ML18057B427
| ML18057B427 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 12/13/1991 |
| From: | Brian Holian Office of Nuclear Reactor Regulation |
| To: | Slade G CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| References | |
| TASK-03-07.B, TASK-3-7.B, TASK-RR TAC-M48726, NUDOCS 9112240262 | |
| Download: ML18057B427 (4) | |
Text
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L Docket No. 50-255 Mr. Gerald B. Slade Plant General Manager Palisades Plant Consumer Power Company 27780 Blue Star Memorial Highway Covert, Michigan 49043
Dear Mr. Slade:
December 13, 199~
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SUBJECT:
PALISADES PLANT - SUPPLEMENTAL EVALUATION OF SEP TOPIC III-7.B.
11 DESIGN CODES, DESIGN CRITERIA AND LOAD COMBINATIONS 11 (TAC NO. M48726)
We have completed our review of your latest submittal (Dated August 7, 1991) related to the the issue of severe weather loads on the Palisades Auxiliary Building roof.
Our review included an assessment of previous evaluations performed by the NRC staff regarding this issue, dating back to the integrated plant safety assessment report, November 1983.
The NRC staff concludes the the Palisades Auxiliary Building roof and the supporting structural components are able to withstand the sever weather loading without exceeding the acceptance criteria in the updated FSAR.
Our Supplemental Safety Evaluation is enclosed.
This letter completes NRC action on TAC No. M48726.
Enclosure:
As stated cc w/enclosure:
See next page OFFICIAL RECORD COPY Document Name:
PALISADES SEP TOPIC 9112240262 1213 ----- ----
PDR ADDCK 05000255 P
PDR Sincerely, Original signed by Brian Holian, Project Manager Project Directorate III-1 Division of Reactor Projects III/IV/V Office of Nuclear Reactor Regulation
Mr. Gerald B. Slade Consumers Power Company cc:
M. I. Miller, Esquire Sidley & Austin 54th Floor One First National Plaza Chicago, Illinois 60603 Mr. Thomas A. McNish, Secretary Consumers Power Company 212 West Michigan Avenue Jackson, Michigan 49201 Judd L. Bacon, Esquire 212 West Michigan Avenue Jackson, Michigan 49201 Regional Administrator, Region III U.S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137 Jerry Sarno Township Supervisor Covert Township 36197 M-140 Highway Covert, Michigan 49043 Office of the Governor Room 1 - Capitol Building Lansing, Michigan 48913 Mr. Patrick M. Donnelly Director, Safety and Licensing Palisades Plant 27780 Blue Star Memorial Hwy.
Covert, Michigan 49043 Resident Inspector c/o U.S. Nuclear Regulatory Commission Palisades Plant 27782 Blue Star Memorial Hwy.
Covert, Michigan 49043 Palisades Plant Nuclear Facilities and Environmental Monitoring Section Office Division of Radiological Health Department of Public Health 3423 N. Logan Street P. 0. Box 30195 Lansing, Michigan 30195 Gerald Charnoff, P.C.
Shaw, Pittman, Potts &
Trowbridge 2300 N. Street, N.W.
Washington, D.C. 20037 Mr. David L. Brannen Vice President Palisades Generating Company c/o Bechtel Power Corporation 15740 Shady Grove Road Gaithersburg, Maryland 20877 Roy W. Jones Manager, Strategic Program Development Westinghouse Electric Corporation 4350 Northern Pike Monroeville, Pennsylvania 15146
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON. D. C. 20555 SUPPLEMENTAL SAFETY EVALUATION OF AUXILIARY BUILDING ROOF STRUCTURE FOR SEVERE WEATHER PHENOMENA CONSUMERS POWER COMPANY PALISADES PLANT DOCKET NO. 50-255
1.0 INTRODUCTION
In the staff 's Integrated Plant Safety Assessment Report (IPSAR-Ref. 1), the staff concluded that, "the licensee has adequately addressed many of the issues identified in Section 4.12 (i.e., SEP Topic III-7.B, 'Design Criteria, Load Combination, and Reactor Cavity Design Criteria' of Ref. 2), while the remainder still require additional confirmatory information to justify the conclusion that the margins of safety provided are adequate.
The staff will present the results of this confirmatory review in a supplemental evaluation.
