2CAN070901, Response to Request for Additional Information for the License Amendment Request to Revise the Departure from Nucleate Boiling Ratio (DNBR) Safety Limit

Response to Request for Additional Information for the License Amendment Request to Revise the Departure from Nucleate Boiling Ratio (DNBR) Safety Limit

ML092050637
Person / Time
Site:	Arkansas Nuclear
Issue date:	07/08/2009
From:	Berryman B Entergy Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
2CAN070901, TAC ME1328
Download: ML092050637 (17)

Text

2CAN070901 July 8, 2009 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555

SUBJECT:

Response to Request for Additional Information for the License Amendment Request to Revise the Departure from Nucleate Boiling Ratio (DNBR) Safety Limit Arkansas Nuclear One, Unit 2 Docket No. 50-368 License No. NPF-6

REFERENCES:

1. Entergy Letter to NRC dated May 13, 2009, License Amendment Request to Revise the Departure From Nucleate Boiling Ratio (DNBR)

Safety Limit (2CAN050901)

2. Email from Kaly Kalyanam (NRC) to Robert W. Clark (Entergy), ANO-2 LAR regarding the DNBR Safety Limit (TAC No. ME1328)

Dear Sir or Madam:

In Reference 1, Entergy Operations, Inc. (Entergy) proposed a change to the Arkansas Nuclear One, Unit 2 (ANO-2) Technical Specifications (TS). In particular, the change would modify the TS 2.1.1.1 Departure from Nucleate Boiling Ratio (DNBR) safety limit based upon the Combustion Engineering 16 x 16 Next Generation Fuel design and the associated DNB correlations.

During the submittal review process, the Nuclear Regulatory Commission (NRC) determined that additional information was required to complete the review of the Entergy request. The Request for Additional Information (RAI) was electronically transmitted to ANO-2 on June 12, 2009 (Reference 2). The response to RAI is to be provided within 30 days of receipt of the email.

The response to the RAI is included in Attachment 1 to this letter.

This letter contains one new commitment. This commitment is summarized in Attachment 2.

Entergy Operations, Inc.

1448 S.R. 333 Russellville, AR 72802 Tel 479-858-7721 Brad L. Berryman Acting - Vice President, Operations Arkansas Nuclear One

2CAN070901 Page 2 of 2 If you have any questions or require additional information, please contact David Bice at (479)-858-5338.

I declare under penalty of perjury that the foregoing is true and correct. Executed on July 8, 2009.

Sincerely, Original signed by Brad Berryman Acting VP for Kevin Walsh BLB/rwc Attachments:

1. Response to RAI

2. List of Regulatory Commitments cc:

Mr. Elmo E. Collins Regional Administrator U. S. Nuclear Regulatory Commission Region IV 612 E. Lamar Blvd., Suite 400 Arlington, TX 76011-4125 NRC Senior Resident Inspector Arkansas Nuclear One P. O. Box 310 London, AR 72847 U. S. Nuclear Regulatory Commission Attn: Mr. Kaly Kalyanam MS O-8B1 One White Flint North 11555 Rockville Pike Rockville, MD 20852 Mr. Bernard R. Bevill Arkansas Department of Health Radiation Control Section 4815 West Markham Street Slot #30 Little Rock, AR 72205

to 2CAN070901 Response to RAI to 2CAN070901 Page 1 of 12 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION By letter dated May 13, 2009, Entergy requested an amendment to the Arkansas Nuclear One, Unit 2 (ANO-2) Technical Specification (TS) 2.1.1.1, Departure from Nucleate Boiling (DNB) ratio safety limit based upon the Combustion Engineering 16 x 16 Next Generation Fuel (NGF) design and the associated DNB correlations (Reference 1). The NRC has reviewed the May 13, 2009, request and has determined that additional information is required to complete their review. Each portion of the Request for Additional Information (RAI) is listed below.

1. Address compliance with the conditions stated in the NRC safety evaluation reports approving the topical reports that allow application of the ABB-NV and WSSV-T critical heat flux correlations to the Next Generation Fuel design for the ANO-2 core.

The following topical reports should be considered when they are applicable:

WCAP-16523-P-A; CENPD-387-P-A; CENPD-161-P-A; CEN-356(V)-P-A; CEN-139(A)-P; and WCAP-16500-P A.

