ML16145A183

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Gnf Additional Information Regarding the Requested Changes to the Technical Specification SLMCPR Cycle 26
ML16145A183
Person / Time
Site: Duane Arnold NextEra Energy icon.png
Issue date: 04/30/2016
From:
NextEra Energy Duane Arnold
To:
Office of Nuclear Reactor Regulation
References
NG-16-0102 GNF-003N5133-R1-NP
Download: ML16145A183 (13)


Text

ATTACHMENT 5 TO NG-16-0102 NEXTERA ENERGY DUANE ARNOLD, LLC DUANE ARNOLD ENERGY CENTER LICENSE AMENDMENT REQUEST (TSCR-161)

For Revision of Technical Specifications 2.1.1.2 Safety Limit Minimum Critical Power Ratio, and to Remove an Outdated Historical Footnote from Table 3.3.5.1-1 GNF Additional Information Regarding the Requested Changes to the Technical Specification SLMCPR Duane Arnold Energy Center Cycle 26 NON-PROPRIETARY VERSION 12 pages follow

April 2016 GNF-003N5133-Rl-NP Non-Proprietary Information - Class I (Public)

GNF Additional Information Regarding the Requested Changes to the Technical Specification SLMCPR Duane Arnold Energy Center Cycle 26 Copyright 2016 Global Nuclear Fuel -Americas, LLC All Rights Reserved

GNF-003N5133-Rl-NP Non-Proprietary Information - Class I (Public)

Information Notice This is a non-proprietary version of the document GNF-003N5133-Rl-P, which has the proprietary information removed. Portions of the document that have been removed are indicated by an open and closed bracket as shown here (( {3} )).

Important Notice Regarding Contents of this Report Please Read Carefully The design, engineering, and other information contained in this document is furnished for the purpose of providing information regarding the requested changes to the Technical Specification SLMCPR for NextEra Energy Duane Arnold Energy Center. The only undertakings of GNF-A with respect to information in this document are contained in the contract between GNF-A and NextEra Energy, and nothing contained in this document shall be construed as changing that contract. The use of this information by anyone other than NextEra Energy, or for purposes other than those for which it is intended is not authorized; and with respect to any unauthorized use, GNF *A makes no representation or warranty, and assumes no liability as to the completeness, accuracy, or usefulness of the information contained in this document.

Information Notice Page 2of12

GNF-003N5133-Rl-NP Non-Proprietary Information - Class I (Public)

Table of Contents 1.0 Summary .............................................................................................................................. 4 2.0 Regulatory Basis .................................................................................................................. 4 3.0 Methodology ........................................................................................................................ 4 3.1. Methodology Restrictions ................................................................................................. 5 4.0 Discussion ............................................................................................................................. 6 4.1. Major Contributors to SLMCPR Change .......................................................................... 6 4.2. Deviations from Standard Uncertainties ............................................................................ 6 4.2.1. R-Factor ...................................................................................................................... 6 4.2.2. Core Flow Rate and Random Effective TIP Reading ................................................. 7 4.2.3. Flow Area Uncertainty ................................................................................................ 7 4.2.4. Fuel Axial Power Shape Penalty................................................................................. 7 5.0 References ............................................................................................................................ 8 List of Tables Table 1. Monte Carlo SLMCPR .................................................................................................. 10 Table 2. Description of Core ........................................................................................................ 11 Table 3. Deviations from Standard Uncertainties ........................................................................ 12 Table of Contents Page 3of12

GNF-003N5133-Rl-NP Non-Proprietary Information - Class I (Public) 1.0 Summary The requested changes to the Technical Specification (TS) Safety Limit Minimum Critical Power Ratio (SLMCPR) values are 1.08 for Two-Loop Operation (TLO) and 1.11 for Single Loop Operation (SLO) for Duane Arnold Energy Center (DAEC) Cycle 26. Additional details are provided in Table 1.

The primary reason for the change is that DAEC is currently using the revised methodology with reduced uncertainties (References 1 and 2) which results in a lower calculated SLMCPR than the previous methodology (Reference 3) that was used to establish the existing TS values.

2.0 Regulatory Basis 10 Code of Federal Regulations (CFR) 50.36(c)(l), "Technical Specifications, requires that power reactor facility TS include safety limits for process variables that protect the integrity of certain physical barriers that guard against the uncontrolled release of radioactivity. The fuel cladding is one of the physical barriers that separate the radioactive materials from the environment. The purpose of the SLMCPR is to ensure that Specified Acceptable Fuel Design Limits (SAFDLs) are not exceeded during steady state operation and analyzed transients.

General Design Criterion (GDC) 10, "Reactor Design," of Appendix A to IO CFR 50 states that the reactor core and associated coolant, control, and protection systems shall be designed with appropriate margin to assure that SAFDLs are not exceeded.

