Text

Response to Request for Additional Information on Technical Specification Change TS-478
	ML13276A063
Person / Time
Site:	Browns Ferry
Issue date:	09/30/2013
From:	James Shea; Tennessee Valley Authority
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	Download: ML13276A063 (35)
	v • d • e

Tennessee Valley Authority, 1101 Market Street, Chattanooga, Tennessee 37402 September 30, 2013 10 CFR 50.90 ATTN: Document Control Desk U. S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Browns Ferry Nuclear Plant, Units 1, 2, and 3 Renewed Facility Operating License Nos. DPR-33, DPR-52, and DPR-68 NRC Docket Nos. 50-259, 50-260, and 50-296

Subject:

Response to Request for Additional Information on Technical Specification Change TS-478

References:

1. Letter from TVA to NRC, "Technical Specification Change TS-478 -

Addition of Analytical Methodologies to Technical Specification 5.6.5 for Browns Ferry 1, 2, and 3, and Revision of Technical Specification 2.1.1.2 for Browns Ferry Unit 2, in Support of ATRIUM-10 XM Fuel Use at Browns Ferry," dated February 28, 2013

2. Letter from NRC to TVA, "Browns Ferry Nuclear Plant, Units 1, 2, and 3, Request For Additional Information For Technical Specification Change TS-478 Regarding Addition of Analytical Methodologies to TS 5.6.5 for Browns Ferry Nuclear Plant Units 1, 2, and 3, and Revision of TS 2.1.1.2 for BFN Unit 2 (TAC Numbers MF0877, MF0878, and MF0879)", dated August 30, 2013 On February 28, 2013, Tennessee Valley Authority (TVA) submitted an application (Reference 1) to the Nuclear Regulatory Commission (NRC) to revise Technical Specification (TS) 5.6.5 to add Analytical Methodologies to support ATRIUM-10 XM fuel use for Browns Ferry Nuclear Plant (BFN) Units 1, 2, and 3, and to revise TS 2.1.1.2 for BFN Unit 2.

By letter from NRC to TVA, dated August 30, 2013, (Reference 2), TVA received a Request for Additional Information (RAI) containing 29 questions regarding the Reference 1 submittal. The NRC has requested that TVA provide the response to this request by September 30, 2013. to this letter provides the response to the 29 NRC RAI questions. Incorporated by reference to Enclosure 2 are the responses provided by AREVA NP, Inc.

The responses in Enclosure 2 contain information that is proprietary to AREVA NP Inc., while provides a non-proprietary version of the same document. ý)D3 6711 Printed on recycled paper

U. S. Nuclear Regulatory Commission Page 2 September 30, 2013 As stated in Enclosure 1, ANP-3144P, "Nuclear Fuel Design Report BFE2-19 LAR ATRIUMTM 1OXM," is provided in Enclosure 5 and ANP-3153P "Browns Ferry Units 1, 2, and 3 LOCA-ECCS Analysis MAPLHGR Limits for ATRIUMTM 1OXM Fuel," is provided in .

Enclosures 2, 5, and 7 to this letter contain information that AREVA NP, Inc. considers to be proprietary in nature and subsequently, pursuant to 10 CFR 2.390, "Public inspections, exemptions, requests for withholding," paragraph (a)(4), it is requested that such information be withheld from public disclosure. Enclosures 3, 6 and 8 contain the redacted versions of Enclosures 2, 5, and 7, respectively, with the proprietary material removed, suitable for public disclosure. provides the AREVA NP, Inc. affidavits supporting these requests.

One new license condition for each unit is being made as part of the response to SNPB RAI-6 b. The proposed wording of the license condition is provided in Enclosure 4.

There are no regulatory commitments associated with this transmittal. Please direct any questions concerning this matter to Edward D. Schrull at (423) 751-3850.

I declare under penalty of perjury that the foregoing is true and correct.

Executed on the 30th day of September 2013.

ice President Nuclear Licensing

Enclosures:

1. TVA Response to Request for Additional Information

2. ANP-3248P, AREVA RAI Responses for Browns Ferry ATRIUM-10 XM Fuel Transition

- Proprietary

3. ANP-3248NP, AREVA RAI Responses for Browns Ferry ATRIUM-10 XM Fuel Transition - Non-Proprietary

4. License Condition Related to Treatment of Channel Bow Uncertainty

5. ANP-3144P, Nuclear Fuel Design Report BFE2-19 LAR ATRIUMTM 1OXM - Proprietary

6. ANP-3144NP, Nuclear Fuel Design Report BFE2-19 LAR ATRIUMTM 1OXM - Non-Proprietary

7. ANP-3153P, Browns Ferry Units 1, 2, and 3 LOCA-ECCS Analysis MAPLHGR Limits for ATRIUMTM 1OXM Fuel- Proprietary

8. ANP-3153NP, Browns Ferry Units 1, 2, and 3 LOCA-ECCS Analysis MAPLHGR Limits for ATRIUMTM 1OXM Fuel - Non-Proprietary

9. Affidavits cc: See Page 3

U. S. Nuclear Regulatory Commission Page 3 September 30, 2013 cc (Enclosures):

NRC Regional Administrator - Region II NRC Senior Resident Inspector - Browns Ferry Nuclear Plant State Health Officer, Alabama State Department of Public Health

Enclosure 1 Browns Ferry Nuclear Plant Units 1, 2, and 3 Technical Specifications (TS) Change 478 TVA Response to Request for Additional Information NRC Question Nuclear Performance and Code Review Branch (SNPB) RAI-1 ANP-3159P. Section 1.0 It has been stated in your LAR [License Amendment Request] submittals that TVA intends to continue use of blended low enriched uranium (BLEU) for the manufacture of fuel pellets for the ATRIUM 1OXM fuel design.

(a) Apart from the difference in density of the BLEU fuel from commercial grade fuel, list other differences in the BLEU fuel such as isotopic composition, physical properties, and neutronics characteristicsfrom the commercial grade fuel.

(b) If the isotopic content of the BLEU fuel is different from that of the commercial grade fuel, what is the impact on the buildup of various uranium isotopes during the depletion of the fuel?

TVA Response:

AREVA, NP Inc., has provided this response r, in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUM m 1OXM Fuel Transition," (Enclosure 2).

NRC Question SNPB RAI-2 ANP-3159P Section 3.2.3 of ANP-3159P, page 3-5 indicatesthat "LHGR [linearheat generation rate]

margins are provided along with uncertaintiesdue to channel bow for input to the statistical analysis." Provide details of how the channel bow uncertaintiesare incorporatedin to the statisticalanalysis.

TVA Response:

AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

NRC Question SNPB RAI-3 ANP-3159P Section 3.2.7 of ANP-3159P indicatesthat a program is in progress to monitor crud buildup and oxidation as water chemistry changes are implemented.

(a) Provide details of this program.

(b) Provide details as to how the guidance on treatmentof corrosion, crud, and hydrogen content per NUREG-0800 Standard Review Plan (SRP), Section 4.2 is satisfied, and El-1 ofll

(c) In ANP-3159P Section 3.2.7, it is stated, in part, that as a result of concerns that were raised on the effect of non-uniform corrosion, such as spallation,and localized hydride formations on the ductility limit on cladding, a regulatory commitment was made to reduce the limit oxide limit to the value in Reference 3 that is listed for ANP-3159P. Provide details of how this regulatorycommitment to reduce the oxide limit to the value specified in Reference 3 of ANP-3159P is implemented at BFN Units 1,2, and 3.

