ML20214Q545

Forwards Request for Addl Info Re 860930 Application for Amend to Rerack Plant Spent Fuel Pool.Response Requested by 861205

ML20214Q545
Person / Time
Site:	Byron
Issue date:	11/25/1986
From:	Olshan L Office of Nuclear Reactor Regulation
To:	Farrar D COMMONWEALTH EDISON CO.
References
NUDOCS 8612050191
Download: ML20214Q545 (6)

Text

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Nsvember 25, 1986 DISTRIBUTION Docket Nos. STN 50-454 w DiiMETE w

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B. Grimes N. Thompson and STN 50-455 NRC PDR~~ ~ ~

Local PDR J. Partlow PD#3 L. 01shan T. Novak S. Varga OGC ACRS(10 Mr. D. L. Farrar E. Jordan i Director of Nuclear Licensing l- Comonwealth Edison Company

Post Office Box 767 l Chicago, Illinois 60690

Dear Mr. Farrar:

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SUBJECT:

BYRON SPENT FUEL POOL EXPANSION - RE0 VEST FOR ADDITIONAL INFORMATION Enclosed is a request for additional information that we need to complete our review of your September 30, 1986 amendment to rerack the Byron spent fuel pool. In order to accommodate your request that we approve the amendment by [

January 1, 1987, we need the responses to these questions by December 5, 1986.

If any further clarification is needed please contact me at (301) 492-4937.

Sincerely, UMginal signed ty:

Leonard N. 01shan, Project Manager Project Directorate #3 Division of PWR Lic.ensing-A

Enclosure:

As stated cc: See next page

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PD#3 PD#3 P

. . L01shan:mak a CVogan 11/ /86 11/4o/86 1* l/86 8612050191 861125 PDR ADOCK 05000454 P PDR

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• Mr.. Dennis L. Farrar * '

Byron Station Comonwealth Edison Company , Units 1 and 2

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cc: .

Mr. William Kortier Ms. Diane Chavez

. Atomic Power Distribution 528 Gregory Street Westinghouse Electric Corporation Rockford, Illinois 61108 Post Office Box 355 Pittsburgh, Pennsylvania 15230 Regional Administrator, Region III U. S. Nuclear Regulatory Comission Michael Miller 799 Roosevelt Road Isham, Lincoln & Beale Glen Ellyn, Illinois 60137 One First National Plaza 42nd Floor Joseph Gallo, Esq.

Chicago, Illinois 60603 Isham, Lincoln & Beale -

Suite 1100 Mrs. Phillip B. Johnson 1150 Connecticut Avenue, N.W.

1907 Stratford Lane Washington, D. C. 20036 Rockford, Illinois 61107 Douglass Cassel, Esq.

Dr. Bruce von 2clien 109 N. Dearborn Street Department of Biological Sciences Suite 1300 Northern Illinois University Chicago, Illinois 60602

_. DeKalb, Illinois 61107 Ms. Pat Morrison Mr. Edward R. Crass 5568 Thunderidge Drive Nuclear Safeguards & Licensing Rockford, Illinois 61107 Sargent & Lundy Engineers 55 East Monroe Street Ms. Lorraine Creek Chicago, Illinois 60603 Rt. 1, Box 182 Manteno, Illinois 60950 Mr. Julian Hinds U. S. Nuclear Regulatory Comission Byron / Resident Inspectors Offices 4448 German Church Road Byron, Illinois 61010 .

Mr. Michael C. Parker, Chief Division of Engineering i Illinois Department of

Nuclear Safety 1 1035 Outer Park Drive Springfield, Illinois 62704

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.o k/ 1 ENCLOSURE REQUEST FOR lDDITIONAL INFORMATION BYRON RERACK AMENDMENT

1. For the spent fuel pool heat exchangers provide the following :

a. heat transfer conductivity in BTU /Hr.

FTz/*F

b. tube surface area in square feet

2. Section 5.1 of the Licensing Report (Attachment B to the September 3, 1986 letter) indicated that Branch Technical Position (BTP) APCSB 9-2 was used, but Reference I to Section 5 indicated BTP ASB 9-2, Revision 1, July 1981 was used. Correct this discrepancy. Also confirm that the guidance in Standard Review Plan Section 9.1.3,III, regarding uncertainty factors, has been used.

3. With respect to the spent fuel pool structure, the licensee provided virtually no documentation attesting to the adequacy of the analytical procedures, the load combination criteria, or the selection of allowable loads and stresses, other thea to reference the original spent fuel pool analyses included in the FSAR. Accordingly, the licensee is requested to provide the following for review:

a. Sketches and/or drawings of any changes to the spent fuel pool structure not considered in the FSAR analysis,

b. A description of the mathematical model of the pool structure, including the finite-element model if used, and the method of analysis.

