ML20196J961

Forwards Request for Addl Structural Info on Plant Spent Fuel Pool Expansion,Per Util 871222 Revised Licensing Rept in Support of Proposed Amend to Increase Storage Capacity

ML20196J961
Person / Time
Site:	Byron
Issue date:	03/08/1988
From:	Olshan L Office of Nuclear Reactor Regulation
To:	Butterfield L COMMONWEALTH EDISON CO.
References
TAC-62112, TAC-63266, NUDOCS 8803150116
Download: ML20196J961 (5)

Text

, 3.

March 8, 1988

. DISTR.:BUTION:

! Docket Files 0GC-Rockville Docket Nos. STN 50-454 NRC~ & Local' PDRs EJordan and STN 50-455-PDIII-2 r/f JPartlow GHolahan ACRS(10)

LLuther Plant File Mr. L. D. Butterfield, Jr. L01shan Nuclear Licensing Manager Comonwealth Edison Company Post Office Box 767 Chicago, Illinois 60690 Der Mr. Butterfield:

SUBJECT:

BYRON SPENT FUEL 900L EXPANSION - REQUEST FOR ADDITIONAL STRUCTURALINFORMATION(TACNOS.: 62112,63266)

By letter dated December 22, 1987 you provided a revised ifcensing report to support your proposed ament'sent to increase the storage capacity of the spent fuel pool at Byron Station. The NRC staff and its consultant, Brookhaven National Laboratory, have evaluated the structural aspects of the revised licensing report. As a result, enclosed is our request for additional information. Although we understand that a different rack configuration is being contemplated, many ofthe enclosed questions will still apply.

For further clarification, please contact Leonard N. Olshan, the Byron ProjectManager,at(301)492-3018. The reporting and/or recordkeeping requirements of this letter affect fewer than ten respondents; therefore, OMB clearance is not required under PL 96-511.

Sincerely,

/

/5 Leonard N. 01shan, Project Manager l Project Directorate III-2 l

Division of Reactor Projects - III, l IV, V and Special Projects

Enclosure:

l As stated cc: See next page l

PDIII-2 PDIII-2 PDIII,p l01shan/ww LLutherM DMgli,dr p3/ 3 /88 3/ 7 /88 3/ 1 /88 l

l 8803150116 880308 DR ADOCK 0500 4 l - ..

Mr. L. D. Butterfield, Jr. Byron Station Commonwealth Edison Company Units 1 and 2 cc:

Mr. William Kortier Regional Administrator, Region III Atomic Power Distribution U.S. Nuclear Regulatory Comission Westinghouse Electric Corporation 799 Roosevcit Road Post Office Box 355 Glen Ellyn, Illinois 60137 Pittsburgh, Pennsylvania 15230 Mr. Michael C. Parker, Chief Michael Miller, Esq. Division of Engineering Sidley and Austin Illirois Department of One First National Plaza Nuclear Safety Chicago, Illinois 60603 1035 Outer Park Drive, 5th Floor Springfield, Illinois 62704 Mrs. Phillip B. Johnson Joseph Gallo Esq.

1907 Stratford Lane Hopkins and Sutter Rockford, Illinois 61107 Suite 1250 1050 Connecticut Avenue, N.W.

Ms. Lorraine Creek Washington, D.C. 20036 Rt. 1 Box 182 Manteno, Illinois 60950 Douglass Cassel, Esq.

109 N. Dearborn Street Dr. Bruce von Zellen Suite 1300 Department of Biological Sciences Chicago, Illinois 60602 Northern Illinois University DeKalb, Illinois 61107 Ms. Pat Morrison 5568 Thunderidge Drive Mr. Edward R. Crass Rockford, Illinois 61107 Nuclear Safeguards & Licensing Sargent & Lundy Engineers Attorney General 55 East Monroe Street 500 South 2nd Street Chicago, Illinois 60603 Springfield, Illinois 62701 U.S. Nuclear Regulatory Commission Chairman, Ogle County Board Byron / Resident Inspectors Offices Post Office Box 357 4448 Gerinan Church Road Oregon Illinois 6'.061 Byron, Illinois 61010 EIS Review Coordinator Environmental Protection Agency Region V 230 S. Dearborn Street Chicago, Illinois 60604 J

,- t ENCLOSURE REQUEST FOR ADDITIONAL STRUCTURAL INFORMATION ON BYRON SPENT FUEL P00L EXPANSION General Items:

1. The revised licensing report indicates that significant design modifica-tions were made since the original submittal, e.g., number of cells / module, spacing between racks, spacing between racks and pool walls, new support leg designs, different materials, component dimensions, etc. In order to make the best use of information reviewed previously, the Licensee should identify all design changes made since the previous submittal and discuss their significance.

