BSEP 12-0031, Areva Document ANP-3086(NP), Brunswick Units 1 and 2 SLMCPR Operability Assessment Critical Power Correlation for Atrium 10XM Fuel - Improved K-factor Model, Enclosure 20 to BSEP 12-0031

Areva Document ANP-3086(NP), Brunswick Units 1 and 2 SLMCPR Operability Assessment Critical Power Correlation for Atrium 10XM Fuel - Improved K-factor Model, Enclosure 20 to BSEP 12-0031

ML12076A087
Person / Time
Site:	Brunswick
Issue date:	02/29/2012
From:	AREVA, AREVA NP
To:	Office of Nuclear Reactor Regulation
References
BSEP 12-0031 ANP-3086(NP), Rev 0
Download: ML12076A087 (42)

Text

BSEP 12-0031 Enclosure 20 AREVA Document ANP-3086(NP), Revision 0.

"Brunswick Unit I and Unit 2 SLMCPR Operability Assessment Critical Power Correlation for ATRIUM IOXM Fuel - Improved K-factor Model" (Non-Proprietary Version)

'Do i,.ýne ANP-3086(NP)

Revision 0 Brunswick Unit 1 and Unit 2 SLMCPR Operability Assessment Critical Power Correlation for ATRIUM 1OXM Fuel -

Improved K-factor Model February 2012 A

AREVA NP Inc. AR EVA

AREVA NP Inc.

ANP-3086(NP)

Revision 0 Brunswick Unit 1 and Unit 2 SLMCPR Operability Assessment Critical Power Correlation for ATRIUM 1OXM Fuel - Improved K-factor Model

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AREVA NP Inc.

ANP-3086(NP)

Revision 0 Brunswick Unit 1 and Unit 2 SLMCPR Operability Assessment Critical Power Correlation for ATRIUM 1OXM Fuel - Improved K-factor Model Copyright © 2012 AREVA NP Inc.

All Rights Reserved

Brunswick Unit 1 and Unit 2 SLMCPR Operability ANP-3086(NP)

Assessment Critical Power Correlation for Revision 0 ATRIUM 1OXM Fuel - Imoroved K-factor Model Paaei Nature of Changes Item Page Description and Justification

1. All New document.

AREVA NP Inc.

Con tro ,1e d~ Do (;L u rYi F Brunswick Unit 1 and Unit 2 SLMCPR Operability ANP-3086(NP)

Assessment Critical Power Correlation for Revision 0 ATRIUM 1OXM Fuel - Improved K-factor Model Page ii Contents 1.0 Introd uctio n a nd S u m m a ry ............................................................................................. 1-1 2.0 Standard Review Plan Requirements ............................................................................ 2-1 3 .0 R ev is ed C o rre la tio n ........................................................................................................ 3 -1 3 .1 R o d Pe a k ing F u n ctio n ........................................................................................

I 3 -1 3.2 Applying Rod Peaking Function in the Critical Power Correlation ...................... 3-3 3.3 Method for Calculating Additive Constants ......................................................... 3-3 3.3.4 Additive Constants for ATRIUM 1OXM Fuel ......................................... 3-8 3.4 Additive Constant Uncertainty .......................................................................... 3-14 3.5 Critical Power Correlation Conservatisms ........................................................ 3-17 4.0 Implementation of Improved K-factor Methodology ....................................................... 4-1 5 .0 R efe re n c e s ..................................................................................................................... 5 -1 AREVA NP Inc.

C 'nroe uii Brunswick Unit 1 and Unit 2 SLMCPR Operability ANP-3086(NP)

Assessment Critical Power Correlation for Revision 0 ATRIUM 1OXM Fuel - Improved K-factor Model Page iii Tables 3-1: Additive Constant Uncertainty for High Local Peaking .................................................... 3-16 Figures 1-1: Comparison of Calculated to Measured Critical Power ..................................................... 1-2 3-1: Adjacent Rod Identification for K-factor Calculation .......................................................... 3-9 3-2: Rods Observed to Dryout in Testing ............................................................................... 3-10 3-3: Peaked Symmetric Rods Not Observed to Dryout in Testing .......................................... 3-1 1 3-4: Brunswick SLMCPR Operability Assessment Additive Constants for AT R IUM 1O XM F u e l ........................................................................................................ 3 -12 3-5: Additive C onstant C om parison ........................................................................................ 3-13 AREVA NP Inc.