Several of the topical reports (TRs) listed above are currently listed in ANO-2 TS 6.6.5, Core Operating Limits Report (COLR), and the Cycle 20 COLR as approved methodologies. When ANO-2 requested the TS to be changed to include these methodologies, the limitations and conditions listed in the safety evaluation reports (SERs) were addressed at that time. The responses provided at the time of the various TS change requests are repeated here. Some of the responses have been updated based on the SER associated with the ANO-2 TS change requests or other actions that have taken place in the interim.

WCAP-16523-P-A, Westinghouse Correlations WSSV and WSSV-T for Predicting Critical Heat Flux in Rod Bundles with Side-Supported Mixing Vanes By application dated July 31, 2007, Entergy requested changes to ANO-2 TS. The proposed changes would revise TS 6.6.5 which would add new analytical methods to support the implementation of NGF (Reference 2). One of these new methods is WCAP-16523-P-A. By the Reference 2 application, the safety evaluation (SE) Conditions and Limitations within each of the licensed TRs being added to the COLR were identified and discussed. The NRC Staff reviewed the disposition of each SE Condition and Limitation and found that ANO-2 adequately addressed each one of them for this TR (Reference 3).

For the ease of review the Limitations and Conditions and how ANO-2 meets them for this TR are repeated below.

1. The WSSV correlation must be used in conjunction with the VIPRE code since the correlation was developed based on VIPRE and the associated VIPRE input specifications. Other uses of the WSSV correlation should reference this TR and be based on appropriate benchmarking with VIPRE.

This condition is not applicable for ANO-2 as the WSSV correlation with VIPRE will not be used at this time.

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2. The WSSV-T correlation must be used in conjunction with the TORC code since the correlation constants were developed based on TORC and the associated TORC input specifications. The correlations may also be used in the CETOP-D code in support of reload design calculations benchmarked by TORC.

The WSSV-T correlation is used in conjunction with TORC and CETOP-D codes in support of reload design calculations.

3. The WSSV and WSSV-T correlations must also be used with the optimized Tong Fc shape factor for non-mixing and side-supported mixing vane grids to correct for non-uniform axial power shapes.

The optimized Tong Fc shape factor was utilized for non-mixing and side-supported mixing vane grids in the ANO-2 NGF Thermal Hydraulic (TH) implementation analyses.

4. The range of applicability for both the WSSV and the WSSV-T correlations are:

Parameter Units Range Pressure psia 1,495 to 2,450 Local coolant quality 0.34 Local mass velocity 106 lbm/hr-ft2 0.90 to 3.46 Matrix heated hydraulic diameter, Dhm inches 0.4635 to 0.5334 Heated hydraulic diameter ratio, Dhm/Dh 0.679 to 1.00 Heated length, HL inches 48* to 150 Grid spacing inches 10.28 to 18.86

• Set as minimum HL value, applied at all elevations below 48 inches.

The WSSV-T correlation was applied according to Section 6.2 of WCAP-16523-P within the above range of applicability in the ANO-2 NGF TH implementation analyses.

CENPD-387-P-A, ABB Critical Heat Flux Correlations for PWR Fuels In Reference 2, Entergy requested changes to ANO-2 TS. The proposed changes would revise TS 6.6.5 which would add new analytical methods to support the implementation of NGF. One of these new methods is CENPD-387-P-A. By the Reference 2 application, the SE Conditions and Limitations within each of the licensed TRs being added to the COLR were identified and discussed. The NRC Staff reviewed the disposition of each SE Condition and Limitation and found that ANO-2 adequately addressed each one of them for this TR (Reference 3). For the ease of review, the Limitations and Conditions and how ANO-2 meets them for this TR are repeated below.

to 2CAN070901 Page 3 of 12 The following conditions are satisfied when applying the ABB-NV correlation for non-mixing vane grid spans for CE 16 x 16 Standard and NGF assemblies:

1. The ABB-NV and ABB-TV correlations indicate a minimum DNBR limit of 1.13 will provide a 95 percent probability with 95 percent confidence of not experiencing CHF on a rod showing the limiting value.

The ABB-NV correlation is applied for non-mixing vane grid spans for CE 16 x 16 standard and NGF assemblies. The minimum DNBR correlation limit of 1.13 is used.

The WSSV-T correlation is applied for the mixing vane grid spans of the NGF fuel as described in Section 6.2 of WCAP-16523-P instead of the ABB-TV correlation.

