ML082120486

License Amendment Request to Revise Technical Specification 4.3.1.1.A Concerning K-Infinity

ML082120486
Person / Time
Site:	Peach Bottom
Issue date:	01/21/2009
From:	John Hughey NRC/NRR/ADRO/DORL/LPLI-2
To:	Cowan P Exelon Generation Co
Hughey J, NRR/DORL, 301-415-3204
References
TAC MD9154, TAC MD9155
Download: ML082120486 (7)

Text

Official Use OFily PF9tJFietaFY IAfQr:MatioA fC UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 January 21,2009 Ms. Pamela B. Cowan Director - Licensing and Regulatory Affairs Exelon Generation Company, LLC Correspondence Control P.O. Box 160 Kennett Square, PA 19348

SUBJECT:

PEACH BOTTOM ATOMIC POWER STATION, UNIT NOS. 2 AND 3: REQUEST FOR PROPRIETARY REVIEW OF REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST TO REVISE TECHNICAL SPECIFICATION 4.3.1.1.A CONCERNING K-INFINITY (TAC NOS. MD9154 AND MD9155)

Dear Ms. Cowan:

By letter to the Nuclear Regulatory Commission (NRC) dated June 25, 2008, (Agencywide Documents Access and Management System (ADAMS) Accession No. ML081820302), Exelon Generation Company, LLC, (Exelon) submitted a license amendment request (LAR) for Peach Bottom Atomic Power Station, Units 2 and 3. The LAR seeks to revise Technical Specification (TS) 4.3.1.1.a concerning the spent fuel pool (SFP) K-infinity value. The NRC staff has reviewed the request submitted by the licensee and has identified a need for additional information as set forth in Enclosure 1. includes information that the licensee has requested to be withheld from public disclosure pursuant to Title 10 of the Code of Federal Regulations (10 CFR) Part 2, Section 2.390.

The draft questions were sent to Mr. Tom Loomis of your staff on December 1, 2008, to confirm that all proprietary information contained in Enclosure 2 was identified with brackets, and to ensure that the questions were understandable, the regulatory basis for the questions was clear, and to determine if the information was previously docketed. Mr. Loomis confirmed that all proprietary information in Enclosure 2 was identified with brackets via e-mail dated December 12, 2008 (ADAMS Accession No. ML083510533), and a teleconference was held between Exelon and NRC staff on December 16, 2008, regarding the questions.

The NRC staff requests that Exelon submit a response within 45 days of the date of this letter.

Please note that if you do not respond to this letter within 45 days or provide an acceptable alternate date in writing, we may reject your application for amendment under the provisions of Title 10 of the Code of Federal Regulations, Section 2.108.

NOTICE: Enclosure 2 contains Proprietary Information. Upon separation from, this letter and Enclosure 1 are DECONTROLLED.

Official Use Only - "rap. ielaly I"fo""ation * ~ ~

Official Use Only* Proprietal") Information fe.

P. Cowan

- 2 If you have any questions, please contact John Hughey at (301) 415-3204.

Sincerely, John D. Hughey, Project Manager Plant Licensing Branch 1-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-277 and 50-278

Enclosures:

1: RAI (non-proprietary version) 2: RAI (proprietary version) cc wlo Enc!. 2: Distribution via Listserv Official Use OI,ly

• Proprietary IRfefFRatieR ~~

REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST TO REVISE TECHNICAL SPECIFICATION 4.3.1.1.A CONCERNING K-INFINITY PEACH BOTTOM ATOMIC POWER STATION, UNITS 2 AND 3 DOCKET NOS. 50-277 AND 50-278 (Non-Proprietary Version)

By letter to the Nuclear Regulatory Commission (NRC) dated June 25, 2008, (Agencywide Documents Access and Management System (ADAMS) Accession No. ML081820302), Exelon Generation Company, LLC, (Exelon) submitted a license amendment request (LAR) for Peach Bottom Atomic Power Station, (PBAPS) Units 2 and 3. The LAR seeks to revise Technical Specification (TS) 4.3.1.1.a concerning the spent fuel pool (SFP) k.. value.

The Nuclear Regulatory Commission (NRC) staff has reviewed the LAR the licensee provided in the June 25, 2008, submittal. In order for the NRC staff to complete its evaluation, response to the following request for additional information (RAI) questions is required.

1.