Guidance on the acceptability of the reactivity control systems, the reactor core, and fuel system design is provided in NUREG-0800, "Standard Review Plan [SRP] for the Review of Safety Analysis Reports for Nuclear Power Plants." Specifically, SRP Section 4.2, "Fuel System Design, specifies all fuel damage criteria for evaluation of whether fuel designs 111eet the SAFDLs. SRP Section 4.4, "Thermal Hydraulic Design, provides guidance on the review of thermal-hydraulic design in meeting the requirement of GDC 10 and the fuel design criteria established in SRP Section 4.2.

3.0 Methodology GNF performs SLMCPR calculations in accordance with NEDE-24011-P-A, "General Electric Standard Application for Reactor Fuel (GESTAR II)" (Reference 4) for plants such as DAEC that are equipped with the GNF 3DMonicore core monitoring system, by using the following Nuclear Regulatory Commission (NRC) approved methodologies and uncertainties:

  • NEDC-32601P-A, "Methodology and Uncertainties for Safety Limit MCPR Evaluations," August 1999. (Reference 1)

Summary Page 4of12

GNF-003N5133-Rl-NP Non-Proprietary Information - Class I (Public)

  • NEDC-32694P-A, "Power Distribution Uncertainties for Si;i.fety Limit MCPR Evaluations," August 1999. (Reference 2)
  • NEDC-32505P-A, "R-Factor Calculation Method for GEll, GE12 and GE13 Fuel,"

Revision 1, July 1999. (Reference 5)

These methodologies were used for the DAEC Cycle 25 and the Cycle 26 SLMCPR calculations.

3.1. Methodology Restrictions Four restrictions were identified on page 3 of NRC's Safety Evaluation (SE) relating to the General Electric (GE) Licensing Topical Reports (LTRs) NEDC-32601P, NEDC-32694P, and in Amendment 25 to NEDE-24011-P-A (Reference 6).

The following statement was extracted from the generic compliance report for the GNF2 fuel assembly design (Reference 7) that GNF sent to the NRC in March of2007:

"The NRC Safety Evaluation (SE) for NEDC-32694P-A provides four actions to follow whenever a new fuel design is introduced. These four conditions are listed in Section 3 of the SE. In the last paragraph of Section 3.2.2 of the Technical Evaluation Repo1i included in the SE are the statements "GE has evaluated this effect for the 8x8, 9x9, and lOxlO lattices and has indicated that the R-Factor uncertainty will be increased . . . to account for the correlation of rod power uncertainties" and "it is noted that the effect of the rod-to-rod correlation has a significant dependence on the fuel lattice (e.g., 9x9 versus lOxlO). Therefore, in order to insure the adequacy of the R-Factor uncertainty, the effect of the correlation of rod power calculation uncertainties should be reevaluated when the NEDC-32601P methodology is applied to a new fuel lattice." Therefore, the definition of a new fuel design is based on the lattice array dimensions (e.g., NxN). Because GNF2 is a lOxlO, and the evaluations in NEDC-32694P-A include lOxlO, theh these four actions are not applicable to GNF2."

In an NRC audit report (Reference 8) for this document, Section 3.4.1 page 59 states:

"The NRC staffs SE of NEDC-32694P-A (Reference 19 of NEDC-33270P) provides four actions to follow whenever a new fuel design is introduced. These four conditions are listed in Section 3.0 of the SE. The analysi~ and evaluation of the GNF2 fuel design was evaluated in accordance with the limitations and conditions stated in the NRC staffs SE, and is acceptable."

Another methodology restriction is identified on page 4 of the NRC's SE relating to the GE LTR NEDC-32505P (Reference 9). Specifically, it states that "if new fuel is introduced, GENE must confimi that the revised R-factor method is still valid based on new test data." NEDC-32505P Methodology Page 5of12

GNF-003N5133-Rl-NP Non-Proprietary Information - Class I (Public) addressed the GE12 lOxlO lattice design (i.e., how the R-Factor for a rod is calculated based upon its immediate surroundings (fuel rods, water rods or channel wall)). Validation is provided by the fact that the methodology generates accurate predictions of Critical Power Ratio (CPR) with reasonable bias and uncertainty. The applicability of the R-Factor method is coupled and documented (along with fuel specific additive constants) with the GEXL c9ITelation development (Reference 10), which is submitted as a part of GESTAR II compliance for each new fuel product line.

4.0 Discussion In this discussion, the TLO nomenclature is used for two recirculation loops in operation, and the SLO nomenclature is used for one recirculation loop in operation.

Table 2 provides the description of the current cycle and previous cycle for the reference loading pattern as defined by NEDE-24011-P-A (Reference 4).