2. The ABB-NV and ABB-TV correlations must be used in conjunction with the TORC code since the correlations were developed on the basis of the TORC and the associated TORC input specifications. The correlations may also be used in the CETOP-D code in support of reload design calculations.

The ABB-NV correlation for non-mixing vane grid spans for CE 16 x 16 standard and NGF assemblies is used in conjunction with both TORC and CETOP-D codes.

3. The ABB-NV and ABB-TV correlations must also be used with the ABB-CE optimized Fc shape factor to correct for non-uniform axial power shapes.

The ABB-NV correlation will be used with the ABB-CE optimized Fc shape factor to correct for non-uniform axial power shapes.

4. Range of applicability for the ABB-NV and ABB-TV correlations:

Parameter ABB-NV Range ABB-TV Range Pressure (psia) 1750 to 2415 1500 to 2415 Local mass velocity (Mlbm/hr/ft2) 0.8 to 3.16 0.9 to 3.40 Local quality

-0.14 to 0.22

-0.10 to 0.225 Heated length, inlet to CHF location (in) 48 to 150 48 to 136.7 Grid Spacing (in) 8 to 18.86 8 to 18.86 Heated hydraulic diameter ratio, Dhm/Dh 0.679 to 1.08 0.679 to 1.000 The specified range of applicability for the designated parameters is used when applying the ABB-NV correlation.

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5. The ABB-NV and ABB-TV correlation will be implemented in the reload analysis in the exact manner described in Section 7.1 of Topical Report CENPD-387-P, Revision 00-P.

The ABB-NV correlation is applied according to Section 7.1 of CENPD-387-P-A for non-mixing vane grid spans for CE 16 x 16 standard and NGF assemblies. The WSSV-T correlation is applied for the mixing vane grid spans of the NGF fuel as described in Section 6.2 of WCAP-16523-P instead of the ABB-TV correlation.

6. Technology transfer will be accomplished only through the process described in Reference 5 which includes ABB-CE performing an independent benchmarking calculation for comparison to the licensee generated results to verify that the new CHF correlations are properly applied for the first application by the licensee.

There is no technology transfer between Westinghouse and Entergy at this time.

CENPD-161-P-A, TORC Code - A Computer Code for Determining the Thermal Margin of a Reactor Core The constraints listed in the SE for this topical were superseded by the review of CENPD-206-P-A, TORC Code Verification and Simplified Modeling Methods. Westinghouse has declared that the information showing how the constraints for the proprietary computer code TORC (CENPD-206-P-A) are being met is proprietary. Entergy has provided this information previously in support of the Power Uprate. In this case, in lieu of repeating the proprietary information and requesting the NRC to withhold this information from the public, a reference to the previously submitted response is provided. Tables 15 and 16 of Reference 4 provide the requested information. In Section 3.6 of Reference 5 the Staff notes that the licensee has provided tabulations to list 1) all computer codes and methodologies applied to each of the transient and accident analyses, 2) the restrictions and limitations identified in the NRC safety evaluation for each of the topical reports relative to computer codes and methodologies, and 3) discussion of how these applicable restrictions and limitations of the computer codes and methodologies specified in the staff safety evaluations are complied with in the ANO-2 power uprate analyses. The staff finds that the licensee has performed a detailed study to confirm that the computer codes and methodologies applied in its power uprate analyses are adequate. The information in these two tables have been reviewed as part of this effort and found to still be true and accurate.

CEN-356(V)-P-A, Modified Statistical Combination of Uncertainties This methodology was originally approved for use at the Palo Verde Nuclear Generation Station, Unit 1 in a safety evaluation dated October 21, 1987. ANO-2 requested to use this methodology as part of a change to the ANO-2 TS 6.9.5.1 (Reference 6). This specification lists the analytical methods used to determine the core operating limits report.

A review of this topical demonstrated that the NRC did not list any Limitations or Conditions for the use of this methodology.

to 2CAN070901 Page 5 of 12 The NRC in Reference 7 states, In this regard, as part of this amendment, TS 6.9.5.1 is modified to indicate that the Modified Statistical Combination of Uncertainties (MSCU) methodology described in CEN-356(V)-P-A, Revision 01-P-A, and approved by the NRC, will be used to obtain uncertainty factors for determining the limiting safety system setting (LSSS) and the limiting condition for operation (LCO) for the COLSS and CPC. The NRC staff has determined that the resultant penalties applied to the COLSS power operating limit and the CPC DNBR and local power density uncertainties at the 95 / 95 probability /

confidence level, and is acceptable for use at ANO-2.