Proprietary and non-proprietary versions of technical report NET-264-02, "Criticality Analysis Of The Peach Bottom Spent Fuel Racks For GNF-2 Fuel With Boraflex Panel Degradation Projected To May 2012," are included in the LAR. NET-264-02 contains estimates of Boraflex degradation using testing conducted in accordance with EPRI

[Electronic Power Research Institute] TR-107335, "BADGER, a Probe for Non-destructive Testing of Residual Boron-10 Absorber Density in Spent-fuel Storage Racks: Development and Demonstration," and projections using EPRI TR-107333, "The Boraflex Rack Life Extension Computer Code - RACKLlFE: Theory and Numerics" and EPRI TR-109926, "The Boraflex Rack Life Extension Computer Code - RACKLlFE: Verification and Validation." NET-264-02 also uses what is described as, "...an advanced methodology..."

and "... special algorithm... " in making the estimates. NET-264-02 asserts that, "The NRC has issued a Safety Evaluation Report accepting the methodology on a plant specific basis." However, the NRC safety evaluation cited was not issued to PBAPS. In addition, there is no description of the "...advanced methodology... " or "...special algorithm..." in the PBAPS SFP LAR or information that would allow the NRC to evaluate them on a plant-specific basis with regard to PBAPS. Please provide additional information that describes and justifies the use of the "advanced methodology" and "special algorithm" at PBAPS.

2.

The Boraflex degradation projected in NET-264-02 is based on an assumed future SFP loading and the associated gamma dose to the Boraflex panels. However, there is no information provided for the NRC to assess the reasonableness of this assumption.

Please provide additional information that justifies the future SFP loading and associated gamma dose assumed in the LAR.

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3.

An "average panel boron carbide loss" is projected in NET-264-02 and converted into an estimated uniform Boraflex panel thinning for the entire SFP. However, Figure 3-5 indicates that a large number of storage cells will have a projected individual "panel boron carbide loss" [

]. These storage cells are collocated, [

]. These localized circumstances are not addressed. Please provide information that addresses the localized effects of collocated storage cells and the localized kef! values relative to the estimated uniform Boraflex panel thinning for the entire SFP.

4.

The Boraflex degradation projected in NET-264-02 is based on an end date of May 1,2012. However, there is no proposed license condition that limits the licensee to that end date. Please provide a proposed license condition for the projected Boraflex degradation end date.

5.

A two dimensional deterministic code, CASMO-4, is utilized in NET-264-02 to compute the reactivity effects due to degraded Boraflex. CASMO-4 is a proprietary computer code created by Studsvik. However, there is no generic Topical Report for CASMO-4, for either in-core analyses or in-rack analyses and the reference cited in NET-264-02 for CASMO-4 is not publicly available. While the NRC has approved the use of CASMO-4 as an approved methodology for in-core analysis methodologies at several licensees, this does not appear to be the case for PBAPS. There is no information provided for the staff to review regarding justifying the use of CASMO-4 specifically at PBAPS. Please provide information that justifies the use of CASMO-4 at PBAPS.

6.

The [

] in Table 5.4 is listed as [

Please provide justification that clarifies the source of the [

] listed in Table 5.4.

7.

The information provided in the LAR and NET-264-02 is insufficient to evaluate the [

] listed in Table 5-4. Please provide additional information to support the use of the [

] listed in Table 5-4.

8.

The information provided in the LAR and NET-264-02 is insufficient to evaluate the [

] listed in Table 5-4. Please provide additional information to support the use of the [

] listed in Table 5-4.

9.

The [

] listed in Table 5.4 of NET-264-02 appears to be the

[

] Please provide additional information to support the selection of a 95/95 statistical tolerance value of 1.7 to the computed eigenvalues for KENO calculations as described on page 29 of NET-264-02.

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10. NET-264-02 indicates the analysis is consistent with USNRC Regulatory Guide 1.13, "Spent Fuel Storage Facility Design Basis," and ANSI/ANS-57.2-1983, "Design Requirements for Light Water Reactor Spent Fuel Storage Facilities at Nuclear Power Plants." Since NRC Regulatory Guide 1.13 does not address any criticality regulatory requirements such as Title 10 of the Code of Federal Regulations Part 50, Appendix A, General Design Criteria 62, "Prevention of criticality in fuel storage and handling," within its scope, Regulatory Guide 1.13 should not be construed as endorsing the criticality requirements of ANSI/ANS-57.2-1983. Provide a justification for using the criticality requirements of ANSI/ANS-57.2-1983 as the methodology for the criticality analysis in the PBAPS SFP criticality analysis. In addition, not all of the items required by ANSJlANS 57.2-1983 paragraph 6.4.2 appear to have been addressed (i.e. the requirements of 6.4.2.2.2 and 6.4.2.2.5 do not appear to be fully addressed). Therefore, please also provide additional information that addresses all items required by ANSI/ANS-57.2-1983 paragraph 6.4.2.

