ML19246C192
| ML19246C192 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 06/21/1979 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Groce R VERMONT YANKEE NUCLEAR POWER CORP. |
| References | |
| NUDOCS 7907230712 | |
| Download: ML19246C192 (1) | |
Text
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KING oF PRUSSIA, PENNSYLVANI A 19406 Docket No. 50-271 21 JUN 1979 Vermont Yankee Nu: lear Power Corporation ATTN:
Mr. Robert !i. Groce Licensing Engineer 20 Turnpike Road Westborough, Massachusetts 01581 Gentlemen:
Enclosed is IE Bulletin No. 79-02 Revision No.1, which requires action by you with regard to your power reactor facility (ies) with an operating license or a construction permit.
Should you have any questions regarding thi.s Bulletin or the actions required by you, please contact this office.
Sincerely, M
oyce H. Grier Director Enciosures:
1.
IE Bulletin No. 79-02 (Revision No. 1) 2.
List of IE Bulletins Issued in Last Twelve Months cc w/encis:
W. F. Conway, Plant Superintendent Ms. J. Abbey, Technical Secretary A. Z. Roisman, Natural Resources Defense Council 6
359 242 q0070 07 \\t
t ENCLOSURE 1 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 IE Bulletin No. 79-02 (Revision No. 1)
Date:
June 21, 1979 Page 1 of 6 PIPE SUPPORT BASE PLATE DESIGNS USING CONCRETE EXPANSION ANCHOR BOLTS Description of Circumstances:
Since the issuance of IE Bulletin 79-02 on March 8,1979, IE inspection AK experience and many inquiries from licensees indicate that additional informa-tion and clarification is needed.
This revision is intended to serve that purpose.
None of the requirements of the original Bulletin have been deleted, and the due date for completion of the requested actions (July 6, 1979) has not been changed The following text supersedes the text of Sulletin 79-02.
Changes frem the original text are identified by lines in the margin.
The purpose of this revision is to identify acceptable ways of satisfying the Bulletin requirements.
While performing inservice inspections during a March-April 1978 refueling outage 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 La assumed to behave as rigid plates.
In addition, licensee inspection of anchor bolt installauions 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 procedures which have been employed for the use of concrete expansion anchors.
The current trends in the industry are toward more rigorous controls and verification of the instal-latica of the bolts.
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ine data available on dynamic testing of fatigue failures can occur at loads subst DUPLICATE DOCUTCENT h,
cities due to material imperfections or n pi also show low cycle dynamic failures at 1 fnntire document 3reviously entered I?
due to joint slippage.
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