ML20154E765
| ML20154E765 | |
| Person / Time | |
|---|---|
| Issue date: | 05/06/1988 |
| From: | Berlinger C Office of Nuclear Reactor Regulation |
| To: | Mccall J TENNESSEE VALLEY AUTHORITY |
| References | |
| REF-PT21-88 NUDOCS 8805200316 | |
| Download: ML20154E765 (3) | |
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Mr. John McCall Tennessee Valley Authority Sumit Hill Drive - W90224 Knoxville, Tennessee 37902 Gentlemen:
The Nuclear Regulatory Comission (NRC) was infonned by Hilti, Inc., in accor-dance with 10 CFR Part 21, of recent tests of Hilti Kwik-Bolts that indicate that the previously recommended minimum edge distance from an anchor bolt to an unsupported concrete edge may be insufficient to develop 100% of the recom-mended an: hor capacity.
The Hilti test results indicate that Hilti Kwik-Bolts placed at a distance of five anchor bolt diameters from an unsupported edge, as re>omended by the Expansion Anchor Manufacturers Institute (EAMI) guidelines, have only 30% of the recommended anchor shear capacity and 78% of the recom-mended tensile capacity. Hilti further indicated, at a meeting with the NRC staff, that the test results are believed to be applicable to other ^xpansion ancher bolts that use the same type of anchor mechanism as Hilti Kwik-Bolts.
The NRC staff feels that the test results indicating a 70% reduction in shear capacity are significant and indicate that there is a potential safety concern that will require further NRC review.
In view of the foregoing, the NRC would like to invite representatives of companies that supply bolts or provide bolt installation services to the nuclear industry, such as your company, to attend a meeting where pertinent information could be freely exchanged between meeting participants. The meeting is scheduled for May 24, 1988, at 1:00 p.m. in Conference Room IP-B-11 at the NRC's White Flint Building which is located at 11555 Rockville Pike in Rockville, FD. We are requesting that attendees present a brief presentation, approximately 15 minutes, that addresses the subjects listed in the meeting agenda and any other aspects related to this issue which you consider important.
If you plan to attend, or if you have any questions or concerns (such as how to present proprietary information), please contact Jaime Guillen at (301) 49?-1153 or Rom Lipinski at (301) 492-0844 before May 16, 1988. Your cooperation on this matter would be greatly appreciated.
Sincerely, Original Signed By Carl H. BnUnger Carl H. Berlinger, Chief 89052003{6 g gQ 71 Generic Comunications Branch PDR P12 PDR Division of Operational Events Assessment 88 Office of Nuclear Reactor Regulation
Enclosures:
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Meeting Agenda 2.
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MAY 6 1988
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May 24, 1988 Meeting Agenda Item Speaker Time I.
Introduction NRC 1:00 - 1:15 p.m.
II. Presentations by A/Es 1:15 - 3:45 p.m.
Architects / Engineers
- 3 III. Discussion / Forum Attendees 3:00 - 4:45 p.m.
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- Invited Architects / Engineers '
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Bechtel Power Corporation 1
Brown & Root, Inc.
l H. J. Degenkolb Ebasco Services, Inc.
Gibbs & Hill, Inc.
t Gilbert / Commonwealth, Inc.
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Sargent & Lundy Engineers Stone & Webster Engineering Corp.
Tennessee Valley Authority URS/ John Blume Associates i
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l MAY 61988 Principal Subjects of Presentations I.
What was the "edge distance" as defined in the job specification in nuclear power facilities that you have designed and/or constructed?
II.
Identify the type of anchors to which the "five diameter" or other edge distance criteria applies (expansion anchors, cast-in-place anchors, or all).
III. Discuss briefly the type of anchorage used for different types of safety-related equipment in nuclear power plants.
IV. Describe the anchorage design methods used for nuclear power facilities.
V.
Describe any anchor tests conducted by your organization and indicate whether any reinforcement, either parallel or normal to the free edge, was present in the test samples,
VI. Based on your experience, estimate the percentage of anchors installed in nuclear power facilities designed and/or constructed by your company that could be affected by the "edge distance" issue.
VII. Present your perspective of the "edge distance" issue.
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