11. Appendix A of NET-264-02 documents benchmark calculations which determine computer code biases and uncertainties for KENO V.a, MCNP5 and CASMO-4. KENO V.a and MCNP5 are benchmarked to five criticality experiments which are common to other SFP criticality analyses and eight which are not. The vintage of the reference cited for the eight unfamiliar criticality experiments makes determining their validation difficult.' Please provide additional information that supports the validation of the eight CSNI criticality experiments referred to in section 4.0 of Appendix A of NET-264-02.

12.

] presented in Appendix A of NET-264-02. [

] presented in Appendix A of NET-264-02.

13. Using the data provided in [

] of Appendix A of NET-264-02 and the description of the treatment of the data, an NRC staff verification using a Microsoft Excel spreadsheet produces different results than those indicated [

] Please provide validation of the information indicated in [

] of Appendix A of I\\IET-264-02.

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14. Section 3.1 of Appendix A of NET-264-02 states the following: "For SCALE-5 the resulting mean bias for this library is -0.00782 +/- 0.00361. For MCNP5, using the continuous energy cross-section library based on ENDF/B-Vl, the resulting variance weighted mean bias is 0.00574 +/-0.00509." Section 4.0 of Appendix A states the following: "At a 95% probability I 95% confidence level, the computed bias for SCALE-5 and MCNP5 are -0.01381 and

-0.01460, respectively." The reason for the discrepancy between Section 3.1 and 4.0 of Appendix A of NET-264-02 is not apparent. Please provide additional information clarifying the apparent discrepancy.

15. Potential abnormal conditions for the PBAPS SFP are evaluated in NET-264-02. Page 39 of NET-264-02 concludes the following, "Therefore, it is concluded that under worst-case accident conditions, the effective multiplication factor remains less than the keffS 0.98 limit, which applies to accident conditions." However, the PBAPS Updated Final Safety Analysis Report (UFSAR), Section 10.3.3.1 states the following: "All arrangements of fuel in the spent fuel storage racks are maintained in a subcritical configuration having a keffS 0.95 for all conditions." The limit of keffS 0.95 is reiterated in Technical Specification 4.3.1.b, which also references Section 10.3 of the PBAPS UFSAR. Therefore, the analysis criteria presented in NET-264-02 does not appear to apply the current licensing basis for the PBAPS SFP. Please provide an explanation for the use of the keffS 0.98 criteria as opposed to the current licensing basis criteria of keffS 0.95 for all conditions. In addition, confirm that the proposed change will result in the current licensing basis being met for all conditions, including worst case accident conditions. For example, adding the predicted keffvalue of [

], reported in Section 5.3.5 of NET-264-02, with the ~keff value associated with a dropped bundle of [

] (Section 5.3.6) results in a keffof [

]

16. Proprietary and non-proprietary versions of the Global Nuclear Fuel (GNF) analysis, GNF 0000-0035-7327-SFP, "GNF Spent Fuel Rack Criticality Analysis For Peach Bottom Atomic Power Station Units 2 and 3," are included in the LAR. The introduction states, "Normal and abnormal spent fuel storage rack configurations were evaluated with two-dimensional geometry models." However, the Geometry Treatment talks about the robust three-dimensional geometry modeling capability of MCNP01A without ever mentioning its two-dimensional geometry modeling capabilities. Therefore, it is not clear whether the SFP was modeled in two or three dimensions in GNF 0000-0035-7327-SFP.

Please clarify the modeling method utilized in GNF 0000-0035-7327-SFP..

17. GNF 0000-0035-7327-SFP determines a Bias and Uncertainty to accompany the in-rack use of MCNP01A. There is no information provided that would allow the NRC staff to evaluate whether or not the criticality experiments used in that determination are appropriate for PBAPS. Additionally, the final Bias and Uncertainty includes several assumptions which are not justified. Please provide information to support use of the criticality experiments for PBAPS and information to justify the assumptions associated with the Bias and Uncertainty determined for the in-rack use of MCNP01A.