11 The staff's consultant Franklin Research Center (FRC) reviewed the licensee's subsequent submittals and provided its findings in a Technical Evaluation Report (Ref. 3).
The report identified two issue related to SEP Topic III-7.B, which are not fully addressed by the licensee:
(1) Masonry Wall Design and (2) Snow Load on Auxiliary Building Roof.
Issue No. 1 was addressed by the staff in Reference 4.
Issue No. 2 is addressed in this evaluation.
2.0 EVALUATION The Auxiliary Building roof structure over the spent fuel pool consists of steel decking supported by steel-trusses.
Reference 3 had identified the roof structure as the most critical structure which may not be able to safely withstand the simultaneous occurrence of three severe weather effects; (1) 100 year mean reoccurrence interval snow, (2) maximum probable winter precipitation, and (3) drift from the higher adjoining structure (i.e., containment).
In SEP Topic II.2A, the combined loading was calculated as 90 lbs. per sq. ft. (psf).
Palisades FSAR indicates that all roofs are designed for a live load of 40 psf for snow and ice using allowable stress design (ASD) method of AISC Building Specification (Ref. 5).
Considering the rare occurrence of the combined loading, in Reference 3, the FRC multiplied the design load of 40 psf by a factor of 1.65 to get an approximate safe allowable value of 64 psf, which is still considerably lower than the above worse case load calculated, i.e., 90 psf.
After two teleconferences between the staff and the licensee, the licensee decided to evaluate the existing Auxiliary Building steel structure in detail to demonstrate that the existing steel structure can safely withstand the combined loading.
1-2 -
In the detailed evaluation (Ref. 6), the licensee used the actual dead loads of the structural components, the combined snow and rain loads of 55 psf for trusses T-2, T-3, T-4 (Figure 1), and the combined snow, rain, and drift load in accordance with the procedure given in Reference 7 for T-5 truss.
For tension members, the licensee used an allowable stress of 1.6 times ASD allowable in Reference 5, and for compression members, the licensee used an allowable stress of 1.2 times the corresponding ASD allowable of Reference 5.
The staff spot checked some of the calculations provided in Reference 6.
The licensee has evaluated the adequacy of the steel deck, purlins, truss members and the columns affected by the postulated severe weather loads.
Having reviewed the above listed information, the staff concluded that the loading calculations, method of evaluation and analysis, and the acceptance criteria used by the licensee were acceptable to the staff.
3.0 CONCLUSION
S Based on an assessment of the staff's prior reviews, evaluation of additional submittals made by the licensee related to the severe weather (specifically, snow+ rain + drift) loading on the Auxiliary Building roof, the staff concluded that the Auxiliary Building roof and the supporting structural components were found to be able to withstand the effects of the postulated severe weather loading without exceeding the acceptance criteria of the updated FSAR.
There-fore, the issue of design adequacy of auxiliary building roof against the postulated snow load is resolved.
- 4. 0 REFERENCE
- 1.
Letter from Mr. Dennis M. Crutchfield (NRC) to Mr. David J. VandeWalle (Consumers Power Company), "Integrated Plant Safety Assessment Report....
11 dated November 1, 1983.
- 2.
NUREG-0820, Supplement 1, "Integrated Plant Safety Assessment - Palisades
- Plant, 11 dated November 1983.
- 3.
TER-C5506-422 by Franklin Research Center, "Review of Licensee Response to Design Codes, Design Criteria, and Loading Combinations, (SEP TOPIC III-7.B) -
Palisades Plant, 11 dated August 6, 1986.
- 4.
Letter from NRC to Consumers Power Company, "Safety Evaluation of Palisades Plant Masonry Wall Design - Response to IE Bulletin 80-11, 11 dated December 27, 1989.
- 5.
AISC Specification For the Design, Fabrication and Erection of Structural Steel for Buildings, 1969 Edition.
- 6.
Letter from Gerald 8. Slade (Consumer Power) to NRC, "SEP TOPIC III-7.B, Severe Weather Load - Additional Information, 11 dated August 7, 1991.
- 7.
ASCE 7-88 (Formerly ANSI A58.l),
11Minimum Design Loads for Building and Other Structures, 11 dated July 1990.
- .