ML19256B483

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Forwards IE Bulletin 79-02,Revision 1, Pipe Support Base Plate Designs Using Concrete Expansion Anchor Bolts. Action Required
ML19256B483
Person / Time
Site: Trojan File:Portland General Electric icon.png
Issue date: 06/21/1979
From: Engelken R
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
To: Goodwin C
PORTLAND GENERAL ELECTRIC CO.
References
TAC-12369, NUDOCS 7907120010
Download: ML19256B483 (1)


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June 21,1979 Docket No. 50-344 Portland General Electric Company 121 S. W. Salmon Street Portland, Oregon 97204 Attention: Mr. Charles Goodwin Assistant Vice President Gentlemen:

Enclosed is IE Bulletin tio. 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, l

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t,' l t R. H. Engelken Director

Enclosure:

IE Bulletin No. 79-02 Revision No. 1 cc w/ enclosures:

B. Withers, PGE F. C. Gaidos, PGE y-835 077 7 9 071200/ d

UNITED STATES flUCLEAR REGULATOP,Y C0!NISSION OFFICE OF INSPECTION AND EtiFORCEMENT UASHINGTON, D.C.

20555 June 21, 1979 IE Bulletin No. 79-02 (Revision No. 1)

(7906200183)

PIPE SUPPORT BASE PLATE DESIGNS USING CONCRETE EXPANSION ANCHOR 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 revision is intended to serve that puroose.

None of the requirements of the cricinal Bulletin have been deleted, and the due date for completion of the requested actions (July 6,1979) has not bsen 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 performina inservice inspections durina a March-Aoril 1978 refuelino outaae at Millstone Unit 1, structural failures of pioina supports for sai

,y equipr ent were observed by the licensee.

Subsequent licensee inspections of undamaqed supports showed a larae 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 riaid 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 rioid 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 Architect Engineering firms have shown a wide ranaa 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-

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lation of the bolts.

The data available on dynamic testina ofR -.7 m_ ' '-.,$.. - ~.-

i fatigue failures can occur at loads subf DUPLICATE DOCUMENT bb0 O!

cities due to material imperfections or also show low cycle dynamic failures at due to joint slippage.

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