Tg:rQp'Documen't Brunswick Unit 1 and Unit 2 SLMCPR Operability ANP-3086(NP)

Assessment Critical Power Correlation for Revision 0 ATRIUM 1OXM Fuel- Improved K-factor Model Page iv Nomenclature Acronym Definition ACE AREVA Critical power Evaluator BT Boiling Transition BWR Boiling Water Reactor CHF Critical Heat Flux CPR Critical Power Ratio ECPR Experimental Critical Power Ratio; the ratio of calculated to the measured MCPR Minimum Critical Power Ratio PLR Part Length Rod SLMCPR Safety Limit Minimum Critical Power Ratio AREVA NP Inc.

~.(atfO+.. -OlJcmen Brunswick Unit 1 and Unit 2 SLMCPR Operability ANP-3086(NP)

Assessment Critical Power Correlation for Revision 0 ATRIUM 1OXM Fuel - Improved K-factor Model Page 1-1 1.0 Introduction and Summary Reference 1 presents the approved ACE/ATRIUM 1OXM critical power correlation for ATRIUM TM* 10XM fuel. A concern with the calculation of the K-factor within the approved ACE correlation was identified. Since K-factor is integrated over the entire heated length of the assembly, it is possible for the local peaking factors in the upper lattices to contribute significantly to the K-factor used, even when dryout occurs much lower in the bundle. The purpose of this document is to present the critical power correlation that will be used in the operability assessment safety limit MCPR calculations for Brunswick Unit 1 and Unit 2 until a revised generically approved critical power correlation applicable to ATRIUM 1OXM fuel is available and included in the Brunswick Plant Technical Specifications. The correlation presented is very similar to the Reference 1 ACE critical power correlation with a couple of exceptions. The K-factor methodology was modified in response to deficiencies found in the axial averaging process. In addition, the additive constants were revised as a result of the change to the K-factor model. Evaluations were performed that confirm the Reference 1 critical power correlation coefficients do not require revision as a result of these changes.

Reference 2 provides a description of the rod local peaking function (called K-factor). The improved K-factor method used in the Brunswick SLMCPR operability assessment critical power correlation for ATRIUM 1OXM fuel is described in this document. This document also describes the minor changes in the method for determining additive constants that became necessary due to the changes in the K-factor methodology.

The comparison between measured and predicted critical power data is shown in Figure 1-1.

The correlation experimental critical power ratio (ECPR) mean with the improved K-factor methodology and updated additive constants is [ ] and the ECPR standard deviation is

[ ]. The ECPR mean and standard deviation from Reference 1 are [ ] and

[ ] respectively.

• ATRIUM is a trademark of AREVA NP Inc.

AREVA NP Inc.

L Brunswick Unit 1 and Unit 2 SLMCPR Operability ANP-3086(NP)

Assessment Critical Power Correlation for Revision 0 ATRIUM 1OXM Fuel - Improved K-factor Model Paae 1-2 The range of applicability of the critical power correlation is the same as that identified in Reference 1. The revised correlation is applicable to Brunswick Unit 1 and Unit 2 operability assessment SLMCPR calculations for the ATRIUM 1OXM fuel design.

Figure 1-1: Comparison of Calculated to Measured Critical Power AREVA NP Inc.

Control ý,J Brunswick Unit 1 and Unit 2 SLMCPR Operability ANP-3086(NP)

Assessment Critical Power Correlation for Revision 0 ATRIUM 1OXM Fuel- Improved K-factor Model Paqe 2-1 2.0 Standard Review Plan Requirements There are no critical power correlation specific requirements in the standard review plan.

AREVA NP Inc.

C o nt i-C1 D)ci C Brunswick Unit 1 and Unit 2 SLMCPR Operability ANP-3086(NP)

Assessment Critical Power Correlation for Revision 0 ATRIUM 1OXM Fuel - Improved K-factor Model Pacie 3-1 3.0 Revised Correlation All modern critical power correlations contain a function that accounts for rod peaking. This function is called K-factor in the ACE formulation of the correlation. The model equation for the ACE correlation is given in Equation 3.1 of Reference 1 (including symbol definitions). The revision is in the [

[ ] term:

] (3.1)

The K-factor, [

I This assumption was found to be inappropriate because (1) it allows downstream conditions above the location of dryout to non-physically influence the critical power, and (2) it provides equal weighting to all axial locations (low power regions as well as regions far from the location of dryout). Both of these problems were found to be capable of influencing the predicted results in a non-conservative manner.

3.1 Rod Peaking Function The K-factor characterizes the rod peaking effect on the bundle critical power. The critical power varies inversely with K-factor. That is, as K-factor increases in value, the critical power decreases in value. [

AREVA NP Inc.