4.1. Major Contributors to SLMCPR Change The existing DAEC SLMCPR TS values were established in Cycle 17. Those SLMCPR TS values have been conservatively maintained through the current operating cycle (Cycle 25).

Cycle 26 is the first cycle for which NextEra Energy has decided to request a change to the TS SLMCPR values in order to reflect the calculated results.

The revised methodology with reduced uncertainties (References 1 and 2) was used to determine the SLMCPR beginning with Cycle 24. Prior cycles used the original methodology with GETAB uncertainties (Reference 3). The revised methodology with reduced uncertainties consistently provides lower SLMCPR results for a given core design than the original methodology with GETAB uncertainties.

4.2. Deviations from Standard Uncertainties Table 3 provides a list of deviations from NRC-approved uncertainties (References 1 and 2). A discussion of deviations from these NRC-approved values follows; all of which are conservative relative to NRC-approved values.

4.2.1. R-FactOr 3

GNF has generically increased the GEXL R-Factor uncertainty from (( { } )) to account for an increase in cham1el bow due to the phenomena called control blade shadow corrosion-induced channel bow, which is not accounted for in the channel bow uncertainty component of the approved R-factor uncertainty. Reference 11 technically justifies that a GEXL R-Factor uncertainty of (( {3} )) accounts for a channel bow uncertainty of up to

(( {3} )). The DAEC Cycle 26 analysis shows an expected channel bow uncertainty of Discussion Page 6of12

GNF-003N5133-Rl-NP Non-Proprietary Information - Class I (Public) 3

(( { } )), which is bounded by a GEXL R-Factor uncertainty of (( {3} )). Thus, the use of a GEXL R-Factor uncertainty of (( {3} )) adequately accounts for the expected control blade shadow corrosion-induced channel bow. The effect of this change is considered not significant (i.e., < 0.005 increase on SLMCPR).

4.2.2. Core Flow Rate and Random Effective TIP Reading*

In Reference 12 GNF committed to the expansion of the state points used in the determination of the SLMCPR. Consistent with the Reference 12 commitments, GNF performs analyses at the rated core power and minimum licensed core flow point in addition to analyses at the rated core power and rated core flow point. The approved SLMCPR methodology is applied at each state.

point that is analyzed.

The available flow range at rated power, 99% to 100% rated core flow, does not warrant analysis at the minimum core flow point.

4.2.3. Flow Area Uncertainty GNF has calculated the flow area uncertainty for GNF2 using the process described in Section 2.7 of Reference 1.

  • It was determined that the flow area uncertainty for GNF2 is conservatively bounded by a value of (( {3} )). Because this is larger than the Reference 1 value of (( {3} )), the bounding value was used in the SLMCPR calculations. The effect of this change is considered not significant (i.e., < 0.005 increase on SLMCPR).

4.2.4. Fuel Axial Power Shape Penalty The GEXL correlation critical power uncertainty and bias are established for each fuel product line according to a process described in NEDE-24011-P-A (Reference 4).

GNF determined that higher uncertainties and non-conservative biases in the GEXL correlations for certain types of axial power shapes could exist relative to the NRC-approved methodology values (References 13, 14, and 15). The GNF2 product line is potentially affected in this manner only by Double-Hump (D-H) axial power shapes.

The D-H axial shape did not occur on any of the limiting bundles (i.e., those contributing to the 0.1 % rods susceptible to transition boiling) in the current and/or prior cycle limiting cases.

Therefore, D-H power shape penalties were not applied to the GEXL critical power uncertainty or bias.

Discussion Page 7of12

GNF-003N5133-Rl-NP Non-Proprietary Information - Class I (Public) 5.0 References

1. -GE Nuclear Energy, "Methodology and Uncertainties for Safety Limit MCPR Evaluations," NEDC-32601P-A, August 1999.
2. GE Nuclear Energy, "Power Distribution Uncertainties for Safety Limit MCPR Evaluations," NEDC-32694P-A, August 1999 .

. 3. General Electric, "General Electric BWR Thermal Analysis Basis (GETAB): Data, Correlation and Design Application," NED0-10958-A, January 1977.

4. Global Nuclear Fuel, "General Electric Standard Application for Reactor Fuel,"

NEDE-24011-P-A, Revision 22, November 2015.

5. GE Nuclear Energy, "R-Factor Calculation Method for GEll, GE12 and GE13 Fuel,"

NEDC-32505P-A, Revision 1, July 1999.

