ML19262B467
| ML19262B467 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 12/07/1979 |
| From: | Daltroff S PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| IEB-79-02, IEB-79-2, NUDOCS 7912280031 | |
| Download: ML19262B467 (4) | |
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.s PHILADELPHIA ELECTRIC COMPANY 2301 M ARKET STREET P.O. BOX 8699 PMILADELPHI A. PA.19101 SHIELDS L DALTROFF ELECTasc pm o csom December 7, 1979 Re:
Docket Nos.:
50-277 50-278 IE Bulletin 79-02 Mr. Boyce H. Grier, Director Office of Inspection & Enforcement Region I United States Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406
Dear Mr. Grier:
This is in response to your letter of November 2, 1979, which forwarded IE Bulletin 79-02, Revision..
The actions requested and our responses as they pertain to the Peach Bottom Atomic Power Station, Units 2 and 3, are listed sequentially below.
Action la hg Taken hy Licensee:
2.
The Bulletin factors of safety were intended for the maximum support load including the SSE.
The NRC has not yet been provided adequate justification that lower factors of safety are acceptable on a long term basis.
Lower factors of safety are allowed on an interim basis by the provisions of Supplement No. 1 to IE Bulletin No. 79-02.
The use of reduced factors of safety in the factored load approach of ACI 349-76 has not yet been accepted by the NRC.
Resconse Where analysis of supports indicates concrete expansion bolt safety factors less than required by the Bulletin, those supports will be modified to meet the factor of safety requirements of the
- Bulletin, i.e.,
four (4) for wedge type anchor bolts, and five (5) for shell type anchor bolts.
This represents a conservative 1648 060 29122so ()I37
Mr. Boyce H. Grier Page 2 departure from our July 6, 1979, response to the Bulletin in which we proposed the use of reduced factors of safety in accordance with ACI 349-76.
4.
Those licensees that have not verified anchor bolt preload are not required to go back and establish preload.
- However, additional information should be submitted which demonstrates the effects of preload on the anchor bolt ultimate capacity under dynamic loading.
Resoonse In our July 6, 1979, response to the Bulletin, we stated that it will be verified, by testing, that bolt preload is equal to, or greater than, the bolt design load resulting from a combination of operating and cyclic loading.
Therefore, no additional response is necessary to this part of the Bulletin.
5.
Determine the extent that expansion anchor bolts were used in concrete block (masonry) walls to attach piping supports in Seismic Category 1 systems (or safety related systems as defined by revision 1 of IE Bulletin No. 79-02).
If expansion anchor bolts were used in concrete block walls:
a.
Provide a list of the systems involved, with the number of supports, type of anchor bolt, line size, and whether these supports are accessible during normal plant operation, b.
Describe in detail any design consideration used to account for this type of installation.
c.
Provide a detailed evaluation of the capability of the supports, including the anchor bolts, and block wall to meet the design loads.
The evaluation must describe how the allowable loads on anchor bolts in concrete block walls were determined and also what analytical method was used to determine the integrity of the block walls under the imposed loads.
Also describe the acceptance criteria, including the numerical values, used to perform this evaluation.
Review the deficiencies identified in the Information Notice on the pipe supports and walls at Trojan to determine if a similar situation exists at your facility with regard to supports using anchor bolts in concrete block walls, d.
Describe the results of testing of anchor bolts in concrete block walls and your plans and schedule for any further action.
1648 06i
Mr. Boyce H. Grier Page 3 Resoonse It has been determined that no Seismic Category I large pipe supports, or computer analyzed small pipe supports are attached to concrete block masonry walls.
A field survey is presently under way to determine if any chart analyzed small piping is supported in concrete block walls.
The survey is expected to be complete by December 15, 1979 in accessible areas; inaccessible areas will be surveyed as permitted by unit outages.
A supplementary response will be forwarded following completion of this work.
6.
Determine the extent that pipe supports with expansion anchor bolts used structural steel shapes instead of base plates.
The systems and lines reviewed must be consistent with the criteria of IE Bulletin No. 79-02, Revision 1.
If expansion anchor bolts were use'd as described above, verify that the anchor bolt and structural steel shapes in these supports were included in the actions performed for the Bulletin.
If these supports cannot be verified to have been included in the Bulletin actions:
a.
Provide a list of the systems involved, with the number of supports, type of anchor bolt, line size, and whether the supports are accessible during normal plant operation.
b.
Provide a detailed evaluation of the adequacy of the anchor bolt design and installation.
The evaluation should address the assumed distribution of loads on the anchor bolts.
The evaluation can be based on the results of previous anchor bolt testing and/or analysis which substantiates operability of the affected system.
c.
Describe your plans and schedule for any further action necessary to assure the affected systems meet Technical Specifications operability requirements in the event of an SSE.
Resconse Pipe supports that use structural steel shapes instead of base plates were included in the analytical work done in accordance with the requirements of the Bulletin, and were included in our response to Revision 1 of the Bulletin.
7.
For those licensees that have had no extended outages to perform the testing of the inaccessible anchor bolts, the testing of anchor bolts in accessible areas is expected to be completed by November 15, 1979.
The testing of the inaccessible anchor bolts should be completed by the next i648 062
Mr. Boyce R. Grier Page 4 extended outage.
For those licensees that have completed the anchor bolt testing in inaccessible areas, the testing in accessible areas should continue as rapidly as possible, but no longer than March 1, 1980.
The analysis for the Bulletin items covering base plate flexibility and factors of safety snould be completed by November 15, 1979.
Provide a schedule that details the completion dates for IE Bulletin No. 79-02, Revision 2, items 1, 2, and 4.
Resconse The analytical work and the verification of bolt safety factors as required by items 1 and 2, respectively, of the Bulletin, were completed prior to November 15, 1979.
The testing required by item 4 of the Bulletin was completed on the Unit 3 large pipe supports on November 3, 1979, at the end of the recent refueling outage.
The Unit 3 small pipe support inspection program is expected to be completed by December 15, 1979.
Testing of Unit 2 accessible large pipe supports is expected to be completed by December 15, 1979, and the Unit 2 small pipe support inspection program 13 expected to be completed by January 1, 1980.
The completion dates for testing and inspection of accessible piping supports which extend beyond November 15, 1979 have been discussed with NRC Region 1 and are the subject of a letter from B. H. Grier to S. L. Daltroff dated October 24, 1979.
Testing of Unit 2 pipe support anchor bolts in
..naccessible areas is expected to be done during the next refueling outage, which is scheduled for Spring, 1980.
Very truly yours,
-s,// [ [/ ['
cc:
United States Nuclear Regulatory Commission Office of Inspection and Enforcement Division of Reactor Operations Inspection Washington, DC 20555 1648 063