ML19210D226
| ML19210D226 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 11/08/1979 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Stampley N MISSISSIPPI POWER & LIGHT CO. |
| References | |
| NUDOCS 7911260146 | |
| Download: ML19210D226 (1) | |
Text
UNITED STATES 8'
NUCLEAR REGULATORY COMMISSION g
- r REGION il b[
101 NARIETTA ST., N.W., SulTE 3100 o,
o ATLANTA, GEORGIA 30303 NOV 81979 In Reply Refer To:
RII:JP0 50-416, 50-417 Mississippi Power and Light Company Attn:
N. L. Stampley Vice President of Production P. O. Box 1640 Jackson, Mississippi 39205 Gentlemen:
Enclosed is IE Bulletin No. 79-02, Revision No. 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 regarding this Bulletin Revision or the actions required by you, please contact this office.
Sincerely, N P
- u_w; - y N.
LM Py James P. O'Reily Director
Enclosure:
IE Bulletin No. 79-02, Revision No. 2 w/encls.
1 7, G i 359 1
(,
1911260 U
NOV 8 1979 d
Mississippi Power and Light Company,
cc w/ encl:
C. K. McCoy Plant Manager Post Office Box 756 Port Gibson, Mississippi 39150 17M1 360
UNITED STATES SSINS No.:
6820 NUCLEAR REGULATORY COMMISSION Accession No.:
OFFICE OF INSPECTION AND ENFORCEMENT 79082201 D WASHINGTON, D.C.
20555 63 November 8, 1979 IE Bulletin No. 79-02 (Revision 2)
PIPE SUPPORT BASE PLATE DESIGNS USING CONCRETE EXPANSION ANCHOR B:1TS 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 R1 and R2 in the margin. The R1 purpose of this revision is to identify acceptable ways of satisfying the R1 Bulletin requirements.
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 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 Shoreham has shown over fifty percent of the bolt installations to be deficient.
Vendor Inspection Audits by KRC at Architect Engine ering firms have shown a wide range of design practices and installation procedur es which have been employed for the use of concrete expansion anchors. The cur rent trends in the industry are toward more rigorous controls bolts.
The data available on dynamic test DUPLICATE DOCUMENT fatigue failures can occur at load cities due to material imperfectio Entire document previously entered i to system under:
R1 and R2 - Identifies those addit ANO 1
1TO1 361 Jl No. of pages:
ff