ML19224D468
| ML19224D468 | |
| Person / Time | |
|---|---|
| Site: | 05000484 |
| Issue date: | 06/21/1979 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Dienhart A NORTHERN STATES POWER CO. |
| References | |
| NUDOCS 7907120244 | |
| Download: ML19224D468 (1) | |
Text
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JllN 211979 Docket No. 50-484 Northerr States Power Company ATTN:
tir. A. V. Dienhart Vice President - Tyrone Energy Park 100 North Barstow Street Eau Claire, WI 54701 Gentlemen:
Enclosed is IE Bulleti; No. 79-02 Revision Nc,.
1, which requires action by you with regard to your power reactor facility with an operating license or a construction permit.
Should you have any questions regarding this Bulletin or the actions required by you, please contact this office.
Sincerely,
/_ 2cr James G. Keppler Director
Enclosure:
IE Bulletin No. 79-02 Revision No. I cc w/ encl:
Central Files Director, NRR/DPM Director, NRR/ DOR PDR Local PDR NSIC TIC Regions I & IV 3l3 m
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U.S. NUCLEAR REGULATORY COMMISSIOS OFFICE OF INSPECTION AND ENFORCEMENT REGION III June 21, 1979 IE Bulletin No. 79-02 (Revision No. 1)
(7906200183)
PIPE SUPPORT BASE PLATE DESIGNS USING CONCRETE EXPANSION ANCHCR BOLTS Description of Circumstances:
Since the issuance of IE Bulletin 79-02 on March 8, 1979, IE inspection experience and many inquiries from licensees indicate that additional informa-tion and clarification is needed.
This revisicn 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 Bulletin 79-02.
Changes from the original text are identified by lines in the margin. The purpose of this revision is to identify accc table ways of satisfying the Bulletin requirements.
While performing inservice inspections during a March-April IV,8 refueling outage at M111st ane 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 us ig rigid plate assumptions has resulted in underestimation af 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 Arenitect 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 in the industry are toward more rigorous controls and verifi~
.nstal-lation of the bolts.
The data available on dynamic te red
}ov gg Cnge fatigue failures can occu" g DOCU gly ga-g cities due to material imp IC M re also show low cycle dynamilDUN gent
' es due to joint slippage.
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