ML19242A087
| ML19242A087 | |
| Person / Time | |
|---|---|
| Site: | Fort Saint Vrain  |
| Issue date: | 07/02/1979 |
| From: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Millen C PUBLIC SERVICE CO. OF COLORADO |
| References | |
| NUDOCS 7907310217 | |
| Download: ML19242A087 (1) | |
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July 2, 1979 Docket No.
50-267 Public Service Company of Colorado ATTN:
Mr. C. K. Millen Senior Vice President P. O. Box 840 Denver, Colorado 80201 Gentle =en:
The enclosed IE Bulletin 79-14 is forwarded to you for action. Written respoases are required.
If you desire additional ir. formation regardia; this natter, please contact this office.
Sincerely, e
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Karl V. Seyfrit, Director
Enclosures:
1.
List of IE Bulletins Issued in Last Twelve Months cc:
D.
'.f. Ware = bourg, Nuclear Production Manager Fort St. Vrain Nuclear Station P. O. Box 368 Platteville, Colorado 80651 L. Brey, Manager, Quality Assurance 7907330237 of7 4,
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UNITED STATES NUCLEAR REGULATORY CO.T11SSION WASHINGTON, D.C.
20555 IE Bulletin No. 79-14 Date:
July 2, 1979 Page 1 of 3 SEISMIC ANALYSES r0R 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 adu.essed 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
'.E and by licensees of the as-built configuration of several piping systems revealed a number of 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 he e occurred in a number of plants, this issue is generic.
The staff has determined, where design specifications and drawings are used to nhtain 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 af fect 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.
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