Describe the assumptions employed and the limitations of the model.

c. Ample description of the loadings used, and justification for the load combinations used.

d. The source of the acceptance criteria and method of determinino the allowable loads and stresses in various parts of the structure.

e. A description of how the dynamic interaction between the pool structure and the rack modules was considered, including the key assumptions used in assessing the interaction effects and the value of any dynamic amplification factors. Also include all assumptions made regarding the summation and phasing consideration of all rack module dynamic loads.

A f. An analysis of the adequacy of the pool floor and liner under rack sliding and impact loads.

g. The critical regions of the pool structure. List the loads or stresses as appropriate. Compare the loads and/or stresses to allowable values and indicate the source of the allowables in accordance with Question 5.d. above,

h. A description of any changes to be made to the leak monitoring system for the fuel pool.

4. It is not quite clear from the report how the support legs of the racks are proposed to be constructed. Provide the following information with respect to the design, construction, and installation of the support legs:

a. Sketch (or sketches) showing the upper and lower parts of the support feet including where the material transition from SA-217-CA15 to SA-351-CF3 occurs.

b. How is the transition accounted for in the analysis of fuel racks?

c. Adjusting the support legs during installation would require a long arm wrench. Provide information regarding the installation of racks when an adequate clearance to adjust the supports may not be available. How is the unevenness (if any) in the installation of the racks accounted for in the analysis?

5. The following information is needed for us to perform independent review of the analysis:

a. A set of fuel rack and fuel assembly drawings,

b. All analytical modeling parameters including:

- dimensions

- masses

- spring constants

- gap element properties l - fluid coupling coefficients

- coefficient for restitution for impacts i - multi-racks to rack and multi-racks to pool wall impacts

c. All supporting calculations for model parameters,

d. Digitized time histories (OBE & SSE) in three directions, as applicable.

l e. Calculations supporting the assumption that the fuel racks are rigid.

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4 7 f. Detailed seismic analysis and results.

g. Detailed seismic stress analysis and results

h. Thermal stress evaluations.

1. Various limiting rack and multi-rack displacements due to seismic loads.

6. Specific questions related to the analysis:

a. Provide justification for ignoring the flexural rigidity of fuel assemblies and modeling them as five separated " rattling" masses.

Provide information on the flexural rigidity of fuel assemblies.

Also discuss the manner in which the flexibilities of the multi-element fuel assemblies and cells are accounted for in the rack module analysis.

b. How is the vertical mass of the fuel assemblies accounted for in the model?

c. How is the mass of the water within the fuel accounted for in the model?

d. Have the effects of hot gaps and cold gaps been considered?

e. The model in Figure 6.7 shows the gap elements between the rack module edges and fixed boundaries are used to simulate inter-rack impacts. This does not simulate the potential increase of gaps due to sliding of a row of rack modules and development of higher impact velocities with larger gaps. Provide further justification that such worst case effects have been accounted for.

f. Demonstrate that inter-rack impacts at mid-height elevations are not possible.

g. Explain the s*,gnificant frequency difference between the EW and the NS SSE time tistories shown in Figures 6.1 and 6.2.

7. Provide the parameters and constants used in the analysis for impact loading due to the drop of a fuel assembly. Also, provide a summary of ductility ratios utilized to absorb kinetic energy in the tensile, flexural, compressive and shearing modes. Provide typical calculations indicating the input constants, equations used, and the results of the impact analysis.

8. Provide the considerations given regarding the potential impact on the functionality of fuel rack modules due to bowing and localized deformations of fuel assemblies and fuel rack cells.

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4 i 9. Provide the estimated occupational dose expected from performing the

" dry" reracking of the Byron spent fuel pool (SFP). These doses should be quantified (e.g.,10 mrem, less than 0.1 mrem) and include the following:

a. occupational dose for each phase of the SFP modification;

b. the basis for the estimate (methodology), including dose rates and manpower;

c. maximum individual dose expected.

10. Provide the information in 9 above for the " wet" reracking, additionally addressing doses to divers. (NOTE: If wet reracking is not addressed, the safety evaluation will consider dry reracking only.)

11. Identify, for " dry" reracking (and " wet" reracking if planned):

1.

radwaste solid liquid,sources gaseous(e.g)., racks, expected filters) volumes, and types (e.g.,

from:

a. the reracking operation, and

b. from subsequent spent fuel pool operations; and

2. the expected occupational dose increases resulting from increased spent fuel storage (e.g., compare pre-mod radwaste doses and post-mod radwaste doses).

12. Quantify the gaseous effluent releases (i.e., Kr 85) and compare the releases expected due to increased spent fuel storage quantitatively with pre-mod and post-mod annual spent fuel pool and overall plant releases (actual or calculated).

13. Provide a quantitative assessment of the impact of releases identified in question 12. above on individual and population doses offsite.

14. Compare the doses from 9 and 10 above with the overall doses projected (or actually experienced) for spent fuel operations in the Byron (or a similar plant) SFP and with doses experienced or project for overall plant operations.

15. Verify that no changes to the SFP ventilation and SFP water cleanup systems will be required for radiological purposes (e.g., need for increased capacit design or layout)y, higher flow rates, additional components, revised

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