ML070670528

Request for Additional Information on the Proposed Amendment to Revise Fuel Storage Pool Boron Concentration

ML070670528
Person / Time
Site:	San Onofre
Issue date:	03/16/2007
From:	Kalyanam N NRC/NRR/ADRO/DORL/LPLIV
To:	Rosenblum R Southern California Edison Co
Kalynanam N, NRR/DORL/LP4, 415-1480
References
TAC MD1405, TAC MD1406
Download: ML070670528 (6)

Text

March 16, 2007 Mr. Richard M. Rosenblum Senior Vice President and Chief Nuclear Officer Southern California Edison Company San Onofre Nuclear Generating Station P.O. Box 128 San Clemente, CA 92674-0128

SUBJECT:

SAN ONOFRE NUCLEAR GENERATING STATION, UNITS 2 AND 3 -

REQUEST FOR ADDITIONAL INFORMATION ON THE PROPOSED AMENDMENT TO REVISE FUEL STORAGE POOL BORON CONCENTRATION (TAC NOS. MD1405 AND MD1406)

Dear Mr. Rosenblum:

By letter dated April 28, 2006 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML061220701), and as supplemented by letters dated November 13 and December 22, 2006 (ADAMS Accession Nos. ML063210425 and ML063610042, respectively), Southern California Edison submitted an application to change the San Onofre Nuclear Generating Station, Units 2 and 3, technical specifications related to fuel storage pool boron concentration. The proposed change will increase the minimum allowed boron concentration of the spent fuel pool and allow credit for soluble boron, guide tube inserts (GT-Inserts) made from borated stainless steel, and fuel storage patterns in place of Boraflex.

After reviewing your request, the Nuclear Regulatory Commission staff has determined that additional information outlined in the enclosure is needed to complete the review. We discussed this information with your staff by telephone and they agreed to provide the additional information requested by March 23, 2007.

If you have any questions, please contact me at (301) 415-1480.

Sincerely,

/RA/

N. Kalyanam, Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-361 and 50-362

Enclosure:

Request for Additional Information cc: See next page

ML063210425 and ML063610042, respectively), Southern California Edison submitted an application to change the San Onofre Nuclear Generating Station, Units 2 and 3, technical specifications related to fuel storage pool boron concentration. The proposed change will increase the minimum allowed boron concentration of the spent fuel pool and allow credit for soluble boron, guide tube inserts (GT-Inserts) made from borated stainless steel, and fuel storage patterns in place of Boraflex.

After reviewing your request, the Nuclear Regulatory Commission staff has determined that additional information outlined in the enclosure is needed to complete the review. We discussed this information with your staff by telephone and they agreed to provide the additional information requested by March 23, 2007.

If you have any questions, please contact me at (301) 415-1480.

Sincerely,

/RA/

N. Kalyanam, Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-361 and 50-362

Enclosure:

Request for Additional Information cc: See next page DISTRIBUTION:

PUBLIC RidsNrrDorl (CHaney/JLubinski) RidsNrrLALFeizollahi LPLIV r/f RidsNrrDorlDpr RidsNrrPMNKalyanam RidsAcrsAcnwMailCenter RidsNrrDorlLpl4 (DTerao) RidsRgn4MailCenter (TPruett)

RidsNrrDciCsgb RidsNrrDeEemb Zuhan Xi, DSS John Ma, DSS RidsOgcRp ADAMS Accession No.: ML070670528 *No major change from Staff provided RAI.

OFFICE NRR/LPL4/PM NRR/LPL4/LA NRR/DE/EMCB* NRR/LPL4/BC NAME NKalyanam LFeizollahi KManoly DTerao DATE 3/15/07 3/15/07 3/8/07 3/16/07 REQUEST FOR ADDITIONAL INFORMATION SAN ONOFRE NUCLEAR GENERATING STATION, UNITS 2 AND 3 SOUTHERN CALIFORNIA EDISON DOCKET NOS. 50-361 AND 50-362 REQUEST TO REVISE FUEL STORAGE POOL BORON CONCENTRATION

1. Were the spent fuel racks licensed for carrying a fuel load of 1,540 lbs only or also for carrying a fuel load of 2,904 lbs? The Nuclear Regulatory Commission (NRC) staff is unclear whether this amendment is seeking approval of spent fuel racks that can carry a fuel load of 2,904 lbs, which is not indicated in your April 28, 2006 letter.

The reason for this question is because the NRC staff is unclear about two specific statements in the amendment request. The first states that, The total dry weight of a fuel assembly with GT-lnserts will be 1,551 lbs which is less than 1% heavier than the estimated standard fuel assembly weight of 1,540 lbs that was considered in the design of the SONGS [San Onofre Nuclear Generating Station ] spent fuel racks. The spent fuel racks were also analyzed using a weight of 2,904 Ibs for the possible future storage of consolidated fuel. The second statement indicates that, The design of the spent fuel racks considered two load cases for each storage cell location: a dry weight of 1,540 lbs for the standard fuel assembly and also a load of 2,904 lbs. The content in the first quotation implies that the licensed racks can only support a fuel load of 1,540 lbs per assembly; however, an analysis was also performed for a fuel load of 2,904 lbs. The content in the second quotation seems to imply that the racks are licensed to include a fuel load of 2,904 lbs. Furthermore, there are evaluation results under two columns:

one for 1,540 lbs fuel load and the other for 2,904 lbs fuel load in Tables 1, 2, and 3.

The reason for having the column for 2,904 lbs fuel load was not explained if the racks were not licensed for a fuel load of 2,904 lbs. Therefore, the NRC staff requests your clarification for including the evaluation results for racks carrying a fuel load of 2,904 lbs.