TVA Response:

(a) AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

(b) AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

(c) The commitment related to complying with the calculated oxide limit will be included in the BWR specific requirements appendix of the TVA procedure that governs the overall process of core design and nuclear analysis as part of the implementation of this license amendment. The requirement to verify that the calculated oxide thickness remains within the commitment value will be included in this appendix as an item to be verified prior to each reload cycle where the RODEX4 code is applied.

This procedural requirement will include a cross reference back to the commitment tracking number, to ensure the requirement is recognized as an NRC commitment.

TVA will include the requirement to meet this calculated oxide limit in the Reload Requirements Specification (RRS) for each reload design. The RRS contains the customer specified core design assumptions and requirements, and is provided to AREVA for each reload design and licensing campaign. TVA has a procedure for performing the final acceptance reviews for vendor analyses. This procedure requires that the reviewer consider NRC Safety Evaluation restrictions on approved methodologies as part of the review, and requires that considerations listed in the aforementioned core design and nuclear analysis procedure be verified for compliance when accepting the design.

NRC Question SNPB RAI-4 ANP-3082P Thermal hydraulic compatibility and characterizationanalyses have been performed and the results are summarized in ANP-3082P. The transitioncores for the Browns Ferry units consist of ATRIUM 10 with both Standard FUELGUARD (SFG) and Improved FUELGUARD (IFG) lower tie plates. Provide a detailed description of the differences between SFG and IFG with respect to their geometry (preferablyusing drawings), contribution to the pressure drop and contribution to thermal margin performance by the improvement in design of the FUELGUARDs.

TVA Response:

AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUM 1OXM Fuel Transition," (Enclosure 2).

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NRC Question SNPB RAI-5 ANP-3082P Section 3.4, ANP-3150P, Section 3.3.5 It is stated in the above section that the rod closure due to rod bow was assessed for impact on thermal margins.

(a) Describe how the CPR [Critical Power Ratio] penalty was determined as function of exposure, (b) Provide an assessment of how the thermal margin calculationsare affected by the rod bow at various exposures, (c) Justify your prediction that less rod bow for A TRIUM I0XM than for A TRIUM 10 by showing typical analysis/calculations,and provide how the rod bow behavioris impacted by fuel bumup.

TVA Response:

AREVA, NP Inc., has provided the response to parts (a), (b), and (c) in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

NRC Question SNPB RAI-6 ANP-10307PA, Section 2.2. Channel Bow It has been stated in Section 2.2.1 the channel growth correlationused to determine the channel bow magnitude is a continuous function of fast fluence from the beginning to the end of life. The model coefficients were computed using databasesconsisting of channel length measurements acquiredby AREVA from European BWRs (Boiling Water Reactors) and from Pressurized Water Reactor guide tube data.

a) Provide supporting details to demonstrate that the above mentioned channel bow databaseis applicableto Browns Ferry units' operatingconditions.

b) During review of Brunswick Steam Electric Plant (BSEP)ATRIUM 1OXM fuel transition LAR, the NuclearRegulatory Commission (NRC) staff determined that the predictive model for channel bow was validated against an empirical data that was not bounding of BSEP's expected performance. To resolve this issue, the licensee for BSEP agreed to increasethe channel bow uncertaintyin the SLMCPR (Safety Limit Minimum CriticalPower Ratio) calculation for the most severely deflected fuel channels. In view of the excessive channel bow that occurred at BSEP a license condition was proposed for BSEP Units I and 2 in connection with the use of AREVA channel bow model outside the range of the channel bow measurement database from which its uncertainty was quantified (

Reference:

Letter, BSEP 13-0002, from Michael J. Annacone (Duke Energy) to NRC, "Supplement to License Amendment Request for Addition of Analytical Methodology Topical Report to Technical Specification 5.6.5, CORE OPERATING LIMITS REPORT (COLR), and Revision to Technical Specification 2.1.1.2 Minimum CriticalPower Ratio Safety Limit," Duke Energy, January 22, 2013). Confirm whether a similarlicense condition is required for the BFN Units 1, 2, and 3.

TVA Response:

(a) AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

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(b) Given that the AREVA channel bow model used for the Brunswick Steam Electric Plant (BSEP) will also be applied to the BFN, it is possible that the calculated channel fluence gradients could exceed the bounds of the channel bow database for a limited number of channels in a given cycle. Therefore, the license condition provided for the BSEP units is also applicable to the BFN units. The proposed license condition wording for each unit is included as enclosure 4 to this RAI response letter.

NRC Question SNPB RAI-7 ANP-3082P, Section 3.5 Discuss the impact on bypass exit subcoding (sic. subcooling) while transitioningbetween transition core combination of AREVA fuel and GE14 to a full core ATRIUM IOXM fuel design at BFN units.

TVA Response:

AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUM TM 1OXM Fuel Transition," (Enclosure 2).

NRC Question SNPB RAI-8 ANP-3082P. Section 3.2 Table 3.4 of ANP-3082 provides input conditions for thermal hydraulic compatibility analysis for two of the statepoints 100 percent power/QO0 percent flow and 62 percent power/37.3 percent flow.

(a) Provide the basis for the thermal margin analysis performed at 62 percent power/37.3 percent flow statepointand (b) Justify why the analysis was not done at 100 percentpower/105 percent flow as indicated in Figure 1.1, BFN Power Flow Map -100 percent originallicensed thermal power (OL TP) of ANP-3167(P), BFN Unit 2 Reload Safety Analysis.

TVA Response:

AREVA, NP Inc., has provided the response to parts (a) and (b) in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 1 OXM Fuel Transition," (Enclosure 2).

NRC Question SNPB RAI-9 ANP-3150P, Section 3.3.1. Table 3.1 Provide details of the procedure,assumptions, methodology and results for the "stress evaluations"that were performed to confirm the design margin and to establish a baseline for adding accidentloads for the determination of loading limits on fuel assembly components.

TVA Response:

AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

NRC Question SNPB RAI-10 ANP-3150P. Section 3.4.4 (a) Describe AREVA ATRIUM 10 and ATRIUM IOXM fuel assemblies'dynamic structuralresponse to combined seismic/loss-of-coolantaccident (LOCA) loadings.

Provide details of the model used for assembly with and without a fuel channel, E 1-4 of 11

accelerationused in the calculations,uncertainty allowances in the calculations, and results with margin to established limits.

(b) Provide details of the testing done to obtain the dynamic characteristicsof the fuel assembly and spacergrids under varying conditions of stiffness, naturalfrequencies and damping values with and without the fuel channel. Provide details of the evaluation of BFN ATRIUM 10/A TRIUM I OXM fuel assembly structuralresponse to externally applied forces (seismic and LOCA) and show how the acceptancecriteria in NUREG-0800, Chapter4.2, Appendix A,Section IV are satisfied.

