ML20093N978
| ML20093N978 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 10/19/1984 |
| From: | Jens W DETROIT EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| 135, EF2-70033, NUDOCS 8411060078 | |
| Download: ML20093N978 (2) | |
Text
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Wayne H. Jens Vm President
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Nuclear Operatens Ferrm-2
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Edison =00NorthOnneHighway 64
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october 19, 1984 EF2-70033 Mr. James G. Keppler Regional Administrator Region III U.S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137
Dear Mr. Keppler:
Reference:
(1)
Fermi 2 i
NRC Docket No. 50-341 (2)
- Letter, W. H. Jens to J. G. Keppler, August 21, 1984, EF2-69668 (3)
Letter, W. H. Jens to J. G. Keppler, September 10, 1984, EF2-69706
Subject:
Final Report of 10CFR50.55(e) Item 135
" Design Deficiency of Conduit Support Weld Details" This is Detroit Edison's final report of Item 135, " Design Deficiency of Conduit Support Weld Details."
Item 135 was originally reported as a potential deficiency on August 9, 1984, and was subsequently documented in reference (3).
This discrepancy was discovered during a review of conduit supports relating to 10CFR50.55(e),
Item 119, Reference (2).
Description of Deficiency Welds were deleted from eight conduit support standards in Edison Specification 3071-128-ED-25-1 by Design Change Request DCR-E-3006 without seismic qualification review.
This deficiency was discovered by Giffels Associates, Inc.
(GAI) during the review of the structural adequacy of unistrut cross arms required to resolve 10CFR50.55(e)
Item 119.
DCR-E-3006 permitted connecting unistrut cross arms to main tube steel support members with two welds as opposed to the four welds originally required.
This new designwasnotinallcasessufficienttowithstanddesgp basis seismic loads.
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Mr. James G. Keppler October 19, 1984 EF2-70033 Page 2 f
Analysis of Safety' Implications The structural-integrity of safety related supports built to a
the deficient standards was not assured for the design. basis seismic event.
Corrective Action The following actions were taken to correct the deficiency-and prevent recurrence:
GAI~ reviewed the structural adequacy of the subject weld details and made necessary design changes to the standards.
DCN-10592, Revision A was issued on August 17, 1984 to' revise the weld details on the design standards.
Detroit Edison Field Engineering Conduit Design Group identified 130 existing conduit supports built to the design requirements of DCR-E-3006.
GAI performed individual design calculations for these supports and determined that only one required rework.
DCR-E-5090 was issued to add welds to this support.
Because of the discovery of conduit support standard deficiencies as reported in Items 119 and 135, GAI made a comprehensive review of the three specifications for which they originally provided calculations:
3071-128-ED (Electrical Engineering Standard-Conduit Supports), 3071-185 (I&C Standards for Tube Supports),
and 3071-232 (I&C Standards for Tube Supports-RHR Complex).
No significant deficiencies ~were identified.
This is Detroit Edison's final report on this item.
If you have questions concerning this matter, please contact Mr.
Lewis Bregni, (313) 586-5083.
Sincerely, cc:
Mr. P. M. Byron Mr. R. C. DcYoung Mr. R. C. Knop
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