CEN-139(A)-P, Revision 000, Statistical Combination of Uncertainties Combination of System Parameter Uncertainties in Thermal Margin Analyses for Arkansas Nuclear One Unit 2 This report describes the methods used to statistically combine system parameter uncertainties in the thermal margin analyses for the ANO-2 Cycle 2 core. A detailed description of the uncertainty probability distributions and response surface techniques used is presented. This report was submitted to the NRC describing the methodology changes for ANO-2 Cycle 2 reload review. There were no Limitations or Conditions listed in the report itself.

The results of this review were documented in Amendments 24 and 26 to the ANO-2 Operating Limits. The discussion of the review SCU is in Amendment 26. The methodology presented in CEN-139(A)-P was found to be acceptable with four exceptions.

These exceptions are listed in Section 2.6(e) of the SE. The first two exceptions, a correlation cross-validation uncertainty and a 5 percent code uncertainty, had to be included which resulted in the third exception. The third exception is the approved DNBR limit was 1.26 as opposed to the proposed value of 1.24. This exception included the combination of uncertainties for the system parameters and an interim rod bow compensation of 2 percent on DNBR. The increase in the limit was accommodated in the addressable constant BERR1. The fourth exception was any changes in codes or correlations used in the analysis will require a reevaluation of the SCU. The reevaluation required by the fourth exception was done subsequent to Cycle 2 when Westinghouse developed and the NRC approved CEN-356(V)-P-A, Modified Statistical Combination of Uncertainties. CEN-356(V)-P-A then superseded CEN-139(A)-P as described above.

It should be noted that the rod bow compensation described above for the third exception was removed via the SE for Amendment 27 of the ANO-2 Operating License. This returned the DNBR limit to 1.24 for Cycle 2. In Cycle 3, the HID-1 spacer grids were introduced as part of the fuel assembly design. The DNBR limit was increased by a 0.01 penalty to 1.25 to conservatively address potential NRC concerns with these spacers. The NGF design does not have the HID-1 spacers.

to 2CAN070901 Page 6 of 12 WCAP-16500-P-A, Revision 0-P-A, CE 16 x 16 Next Generation Fuel Core Reference Report In Reference 2, Entergy requested changes to ANO-2 TS. The proposed changes would revise TS 6.6.5 which would add new analytical methods to support the implementation of NGF. One of these new methods is WCAP-16500-P-A. By the Reference 2, application, the SE Conditions and Limitations within each of the licensed TRs being added to the COLR were identified and discussed. The NRC Staff reviewed the disposition of each SE Condition and Limitation and found that ANO-2 adequately addressed each one of them for this TR, except for Conditions #5, #6 and #7 for this TR (Reference 3). For the ease of review the Limitations and Conditions and how ANO-2 meets them for this TR are repeated below. Any updates since the original submittal is provided below as well.

1. Using approved methods, the licensee must ensure that all of the design criteria specified in TR WCAP-16500-P are satisfied on a cycle-specific basis (SE Section 3.3.1).

As part of the reload methodology, all of the new design criteria specified for CE 16 x 16 NGF per WCAP-16500-P, Table 1-1 has become part of the reload analysis basis. Using approved models and methods, the reload analysis, which is reviewed per the requirements of 10 CFR 50.59, will check/confirm that these design criteria are met.

2. Fuel assembly component design and configuration (e.g., type and distribution of spacer grids and IFM grids) are limited to the five designs described in TR WCAP-16500-P and in response to RAI No. 2 (SE Section 3.2).

The ANO-2 NGF assembly is consistent with the Plant A design defined in Figure 1-1 of WCAP-16500-P and for the Plant A design documented in the response to RAI No. 2 of Reference 2.

3. The reference fuel assembly design, CE 16 x 16 NGF, its fuel mechanical design methodology and design criteria, are approved up to a peak rod average burnup of 62 GWd/MTU. A fuel burnup limit may exist, either explicitly or implicitly, in other portions of a plants licensing basis. The NRC staffs approval of this topical report allows the CE 16 x 16 NGF assembly to reach a rod average burnup of 62 GWd/MTU.

