ML19274F275
| ML19274F275 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 06/21/1979 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Johari Moore SOUTHERN CALIFORNIA EDISON CO. |
| References | |
| NUDOCS 7907120014 | |
| Download: ML19274F275 (1) | |
Text
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'c, UNITED STATES
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REGION V
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1990 N. CALIFORNI A P.OULEVAf]D 5
b SUITE 202 WALNUT CREEK PEAZA o
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WALNUT CREE K, CALIFORfJI A 94596 JUN 21 n??
Docket ilos. 50-351 50-362 Southern California Edison Company P. O. Box 800 2244 Walnut Grove Avenue Rosemead, California 91770 Attention: Mr. J. B. fiocre Vice President Gentlemen:
Enclosed is IE Bulletin fio. 79-02, Revision fio.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, ii./i/,'.y (f.
-t R. H. Engelken Director
Enclosure:
IE Bulletin fio. 79-02 Revision fio. 1 cc w/ enclosures:
J. H. Drake, SCE b
3 790'21200/y
UNITED STATES fiUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND EfiFORCEP.ENT WASHINGTON, D.C.
20555 June 21, 1979 IE Bulletin No. 79-02 (Revision No. 1)
(7906200183)
PIPE SUPPORT BASE PLATE DESIGNS USING CONCRETE EXPANSION AflCHOR BOLTS Description of Circunstances:
Since the issuance of IE Bulletin 79-02 on 11 arch 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 puroose.
None of the reauirements of the criainal Bulletin have been deleted, and the due date for completion of the requested actions (July 6,1979) has not been changed. The followinq text supersedes the text of Bulletin 79-02.
Changes from the original text are identified by lines in the nargin. The purpose of this revision is to identify acceptable ways of satisfyina the Bulletin requirements.
While performina inservice inspections during a flarch-April 1978 refuelina outaae at Millstone Unit 1, structural failures of pipina supports for safety equipment were observed by the licensee. Subsequent licensee inspections of undanaged supports showed a larae cercentage of the concrete anchor bolts were not tightened procerly.
Deficiency reports, in accordance with 10 CFR 50.55(e), filed by Lona Island Lightinq Company on Storehan Unit 1, indicate that design of base plates using rigid plate assumptions has resulted in underestimation of. loads on some anchor boli.s.
Initial investigation indicated that nearly fifty percent of the base plates could not be assuned to behave as riaid plates.
In addition, licensee inspection of anchor bolt installations at Shoreham has shown over fifty percent of the bolt installations to be deficient.
Vendor Inspec. tion Audits by NRC at Architect Engineering firms have shown a 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.
pMvq:M; y myrmwwwwqn The data available on dynamic testing a
fatigue failures can occur at loads st DUPLICATE DOCUMENT l
cities due to material imperfections.
also show low cycle dynamic failures i Entire document previously entered due to joint slippage.
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- Lines indicate changes to previous No. of pages:
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