ML19282B476
| ML19282B476 | |
| Person / Time | |
|---|---|
| Site: | Marble Hill |
| Issue date: | 03/08/1979 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Coughlin J PSI ENERGY, INC. A/K/A PUBLIC SERVICE CO. OF INDIANA |
| References | |
| NUDOCS 7903150045 | |
| Download: ML19282B476 (1) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION e
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MI REGION 111 2
799 ROOSEVELT ROAD
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NE -a 1979 Docket No. 50-546 Docket No. 50-547 Public Service of Indiana
- ATTN:
Dr. James Coughlin Vice President, Nuclear 1000 East Main Street Plainfield, IN 4616S Gentlemen:
The enclosed IE Bulletin No. 79-02 is forwarded to you for action. A written response is required.
If you desire additional information regarding this matter, please contact this office.
Sincerely, WY ames G. Keppler !
Director
Enclosures:
1.
List of IE Bulletins Issued in Last Twelve Months cc w/encls:
Mr. R. M. Brown, Construction Project Engineer Central Files Director, NRR/DPM Director, NRR/ DOR PDR Local PDR NSIC TIC LeBoeuf, Lamb, Leiby & MacRae 7903150045
-6 U.S. NUCLEAR REGULATORY ComfISSION OFFICE OF INSPECTION AND ENFORCEMENT REGION III March 8, 1979 IE Bulletin No. 79-02 PIPE SUPPORT BASE PLATE DESIGNS USING CONCRETE EXPANSION ANCHOR BOLTS Description of Circumstances:
While performing inservice inspections during a March-April 1978 refueling outage at Millstone Unit 1, structural failures of piping support for safety equipment were observed by the licensee.
Subsequent licensee inspections of undemaged 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 underestima-tion of loads on some anchor bolts. Initial investigation indicated that near.ly fifty percent of the base plates could not be assumed to behave as rigid plates. In addition, licensee inspection of ancher 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 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 installation of the bolts.
The data available on dynamic testing of the concrete expansion anchors show fatigue failures can occur at loads substantially below the bolt static capacities due to material imperfections or notch type stress risers. The data also show low cycle dynamic failures at loads below the bolt static capacities due to joint slippage.
Action to be Taken by Licensees and Permit Holders:
For pipe support base plates that use concrete expansion anchor bolts in Seismic Category I systems as defined by Regulatory Guide 1.29, " Seismic Design Classification" Revision 1, dated August 1973 or an defined in the applicable FSAR.
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Verify that pipe support base plate flexibility was accounted for in the ca: - '"
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