However, a license amendment request, specifically addressing each plants licensing basis including radiological consequences, is required prior to extending burnup beyond current levels. Further, the NRC staffs SE for Optimized ZIRLOTM (Addendum 1 to TR WCAP-12610-P-A and TR CENPD-404-P-A) specified a 60 MWd/kgU burnup limit and this limitation must be revised prior to extending the peak rod average burnup for the NGF design (SE Section 3.4).

The current ANO-2 Operating License restricts peak rod average burnup to 60 MWd/kgU. Entergy is not proposing a change to this limit.

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4. Licensees shall demonstrate the accuracy of their growth predictions based upon measured data and this validation shall be ahead of the burnups achieved by batch implementation. The growth model validation (e.g., measured versus predicted) should be documented in a letter(s) to the NRC (SE Section 3.2.1).

The growth data presented in Figure 2-15 of WCAP-16500-P Supplement 1-P is ahead of the projected exposure for the first cycle implementation of NGF. The fluence for the data is approximately 7 x 1021 nvt, which corresponds to an assembly average burnup of 39 MWD/kgU. The projected end of first cycle assembly average burnup is approximately 27 MWD/kgU. Additional growth data will be obtained from future Lead Test Assembly (LTA) exams ahead of the exposure achieved by batch implementation.

Subsequent to the response provided above in Reference 2, Westinghouse submitted a letter (Reference 8) that provided additional data and information from on-going LTA programs. It was determined that the existing models remain applicable for NGF fuel for two cycles of operation. Cycle 21 will be the second cycle of operation of the NGF fuel design at ANO-2. Additional data will be provided to the NRC as it becomes available.

5. To compensate for NRC staff concerns related to the digital setpoints process, an interim margin penalty of 6 percent must be applied to the final addressable constants (e.g., BERR1* 1.06, [(1+EPOL2)*1.06 - 1.0]) calculated following the 1/64 hypercube setpoints process (Response No. 6 of Reference 6). Removal of this interim margin penalty will be considered after the digital setpoints methods have been formalized, documented (e.g., revision to TR WCAP-16500-P), and approved by the NRC (SE Section 3.7).

As discussed in the response to the Limitations and Conditions #6 (below), the potential DNB margin gain for the first cycle of ANO-2 that contains a reload batch of NGF (Cycle 20), after accounting for flow redistribution, is expected to be 16%. For this transition cycle, the analysis that calculates the uncertainty addressable constants for the Core Operating Limit Supervisory System (COLSS) on-line monitoring system and the Core Protection Calculator (CPC) System will not explicitly account for the NGF design and Critical Heat Flux (CHF) correlations. Therefore, the resultant DNB uncertainty addressable constants will not explicitly credit the potential DNB margin gain, will not require application of the interim 6% margin penalty and will not require use of the 1/64 hypercube setpoints process.

If required to maintain acceptable COLSS and CPC DNB operating margin throughout the cycle, a portion of the potential DNB margin gain may be credited to reduce the DNB uncertainty addressable constants for COLSS and CPC. In this case even after applying a conservative 6% margin penalty, no more than one half of the net margin gain, will be credited to reduce the COLSS and CPC DNB uncertainty addressable constants. For a potential DNB margin gain of 16%, up to 5% would be credited. The reduction in the credit from 16% to 5% would be sufficient to compensate for any negative impact of the mixed core on transient and setpoint analyses. The credit would be applied to the COLSS and CPC DNB margin by adjusting the COLSS and CPC DNB uncertainty addressable constants.

to 2CAN070901 Page 8 of 12 Full DNB margin credit for NGF will begin with the next cycle (Cycle 21) where the NGF CETOP-D model with the WSSV-T and ABB-NV CHF correlations will be used in the COLSS and CPC uncertainty analyses. The Modified Statistical Combination of Uncertainties (MSCU) analysis performed each cycle, as described in Reference 3, will automatically calculate appropriate DNB uncertainty addressable constants for COLSS and CPC reflecting the DNB margin impact of NGF. The 1/64 hypercube setpoints process as well as other process steps described in response to RAI 6 of WCAP-16500-P Supplement 1-P (Reference 4) will be utilized in this analysis. In addition, the 6% interim margin penalty will be applied to the resultant addressable constants until its removal has been approved by the NRC.