Brunswick Unit 1 and Unit 2 SLMCPR Operability ANP-3086(NP)

Assessment Critical Power Correlation for Revision 0 ATRIUM 1OXM Fuel - Improved K-factor Model PaQe 3-2 This description of the local rod peaking function is the same as the descriptions presented in References 1 and 2.

AREVA NP Inc.

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Brunswick Unit 1 and Unit 2 SLMCPR Operability ANP-3086(NP)

Assessment Critical Power Correlation for Revision 0 ATRIUM 1OXM Fuel - Improved K-factor Model Paae 3-3 3.2 Applying Rod Peaking Function in the Critical Power Correlation

[

] The maximum of the averaged K-factors over all the rods was then chosen for use in the critical power correlation according to Equation 3.46 in Reference 2. This averaging of the axial K-factor distribution for each rod was found to be inappropriate for the reasons discussed in Section 3.0 and is therefore excluded in the improved K-factor method.

[

] Thus this solution explicitly addresses both problems noted in Section 3.0.

In the improved method, [

I 3.3 Method for CalculatingAdditive Constants The spacers and bundle geometry characteristics influence the critical power behavior of the individual rods within the fuel bundle. Therefore, a factor is needed to distinguish the critical power performance of each rod. These position dependent factors are termed additive constants. Additive constants can be considered as a flow/enthalpy redistribution characteristic for a given bundle and spacer design.

In critical power testing, [

I AREVA NP Inc.

Brunswick Unit 1 and Unit 2 SLMCPR Operability ANP-3086(NP)

Assessment Critical Power Correlation for Revision 0 ATRIUM 1OXM Fuel - Improved K-factor Model Page 3-4 In accordance with the [ ] the CHF database was randomly divided into a defining data set and a validating data set.

Approximately ] was set aside as the validating set of data. The remaining [ ] form the defining data set and were used to develop the critical power correlation. The additive constants for all the rod positions were determined from the defining data set. The calculation of additive constants uses the same partition of data as was used during the critical power correlation development. [

I The defining and validating data sets used for correlation development in Reference 1 are unchanged. The additive constants are determined [

I AREVA NP Inc,

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Assessment Critical Power Correlation for Revision 0 ATRIUM 1OXM Fuel - Improved K-factor Model Page 3-5 AREVA NP Inc.

Controlled DoCumen" Brunswick Unit 1 and Unit 2 SLMCPR Operability ANP-3086(NP)

Assessment Critical Power Correlation for Revision 0 ATRIUM 1OXM Fuel - Improved K-factor Model Paqe 3-6 AREVA NP Inc.

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Assessment Critical Power Correlation for Revision 0 ATRIUM 1OXM Fuel - Improved K-factor Model Paqe 3-7 AREVA NP Inc.

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Assessment Critical Power Correlation for Revision 0 ATRIUM 1OXM Fuel - Improved K-factor Model Page 3-8 3.3.4 Additive Constants for ATRIUM 1OXM Fuel The revised ATRIUM 1OXM additive constants are shown in Figure 3-4. For comparison purposes, both the revised ATRIUM 1OXM additive constants and the ACE/ATRIUM 1OXM additive constants from Reference 1 are presented in Figure 3-5. The observed changes in additive constant are generally small and [

I AREVA NP Inc.

Brunswick Unit 1 and Unit 2 SLMCPR Operability ANP-3086(NP)

Assessment Critical Power Correlation for Revision 0 ATRIUM 1OXM Fuel - Improved K-factor Model Page 3-9 Figure 3-1: Adjacent Rod Identification for K-factor Calculation AREVA NP Inc.

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Brunswick Unit 1 and Unit 2 SLMCPR Operability ANP-3086(NP)

Assessment Critical Power Correlation for Revision 0 ATRIUM 1OXM Fuel - Improved K-factor Model Page 3-10 Figure 3-2: Rods Observed to Dryout in Testing AREVA NP Inc.

I.Dontrolled Documrne Brunswick Unit 1 and Unit 2 SLMCPR Operability ANP-3086(NP)

Assessment Critical Power Correlation for Revision 0 ATRIUM 1OXM Fuel - Improved K-factor Model Page 3-11 Figure 3-3: Peaked Symmetric Rods Not Observed to Dryout in Testing AREVA NP Inc.