TVA Response:

AREVA, NP Inc., has provided the response to parts (a) and (b) in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

NRC Question SNPB RAI-11 ANP-3170P. Section 3.1 The core average gap conductance used in COTRANSA2 system calculationsand the hot channel gap conductance used in XCOBRA-T hot channel calculationsare obtained from RODEX2 calculations. The sensitivity to conductivity and gap conductance for Anticipated OperationalOccurrence (A 00) analyses is in the opposite directionsfor the core and the hot channel. This means that putting more energy into the coolant (higherthermal conductivity/highergap conductance) is nonconservative for the system calculation but conservative for the hot channel calculations. Provide, with quantitative examples, how these competing effects between the core and hot channel calculations are balancedto minimize the overall impact of thermal conductivity degradation.

TVA Response:

AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

NRC Question SNPB RAI-12 ANP-3145P. ANP-2637 Section 3.0 Nuclear core design analyses establish operatingmargins for minimum criticalpower ratio (MCPR), maximum averageplanarLHGR (LinearHeat GenerationRate) (MAPLHGR), and LHGR. Two exposure dependent LHGR limits are established for each fuel design; one a steady state operating fuel design limit (FDL) and the other for the protection againstthe power transient(PAPT)limit.

(a) Provide the details of the FDL and PAPT limits as a function of exposure and show that sufficient margin exists between the steady state and transientLHGR limits, (b) Show that the transientLHGR design limit satisfies the strain and fuel overheating design criteria.

(c) Confirm that the fuel Thermal Conductivity Degradation(TCD) with exposure has been taken into account in generating/adjustingthe LHGR limits.

(d) Section 2.0 of ANP-3145P suggests that for a complete description of fresh reload assemblies, see Reference 6, which is listed as ANP-3144(P)Revision 0, Nuclear Fuel Design Report BFE-19 LAR ATRIUM IOXM, August 2012. This report is not E 1- 5 of 11

availableto the NRC staff. Please submit a copy of this report to the NRC or provide a complete description in your response.

TVA Response:

AREVA, NP Inc., has provided the response to parts (a), (b), and (c) in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

(d) A proprietary version of ANP-3144P Revision 0 is included as Enclosure 5. The non-proprietary version is included as Enclosure 6 to this letter.

NRC Question SNPB RAI-13 ANP-3148P. Section 3.3 Describe how the hot excess reactivity and shutdown margin are maintainedper Technical Specification values during the transitioncycles and during the equilibrium cycle of operation of the Browns Ferry units.

TVA Response:

The design and licensing process requires that cycle exposure dependent hot and cold critical eigenvalues be selected for the design cycle of interest. Once the design eigenvalue bases of a cycle are established, and the core is designed and licensed, the site is provided with data to support the testing used to demonstrate compliance with the reactivity-related Technical Specifications. While there is no Technical Specification related to hot excess reactivity, there is a specification (TS 3.1.2, Reactivity Anomalies) for reactivity anomaly in the hot operating condition. The hot eigenvalue as a function of cycle exposure is provided to the site via a Cycle Management Report, and the surveillance procedure for reactivity anomaly for the unit of interest is updated to include the cycle specific data from this report. The surveillance is carried out in accordance with the requirements of the Technical Specifications. The difference between the calculated eigenvalue for the current core state point conditions and the design eigenvalue at the cycle exposure where the test is being performed is computed, to verify the difference is within the +/-1% Ak/k tolerance required by the Technical Specifications.

For cold shutdown margin, data is provided to the site in the Cycle Management Report to support the Technical Specification 3.1.1, Shutdown Margin (SDM), related surveillance test.

The cold shutdown margin test is performed at beginning of cycle (BOC). The test determines the k-effective of the core in the state point condition where criticality was achieved, and then calculates the difference between this k-effective and the analytically determined strong rod out k-effective. This difference is the BOC demonstrated cold shutdown margin. The test data provided to the site also includes the R value, which is the calculated difference between the BOC and cycle minimum calculated shutdown margin values. The BOC demonstrated shutdown margin value is reduced by the R value prior to comparing to the Technical Specification criteria of 0.38% Ak/k. The cold eigenvalues for cycle exposures past BOC are chosen to be conservative, because the amount of cold critical benchmark data past BOC is more limited in comparison to the available hot data. In addition to the selection of a conservative cold eigenvalue assumption, the core is designed to a minimum target shutdown margin of 1% Ak/k, which allows for additional uncertainty in the design calculations. The combination of these two conservatisms provides a high degree of confidence that the Technical Specification shutdown margin will be maintained.

The same procedures for reactivity anomaly and cold shutdown margin testing will be applied for both the transition core and equilibrium core situations.

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It should be noted that the design basis eigenvalue selection is not a static process. The hot and cold eigenvalues assumed for the transition and equilibrium cycles should be expected to change somewhat over time, as additional benchmarking data becomes available from BFN transition cycles, and from other relevant plants where similar fuel transitions either have or are in the process of occurring.

NRC Question SNPB RAI-14 ANP-3140, Section 3 In BWR terminology, assembly criticalpower is defined as the minimum assembly power that results in onset of Boiling Transition (BT) (dryout) at any location in the assembly. The acceptance criterionrelated to BT in BWRs is that the limiting value of Minimum CriticalPower Ratio (MCPR) such that at least 99.9 percent of the fuel rods in the core are not expected to experience BT during normal operation and AQOs. The SLMCPR is determined such that at least 99.9 percent of the fuel rods in the core are expected to avoid BT if the MCPR is greater than or equal to the SLMCPR. The SMPCPR methodology uses a criticalpower correlationto calculate CPR for a fuel assembly based on thermal hydraulic conditions and power distribution in the assembly.

(a) Section 3.3.1 of ANP-3140P describeshow an additive constant (that accounts for local effects such as spacing and geometry) is determined based on predictions of the criticalpower correlationand comparisonsto test data. Figure 3-2 of ANP-3140P identifies the test bundle where majority of the rods were dryout was observed.

Explain how the test results (with majority rods in dryout) are used in the accurate determinationof CPR correlationadditive constants?

(b) Figure 3-5 of ANP-3140P lists additive constants comparison of original ACE/ATRIUM IOXM and revised ACE/ATRIUM IOXM. Section 3.3.4 indicates that the observed changes in additive constants are generally small. However, a random check by staff on the changes in additive constants has shown that the changes vary from 2 percentto 80 percent in magnitude. Please explain why there are larger variationscontrary to what is stated in Section 3.3.4.

TVA Response:

AREVA, NP Inc., has provided the response to parts (a) and (b) in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 10XM Fuel Transition," (Enclosure 2).

NRC Question SNPB RAI-15 ANP-3140, Section 5.0 Provide a detailed summary of the K-factor method that is described in Section 5 of ANP-3140.

If the methodology appearsin an NRC-accepted topical report,please refer to the topical report and identify the appropriatesections of the topical report that discuss the K-factor method.

TVA Response:

AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

NRC Question SNPB RAI-16 ANP-3152, ANP-3167P E 1- 7 of 11

While reviewing ANP-3167P, Browns Ferry Unit 2 Cycle 19 Reload Analysis, the NRC staff noticed that the Reference 7 listed in Section 9.0 of ANP-3167P, ANP-3153(P) Browns Ferry Units 1, 2 and 3 LOCA-ECCS [emergency core cooling system] Analysis MAPLHGR Limit for ATRIUM IOXM Fuel, is NOT included in your LAR package. Submit this reference to the NRC for staff's review and evaluationof LOCA-ECCS analysis with the MAPLHGR limits for the ATRIUM IOXM fuel design.