6. Letter, Frank Akstulewicz (NRC) to Glen A. Watford (GNF-A) "Acceptance for Referencing of Licensing Topical Reports NEDC-32601P, Methodology and Uncertainties for Safety Limit MCPR Evaluations; NEDC-32694P, Power Distribution Uncertainties for Safety Limit MCPR Evaluation; and Amendment 25 to NEDE-24011-P-A on Cycle-Specific Safety Limit MCPR (TAC Nos. M97490, M99069 and M97491),"

MFN-003-099, March 11, 1999.

7. Letter, Andrew A. Lingenfelter (GNF-A) to NRC Document Control Desk with cc to MC Honcharik (NRC), "GNF2 Advantage Generic Compliance with NEDE-2401 lP-A (GESTAR II), NEDC-33270P, March 2007, and GEXLl 7 Correlation for GNF2 Fuel, NEDC-33292P, March 2007," FLN-2007-011, March 14, 2007.
8. Memorandum, Michelle C. Honcharik (NRC) to Stacy L. Rosenberg (NRC), "Audit Report for Global Nuclear Fuels GNF2 Advantage Fuel Assembly Design GESTAR II Compliance Audit," September 25, 2008, (ADAMS Accession Number ML081630579).
9. Letter, Thomas H. Essig (NRC) to Glen A. Watford (GNF-A), "Acceptance for Referencing of Licensing Topical Report NEDC-32505P, Revision 1, 'R-factor Calculation Method for GEll, GE12 and GE13 Fuel,"' (TAC Nos. M99070 and M95081)," MFN-046-98, January 11, 1999.
10. Global Nuclear Fuel, "GEXLl 7 Correlation for GNF2 Fuel," NEDC-33292P, Revision 3, April 2009.

References Page 8of12

GNF-003N5133-Rl-NP Non-Proprietary Information - Class I (Public)

11. Letter, John F. Schardt (GNF-A) to NRC Document Control Desk with attention to Mel B. Fields (NRC), "Shadow Corrosion Effects on SLMCPR Channel Bow Uncertainty,"

FLN-2004-030, November 10, 2004.

12. Letter, Jason S. Post (GENE) to U.S. NRC Document Control Desk with attention to Chief, Information Management Branch, et al. (NRC), "Part 21 Final Report: Non-Conservative SLMCPR," MFN 04-108, September 29, 2004.
13. Letter, Glen A. Watford (GNF-A) to NRC Document Control Desk with attention to Joseph E. Donoghue (NRC), "Final Presentation Material for GEXL Presentation -

February 11, 2002," FLN-2002-004, February 12, 2002.

14. Letter, Glen A. Watford (GNF-A) to NRC Document Control Desk with attention to Alan Wang (NRC), "NRC Technology Update - Proprietary Slides - July 31 - August 1, 2002," FLN-2002-015, October 31, 2002.
15. Letter, Jens G. Munthe Andersen (GNF-A) to NRC Document Control Desk with attention to Alan "Wang (NRC), "GEXL Correlation for lOXlO Fuel," FLN-2003-005, May 31, 2003.

References Page 9of12

GNF-003 N5 I 33-R l-NP Non-Proprietary Info rmation - Class J (Public)

Table J. Monte Carlo SLM CPR Previous Cycle Current Cycle Limiting Case Limiting Case Description Rated Power Rated Rated Power Rated Core Core F low Flow Limiting Cycle Exposure Point Beginning of Cycle (BOC) I EOC EOC Middle of Cycle (MOC) I End of Cycle (EOC)

Cycle Exposure at Limiting Point (MWd/STU) 14,220 14, 100

{3 1 {3 ) (3)

([

(3) (3 ) {3)

(3) (3) (3) ))

Requested Change to the TS SLMCPR NIA 1.08 TLO I 1.11 SLO Table I. Monte Carlo SLMCPR Page 10 of l 2

GNF-003N5 133 -Rl-NP Non-Proprietary In formation - Class I (Public)

Table 2. Description of Core Description Previou s Cycle Current Cycle Core Rated Power (MWt) 1912.0 1912.0 Minimum Flow at Rated Power 99.0 99.0

(%rated core flow)

Number of B undles in the Core 368 368 Batch Sizes and Types:

(N um ber of Bundles in the Core)

Fresh 152 GNF2 152 GNF2 Once-Burnt 152 GNF2 152 GNF2 Twice-Burnt 64 GE l4 64 GNF2 Thrice-Burnt or more None None Fresh Fuel Batch Average Emichment 4.11 4.09 (Weight%)

Core Mon itoring System 3DMonicore 3DMonicore Table 2. Description of Core Page 11 of 12

GNF-003N5 l 33-R I-NP Non-Proprietary Informatio n - Class I (Public)

Table 3. Deviations from Standard Uncertainties NRC Approved Value Description Previous Cycle Current Cycle

+/-(I(%)

Power Distribution Uncertainties (3) (3) {3} ))