6. Licensees are required to demonstrate that during transition cores, DNB margin gains associated with the NGF design offset (1) any impacts of flow starvation due to increased pressure drop and (2) uncertainty associated with predicting local flow characteristics. Further, licensees must detail the analytical methods and results of their transition core LOCA and non-LOCA analyses (SE Sections 3.7 and 3.10).

First time engineering implementation analyses have been performed for transition and full cores of NGF. The analytical methods are defined in WCAP-16500-P for NGF implementation. For the transition cycle the COLSS on-line monitoring system and the CPC system will continue to utilize the current models and the CE-1 CHF correlation.

For the first cycle of ANO-2 that contains a batch of NGF (Cycle 20), the potential DNB margin gain, after accounting for the flow redistribution, is expected to be 16%. This margin gain is sufficient to compensate for any negative impact of the mixed core of NGF and standard fuel on transient and setpoint analyses. For non-LOCA analysis of the transition core NRC approved analytical methods are applied and results are based on a CETOP-D model for standard fuel so there is no transition core impact on transients. Full DNB margin credit for NGF will begin with the next cycle (Cycle 21) where the WSSV-T and ABB-NV DNB correlations will be used in the NGF CETOP-D model. The transition core LOCA evaluations for ECCS Performance including the implementation of CE 16 x 16 NGF assemblies are being finalized and will be submitted to NRC for review.

As noted in Reference 3, Conditions #5 and #6 above deal with COLSS and CPC System setpoint methodology and the effects of a mixed core of NGF and non-NGF assemblies. There was a question whether any credit for the NGF thermal characteristics in a mixed core configuration represented a deviation from approved methodologies.

In order to resolve these issues, the NRC staff conducted an audit of the Westinghouse engineering calculations supporting the ANO-2 Cycle 20. Based on the audit, the Staff found that the partial credit methodology deviated from the original MSCU methodology and the NGF setpoint methodology listed in WCAP-16500-P-A.

Recognizing the NGF mixed-core partial credit as a deviation from previously approved methods, the NRC Staff expanded the scope of the audit to review and approve a one-time methodology deviation for ANO-2 Cycle 20. The DNB adjustment equation includes the 6 percent interim margin penalty (Condition #5).

to 2CAN070901 Page 9 of 12 COLSS and CPCS addressable constants were calculated following the approved MSCU methodology and standard process. CETOP-D calculations were performed with the standard assembly dimensions and CE-1 DNB statistics. CETOP-to-TORC multipliers were based on a full core of standard assemblies. Within the statistical analyses, no credit was taken for the improved thermal performance of the NGF design. The partial credit DNB adjustment was applied directly to the final BERR1 and EPOL 2/4 addressable constants.

Based on the information reviewed during the meeting, the Staff found the one-time application of the partial credit to be acceptable for ANO-2 Cycle 20.

It should be noted that ANO-2 has committed to maintain the 6 percent interim margin penalty until Supplement 1, Revision 1 of WCAP-16500-P-A has been reviewed and approved by the NRC (Condition #5) (Reference 1).

Also Condition #6 is for transition cores. Cycle 20 at ANO-2 had both NGF and non-NGF assemblies in it. For Cycle 21, the entire core will be NGF; therefore this condition is no longer applicable to ANO-2.

7. Implementation of CE 16 x 16 NGF assemblies necessitates re-analysis of the plant-specific LOCA analyses. Licensees are required to submit a license amendment containing the revised LOCA analyses for NRC review. Upon approval, the revised LOCA analyses constitute the analysis-of-record and baseline for which future changes will be measured against in accordance with 10CFR50.46(a)(3) (SE Section 3.7).

The revised LOCA analyses for ECCS Performance including the implementation of CE 16 x 16 NGF assemblies for full core configuration are being finalized and will be submitted to NRC for review. Subsequent to this commitment being made in Reference 2, the reanalysis of the LOCA event was submitted to the NRC in Reference 9.

In Reference 3, the Staff states they have reviewed the assumptions, plant design data, and the results of the revised Emergency Core Cooling System (ECCS) performance analysis for both the large break and small break LOCA analyses and found them to be acceptable because conservative assumptions were used and the results meet the ECCS acceptance criteria of 10 CFR 50.46(b).