TVA Response:

A proprietary version of ANP-3153P Revision 0 is included as Enclosure 7 to this letter. The non-proprietary version is included as Enclosure 8 to this letter. The MAPLHGR limits for ATRIUM 1OXM fuel are shown in Figure 2.1 of ANP-3153P.

NRC Question SNPB RAI-17 ANP-3152P. Section 2.0 Section 2.0 of ANP-3152P suggests that "analysesfor core flows less than 70% [percent) rated with 10% mismatch would not be limiting in PCT[peak cladding temperature]because of the lower power level, therefore the analyses at higher flow with 5% mismatch inherentlybound the lower flows where the mismatch is 10%". Pleaseprovide detailed summary results of your analyses that support your statement above.

TVA Response:

AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

NRC Question SNPB RAI-18 ANP-3152P, ANP-3170P RODEX4 computer code was used to assess the potential impact of exposure (burnup) degradationof U0 2 thermal conductivity (TCD) on the fuel parametersand this assessment was used to make adjustments to input for RODEX2 TCD with exposure that was used in the LOCA analysis.

a) Provide details of the adjustments made to RODEX2 input for LOCA analysis.

b) Provide a discussion of impact of gap conductance between the fuel pellet and the cladding on ECCS performance analysis results resulting from fuel thermal conductivity degradationwith exposure and irradiationeffects on the ceramic fuel.

TVA Response:

AREVA, NP Inc., has provided the response to parts (a) and (b) in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

NRC Question SNPB RAI-19 ANP-3152 Figure 6.19 of ANP-3152P illustrates the variationof cladding temperature with time for the limiting recirculationline break. The cladding temperature experiences the first peak at around 190 seconds into the transient. Please explain the cause of this intermediate temperaturepeak.

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TVA Response:

AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMm 10OXM Fuel Transition," (Enclosure 2).

NRC Question SNPB RAI-20 ANP-3152, Section 8.0 Explain the basis for applying a factor of 0.85 multiplier to the two-loop operation (TLO)

MAPLHGR limit for the single-loop operation (SLO) Single failure-Battery(DC) power board A (SF-BA TTIBA) LOCA analysis.

TVA Response:

AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 1 OXM Fuel Transition," (Enclosure 2).

NRC Question SNPB RAI-21 ANP-3152 Explain the impact on LOCA (ECCS performance) analysis and Title 10 of Code of Federal Regulations, Section 50.46 acceptance criteria for BFN Units 1, 2, and 3 coastdown operation with final feedwater temperature reduction (FFTR) as well as operation with feedwater heaters out-of-service (FHOOS).

TVA Response:

AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

NRC Question SNPB RAI-22 ANP-3167P. Section 4.2 BFN Unit 2 Cycle 19 SLMCPR calculatedfrom Reference 12 (ANP-10307P)resulted in a value of 1.04 for TLO and a value of 1.05 for SLO and listed in Reference 8 (Document No. 51-9191258-001). These SLMCPR values are conservatively increasedto 1.06 for TLO and 1.08 for SLO. Provide basis for the adoption of these new values.

TVA Response:

TVA sets the SLMCPR value in the Technical Specifications such that the SLMCPR has a high likelihood of being cycle independent. The SLMCPR is calculated each cycle as part of the reload licensing process, in order to validate that the cycle specific results are equal to, or bounded by, the value in the Technical Specifications. The cycle to cycle results will have some variability, based on the specifics of the core design each cycle.

Considering the variability in cycle by cycle SLMCPR results using the SAFLIM-3D method, TVA decided that setting the TLO and SLO values to 1.06 and 1.08, respectively, would provide a reasonable assurance that the TVA goal of cycle independent SLMCPR values could be met.

The use of these conservative values still provides a significant improvement in SLMCPR relative to the current 1.08 TLO and 1.10 SLO values in the Unit 2 Technical Specifications.

If a future Unit 2 cycle core design produces SLMCPR values not bounded by the 1.06 and 1.08 values proposed in TS-478, TVA will submit a License Amendment Request to increase the SLMCPR values accordingly. TVA plans to submit a SLMCPR License Amendment Request E 1-9 of 11

for both Unit 1 and Unit 3, on a schedule commensurate with the first cycle of application of the SAFLIM3-D methodology, for each of these units.

NRC Question SNPB RAI-23. ANP-3167P. Section 4.3 Provide a summary of the analysis and results for BFN units operation with FFTR and FHOOS that complies with the licensing requirementsfor the Option Ill (Oscillation PowerRange Monitor (OPRM)) stability solution. Also provide details and results for the analysis that supports BFN operation with backup stabilityprotection regions, if the Option Ill OPRM system is declared inoperable.

TVA Response:

AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

NRC Question SNPB RAI-24 ANP-3167P. Section 5.1.3 For feedwater controllerfailure (FWCF)event scenario, Figure 5.4 (PercentRated Versus Time) indicates a sharp spike in relative ratedpower to about 375 percent and a simultaneous sharp reduction in relative steam flow at about 15 seconds into the event. Please describe the cause of this behaviorduring the FWCF event.

TVA Response:

AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

NRC Question SNPB RAI-25 ANP-3167P. Section 6.1 Section 6.1 reports that A TRIUM I OXM LOCA analysis for BFN Units PCT is 1903 OF and the peak local metal water reaction is 1.16 percent. However, ANP-3152P, Browns Ferry Units 1, 2, and 3 LOCA Break Spectrum Analysis for ATRIUM IOXM Fuel, Table 6.1 reports that the PCT is 1909 OF and the maximum local cladding oxidation is 1.20 percent. Clarify the discrepancy between the information on LOCA results from these two documents.

TVA Response:

AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

NRC Question SNPB RAI-26 ANP-3172P. Section 7.1 Table 7.1 lists the ASME (American Society of MechanicalEngineers) Overpressurization analysis results for maximum vessel pressure for lower-plenum and the maximum dome pressure. Please specify whether the pressure results include any other analysis/measurement uncertaintiesin addition to the 7 pounds per square inch increase that binds a bias in the void-quality correlationsas indicated.

TVA Response:

AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

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NRC Question Reactor Systems Branch (SRXB) RAI-1 In page 2 of Enclosure to the LAR, it was stated, The currentACE correlationfor XM fuel has an identified deficiency. The deficiency involves a nonconservatismin the axial averagingprocess used to determine the K factor, which is an input to the correlation.... TVA is including a BFN specific ACE supplement in Attachments 27 and 28.

Did the deficiency in the currentACE correlationidentified above impact BFN Unit 2 Cycle 19 SLMCPR values? If it did, was the updated methodology as provided in the generic and/or BFN-specific ACE supplements used for BFN Unit 2 Cycle 19 SLMCPR calculation?Explain if updatedACE correlationwas not used.

TVA Response:

AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

NRC Question SRXB RAI-2 Since Unit 2 Cycle 19 core is expected to include both ATRIUM-IC and ATRIUM IOXM fuel designs, which fuel design is more limiting from the standpointof SLMCPR, and why?

