ML19256B485
| ML19256B485 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 06/21/1979 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| References | |
| NUDOCS 7907120015 | |
| Download: ML19256B485 (1) | |
Text
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REGION V g,,;i 'hh '. c8 1990 N. CALIFORNIA BOULEVARD o,, "N e
SUITE 202, WALNUT CREEK PLAZA
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WALNUT CREEK, CALIFORNIA 94596 June 21,1979 Docket l'o. 50-312 Sacramento Municipal Utility District P. O. Box 15830 Sacramento, California 95813 Attention:
Mr. John J. Mattimoe Assistant General Manager 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 questions regarding this Bulletin or the actions required of you, please contact this office.
Sincerely, V,! Y. g (['l R. H. Engelken Director
Enclosure:
IE Bulletin No. 79-02 Revision No. 1 cc w/ enclosures:
R. J. Rodriguez, SMUD L. G. Schwieger, SMUD
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UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 June 21, 1979 IE Bulletin No. 79-02 (Revision No. 1)
(7906200183)
PIPE SUPPORT BASE PLATE DESIGNS USING CONCRETE EXPANSION ANCHOR BCLTS 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 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 Bulletin 79-02.
Changes from the original text are identified by lines in the margin. The purpose of this revision is to identify acceptable ways of satisfyina the Bulletin requirements.
While performing inservice inspections during a March-Aoril 1978 refuelina outaae at Millstone Unit 1, structural failures of pipina supports for safety equipment vere observed by the licensee.
Subsequent licensee inspections of undamaged supports showed a large percentage of the concrete anchor colts were not tightened properly.
Deficiency reports, in accordance with 10 CFR 50.55(e), filed by Lona Island Lighting Company on Shorehan 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 Shorehan has shown over fifty percent of the bolt installations to be deficient.
Vendor Inspection Audits by NRC at Architect Engineering firms have shown c wide rance 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-lation of the bolts.
The data available on dynamic testing cb
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