The Staff also agreed with the licensees conclusion that no small break LOCA mixed-core analysis was necessary during transition core cycles, due to the negligible effect of variation in core hydraulic losses on small break LOCA analysis results.

The Staff agreed with the licensees conclusion that no plant-specific post-LOCA long-term cooling analysis was required to support the introduction of the NGF assembly, based on the result of the analyses performed that showed the evaluation model is not sensitive to the fuel assembly changes being introduced with NGF.

The Staff has reviewed the request by Entergy to approve the revised ECCS analysis to support the implementation of NGF. The Staff has concluded that the revised ECCS analysis is acceptable and meets the Limitation and Condition #7 because the analyses used approved methodologies and results meet the ECCS acceptance criteria of 10 CFR 50.46(b).

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8. Using approved models and methods, Westinghouse will continue to limit peak local power experienced during Condition I and II events to ensure that fuel temperature remains below melting temperature at all burnups. This evaluation may be both plant and cycle-specific (SE Section 3.3.4).

Peak local power experienced during Condition I and II events will be limited to ensure fuel temperature remains below melting temperature at all burnups in accordance with ANO-2 TS 2.1.1.2. This will be confirmed during each reload analysis.

9. The NRC staffs approval of TR WCAP-16500-P establishes the licensing basis for batch implementation of the CE 16 x 16 NGF assembly design. Licensees wishing to implement this fuel design are required to submit a license amendment request, where applicable, updating their Core Operating Limits Report list of methodologies with the A version of this TR.

Reference 2 made this request and Reference 3 approved the request.

10. The NRC staffs review did not include the LOCA model changes described in Appendix A of TR WCAP-16500-P. Therefore, a licensee will have to submit a license amendment, if they desire to use The Appendix A LOCA model changes.

Changes to the LOCA model outlined in Appendix A of TR WCAP-16500-P were resubmitted to the NRC by Westinghouse under CENPD-132, Supplement 4-P-A, Addendum 1-P, and have been approved for use in license amendment applications as described below.

The conclusion of the SE for CENPD-132, Supplement 4-P-A, Addendum 1-P states that Limitations and Conditions 3, 4, and 5 are appropriate for use when evaluating CE 16 x 16 NGF design fuel assemblies (Reference 2). The first two Limitations and Conditions included in the SE for CENPD-132, Supplement 4-P-A, Addendum 1-P are for fuel designs other than CE 16 x 16 NGF. The optional steam cooling model is not being used to support the implementation of CE 16 x 16 NGF assemblies in ANO-2 at this time. However, the applicable Limitations and Conditions and the means of satisfying them are included below for future reference.

3. Limitation on the Optional Steam Cooling Heat Transfer Model The result of the grid model enhancement cannot result in the use of a heat transfer coefficient greater than FLECHT. The FLECHT upper-bound heat transfer coefficient, as required by the current NRC licensing constraint, is also applied to the spacer grid optional steam cooling model improvement.

The computer code logic for the optional steam cooling heat transfer model in the STRIKIN-II hot rod heatup computer code contains a specific algorithm to insure that the current NRC licensing constraint on the use of the FLECHT upper-bound heat transfer coefficient is also applied to the spacer grid steam cooling model improvement calculated in the PARCH steam cooling module. Therefore, this limitation and condition is automatically satisfied when performing the ANO-2 licensing calculations using the version of the STRIKIN-II computer code containing the approved optional steam cooling heat transfer model.

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4. Use of the Optional Steam Cooling Model If a licensee wants to use the optional steam cooling model, then a license amendment request should be submitted including the analyses performed to determine its applicability to the specific fuel design being evaluated, as discussed in Section 3.3.1, 3.3.2, and 3.3.3 above. In addition, the licensee should provide the results of the evaluation with and without the optional steam cooling model, in a format similar to the graphical results provided in the reference calculations presented in the supplemental TR. The PCT, local oxidation, and steam cooling flow rates should be included in the submittal. These comparisons will enable the NRC staff to confirm the acceptability of the use of the optional steam cooling model.

If the optional steam cooling model were to be used for ANO-2 ECCS Performance Analyses at some time in the future, then a license amendment request would be submitted including the analyses and comparison graphical results needed to confirm the acceptability of the use of the optional steam cooling model.

