ML19250C422
| ML19250C422 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 11/08/1979 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Groce R VERMONT YANKEE NUCLEAR POWER CORP. |
| References | |
| NUDOCS 7911260096 | |
| Download: ML19250C422 (1) | |
Text
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UNITED STATES E y).. 3 r ' j NUCLEAR REGULATORY COMMISSION
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,e KING OF PRUSSIA, PENNSYLVANIA 19406 Docket No. 50-271 Vermont Yankee Nuclear Power Corporation t!Q'l 0 8 W 3 ATTN:
Mr. Robert H. Groce Licensing Engineer 20 Turnpike Road Westborough, Massachusetts 01581 Gentlemen:
Enclosed is IE Bulletin No. 79-02, Revision 2, which requires action by you with regard to your power reactor facility (ies) with an operating license or a construction permit.
Should you have questions regarding this Bulletin or the actions required of you, please contact this office.
Sincerely, Q s & W.. $ n 4
oyce M. Grier
- Director
Enclosures:
1.
IE Bulletin No. 79-02, Revision 2 2.
List of IE Bulletins Issued in the Last Six Months CONTACT:
L. E. Tripp (215-337-5282) cc w/encls:
W. F. Conway, Plant Superintendent Ms. J. Abbey, Technical Secretary I b k
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i 7911260
UNITED STATES SSINS No.:
6820 NUCLEAR REGULATORY COMMISSION Accession No.:
OFFICE OF INSPECTION AND ENFORCEMENT 7908220136 WASHINGTON, D.C.
20555 Q
IE Bulletin No. 79-02 (Revision 2)
Date:
November 8, 1979 Page 1 of 8 PIPE SUPPORf BASE PLATE DESIGNS USING CONCRETE EXPANSION ANCHOR BOLTS Description of Circumstances:
Inspection experiences and the review of licensee respcnse have identified several R2 areas where the Bulletin intent has not been adequately addressed by licensees.
R2 Revision No. 2 of the Bulletin is intended to <:larify the intent of the Bulletin R2 and establish the NRC positions on minimum factors of safety, anchor bolt preload, R2 and the expected date of completion for certain Bulletin cr^ ions.
R2 Since the issuance of IE Bulletin No. 79-02 on March 8, 1979, IE inspection R1 experience and many inquiries from licensees indicate that additional informa-R1 tion and clarification is needed.
This revision is intended to serve that R1 purpose.
None of the requirements of the original Bulletin have been deleted, R1 and the due date for completion of the requestad actions (July 6, 1979) has R1 not been changed.
The following text supersedes the text of Bulletin No. 79-02.
R1 Changes from the original text are identified by R1, R2 in the margin.
The purpose R1 of this revision is to identify acceptable ways of satisfying the Bulletin R1 requirements.
R1 While performing inservice inspections during a March-April 1978 refueling cutage at Millstone Unit 1, structural failures of piping supports for safety equipment were observed by the licensee.
Subsequent licensee inspections of undamaged supports.showed a large percentage of the concrete anchor bolts were not tightened properly.
Deficiency reports, in accordance with 10 CFR 50.55(e), filed by Long Island Lighting Company on Shoreham Unit 1, indicate that design of base plates using rigid plate assumptions has resulted in underestimation of loads on some anchor bolts.
Initial investigation indicated that nearly fifty percent of the base plates could not be assumed to behave as rigid plates.
In addition, licensee inspection of anchor bolt installations at Shoreham has shown over fifty percent of the bolt installations to be deficient.
Vendor Inspection Audits by NRC at Architect Engineering firms have shown a wide range of design practices and installation rocedures which have been employed for the use of concrete expansion are toward more rigorous controls bolts.
DUPLICATE DOCUMENT The data available on dynamic tes Entire document previously fatigue failures can occur at loa entered into system under:
ANO R1 and R2 - Identifies those addi j[k N}
N o.
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