TVA Response:

AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

NRC Question SRXB RAI-3 Regarding the calculationsperformed for Unit 2 Cycle 19 reloadsafety analysis, as provided in ANP-3167(P), Revision 0, AREVA NP Inc., November 2012 (Attachment 12), confirm that most recently approved methodologies were used, including RODEX4, which accounts for the degradationof thermal conductivity with increasingfuel bumup using upper limit on calculated clad oxide thickness, and the updated methodology for ACE correlationthat addresses a nonconservatismin the axial averagingprocess used to determine the K factor, which is an input to the correlation(as discussed in page 2 of Enclosure to the LAR). If the most recently updated and approved methodologies were not used for BFN Unit 2 Cycle 19 reload safety analyses, then please provide justification.

TVA Response:

AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

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Enclosure 1 Browns Ferry Nuclear Plant Units 1, 2, and 3 Technical Specifications (TS) Change 478 TVA Response to Request for Additional Information NRC Question Nuclear Performance and Code Review Branch (SNPB) RAI-1 ANP-3159P. Section 1.0 It has been stated in your LAR [License Amendment Request] submittals that flVA intends to continue use of blended low enriched uranium (BLEU) for the manufacture of fuel pellets for the ATRIUM IOXM fuel design.

(a) Apart from the difference in density of the BLEU fuel from commercial grade fuel, list other differences in the BLEU fuel such as isotopic composition, physical properties, and neutronics characteristicsfrom the commercial grade fuel.

(b) If the isotopic content of the BLEU fuel is different from that of the commercial grade fuel, what is the impact on the buildup of various uranium isotopes during the depletion of the fuel?

TVA Response:

AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

NRC Question SNPB RAI-2 ANP-3159P Section 3.2.3 of ANP-3159P, page 3-5 indicates that "LHGR [linearheat generation rate]

marginsare provided along with uncertaintiesdue to channel bow for input to the statistical analysis." Provide details of how the channel bow uncertaintiesare incorporatedin to the statisticalanalysis.

TVA Response:

AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

NRC Question SNPB RAI-3 ANP-3159P Section 3.2.7 of ANP-3159P indicates that a program is in progress to monitor crud buildup and oxidation as water chemistry changes are implemented.

(a) Provide details of this program.

(b) Provide details as to how the guidance on treatment of corrosion, crud, and hydrogen content per NUREG-0800 StandardReview Plan (SRP), Section 4.2 is satisfied, and E1-1 of 11

(c) In ANP-3159P Section 3.2.7, it is stated, in part, that as a result of concerns that were raised on the effect of non-uniform corrosion, such as spallation,and localized hydride formations on the ductility limit on cladding, a regulatory commitment was made to reduce the limit oxide limit to the value in Reference 3 that is listed for ANP-3159P. Provide details of how this regulatorycommitment to reduce the oxide limit to the value specified in Reference 3 of ANP-3159P is implemented at BFN Units 1,2, and 3.

TVA Response:

(a) AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

(b) AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

(c) The commitment related to complying with the calculated oxide limit will be included in the BWR specific requirements appendix of the TVA procedure that governs the overall process of core design and nuclear analysis as part of the implementation of this license amendment. The requirement to verify that the calculated oxide thickness remains within the commitment value will be included in this appendix as an item to be verified prior to each reload cycle where the RODEX4 code is applied.

This procedural requirement will include a cross reference back to the commitment tracking number, to ensure the requirement is recognized as an NRC commitment.

TVA will include the requirement to meet this calculated oxide limit in the Reload Requirements Specification (RRS) for each reload design. The RRS contains the customer specified core design assumptions and requirements, and is provided to AREVA for each reload design and licensing campaign. TVA has a procedure for performing the final acceptance reviews for vendor analyses. This procedure requires that the reviewer consider NRC Safety Evaluation restrictions on approved methodologies as part of the review, and requires that considerations listed in the aforementioned core design and nuclear analysis procedure be verified for compliance when accepting the design.

NRC Question SNPB RAI-4 ANP-3082P Thermal hydraulic compatibility and characterizationanalyses have been performed and the results are summarized in ANP-3082P. The transitioncores for the Browns Ferryunits consist of ATRIUM 10 with both Standard FUELGUARD (SFG) and Improved FUELGUARD (IFG) lower tie plates. Provide a detailed description of the differences between SFG and IFG with respect to their geometry (preferably using drawings), contribution to the pressure drop and contribution to thermal margin performance by the improvement in design of the FUELGUARDs.

TVA Response:

AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUM 1OXM Fuel Transition," (Enclosure 2).

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NRC Question SNPB RAI-5 ANP-3082P Section 3.4. ANP-3150P. Section 3.3.5 It is stated in the above section that the rod closure due to rod bow was assessed for impact on thermal margins.

(a) Describehow the CPR [CriticalPower Ratio] penalty was determined as function of exposure, (b) Provide an assessment of how the thermal margin calculationsare affected by the rod bow at various exposures, (c) Justify your prediction that less rod bow for A TRIUM IOXM than for A TRIUM 10 by showing typical analysis/calculations,andprovide how the rod bow behavioris impacted by fuel bumup.

TVA Response:

AREVA, NP Inc., has provided the response to parts (a), (b), and (c) in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

NRC Question SNPB RAI-6 ANP-10307PA, Section 2.2. Channel Bow It has been stated in Section 2.2.1 the channel growth correlationused to determine the channel bow magnitude is a continuous function of fast fluence from the beginning to the end of life. The model coefficients were computed using databasesconsisting of channel length measurements acquiredby AREVA from EuropeanBWRs (Boiling Water Reactors) and from Pressurized Water Reactor guide tube data.

a) Provide supporting details to demonstrate that the above mentioned channel bow databaseis applicable to Browns Ferry units' operating conditions.

b) During review of Brunswick Steam Electric Plant (BSEP)ATRIUM IOXM fuel transitionLAR, the Nuclear Regulatory Commission (NRC) staff determined that the predictive model for channel bow was validated against an empirical data that was not bounding of BSEP's expected performance. To resolve this issue, the licensee for BSEP agreed to increase the channel bow uncertaintyin the SLMCPR (Safety Limit Minimum Critical Power Ratio) calculation for the most severely deflected fuel channels. In view of the excessive channel bow that occurredat BSEP a license condition was proposed for BSEP Units I and 2 in connection with the use of AREVA channel bow model outside the range of the channel bow measurement database from which its uncertaintywas quantified (

Reference:

Letter, BSEP 13-0002, from Michael J. Annacone (Duke Energy) to NRC, "Supplement to License Amendment Request for Addition of Analytical Methodology Topical Report to Technical Specification 5.6.5, CORE OPERATING LIMITS REPORT (COLR), and Revision to Technical Specification 2.1.1.2 Minimum CriticalPower Ratio Safety Limit," Duke Energy, January22, 2013). Confirm whether a similarlicense condition is required for the BFN Units 1, 2, and 3.

TVA Response:

(a) AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA Responses for Browns Ferry ATRIUMTM 10XM Fuel Transition," (Enclosure 2).

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(b) Given that the AREVA channel bow model used for the Brunswick Steam Electric Plant (BSEP) will also be applied to the BFN, it is possible that the calculated channel fluence gradients could exceed the bounds of the channel bow database for a limited number of channels in a given cycle. Therefore, the license condition provided for the BSEP units is also applicable to the BFN units. The proposed license condition wording for each unit is included as enclosure 4 to this RAI response letter.

