ML20100K730

Final Deficiency Rept,Item 129 Re Lack of Design Calculations for HVAC Duct Supports.Initially Reported on 840614.Supports & Base Plates Modified & Installation Discrepancies Documented on Nonconformance Repts

ML20100K730
Person / Time
Site:	Fermi
Issue date:	11/27/1984
From:	Jens W DETROIT EDISON CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
129, EF2-70042, NUDOCS 8412110264
Download: ML20100K730 (3)

Text

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• Wayne H. Jens g V=) President

. Nuclear Operatons Edison =eorthOmeHighway r -" Novemser 27, 1984 EF2-70042 Mr. James G. Keppler Regional Administrator Region III U. S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137

Dear Mr. Keppler:

References (1) Fermi 2 NRC Docket No. 50-341 (2) Letter, W. H. Jens to J. G. Keppler, July 16,1984, EF2-69287 (3) Letter, W. H. Jens to J. G. Keppler, October 17, 1984, EF2-70027

Subject:

Final Report of 10CFR50.55(e) Item 129

" Lack of Design Calculations for HVAC Duct Supports" This is Detroit Edison's final report of Item 129, " Lack of Design Calculations for HVAC Duct Supports." Item 129 was originally reported an a potential design deficiency on June 14, 1984, and supplemental information was provided in References (2) and (3).

Description of Deficiency As reported in Reference (2), design calculations for safety related heating, ventilation and air conditioning (HVAC) ductwork supports cannot be located. Safety-related HVAC ductwork design, fabrication and installation was contracted to the Robert Irsay Company of Chicago, Illinois. Seismic qualification of the ductwork and structural design of the supports was subcontracted to the Fluor-Pioneer Company, an Architect / Engineer firm from Chicago, Illinois.

Reference (2) reported that Detroit Edison's preliminary assessment indicated that at least one HVAC support design did not meet the rigid support assumption used in the duct-work seismic analysis. Detroit Edison committed to reana-lyze the safety-related ductwork supports for which calcula-tions could not be located. This analysis consisted of g))

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Mr. James G. Keppler November 27, 1984 EF2-70042 Page 2 determining, for each support, the bounding conditions necessary to assure the validity of the seismic qualifica-tion of the ductwork supports. When the support drawings were compared to its calculated bounding conditions, 11 of the 567 supports required modifications to maintain the ductwork seismic qualification.

As reported in reference (3), a sample of the HVAC supports was inspected to verify the support drawings. This inspec-tion revealed that some of the hanger attachment points were noticeably off the center of the base plates. The attach-ment points of the hangers to the base plates were not detailed on the support drawings although the base plate design assumptions placed the attachment point at the center of the base plate. Although this situation did not directly affect the seismic design of the supports, the off center attachment had an adverse affect on the base plate anchor bolt loading.

To permit a detailed assessment of the affect on anchor bolt loading, Detroit Edison performed a walkdown of the safety related Irsay/ Fluor designed HVAC supports in the reactor and auxiliary buildings. During this walkdown, the support configurations were verified; the hanger attachment points were identified; and, any installation deficiencies were identified and documented. During this walkdown, approxi-mately 4% of the base plates were discovered to have instal-lation deficiences which included a hanger with welding incomplete, a base plate with 2 hangers attached, oversized bolt holes and shell type anchors pulling out of the con-crete. The nonconforming conditions identified were docu-mented on nonconformance reports.

Analysis of Safety Implications HVAC system supports failure during a seismic event could result in the loss or impaired operation of safety-related HVAC systems.

Corrective Action All safety-related and seismic 2 over 1 duct systems and supports designed and installed by Irsay/ Fluor have been reviewed by Detroit Edison engineering to determine if similar deficiencies exist.

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' Mr. James G. Keppler November 27, 1984 EF2-70042 Page 3 Detroit Edison's reanalysis of the supports indicated that 11 of~the 567 HVAC duct supports required modifications to allow the'ductwork to meet seismic qualification criteria.

These modifications consisted of adding braces, replacing structural members and reinforcing existing support members.

Hopper and Associates verified the mathodology, organization of calculations and assumptions of this re-analysis.. No discrepancies were identified.

The concern about the potential for excessive base plate anchor bolt loading was fully investigated. Worst case loads were used to establish bounding conditions for the location of the attachment point. Base plates with attach-ment points outside the bounding limits were individually analyzed. About 27 of the estimated 1900 base plates required modification to avoid exceeding allowable anchor bolt loads during the design seismic event.

The installation discrepancies discovered during the walk-down of the HVAC supports were documented on nonconformance reports and are being dispositioned individually.-

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.

j Sincerely, l

I cc P. M. Byron /

R. C. DeYoung y

R. C. Knop USNRC, Document Control Desk t

Washington, D.C. 20555 i

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