GEXL R-Factor (( )) (( )) ((

Non-Power Distribution Uncertainties

{3 ) (3) {3)

Channe l Flow Area Variation (( )) (( )) (( ))

Table 3. Deviations from Standard Uncertainties Page 12of12

ATTACHMENT 5 TO NG-16-0102 NEXTERA ENERGY DUANE ARNOLD, LLC DUANE ARNOLD ENERGY CENTER LICENSE AMENDMENT REQUEST (TSCR-161)

For Revision of Technical Specifications 2.1.1.2 Safety Limit Minimum Critical Power Ratio, and to Remove an Outdated Historical Footnote from Table 3.3.5.1-1 GNF Additional Information Regarding the Requested Changes to the Technical Specification SLMCPR Duane Arnold Energy Center Cycle 26 NON-PROPRIETARY VERSION 12 pages follow

April 2016 GNF-003N5133-Rl-NP Non-Proprietary Information - Class I (Public)

GNF Additional Information Regarding the Requested Changes to the Technical Specification SLMCPR Duane Arnold Energy Center Cycle 26 Copyright 2016 Global Nuclear Fuel -Americas, LLC All Rights Reserved

GNF-003N5133-Rl-NP Non-Proprietary Information - Class I (Public)

Information Notice This is a non-proprietary version of the document GNF-003N5133-Rl-P, which has the proprietary information removed. Portions of the document that have been removed are indicated by an open and closed bracket as shown here (( {3} )).

Important Notice Regarding Contents of this Report Please Read Carefully The design, engineering, and other information contained in this document is furnished for the purpose of providing information regarding the requested changes to the Technical Specification SLMCPR for NextEra Energy Duane Arnold Energy Center. The only undertakings of GNF-A with respect to information in this document are contained in the contract between GNF-A and NextEra Energy, and nothing contained in this document shall be construed as changing that contract. The use of this information by anyone other than NextEra Energy, or for purposes other than those for which it is intended is not authorized; and with respect to any unauthorized use, GNF *A makes no representation or warranty, and assumes no liability as to the completeness, accuracy, or usefulness of the information contained in this document.

Information Notice Page 2of12

GNF-003N5133-Rl-NP Non-Proprietary Information - Class I (Public)

Table of Contents 1.0 Summary .............................................................................................................................. 4 2.0 Regulatory Basis .................................................................................................................. 4 3.0 Methodology ........................................................................................................................ 4 3.1. Methodology Restrictions ................................................................................................. 5 4.0 Discussion ............................................................................................................................. 6 4.1. Major Contributors to SLMCPR Change .......................................................................... 6 4.2. Deviations from Standard Uncertainties ............................................................................ 6 4.2.1. R-Factor ...................................................................................................................... 6 4.2.2. Core Flow Rate and Random Effective TIP Reading ................................................. 7 4.2.3. Flow Area Uncertainty ................................................................................................ 7 4.2.4. Fuel Axial Power Shape Penalty................................................................................. 7 5.0 References ............................................................................................................................ 8 List of Tables Table 1. Monte Carlo SLMCPR .................................................................................................. 10 Table 2. Description of Core ........................................................................................................ 11 Table 3. Deviations from Standard Uncertainties ........................................................................ 12 Table of Contents Page 3of12

GNF-003N5133-Rl-NP Non-Proprietary Information - Class I (Public) 1.0 Summary The requested changes to the Technical Specification (TS) Safety Limit Minimum Critical Power Ratio (SLMCPR) values are 1.08 for Two-Loop Operation (TLO) and 1.11 for Single Loop Operation (SLO) for Duane Arnold Energy Center (DAEC) Cycle 26. Additional details are provided in Table 1.

The primary reason for the change is that DAEC is currently using the revised methodology with reduced uncertainties (References 1 and 2) which results in a lower calculated SLMCPR than the previous methodology (Reference 3) that was used to establish the existing TS values.

2.0 Regulatory Basis 10 Code of Federal Regulations (CFR) 50.36(c)(l), "Technical Specifications, requires that power reactor facility TS include safety limits for process variables that protect the integrity of certain physical barriers that guard against the uncontrolled release of radioactivity. The fuel cladding is one of the physical barriers that separate the radioactive materials from the environment. The purpose of the SLMCPR is to ensure that Specified Acceptable Fuel Design Limits (SAFDLs) are not exceeded during steady state operation and analyzed transients.

General Design Criterion (GDC) 10, "Reactor Design," of Appendix A to IO CFR 50 states that the reactor core and associated coolant, control, and protection systems shall be designed with appropriate margin to assure that SAFDLs are not exceeded.