NRC Question SNPB RAI-7 ANP-3082P. Section 3.5 Discuss the impact on bypass exit subcoding (sic. subcooling) while transitioningbetween transition core combination of AREVA fuel and GE14 to a full core ATRIUM I OXM fuel design at BFN units.

TVA Response:

AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUM m1OXM Fuel Transition," (Enclosure 2).

NRC Question SNPB RAI-8 ANP-3082P. Section 3.2 Table 3.4 of ANP-3082 provides input conditions for thermal hydraulic compatibility analysis for two of the statepoints 100 percent power/l 0 percent flow and 62 percent power/3 7.3 percent flow.

(a) Provide the basis for the thermal margin analysis performed at 62 percent power/37.3 percent flow statepointand (b) Justify why the analysis was not done at 100 percentpower/105 percent flow as indicated in Figure 1.1, BFN Power Flow Map -100 percent originallicensed thermal power (OL TP) of ANP-3167(P), BFN Unit 2 Reload Safety Analysis.

TVA Response:

AREVA, NP Inc., has provided the response to parts (a) and (b) in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

NRC Question SNPB RAI-9 ANP-3150P. Section 3.3.1, Table 3.1 Provide details of the procedure, assumptions, methodology and results for the "stress evaluations"that were performed to confirm the design margin and to establish a baseline for adding accidentloads for the determination of loading limits on fuel assembly components.

TVA Response:

AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

NRC Question SNPB RAI-10 ANP-3150P. Section 3.4.4 (a) Describe AREVA ATRIUM 10 and ATRIUM IOXM fuel assemblies' dynamic structuralresponse to combined seismic/loss-of-coolantaccident (LOCA) loadings.

Provide details of the model used for assembly with and without a fuel channel, E 1-4 of 11

accelerationused in the calculations, uncertaintyallowances in the calculations, and results with margin to establishedlimits.

(b) Provide details of the testing done to obtain the dynamic characteristicsof the fuel assembly and spacer grids under varying conditions of stiffness, naturalfrequencies and damping values with and without the fuel channel. Provide details of the evaluation of BFN ATRIUM 10/A TRIUM IOXM fuel assembly structural response to externally appliedforces (seismic and LOCA) and show how the acceptance criteria in NUREG-0800, Chapter4.2, Appendix A,Section IV are satisfied.

TVA Response:

AREVA, NP Inc., has provided the response to parts (a) and (b) in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

NRC Question SNPB RAI-11 ANP-3170P, Section 3.1 The core average gap conductance used in COTRANSA2 system calculationsand the hot channel gap conductance used in XCOBRA-T hot channel calculationsare obtained from RODEX2 calculations. The sensitivity to conductivity and gap conductance for Anticipated OperationalOccurrence (AO0) analyses is in the opposite directionsfor the core and the hot channel. This means that putting more energy into the coolant (higherthermal conductivity/highergap conductance) is nonconservative for the system calculationbut conservative for the hot channel calculations.Provide, with quantitativeexamples, how these competing effects between the core and hot channel calculationsare balanced to minimize the overall impact of thermal conductivity degradation.

TVA Response:

AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 1 OXM Fuel Transition," (Enclosure 2).

NRC Question SNPB RAI-12 ANP-3145P. ANP-2637 Section 3.0 Nuclear core design analyses establish operatingmargins for minimum criticalpower ratio (MCPR), maximum average planarLHGR (LinearHeat GenerationRate) (MAPLHGR), and LHGR. Two exposure dependent LHGR limits are established for each fuel design; one a steady state operatingfuel design limit (FDL) and the other for the protection againstthe power transient(PAPT)limit.

(a) Provide the details of the FDL and PAPT limits as a function of exposure and show that sufficient margin exists between the steady state and transientLHGR limits, (b) Show that the transientLHGR design limit satisfies the strain and fuel overheating design criteria.

(c) Confirm that the fuel Thermal Conductivity Degradation(TCD) with exposure has been taken into account in generating/adjustingthe LHGR limits.

(d) Section 2.0 of ANP-3145P suggests that for a complete description of fresh reload assemblies, see Reference 6, which is listed as ANP-3144(P)Revision 0, Nuclear Fuel Design Report BFE-19 LAR ATRIUM IOXM, August 2012. This report is not E 1-5 of 11

availableto the NRC staff. Please submit a copy of this report to the NRC or provide a complete descriptionin your response.

TVA Response:

AREVA, NP Inc., has provided the response to parts (a), (b), and (c) in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

(d) A proprietary version of ANP-3144P Revision 0 is included as Enclosure 5. The non-proprietary version is included as Enclosure 6 to this letter.

NRC Question SNPB RAI-13 ANP-3148P. Section 3.3 Describe how the hot excess reactivity and shutdown margin are maintainedper Technical Specification values during the transitioncycles and during the equilibrium cycle of operation of the Browns Ferryunits.

TVA Response:

The design and licensing process requires that cycle exposure dependent hot and cold critical eigenvalues be selected for the design cycle of interest. Once the design eigenvalue bases of a cycle are established, and the core is designed and licensed, the site is provided with data to support the testing used to demonstrate compliance with the reactivity-related Technical Specifications. While there is no Technical Specification related to hot excess reactivity, there is a specification (TS 3.1.2, Reactivity Anomalies) for reactivity anomaly in the hot operating condition. The hot eigenvalue as a function of cycle exposure is provided to the site via a Cycle Management Report, and the surveillance procedure for reactivity anomaly for the unit of interest is updated to include the cycle specific data from this report. The surveillance is carried out in accordance with the requirements of the Technical Specifications. The difference between the calculated eigenvalue for the current core state point conditions and the design eigenvalue at the cycle exposure where the test is being performed is computed, to verify the difference is within the +/-1% Ak/k tolerance required by the Technical Specifications.

For cold shutdown margin, data is provided to the site in the Cycle Management Report to support the Technical Specification 3.1.1, Shutdown Margin (SDM), related surveillance test.

The cold shutdown margin test is performed at beginning of cycle (BOC). The test determines the k-effective of the core in the state point condition where criticality was achieved, and then calculates the difference between this k-effective and the analytically determined strong rod out k-effective. This difference is the BOC demonstrated cold shutdown margin. The test data provided to the site also includes the R value, which is the calculated difference between the BOC and cycle minimum calculated shutdown margin values. The BOC demonstrated shutdown margin value is reduced by the R value prior to comparing to the Technical Specification criteria of 0.38% Ak/k. The cold eigenvalues for cycle exposures past BOC are chosen to be conservative, because the amount of cold critical benchmark data past BOC is more limited in comparison to the available hot data. In addition to the selection of a conservative cold eigenvalue assumption, the core is designed to a minimum target shutdown margin of 1% Ak/k, which allows for additional uncertainty in the design calculations. The combination of these two conservatisms provides a high degree of confidence that the Technical Specification shutdown margin will be maintained.

The same procedures for reactivity anomaly and cold shutdown margin testing will be applied for both the transition core and equilibrium core situations.

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It should be noted that the design basis eigenvalue selection is not a static process. The hot and cold eigenvalues assumed for the transition and equilibrium cycles should be expected to change somewhat over time, as additional benchmarking data becomes available from BFN transition cycles, and from other relevant plants where similar fuel transitions either have or are in the process of occurring.

