was sent to all power reactor licensees.
The other issue involves the accuracy of the information input for seismic analyses.
In this regard, several potentially unconservative factors were discovered and subsequently addressed in IE Bulletin 79-02 (pipe supports) and 79-04 (valve weights).
During resolution of these concerns, inspection by IE and by licensees of the as-built configuration of several piping systems revealed a number 01 nonconformances to design documents which could potentially affect the validity of seismic analyses.
Nonconformances are identified in Appendix A to this bulletin.
Because apparently significant non-conformances to design documents have occurred in a number of plants, this issue is generic.
The staff has determined, where design specifications and drawings are used to obtain input information for seismic analysis of safety-related piping systems, that it is essential for these documents to reflect as-built con-figurations.
Where subsequent use, damage or modifications affect the con-dition or configuration of safety-related piping systems as described in documents from which seismic analysis input information was obtained, the licensee must consider the need to re-evaluate the seismic analyses to con-sider the as-built configuration.
Action to be taken by Licensees and Permit Holders:
All power reactor facility licensees and construction permit holders are requested to verify, unless verified to an equivalent degree within the last 12 months, that the seismic analysis applies to the actual configura-tion of safety-related piping systems.
The safety related piping includes Seismic Category I systems as defined by Renulatorv Guid.e.l.29, " Seismic.
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