2. Were there any new structural/seismic analyses performed related to this amendment?

If yes, describe the analyses.

The reason for this question is because the NRC staff is unclear about two specific statements in the amendment request. The first indicates that, The results of criticality, boron dilution, radiological decay heat, and structural/seismic analyses show that SONGS Units 1, 2, and 3 fuel assemblies can be safely stored in the SONGS Units 2 and 3 spent fuel racks assuming no Boraflex is present by taking credit for soluble boron, using GT-lnserts, and/or storing the fuel in analyzed fuel storage patterns. The second statement states that, The structural effect of adding GT-lnserts into the fuel assemblies will be small and within the capability of the spent fuel racks and the spent fuel pool. The first quotation implies that new structural/seismic analyses were performed. However, the content in the second quotation seems to imply that no structural/seismic analysis was necessary. Furthermore, the analyses results in Tables 1, 2, and 3 are listed only for fuel loads of 1,540 lbs and 2,904 lbs. The NRC

staff would expect the analyses results for fuel loads of 1,650 lbs (the 1,540 lbs fuel load plus the 110 lbs of the GT-Insert) listed in Tables 1, 2, and 3 if a new structural/seismic analysis has been performed.

3. Your evaluation indicates that the spent fuel racks are qualified based on conformance with provisions in American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (Code),Section III, NF 3340. Please clarify that NF 3340 of ASME Code,Section III, is your current licensing basis for the design of the spent fuel racks.

The NRC staff is unclear whether your statement The acceptance limit is the limit load of the structural component (see NF 3340 of ASME Code Section III) for rack analyses was intended to describe the criteria used in the analysis for licensed racks or the criteria only used in the new analyses.

4. According to the SONGS Units 2 and 3 Updated Final Safety Analysis Report, the spent fuel pool was designed based on American Concrete Institute (ACI)-318 code. It appears that the evaluation methodology for the spent fuel pool is not consistent with the design licensing basis. Please provide justification for the deviation between the licensed design and the evaluation methodology.

The amendment request included the statement, The utilization factors for the governing concrete elements are presented in Table 3 for the two load cases. The utilization factor is defined as the percentage of resistance of the reinforced concrete section that has been utilized relative to the zero curvature line. A utilization factor of 100 percent indicates that the section is fully utilized by the design load. The largest utilization factor for a concrete section is 94 percent (at least a 6 percent margin remains against the section allowable). The results show that the spent fuel pool will be capable of maintaining its structural integrity for the increase in weight from the GT-lnserts. This statement implies that the acceptance criteria for the evaluation of the spent fuel pool is different from that of the original licensing basis for the spent fuel pool.

The primary concerns with your criteria or method of using a utilization factor referenced to the zero curvature line are that (1) the method is not recognized by codes and standards accepted by the NRC, (2) the method only applies to bending deformations but does not apply to stresses caused by compression, shear, and torsion, and (3) the effects of load or stress combinations resulting from forces of bending, axial, shear, and torsion on a cross-section are not considered.

San Onofre Nuclear Generating Station Units 2 and 3 cc:

Mr. Daniel P. Breig Director, Radiologic Health Branch Southern California Edison Company State Department of Health Services San Onofre Nuclear Generating Station P.O. Box 997414, MS 7610 P. O. Box 128 Sacramento, CA 95899-7414 San Clemente, CA 92674-0128 Resident Inspector/San Onofre NPS Mr. Douglas K. Porter, Esquire c/o U.S. Nuclear Regulatory Commission Southern California Edison Company Post Office Box 4329 2244 Walnut Grove Avenue San Clemente, CA 92674 Rosemead, CA 91770 Mayor Mr. David Spath, Chief City of San Clemente Division of Drinking Water and 100 Avenida Presidio Environmental Management San Clemente, CA 92672 P. O. Box 942732 Sacramento, CA 94234-7320 Mr. James T. Reilly Southern California Edison Company Chairman, Board of Supervisors San Onofre Nuclear Generating Station County of San Diego P.O. Box 128 1600 Pacific Highway, Room 335 San Clemente, CA 92674-0128 San Diego, CA 92101 Mr. James D. Boyd, Commissioner Mark L. Parsons California Energy Commission Deputy City Attorney 1516 Ninth Street (MS 31)

City of Riverside Sacramento, CA 95814 3900 Main Street Riverside, CA 92522 Mr. Ray Waldo, Vice President Southern California Edison Company Mr. Gary L. Nolff San Onofre Nuclear Generating Station Assistant Director - Resources P.O. Box 128 City of Riverside San Clemente, CA 92764-0128 3900 Main Street Riverside, CA 92522 Mr. Brian Katz Southern California Edison Company Regional Administrator, Region IV San Onofre Nuclear Generating Station U.S. Nuclear Regulatory Commission P.O. Box 128 611 Ryan Plaza Drive, Suite 400 San Clemente, CA 92764-0128 Arlington, TX 76011-8064 Mr. Michael R. Olson San Diego Gas & Electric Company 8315 Century Park Ct. CP21G San Diego, CA 92123-1548 March 2006

San Onofre Nuclear Generating Station Units 2 and 3 cc:

Mr. Steve Hsu Department of Health Services Radiologic Health Branch MS 7610, P.O. Box 997414 Sacramento, CA 95899 Mr. A. Edward Scherer Southern California Edison Company San Onofre Nuclear Generating Station P.O. Box 128 San Clemente, CA 92674-0128 March 2006