Guidance on the acceptability of the reactivity control systems, the reactor core, and fuel system design is provided in NUREG-0800, "Standard Review Plan [SRP] for the Review of Safety Analysis Reports for Nuclear Power Plants." Specifically, SRP Section 4.2, "Fuel System Design, specifies all fuel damage criteria for evaluation of whether fuel designs 111eet the SAFDLs. SRP Section 4.4, "Thermal Hydraulic Design, provides guidance on the review of thermal-hydraulic design in meeting the requirement of GDC 10 and the fuel design criteria established in SRP Section 4.2.

3.0 Methodology GNF performs SLMCPR calculations in accordance with NEDE-24011-P-A, "General Electric Standard Application for Reactor Fuel (GESTAR II)" (Reference 4) for plants such as DAEC that are equipped with the GNF 3DMonicore core monitoring system, by using the following Nuclear Regulatory Commission (NRC) approved methodologies and uncertainties:

  • NEDC-32601P-A, "Methodology and Uncertainties for Safety Limit MCPR Evaluations," August 1999. (Reference 1)

Summary Page 4of12

GNF-003N5133-Rl-NP Non-Proprietary Information - Class I (Public)

  • NEDC-32694P-A, "Power Distribution Uncertainties for Si;i.fety Limit MCPR Evaluations," August 1999. (Reference 2)
  • NEDC-32505P-A, "R-Factor Calculation Method for GEll, GE12 and GE13 Fuel,"

Revision 1, July 1999. (Reference 5)

These methodologies were used for the DAEC Cycle 25 and the Cycle 26 SLMCPR calculations.

3.1. Methodology Restrictions Four restrictions were identified on page 3 of NRC's Safety Evaluation (SE) relating to the General Electric (GE) Licensing Topical Reports (LTRs) NEDC-32601P, NEDC-32694P, and in Amendment 25 to NEDE-24011-P-A (Reference 6).

The following statement was extracted from the generic compliance report for the GNF2 fuel assembly design (Reference 7) that GNF sent to the NRC in March of2007:

"The NRC Safety Evaluation (SE) for NEDC-32694P-A provides four actions to follow whenever a new fuel design is introduced. These four conditions are listed in Section 3 of the SE. In the last paragraph of Section 3.2.2 of the Technical Evaluation Repo1i included in the SE are the statements "GE has evaluated this effect for the 8x8, 9x9, and lOxlO lattices and has indicated that the R-Factor uncertainty will be increased . . . to account for the correlation of rod power uncertainties" and "it is noted that the effect of the rod-to-rod correlation has a significant dependence on the fuel lattice (e.g., 9x9 versus lOxlO). Therefore, in order to insure the adequacy of the R-Factor uncertainty, the effect of the correlation of rod power calculation uncertainties should be reevaluated when the NEDC-32601P methodology is applied to a new fuel lattice." Therefore, the definition of a new fuel design is based on the lattice array dimensions (e.g., NxN). Because GNF2 is a lOxlO, and the evaluations in NEDC-32694P-A include lOxlO, theh these four actions are not applicable to GNF2."

In an NRC audit report (Reference 8) for this document, Section 3.4.1 page 59 states:

"The NRC staffs SE of NEDC-32694P-A (Reference 19 of NEDC-33270P) provides four actions to follow whenever a new fuel design is introduced. These four conditions are listed in Section 3.0 of the SE. The analysi~ and evaluation of the GNF2 fuel design was evaluated in accordance with the limitations and conditions stated in the NRC staffs SE, and is acceptable."

Another methodology restriction is identified on page 4 of the NRC's SE relating to the GE LTR NEDC-32505P (Reference 9). Specifically, it states that "if new fuel is introduced, GENE must confimi that the revised R-factor method is still valid based on new test data." NEDC-32505P Methodology Page 5of12

GNF-003N5133-Rl-NP Non-Proprietary Information - Class I (Public) addressed the GE12 lOxlO lattice design (i.e., how the R-Factor for a rod is calculated based upon its immediate surroundings (fuel rods, water rods or channel wall)). Validation is provided by the fact that the methodology generates accurate predictions of Critical Power Ratio (CPR) with reasonable bias and uncertainty. The applicability of the R-Factor method is coupled and documented (along with fuel specific additive constants) with the GEXL c9ITelation development (Reference 10), which is submitted as a part of GESTAR II compliance for each new fuel product line.

4.0 Discussion In this discussion, the TLO nomenclature is used for two recirculation loops in operation, and the SLO nomenclature is used for one recirculation loop in operation.

Table 2 provides the description of the current cycle and previous cycle for the reference loading pattern as defined by NEDE-24011-P-A (Reference 4).

4.1. Major Contributors to SLMCPR Change The existing DAEC SLMCPR TS values were established in Cycle 17. Those SLMCPR TS values have been conservatively maintained through the current operating cycle (Cycle 25).

