ML19242A110
| ML19242A110 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 07/02/1979 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Stampley N MISSISSIPPI POWER & LIGHT CO. |
| References | |
| NUDOCS 7907310258 | |
| Download: ML19242A110 (1) | |
Text
s m mac
- o, UNITED STATES if(
!['e 7,
NUCLEAR REGULATORY COMMISSION i
I i
REGION il o,
[
101 MARIETT A ST., N W., SUIT E 3100 ATLANTA GEORGI A 30303 6
/
JUL 2 1979 In Reply Refer To:
RII:JPO 50-416 50-417 Mississippi Power and Light Company ATTN:
N. L. Stampley Vice President of Production P. O. Box 1640 Jack. son, MS 39205 Gentlemen:
ne enclosed Eu11etin 79-14 is f orwarded to you '.'sr action. Written responses are required.
If you desire additional informttion regarding this matter, please contact this office.
Sincerely,
~[bnn-A James P, O'Reilly t
Director
Enclosure:
1.
IE Eulletin No. 79-14 2.
Listing of IE B.211etins Issued In Last Twelve Months 7907310258 o,-
Y f_ ~
\\1
JUL 2 1979 Mississippi Power and Light Company cc w/ enc 1:
O. K. McCoy Plant. Manager Post Office Box 75',
39150 Port Gibson, Mississippi h
e 9
\\)-
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C.
20555 July 2, 1979 IE Bulletin No. 79-14 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 resul'.s.
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 sll 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 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 have occurred in a number of plants, this issue is generic.
The staf f 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 f rom 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 takren by Licensees and Permit Holders:
All power ces ctor facility licensees and construction permit holders are r quested to verify, unless verified to an equivalent degree within the last 12 months, that the seismic analysis appl:es to the actual configura-tion of safetyrelated piping systems.
Tl erf-*" '-!stad ninine. includes Seismic Category I systems as defined be Design Classification" Revision 1, dated DUPLICATE DOCUMENT the applicable FSAR.
For older plac'.s, '
ments did not exist at the time of licen Entire document previously entered actual configuration of these safety-rel into system under:
g meats.
k ANO 7 9 070loDM S k
No. of pages:
}
46Oz c37
._.