ML19256B484
| ML19256B484 | |
| 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 7907120012 | |
| Download: ML19256B484 (1) | |
Text
UNITED STATES Y,
f Io, NUCLE AR REGULATORY COMMISSION p 7;;g '.,gc REGION V k ', h E
1990 N. CA IFORNIA BOULEVARD g _ '
p SUITE 202, WALNUT CHEEK PLAZA g
WALNUT CREE K. CALIFORNIA 9459G y%f.
JUN 21. eJ3 Docket flo. 50-206 Southern California Edison Company P. O. Box 800 2244 Walnut Grove Avenue Rosemead, California 91770 Attention: Mr. J. B, Moore 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, b
(O l %gYN -
R. H. Engelken Director
Enclosure:
IE Bulletin flo. 79-02 Revision flo. 1 cc w/ enclosures:
J. M. Curran, SCE m
J. T. Head, SCE 835 079
~D07120012
UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF IllSPECTION AND ENFORCEMEflT UASHINGTON, D.C.
20555 June 21, 1979 IE Bulletin No. 79-02 (Revision No. 1)
(7906200183)
PIPE SUPPORT BASE PLATE DESIGNS USING C0flCRETE EXPANSION ANCHOR BOLTS Description of Circunstances:
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 puroose.
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 satisfyino the Bulletin requirements.
While performing inservice inspections during a March-April 1978 refuelina outaae at Millstone Unit 1, structural failures of pipina supports for safety equiprent were observed by the licensee.
Subsequent licensee inspections of undanaged supports showed a larce cercentage of the concrete anchor bolts were not tiahtened properly.
Deficiency reports, in accordance with 10 CFR 50.55(e), filed by lona Island Lighting Company on Shoreham Unit 1, indicate that design of base plates using rigid plate assumptions has re.;uited 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 riaid pletes.
In addition, licensee inspection of anchor bolt installatinns 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 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-latio" n' the bolts. '
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