Cycle 26 is the first cycle for which NextEra Energy has decided to request a change to the TS SLMCPR values in order to reflect the calculated results.

The revised methodology with reduced uncertainties (References 1 and 2) was used to determine the SLMCPR beginning with Cycle 24. Prior cycles used the original methodology with GETAB uncertainties (Reference 3). The revised methodology with reduced uncertainties consistently provides lower SLMCPR results for a given core design than the original methodology with GETAB uncertainties.

4.2. Deviations from Standard Uncertainties Table 3 provides a list of deviations from NRC-approved uncertainties (References 1 and 2). A discussion of deviations from these NRC-approved values follows; all of which are conservative relative to NRC-approved values.

4.2.1. R-FactOr 3

GNF has generically increased the GEXL R-Factor uncertainty from (( { } )) to account for an increase in cham1el bow due to the phenomena called control blade shadow corrosion-induced channel bow, which is not accounted for in the channel bow uncertainty component of the approved R-factor uncertainty. Reference 11 technically justifies that a GEXL R-Factor uncertainty of (( {3} )) accounts for a channel bow uncertainty of up to

(( {3} )). The DAEC Cycle 26 analysis shows an expected channel bow uncertainty of Discussion Page 6of12

GNF-003N5133-Rl-NP Non-Proprietary Information - Class I (Public) 3

(( { } )), which is bounded by a GEXL R-Factor uncertainty of (( {3} )). Thus, the use of a GEXL R-Factor uncertainty of (( {3} )) adequately accounts for the expected control blade shadow corrosion-induced channel bow. The effect of this change is considered not significant (i.e., < 0.005 increase on SLMCPR).

4.2.2. Core Flow Rate and Random Effective TIP Reading*

In Reference 12 GNF committed to the expansion of the state points used in the determination of the SLMCPR. Consistent with the Reference 12 commitments, GNF performs analyses at the rated core power and minimum licensed core flow point in addition to analyses at the rated core power and rated core flow point. The approved SLMCPR methodology is applied at each state.

point that is analyzed.

The available flow range at rated power, 99% to 100% rated core flow, does not warrant analysis at the minimum core flow point.

4.2.3. Flow Area Uncertainty GNF has calculated the flow area uncertainty for GNF2 using the process described in Section 2.7 of Reference 1.

  • It was determined that the flow area uncertainty for GNF2 is conservatively bounded by a value of (( {3} )). Because this is larger than the Reference 1 value of (( {3} )), the bounding value was used in the SLMCPR calculations. The effect of this change is considered not significant (i.e., < 0.005 increase on SLMCPR).

4.2.4. Fuel Axial Power Shape Penalty The GEXL correlation critical power uncertainty and bias are established for each fuel product line according to a process described in NEDE-24011-P-A (Reference 4).

GNF determined that higher uncertainties and non-conservative biases in the GEXL correlations for certain types of axial power shapes could exist relative to the NRC-approved methodology values (References 13, 14, and 15). The GNF2 product line is potentially affected in this manner only by Double-Hump (D-H) axial power shapes.

The D-H axial shape did not occur on any of the limiting bundles (i.e., those contributing to the 0.1 % rods susceptible to transition boiling) in the current and/or prior cycle limiting cases.

Therefore, D-H power shape penalties were not applied to the GEXL critical power uncertainty or bias.

Discussion Page 7of12

GNF-003N5133-Rl-NP Non-Proprietary Information - Class I (Public) 5.0 References

1. -GE Nuclear Energy, "Methodology and Uncertainties for Safety Limit MCPR Evaluations," NEDC-32601P-A, August 1999.
2. GE Nuclear Energy, "Power Distribution Uncertainties for Safety Limit MCPR Evaluations," NEDC-32694P-A, August 1999 .

. 3. General Electric, "General Electric BWR Thermal Analysis Basis (GETAB): Data, Correlation and Design Application," NED0-10958-A, January 1977.

4. Global Nuclear Fuel, "General Electric Standard Application for Reactor Fuel,"

NEDE-24011-P-A, Revision 22, November 2015.

5. GE Nuclear Energy, "R-Factor Calculation Method for GEll, GE12 and GE13 Fuel,"

NEDC-32505P-A, Revision 1, July 1999.

6. Letter, Frank Akstulewicz (NRC) to Glen A. Watford (GNF-A) "Acceptance for Referencing of Licensing Topical Reports NEDC-32601P, Methodology and Uncertainties for Safety Limit MCPR Evaluations; NEDC-32694P, Power Distribution Uncertainties for Safety Limit MCPR Evaluation; and Amendment 25 to NEDE-24011-P-A on Cycle-Specific Safety Limit MCPR (TAC Nos. M97490, M99069 and M97491),"

MFN-003-099, March 11, 1999.