2. In consideration of the significant design changes and complete reanalysis of the fuel racks, the licensee should review and update the responses to all previous NRC questions. Any information previously submitted such as drawings, calculations, reports, etc., should be resubmitted if superseded.

This includes the Holtec seismic report.

3. The rack seismic reanalysis assumed a consolidated fuel weight of 3000 lb/

cell. Does the licensee intend to use consolidated fuel in these racks?

If so, additional information justifying its use will be required.

4. Has the fuel pool structure and liner been reanalyzed to consider increased fuel weight and increased seismic loads? Provide details.

Specific Items:

1. Where is SA479-410 stainless steel used? Its material properties were not included in Tables 6.3 or 6.4. Provide this data.

2. Provide additional design drawings and infomation on the use of "short" adjustable support legs (Fig. 3.6B) and "small" fixed support legs (Fig.

3.6C). Are they used in place of, or in addition to, standard support legs? Do the racks that use them have a different baseplate elevation?

3. Do the fuel racks rest directly on the pool floor liner? Are bearing pads or shim plata used between the rack feet and the pool floor? If so, pro-vide details.

4. Provide additional design information on the fuel pool shipping cask area.

Are there any physical restraints which would prevent the rocks from slid-ing into this area during an earthquake? Is the peal floor et a different elevation in this area?

5. Did the multiple rack study (page B-3, answer #4) analyze the row which contains racks 81, C2, C6, and D47 The response lists C4 instead of C6.

Is this a typing error or an error in the pool layout figure 2.1?

6. Provide additional details on the multiple rack analysis. Include all modeling parameters and discuss any modeling input differences between the single and multiple rack models. Include all load and displacement results for each of the four racks included in the model. Response versus time plots would be helpful if available. Provide an explanation of significant differences between single and multiple rack results including the results presented on page B-3 of the report.

7. The multiple rack analysis results presented on page B-3 indicate displace-ments that are three to eight times the displacements predicated by the curresponding single rack model. This, in itself, does not demonstrate the conservatism of the single rack models. Provide additional justification for using single rack models to predict design basis loads, displacerrents and stresses. This response should also consider and address the following potentially unconservative modeling assumption used in the multiple rack analysis:

a) The row of racks modeled was an interior row and probably does not represent a worst case. An exterior row would have lower fluid coupl-ling forces due to larger side gaps. This could result in even larger displacements.

b) The multiple rack analysis was 2 dimensional instead of 3 dimensional.

Cross-coupling effects cannot be accounted for in a 2-D model. Only one horizontal component of the earthquake was applied. These 3-D effects would most likely result in large displacements.

8. If rack to wall impact loads occurred as the result of an earthquake, are the pool walls capable of withstanding the maximum impact loads? Provide relevant design data.

9. Tables 6.5 e, f, k,1 on the 12 x 14 rack analysis surrrrary refers to both the C1 and C3 racks. C1 is an edge rack while C3 is an interior rack. l Which of these two racks was analysed?

10. Section 6.2.lc states that the local flexibility of the rack-support inter-face is modeled "conservatively" in the analysis. Does this rnean that the spring elements representing this interface were assigned a much higher stiffness than expected? Provide further clarification and justification.

11. Table 6.5g lists' load cases in which the J1 rack (7x5 module) was filled with fuel assemblies as follows: 1) 35 cells with 3000 lb assemblies, 2) i 70cellswith3000lbassemblies,and3)12largecellsfilledwith10,000 I lb assemblies. Explain the physical significance of each load case. Does a 10,000 lb fuel asserrbly also represent consolidated fuel? Provide draw-ings to clarify the J1 module design.

I

r. <>

12. Does the J1 rack and the other racks which are located adjacent to the shipping cask area meet the safety factors against sliding and overturning given in Section 6 of SRP 3.8.4, Appendix D?

13. Rack to rack impact loads presented in Table 6.5 are significantly higher (206,000 lb) then reported in the previous submittal. What is the allow-able load? Provide supporting calculations to justify the allowable.

14. Were the misa11gned rack configurations discussed in Section 6.2.lk intended to represent a rack with initial rigid body rotation about its reference position er 3 rack that is deformed (twisted or out of tolerance)?

15. Provide a summary of .iafety margins for all fuel rack load combinations considering both ovr.rall and local effects.

16. The fuel assembly veight used in the dropped fuel assembly accident analy-sis is about half of the weight used in the seismic analysis. Explain and justify this apparent inconsistency.

17. Explain how the rack floor loads (vertical and shear) were applied in the spent fuel pool analysis. Since only three of the 23 modules were analyzed, were maximum floor loads applied at every rack location? Were these loads assumed to be in phase?

18. Did the spent fuel pool analysis account for the additional pressure loads on the pool walls resulting from seismic motion of racks (fluid coupling effects between racks and wall)? Provide details or justification for not including these loads.

.