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18. GNF 0000-0035-7327-SFP indicates the analysis is consistent with USNRC Regulatory Guide 1.13, "Spent Fuel Storage Facility Design Basis," and ANSlfANS-57.2-1983, "Design Requirements for Light Water Reactor Spent Fuel Storage Facilities at Nuclear Power Plants." Since USNRC Regulatory Guide 1.13 does not address any criticality regulatory requirements such as 10 CFR 50 Appendix A General Design Criteria 62, "Prevention of criticality in fuel storage and handling," within its scope, Regulatory Guide 1.13 should not be construed as endorsing the criticality requirements of ANSlfANS-57.2-1983. Provide a justification for using the criticality requirements of ANS IfANS-57.2-1983 as the methodology for the criticality analysis in the PBAPS SFP criticality analysis. In addition, not all of the items required by ANSlfANS-57.2-1983 paragraph 6.4.2 appear to have been addressed (Le. the requirements of 6.4.2.2.5, 6.4.2.2.6 and 6.4.2.2.7 do not appear to have been fully considered). Therefore, please also provide additional information that addresses all items required by ANSlfANS-57.2 1983 paragraph 6.4.2.

19. Some analysis parameters used in calculating kelt in the NET-264-02 report are not included in GNF 0000-0035-7327-SFP. For example, not all items listed in Table 5-4 of NET-264-02 are included in GNF 0000-0035-7327-SFP. The justification for the analysis parameters included in NET-264-02, but excluded from GNF 0000-0035-7327-SFP, is insufficient. Please provide additional justification for the analysis parameters utilized in calculating kelt in NET-264-02 that were excluded from GNF 0000-0035-7327-SFP.

20. A Boraflex degradation has been applied in the analyses contained in GNF 0000-0035-7327-SFP. The report indicates that the value for Boraflex degradation originated from the NET-264-02 report as well as an AEA Technology Report listed as Reference 10. Therefore, the source of this bias is not clear. Please clarify the source for the value for Boraflex degradation used in GNF 0000-0035-7327-SFP.

21. Section 3.4 of GNF 0000-0035-7327-SFP states the following: "Confirmatory calculations were performed for the bounding GNF2 lattice to verify that the reactivity bias obtained from Reference 10 could be conservatively applied to GNF2." However, no information regarding these confirmatory calculations is included in GNF 0000-0035-7327-SFP or the LAR. Please provide additional information supporting the assertion that confirmatory calculations justify the use of the reactivity bias from Reference 10 of GNF 0000-0035-7327-SFP.

22. GNF 0000-0035-7327-SFP calculates a k, under nominal conditions of [

]. In this determination the temperature bias is treated as an uncertainty. This is inconsistent with staff guidance and industry practice. Provide a revised k, under nominal conditions where the temperature bias is applied as a bias instead of an uncertainty.

23. Please provide a description of the process used to determine that fuel assemblies have attained proper burnup for storage in the burnup dependent racks.

24. Please provide a description of the process used to control movement of items within the SFP is needed.

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25. The information provided in the LAR and GNF 0000-0035-7327-SFP is insufficient to evaluate the [

] listed in Table 5. In particular, it is unclear why the maximum in-rack nominal eigenvalue in Table 5 is less than the maximum in-rack nominal eigenvalue in Table 4. Please provide additional information to support the use of the [

] listed in Tables 5 and 4.

Official Use Only* Proprietary IRformatieR f&

P. Cowan

-2 If you have any questions, please contact John Hughey at (301) 415-3204.

Sincerely, Ira!

John D. Hughey, Project Manager Plant Licensing Branch 1-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-277 and 50-278 Enclosures 1: RAI (non-proprietary version) 2: RAI (proprietary version) cc w/o Encl. 2: Distribution via Listserv DISTRIBUTION: (w/o Enclosure 2)

NON-PUBLIC LPLI-2 RtF RidsNrrPM...IHughey Resource RidsNrrLAABaxter Resource RidsNrrDssSrxb Resource RidsRgn1 MailCenter Resource RidsNrrDorlLpl1-2 Resource RidsOgcRP Resource RidsNrrDorlDpr Resource RidsAcrsAcrw_MailCTR Resource ADAMS Accession Number: Letter & enclosure 1: ML082120486 ' ML083030294 OFFICE LPL1-2/PM LPL1-2/LA SRXB/BC LPL1-2/BC NAME JHughey ABaxter GCranston HChernoff (w/commentsl DATE 115/2009 01105/2009 11/13/2008 112112009 OFFICIAL RECORD COpy

-,~

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