7. Letter, Andrew A. Lingenfelter (GNF-A) to NRC Document Control Desk with cc to MC Honcharik (NRC), "GNF2 Advantage Generic Compliance with NEDE-2401 lP-A (GESTAR II), NEDC-33270P, March 2007, and GEXLl 7 Correlation for GNF2 Fuel, NEDC-33292P, March 2007," FLN-2007-011, March 14, 2007.
8. Memorandum, Michelle C. Honcharik (NRC) to Stacy L. Rosenberg (NRC), "Audit Report for Global Nuclear Fuels GNF2 Advantage Fuel Assembly Design GESTAR II Compliance Audit," September 25, 2008, (ADAMS Accession Number ML081630579).
9. Letter, Thomas H. Essig (NRC) to Glen A. Watford (GNF-A), "Acceptance for Referencing of Licensing Topical Report NEDC-32505P, Revision 1, 'R-factor Calculation Method for GEll, GE12 and GE13 Fuel,"' (TAC Nos. M99070 and M95081)," MFN-046-98, January 11, 1999.
10. Global Nuclear Fuel, "GEXLl 7 Correlation for GNF2 Fuel," NEDC-33292P, Revision 3, April 2009.

References Page 8of12

GNF-003N5133-Rl-NP Non-Proprietary Information - Class I (Public)

11. Letter, John F. Schardt (GNF-A) to NRC Document Control Desk with attention to Mel B. Fields (NRC), "Shadow Corrosion Effects on SLMCPR Channel Bow Uncertainty,"

FLN-2004-030, November 10, 2004.

12. Letter, Jason S. Post (GENE) to U.S. NRC Document Control Desk with attention to Chief, Information Management Branch, et al. (NRC), "Part 21 Final Report: Non-Conservative SLMCPR," MFN 04-108, September 29, 2004.
13. Letter, Glen A. Watford (GNF-A) to NRC Document Control Desk with attention to Joseph E. Donoghue (NRC), "Final Presentation Material for GEXL Presentation -

February 11, 2002," FLN-2002-004, February 12, 2002.

14. Letter, Glen A. Watford (GNF-A) to NRC Document Control Desk with attention to Alan Wang (NRC), "NRC Technology Update - Proprietary Slides - July 31 - August 1, 2002," FLN-2002-015, October 31, 2002.
15. Letter, Jens G. Munthe Andersen (GNF-A) to NRC Document Control Desk with attention to Alan "Wang (NRC), "GEXL Correlation for lOXlO Fuel," FLN-2003-005, May 31, 2003.

References Page 9of12

GNF-003 N5 I 33-R l-NP Non-Proprietary Info rmation - Class J (Public)

Table J. Monte Carlo SLM CPR Previous Cycle Current Cycle Limiting Case Limiting Case Description Rated Power Rated Rated Power Rated Core Core F low Flow Limiting Cycle Exposure Point Beginning of Cycle (BOC) I EOC EOC Middle of Cycle (MOC) I End of Cycle (EOC)

Cycle Exposure at Limiting Point (MWd/STU) 14,220 14, 100

{3 1 {3 ) (3)

([

(3) (3 ) {3)

(3) (3) (3) ))

Requested Change to the TS SLMCPR NIA 1.08 TLO I 1.11 SLO Table I. Monte Carlo SLMCPR Page 10 of l 2

GNF-003N5 133 -Rl-NP Non-Proprietary In formation - Class I (Public)

Table 2. Description of Core Description Previou s Cycle Current Cycle Core Rated Power (MWt) 1912.0 1912.0 Minimum Flow at Rated Power 99.0 99.0

(%rated core flow)

Number of B undles in the Core 368 368 Batch Sizes and Types:

(N um ber of Bundles in the Core)

Fresh 152 GNF2 152 GNF2 Once-Burnt 152 GNF2 152 GNF2 Twice-Burnt 64 GE l4 64 GNF2 Thrice-Burnt or more None None Fresh Fuel Batch Average Emichment 4.11 4.09 (Weight%)

Core Mon itoring System 3DMonicore 3DMonicore Table 2. Description of Core Page 11 of 12

GNF-003N5 l 33-R I-NP Non-Proprietary Informatio n - Class I (Public)

Table 3. Deviations from Standard Uncertainties NRC Approved Value Description Previous Cycle Current Cycle

+/-(I(%)

Power Distribution Uncertainties (3) (3) {3} ))

GEXL R-Factor (( )) (( )) ((

Non-Power Distribution Uncertainties

{3 ) (3) {3)

Channe l Flow Area Variation (( )) (( )) (( ))

Table 3. Deviations from Standard Uncertainties Page 12of12