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Brunswick Unit 1 and Unit 2 SLMCPR Operability ANP-3086(NP)

Assessment Critical Power Correlation for Revision 0 ATRIUM 1OXM Fuel- Improved K-factor Model Page 3-12 Figure 3-4: Brunswick SLMCPR Operability Assessment Additive Constants for ATRIUM 10XM Fuel AREVA NP Inc.

~1io~>Documen Brunswick Unit 1 and Unit 2 SLMCPR Operability ANP-3086(NP)

Assessment Critical Power Correlation for Revision 0 ATRIUM 1OXM Fuel - Improved K-factor Model Page 3-13 Figure 3-5: Additive Constant Comparison AREVA NP Inc.

ControC t Uiioontef Brunswick Unit 1 and Unit 2 SLMCPR Operability ANP-3086(NP)

Assessment Critical Power Correlation for Revision 0 ATRIUM 1OXM Fuel - Improved K-factor Model Page 3-14 3.4 Additive Constant Uncertainty The overall uncertainty in additive constants is determined [

]. The following steps are applied:

AREVA NP Inc.

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Brunswick Unit 1 and Unit 2 SLMCPR Operability ANP-3086(NP)

Assessment Critical Power Correlation for Revision 0 ATRIUM 1OXM Fuel - Improved K-factor Model Page 3-15 The resulting overall additive constant uncertainty for the Brunswick SLMCPR operability assessment ATRIUM 1OXM correlation is [ ]. The additive constant uncertainty from Reference 1 is [

An additional high peaking uncertainty is imposed in the MCPR safety limit methodology for those rods whose local peaking exceeds [

] Table 3-1 shows the results of these calculations.

AREVA NP Inc.

% C1 Brunswick Unit 1 and Unit 2 SLMCPR Operability ANP-3086(NP)

Assessment Critical Power Correlation for Revision 0 ATRIUM 1 OXM Fuel - Improved K-factor Model Paqe 3-16 Table 3-1: Additive Constant Uncertainty for High Local Peaking AREVA NP Inc.

Brunswick Unit 1 and Unit 2 SLMCPR Operability ANP-3086(NP)

Assessment Critical Power Correlation for Revision 0 ATRIUM 10XM Fuel - Improved K-factor Model Page 3-17 3.5 CriticalPower CorrelationConservatisms With the improved K-factor model, the Brunswick SLMCPR operability assessment ATRIUM 1OXM correlation has an average ECPR of [ ] with a standard deviation of [ ]. For the Reference 1 correlation, the average ECPR was [ ] with a standard deviation of

[ ]. The correlation was used to assess each rod in each of the tests. The associated critical powers of each rod were then compared to the measured critical power and a count made of the number of rods which were predicted to be in boiling transition (BT) and this was compared to the number of rods actually observed to be in boiling transition in the experimental data. With the improved K-factor methodology and revised additive constants, this ratio of predicted to measured rods in boiling transition is [ ]. This compares with a value of

[ ] in Reference 1.

AREVA NP Inc.

0 1"i.tc~c Lic;yr, Brunswick Unit 1 and Unit 2 SLMCPR Operability ANP-3086(NP)

Assessment Critical Power Correlation for Revision 0 ATRIUM 1OXM Fuel - Improved K-factor Model Paqe 4-1 4.0 Implementation of Improved K-factor Methodology The improved K-factor methodology has been implemented into MICROBURN-B2 (Reference 5) and SAFLIM3D (Reference 6) for use in the Brunswick Unit 1 and Unit 2 SLMCPR operability assessment analyses. [

]

The MCPR safety limit methodology performs a rod-by-rod evaluation to estimate the number of rods in BT associated with a particular safety limit. [

AREVA NP Inc.

Brunswick Unit 1 and Unit 2 SLMCPR Operability ANP-3086(NP)

Assessment Critical Power Correlation for Revision 0 ATRIUM 1OXM Fuel - Improved K-factor Model Page 5-1 5.0 References

1. ANP-10298PA, Revision 0, "ACE/ATRIUM 1OXM Critical Power Correlation," AREVA NP Inc., March 2010.

2. ANP-10249PA, Revision 1, "ACE/ATRIUM-10 Critical Power Correlation," AREVA NP Inc.,

September 2009.

3. [

4. C. Bennett and N. L. Franklin. "Statistical Analysis in Chemistry and the Chemical Industry,"

Marbern House, October 1987.

5. EMF-2158(P)(A), Revision 0, "Siemens Power Corporation Methodology for Boiling Water Reactors: Evaluation and Validation of CASMO-4 / MICROBURN-B2," Siemens Power Corporation, October 1999.