5. Use of Flow Blockage and Reynolds Number Limits (Section 3.3.3)

For use of this topical report at a specific plant, the flow blockage and Reynolds number limits, as discussed in Section 3.3.3 above, should be confirmed by plant-specific analyses.

The computer code logic for the optional steam cooling heat transfer model in the PARCH module of the STRIKIN-II hot rod heatup computer code contains specific computational constraints to print warning and diagnostic output messages to alert the user if the calculation is found to be outside the range of applicability for flow blockage and Reynolds number. Therefore, this Limitation and Condition is automatically satisfied when performing the ANO-2 licensing calculations using the version of the STRIKIN-II computer code containing the approved optional steam cooling heat transfer model.

The NRC Staff reviewed the disposition of each SE condition and limitation for CENPD-132, Supplement 4-P-A, Addendum 1-P and found that ANO-2 adequately addressed each one of them for this TR (Reference 3).

References

1.

Entergy Letter to NRC, dated May 13, 2009, License Amendment Request to Revise the Departure From Nucleate Boiling Ratio (DNBR) Safety Limit (2CAN050901)

2.

Entergy Letter to NRC, dated July 31, 2007, License Amendment Request to Revise Technical Specification 6.6.5, Core Operating Limits Report, (2CAN070701)

3.

NRC Letter to Entergy, dated March 26, 2008, Arkansas Nuclear One, Unit 2 -

Issuance of Amendment RE: Technical Specification 6.6.5, Core Operating Limits Report (COLR), (2CNA030807) to 2CAN070901 Page 12 of 12

4.

Entergy Letter to NRC, dated November 16, 2001, Response to Follow-up Request for Additional Information Concerning Peak Rod Axial Average Burnup and Codes/Methodologies used in Support ANO-2 Power Uprate, (2CAN110109)

5.

NRC Letter to Entergy, dated April 24, 2002, Arkansas Nuclear One, Unit No. 2 -

Issuance of Amendment RE: Increase in Licensed Power Level, (2CNA040207)

6.

Entergy Letter to NRC, dated March 17, 1995, Proposed Technical Specification Change Request Concerning the Core Operating Limits Report, (2CAN039502)

7.

NRC Letter to Entergy, dated September 19, 1995, Issuance of Amendment No. 164 to Facility Operating License No. NPF Arkansas Nuclear One, Unit No. 2, (2CNA099504)

8.

Westinghouse Letter to NRC, dated May 19, 2009, Compliance with WCAP-16500-P-A SER Condition 4, (LTR-NRC-09-28)

9.

Entergy Letter to NRC, dated July 31, 2007, Emergency Core Cooling System Performance Analysis, (2CAN070702)

Any conditions resulting from the review of the Supplement 1 of WCAP-16500 (Revision 1) should also be met.

When the SER for WCAP-16500-P-A, Supplement 1, Revision 1 is issued, any limitation and condition listed will be evaluated and how they are met will be documented in the implementation package of the revision to the COLSS and CPC setpoints and the cycle-specific COLR.

2. The NRC Staff may need to perform an audit of the Westinghouse calculation, at its Rockville, Maryland, offices. These calculations show how the value of 1.23 was determined from the WSSV-T and ABB-NV values of 1.12 and 1.13. This audit can be arranged for the week of July 13, 2009. The exact date has to be decided.

The proposed audit has been scheduled for July 20 and 21, 2009, in Westinghouses Rockville, MD, office. The scope of this audit are the appropriate calculations documenting how the DNBR safety limit of 1.23 was determined from the WSSV-T and ABB-NV determined DNBR limits of 1.12 and 1.13, respectively. Westinghouse will have representatives available at the Rockville and Windsor, CT, offices to answer questions that may come up during the audit.

to 2CAN070901 List of Regulatory Commitments to 2CAN070901 Page 1 of 1 LIST OF REGULATORY COMMITMENTS The following table identifies those actions committed to by Entergy in this document.

Any other statements in this submittal are provided for information purposes and are not considered to be regulatory commitments.

COMMITMENT TYPE (Check one)

SCHEDULED COMPLETION DATE ONE-TIME ACTION CONTINUING COMPLIANCE Any limitation and condition listed will be evaluated and how they are met will be documented in the implementation package of the revision to the COLSS and CPC setpoints and the cycle-specific COLR.

When the SER for WCAP-16500-P-A, Supplement 1, Revision 1 is issued.