ML19250C474
| ML19250C474 | |
| Person / Time | |
|---|---|
| Site: | Humboldt Bay |
| Issue date: | 11/08/1979 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Crane P PACIFIC GAS & ELECTRIC CO. |
| References | |
| NUDOCS 7911260260 | |
| Download: ML19250C474 (1) | |
Text
ef
'o,,
UNITED STATES NUCLEAR REGULATORY COMMISSION
.,,7 g
g..
c e REGION V t'['
o, ~
1990 N. CALIFORNIA BOULEVARD SUITE 202, WALNUT CREEK PLAZA
- ,,,#1 WALNUT CREEK CALIFORNIA 94596 November 8, 1979 Docket No. 50-133 Pacific Gas and Electric Company 77 Beale Street San Francisco, California 94106 Attention: Mr. Philip A. Crane, Jr.
Assistant General Counsel Gentlemen:
Enclosed is IE Culletin No. 79-02, Revision 2 which requires action by you with regard to your power reactor facility (ies) with an operating license or a construction permit.
Should you have any questions rqarding this Bulletin revision or the actions required by you, please contact this office.
Sincerely,
$%,dC.~
R. H. Engelken Director Encl,sure:
IE Bulletin No. 79-02 Revision No. 2 cc w/ enclosure:
W. Barr, PG&E W. Raymond, PG&E E. Weeks, PG&E, Humboldt Bay 1388 057 7 911260 2 b
9
.3 UNITED STATES SSINS No.:
6820 NUCLEAR REGULATORY COMMISSION Accession No.:
0FFICE OF INSPECTION AND ENFORCEMENT 7908220136 WASHINGTON, D.C.
20555 November 8, 1979 IE Bulletin No. 79-02 (Revision 2)
PIPE SUPPORT BASE PLATE DESIGNS USING CONCRETE EXPANSION ANCHOR BOLTS Description of Circumstances:
Inspection experiences and the review of licensee response have identified several R2 areas where the Bulletin intent has not been adequately addressed by licensees.
R2 Revision No. 2 of the Bulletin is intended to clarify the intent of the Bulletin R2 and establish the NRC positions on minimum factors of safety, anchor bolt preload, R2 and the expected date of completion for certain Bulletin actions.
R2 Since the issuance of IE Bulletin No. 79-02 on March 8,1979, IE inspection R1 experience and many inquiries from licensees indicate that additional informa-R1 tion and clarification is needed.
This revision is intended to serve that R1 purpose. None of the requirements of the original Bulletin have been deleted, R1 and the due date for completion of the requested actions (July 6,1979) has R1 not been changed. The following text supersedes the text of Bulletin No. 79-02.
R1 Changes from the original text are identified by H1 and R2 in the margin. The R1 purpose of this revision is to identify acceptable ways of satisfying the R1 Bulletin requirements.
R1 While performing inservice inspections during a March-April 1978 refueling outage at Millstone 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 using rigid plate assumptions has resulted in underestimation of loads on some anchor bol ts.
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 /> dits by NRC at Architect 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 trends in the industry are toward more rigorous controls and verification of the installation of the bolts.
The data available on dynamic testing of th fatigue failures can occur at loads substan DUPLICATE DOCUMENT Entire document previously R1 and R2 - Identifies those additions or r entered into system under:
7, 9. 0, % M 6, W 3 1388 0S8
^No N o. of pages:
W l