ML19291C474
| ML19291C474 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 12/07/1979 |
| From: | Counsil W NORTHEAST NUCLEAR ENERGY CO. |
| To: | Grier G NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| IEB-79-02, IEB-79-2, NUDOCS 8001240468 | |
| Download: ML19291C474 (2) | |
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December 7, 1979 Docket No. 50-245 Mr. Boyce H. Grier, Director Region I Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406
References:
(1)
B. H. Grier letter to W. G. Counsil dated March 8,1979, transmitting I&E Bulletin No. 79-02.
(2)
W. G. Counsil letter to B. H. Grier dated June 8, 1979.
(3)
B. H. Grier letter to W. G. Counsil dated June 21, 1979, transmitting I&E Bulletin No. 79-02, Revision 1.
(4)
W. G. Counsil letter to B. H. Grier dated July 6, 1979.
(5)
B. H. Grier letter to W. G. Counsil dated August 20, 1979, transmitting I&E Bulletin No. 79-02, Revision 1, Supplement 1.
(6) Teledyne Engineering Services Report TR-3501-1, Revision 1, submitted to U.S. NRC Region I, dated September 7,1979.
(7)
W. G. Counsil letter to B. H. Grier dated September 19, 1979.
(8)
B. H. Grier letter to W. G. Counsil dated November 8,1979.
trensmittit, I&E Bulletin No. 79-02, Revision 2.
Gentlemen:
Millstore Nuclear Power Station, Unit No. 1 Pipe Support Base Plate Design Using Concrete Expansion Anchor Bolts - I&E Bulletin No. 79-02 Reference (1), as supplemented by References (3), (5), and (8), requested that Northeast Nuclear Energy Company (NNECO) provide information regarding pipe support base plate designs using concrete expansion anchor bolts on Category I systems. Additionally, Reference (8) requested NNECO provide a schedule that details the completion dates for Items 1, 2, and 4 of Reference (8).
As reported in References (4) and (7), NNECO is a member of the Owners Group who contracted with Teledyne Engineering Services (TES) to address the generic questions of the subject bulletin.
(1)
In response to Question 1 of I&E Bulletin No. 79-02, the base plates uti..izing concrete expansion bolts are being analyzed using the TES modeling approach as described in Reference (6).
Shear tension inter-action is being accounted for as vell as minimum edge distance and proper bolt spacing.
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(2) In response to Question 2 of I&E Bulletin No. 79-02, ultimate shear-tension interaction values as listed in Ref arence (6) are used and appropriate factors of safety applied to determine allowable design loads on the expansion bolts.
(3) In response to Question 3 of I&E Bulletin No. 79-02, Reference (6) specifically addresses the cyclic load carrying ability of expansion bolts at both h1gh and low frequencies.
No significant decrease in the static load carrying ability was detected for the types of bolts used at Millstone Unit No. 1.
(4)
In response to Question 4(a) of I&E Bulletin No. 79-02, Reference (6) concluded that preload is not required to develop cyclic capacity if the expansion bolts are installed properly.
In response to Question 4(b) of I&E Bulletin No. 79-02, Reference (2) reported NNECO's replacement program in which all concrete expansion anchor bolts utilized in safety-related systems were replaced with lillti-Kwik bolts. Tension-testing of the Phillips shell-type anchor bolts on the remaining Category I system supports is complete. The results of this testing are presently being evaluated.
(5)
In response to Question 5 of I&E Bulletin No. 79-02, there are no Category I piping supports deriving their support from concrete block walls at Millstone Unit No. 1.
(6)
In response to Question 6 of I&E Bulletin No. 79-02, NNECO has made no distinction between base plates and structural steel shapes in the evaluation performed pursuant to the criteria of I&E Bulletin No. 79-02.
Structural steel shapes were included in NNECO's evaluation performed in response to References (1), (3), (5), and (8).
(7)
In response to Item 7 of I&E Bulletin No. 79-02, flexibility analysis on five percent (5%) of the base plates supporting Category I piping systems remain to be completed per TES analysis.
These analyses are scheduled to be completed on or about February 1,1980, at which time the responses to Questions 1 and 2 of the Bulletin will be completed.
The testing and inspections of the anchor bolts required by Question 4 have been completed. All concrete expansion anchor bolts on safety-related systems were replaced with Hilti-Kwik bolts as reported in Reference (2).
The remaining shell-type anchor bolts in Category I piping supports were tension-tes t ed.
The results of these tests are presently being evaluated.
A final report will be submitted following completion of all analyses.
We trust this information satisfactorily dispositions the concerns of References (1), (3), (5), and (8).
Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY l
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W. G. Counsil Vice President i794 257