NRC Question SNPB RAI-14 ANP-3140, Section 3 In BWR terminology, assembly criticalpower is defined as the minimum assembly power that results in onset of Boiling Transition (BT) (dryout)at any location in the assembly. The acceptance criterionrelated to BT in BWRs is that the limiting value of Minimum CriticalPower Ratio (MCPR) such that at least 99.9 percent of the fuel rods in the core are not expected to experience BT during normal operation and AQOs. The SLMCPR is determined such that at least 99.9 percent of the fuel rods in the core are expected to avoid BT if the MCPR is greater than or equal to the SLMCPR. The SMPCPR methodology uses a criticalpower correlationto calculate CPR for a fuel assembly based on thermal hydraulic conditions and power distribution in the assembly.

(a) Section 3.3.1 of ANP-3140P describes how an additive constant(that accounts for local effects such as spacing and geometry) is determined based on predictionsof the criticalpower correlationand comparisonsto test data. Figure 3-2 of ANP-3140P identifies the test bundle where majority of the rods were dryout was observed.

Explain how the test results (with majority rods in dryout) are used in the accurate determinationof CPR correlationadditive constants?

(b) Figure 3-5 of ANP-3140P lists additive constants comparison of original ACE/ATRIUM IOXM and revised ACE/ATRIUM IOXM. Section 3.3.4 indicates that the observed changes in additive constants are generally small. However, a random check by staff on the changes in additive constants has shown that the changes vary from 2 percent to 80 percent in magnitude. Please explain why there are larger variationscontrary to what is stated in Section 3.3.4.

TVA Response:

AREVA, NP Inc., has provided the response to parts (a) and (b) in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

NRC Question SNPB RAI-15 ANP-3140, Section 5.0 Provide a detailed summary of the K-factor method that is described in Section 5 of ANP-3140.

If the methodology appearsin an NRC-accepted topical report, please refer to the topical report and identify the appropriatesections of the topical report that discuss the K-factor method.

TVA Response:

AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 10XM Fuel Transition," (Enclosure 2).

NRC Question SNPB RAI-16 ANP-3152, ANP-3167P E 1- 7 of 11

While reviewing ANP-3167P, Browns Ferry Unit 2 Cycle 19 Reload Analysis, the NRC staff noticed that the Reference 7 listed in Section 9.0 of ANP-3167P, ANP-3153(P) Browns Ferry Units 1, 2 and 3 LOCA-ECCS [emergency core cooling system] Analysis MAPLHGR Limit for ATRIUM IOXM Fuel, is NOT included in your LAR package. Submit this reference to the NRC for staff's review and evaluation of LOCA-ECCS analysis with the MAPLHGR limits for the ATRIUM IOXM fuel design.

TVA Response:

A-proprietary version of ANP-3153P Revision 0 is included as Enclosure 7 to this letter. The non-proprietary version is included as Enclosure 8 to this letter. The MAPLHGR limits for ATRIUM 1OXM fuel are shown in Figure 2.1 of ANP-3153P.

NRC Question SNPB RAI-17 ANP-3152P. Section 2.0 Section 2.0 of ANP-3152P suggests that "analysesfor core flows less than 70% [percent) rated with 10% mismatch would not be limiting in PCT [peak cladding temperature]because of the lower power level, therefore the analyses at higher flow with 5% mismatch inherently bound the lower flows where the mismatch is 10%". Please provide detailed summary results of your analyses that support your statement above.

TVA Response:

AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

NRC Question SNPB RAI-18 ANP-3152P. ANP-3170P RODEX4 computer code was used to assess the potentialimpact of exposure (bumup) degradationof U0 2 thermal conductivity (TCD) on the fuel parametersand this assessment was used to make adjustments to input for RODEX2 TCD with exposure that was used in the LOCA analysis.

a) Provide details of the adjustments made to RODEX2 input for LOCA analysis.

b) Provide a discussion of impact of gap conductance between the fuel pellet and the cladding on ECCS performance analysis results resulting from fuel thermal conductivity degradationwith exposure and irradiationeffects on the ceramic fuel.

TVA Response:

AREVA, NP Inc., has provided the response to parts (a) and (b) in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

NRC Question SNPB RAI-19 ANP-3152 Figure 6.19 of ANP-3152P illustrates the variationof cladding temperature with time for the limiting recirculationline break. The cladding temperature experiences the first peak at around 190 seconds into the transient.Please explain the cause of this intermediate temperaturepeak.

E 1- 8 of 11

TVA Response:

AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 1 0XM Fuel Transition," (Enclosure 2).

NRC Question SNPB RAI-20 ANP-3152, Section 8.0 Explain the basis for applying a factor of 0.85 multiplier to the two-loop operation (TLO)

MAPLHGR limit for the single-loop operation (SLO) Single failure-Battery(DC) power boardA (SF-BA TTIBA) LOCA analysis.

TVA Response:

AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

NRC Question SNPB RAI-21 ANP-3152 Explain the impact on LOCA (ECCS performance) analysis and Title 10 of Code of Federal Regulations, Section 50.46 acceptance criteriafor BFN Units 1, 2, and 3 coastdown operation with final feedwater temperaturereduction (FFTR) as well as operation with feedwater heaters out-of-service (FHOOS).

TVA Response:

AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 10XM Fuel Transition," (Enclosure 2).

NRC Question SNPB RAI-22 ANP-3167P, Section 4.2 BFN Unit 2 Cycle 19 SLMCPR calculated from Reference 12 (ANP-10307P)resulted in a value of 1.04 for TLO and a value of 1.05 for SLO and listed in Reference 8 (Document No. 51-9191258-001). These SLMCPR values are conservatively increasedto 1.06 for TLO and 1.08 for SLO. Provide basis for the adoption of these new values.

TVA Response:

TVA sets the SLMCPR value in the Technical Specifications such that the SLMCPR has a high likelihood of being cycle independent. The SLMCPR is calculated each cycle as part of the reload licensing process, in order to validate that the cycle specific results are equal to, or bounded by, the value in the Technical Specifications. The cycle to cycle results will have some variability, based on the specifics of the core design each cycle.

Considering the variability in cycle by cycle SLMCPR results using the SAFLIM-3D method, TVA decided that setting the TLO and SLO values to 1.06 and 1.08, respectively, would provide a reasonable assurance that the TVA goal of cycle independent SLMCPR values could be met.

The use of these conservative values still provides a significant improvement in SLMCPR relative to the current 1.08 TLO and 1.10 SLO values in the Unit 2 Technical Specifications.

If a future Unit 2 cycle core design produces SLMCPR values not bounded by the 1.06 and 1.08 values proposed in TS-478, TVA will submit a License Amendment Request to increase the SLMCPR values accordingly. TVA plans to submit a SLMCPR License Amendment Request E 1-9 of 11

for both Unit 1 and Unit 3, on a schedule commensurate with the first cycle of application of the SAFLIM3-D methodology, for each of these units.

NRC Question SNPB RAI-23, ANP-3167P. Section 4.3 Provide a summary of the analysis and results for BFN units operation with FFTR and FHOOS that complies with the licensing requirements for the Option Ill (OscillationPower Range Monitor (OPRM)) stability solution. Also provide details and results for the analysis that supports BFN operation with backup stabilityprotection regions, if the Option Ill OPRM system is declared inoperable.

TVA Response:

AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUM M 1OXM Fuel Transition," (Enclosure 2).

NRC Question SNPB RAI-24 ANP-3167P. Section 5.1.3 For feedwater controllerfailure (FWCF)event scenario, Figure 5.4 (PercentRated Versus Time) indicates a sharp spike in relative ratedpower to about 375 percent and a simultaneous sharp reduction in relative steam flow at about 15 seconds into the event. Please describe the cause of this behavior during the FWCF event.

TVA Response:

AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

NRC Question SNPB RAI-25 ANP-3167P, Section 6.1 Section 6.1 reports that ATRIUM IOXM LOCA analysis for BFN Units PCT is 1903 OF and the peak local metal water reaction is 1.16 percent.However, ANP-3152P, Browns Ferry Units 1, 2, and 3 LOCA Break Spectrum Analysis for A TRIUM IOXM Fuel, Table 6.1 reports that the PCT is 1909 OF and the maximum local cladding oxidation is 1.20 percent. Clarify the discrepancy between the information on LOCA results from these two documents.

TVA Response:

AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUM M 1OXM Fuel Transition," (Enclosure 2).

NRC Question SNPB RAI-26 ANP-3172P, Section 7.1 Table 7.1 lists the ASME (American Society of Mechanical Engineers) Overpressurization analysis results for maximum vessel pressure for lower-plenum and the maximum dome pressure. Please specify whether the pressure results include any other analysis/measurement uncertaintiesin addition to the 7 pounds per square inch increase that binds a bias in the void-quality correlationsas indicated.

TVA Response:

AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

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NRC Question Reactor Systems Branch (SRXB) RAI-1 In page 2 of Enclosure to the LAR, it was stated, The currentACE correlationfor XM fuel has an identified deficiency. The deficiency involves a nonconservatism in the axial averagingprocess used to determine the K factor, which is an input to the correlation.... TVA is including a BFN specific ACE supplement in Attachments 27 and 28.

Did the deficiency in the currentACE correlationidentified above impact BFN Unit 2 Cycle 19 SLMCPR values? If it did, was the updated methodology as provided in the generic and/or BFN-specific ACE supplements used for BFN Unit 2 Cycle 19 SLMCPR calculation? Explain if updated ACE correlationwas not used.

TVA Response:

AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

NRC Question SRXB RAI-2 Since Unit 2 Cycle 19 core is expected to include both ATRIUM-10 and A TRIUM IOXM fuel designs, which fuel design is more limiting from the standpoint of SLMCPR, and why?

TVA Response:

AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

NRC Question SRXB RAI-3 Regarding the calculationsperformed for Unit 2 Cycle 19 reload safety analysis, as provided in ANP-3167(P), Revision 0, AREVA NP Inc., November 2012 (Attachment 12), confirm that most recently approved methodologies were used, including RODEX4, which accounts for the degradationof thermal conductivity with increasingfuel burnup using upper limit on calculated clad oxide thickness, and the updated methodology for ACE correlationthat addresses a nonconservatism in the axial averagingprocess used to determine the K factor, which is an input to the correlation(as discussed in page 2 of Enclosure to the LAR). If the most recently updated and approved methodologies were not used for BFN Unit 2 Cycle 19 reload safety analyses, then please provide justification.

TVA Response:

AREVA, NP Inc., has provided this response in section 2 of ANP-3248P, "AREVA RAI Responses for Browns Ferry ATRIUMTM 1OXM Fuel Transition," (Enclosure 2).

E 1- 11 of 11 Affidavits

AFFIDAVIT STATE OF WASHINGTON )

) ss.

COUNTY OF BENTON )

1. My name is Alan B. Meginnis. I am Manager, Product Licensing, for AREVA NP Inc. and as such I am authorized to execute this Affidavit.

2. I am familiar with the criteria applied by AREVA NP to determine whether certain AREVA NP information is proprietary. I am familiar with the policies established by AREVA NP to ensure the proper application of these criteria.

3. I am familiar with the AREVA NP information contained in the report ANP-3248P, Revision 1, "AREVA RAI Responses for Browns Ferry ATRIUM 1OXM Fuel Transition," dated September 2013 and referred to herein as "Document." Information contained in this Document has been classified by AREVA NP as proprietary in accordance with the policies established by AREVA NP for the control and protection of proprietary and confidential information.

4. This Document contains information of a proprietary and confidential nature and is of the type customarily held in confidence by AREVA NP and not made available to the public. Based on my experience, I am aware that other companies regard information of the kind contained in this Document as proprietary and confidential.

5. This Document has been made available to the U.S. Nuclear Regulatory Commission in confidence with the request that the information contained in this Document be withheld from public disclosure. The request for withholding of proprietary information is made in accordance with 10 CFR 2.390. The information for which withholding from disclosure is

requested qualifies under 10 CFR 2.390(a)(4) "Trade secrets and commercial or financial information."

6. The following criteria are customarily applied by AREVA NP to determine whether information should be classified as proprietary:

(a) The information reveals details of AREVA NP's research and development plans and programs or their results.

(b) Use of the information by a competitor would permit the competitor to significantly reduce its expenditures, in time or resources, to design, produce, or market a similar product or service.

(c) The information includes test data or analytical techniques concerning a process, methodology, or component, the application of which results in a competitive advantage for AREVA NP.

(d) The information reveals certain distinguishing aspects of a process, methodology, or component, the exclusive use of which provides a competitive advantage for AREVA NP in product optimization or marketability.

(e) The information is vital to a competitive advantage held by AREVA NP, would be helpful to competitors to AREVA NP, and would likely cause substantial harm to the competitive position of AREVA NP.

The information in the Document is considered proprietary for the reasons set forth in paragraphs 6(b), 6(d) and 6(e) above.

7. In accordance with AREVA NP's policies governing the protection and control of information, proprietary information contained in this Document have been made available, on a limited basis, to others outside AREVA NP only as required and under suitable agreement providing for nondisclosure and limited use of the information.

8. AREVA NP policy requires that proprietary information be kept in a secured file or area and distributed on a need-to-know basis.

9. The foregoing statements are true and correct to the best of my knowledge, information, and belief.

SUBSCRIBED before me this c V day of . ,2013.,

Susan K. McCoy NOTARY PUBLIC, STATE OF WASHING MY COMMISSION EXPIRES: 1/14/2016

AFFIDAVIT STATE OF WASHINGTON )

) ss.

COUNTY OF BENTON )

1. My name is Alan B. Meginnis. I am Manager, Product Licensing, for AREVA NP Inc. and as such I am authorized to execute this Affidavit.

2. I am familiar with the criteria applied by AREVA NP to determine whether certain AREVA NP information is proprietary. I am familiar with the policies established by AREVA NP to ensure the proper application of these criteria.

3. I am familiar with the AREVA NP information contained in the report ANP-3144(P), Revision 0, "Nuclear Fuel Design Report BFE2-19 LAR ATRIUMTM 1OXM," dated August 2012 and referred to herein as "Document." Information contained in this Document has been classified by AREVA NP as proprietary in accordance with the policies established by AREVA NP for the control and protection of proprietary and confidential information.