6. ANP-10307PA, Revision 0, "AREVA MCPR Safety Limit Methodology for Boiling Water Reactors," AREVA NP Inc., June 2011.

AREVA NP Inc.

.'~r. -,t A

20004-018 (10/18/2010)

AREVA AREVA NP Inc.

ENGINEERING INFORMATION RECORD Document No: 51 - 9177316 - 000 Brunswick Unit 2 Cycle 20 SLMCPR Analysis With SAFLIM3D Methodology - Operability Assessment (Nonproprietary Version)

Page 1 of 12

C -J, 0 L A 20004-018 (10/18/2010) 51-9177316-000 AR EVA Brunswick Unit 2 Cycle 20 SLMCPR Analysis With SAFLIM3D Methodology - Operability Assessment (Nonproprietary Version)

Safety Related? ZN YES F] NO Does this document contain assumptions requiring verification? - YES Z NO Does this document contain Customer Required Format? [1 YES [7 NO Signature Block P/LP, R/LR, PageslSections Name and A/A-CRF, PreparedlReviewed/

Title/Discipline Signature AIA-CRI Date Approved or Comments D.G. Carr, Supervisor ,P . ..

Thermal-Hydraulics Richland G,( A -

D.R. Tinkler, Engineer R 4 Thermal-Hydraulics Richland ' 7/1 2 //z D.W. Pruitt, Manager A/A-CRI Thermal-Hydraulics Richland 6,,

A. B. Meginnis, Manager A Product Licensing Z 21 &1 2_

Note: P/LP designates Preparer (P), Lead Preparer (LP)

R/LR designates Reviewer (R), Lead Reviewer (LR)

A/A-CRF designates Approver (A), Approver of Customer Requested Format (A-CRF)

A/A-CRI designates Approver (A), Approver - Confirming Reviewer Independence (A-CRI)

Record of Revision Revision PageslSectionsl Brief Description I No. Paragraphs Changed Change Authorization 000 All Initial issue of document Page 2

Gcjiodroet_( Docul 1E,~i 20004-018 (10/18/2010) 51-9177316-000 Brunswick Unit 2 Cycle 20 SLMCPR Analysis With SAFLIM3D Methodology - Operability Assessment (Nonproprietary Version)

Contents 1 .0 P u rp os e ...................................................................................................................................... 4 2 .0 Me th od o lo g y .............................................................................................................................. 4 3 .0 A n a ly s is ...................................................................................................................................... 5 4 .0 D is c u s s io n o f R e s u lts ................................................................................................................. 6 5 .0 R efe re n c e s ................................................................................................................................. 6 Tables 1 Fuel- and Plant-Related Uncertainties for BRK2-20 SLMCPR Analyses ................................. 8 2 BRK-2-20 Results Summary for SLMCPR Analysis (Operability Assessment CPR Correlation for ATRIUM 1OXM) .................................................................. 9 3 Contribution of Total Predicted Rods in BT by Nuclear Fuel Type ........................................... 9 4 BRK2-20 Results Summary for SLMCPR Analysis (Reference 4 ACE/ATRIUM 20XM CPR Correlation) .................................................................................. 9 Figures 1 Brunswick Unit 2 Cycle 20 Core Loading Map ..................................................................... 10 2 Brunswick Unit 2 Power/Flow Map With Nominal Feedwater T e m pe rature B S P R eg io ns ....................................................................................................... 11 3 Radial Power Distribution for Brunswick Unit 2 Cycle 20 SLMCPR

[ ] With Operability Assessment CPR Correlation ............................ 12 Page 3

51-9177316-000 Brunswick Unit 2 Cycle 20 SLMCPR Analysis With SAFLIM3D Methodology - Operability Assessment (Nonproprietary Version) 1.0 Purpose Reference 1 presents an AREVA methodology for determining the safety limit minimum critical power ratio (SLMCPR) that was recently approved by the NRC. The methodology is an update or extension of the previously approved methodology presented in Reference 2. The SLMCPR methodology was updated to incorporate full implementation of the ACE critical power correlation (References 3 and 4), a realistic fuel channel bow model (Reference 5), and expanded coupling with the MICROBURN-B2 core simulator (Reference 6). More detailed descriptions of these improvements are discussed in Reference 1.

Reference 7 presents results of the Brunswick Unit 2 Cycle 20 (BRK2-20) SLMCPR analysis using the currently approved Reference 4 ACE/ATRIUM TM 1OXM* critical power correlation. As discussed in Reference 8, a concern was identified in the calculation of the K-factor within the approved ACE/ATRIUM 1OXM correlation. The K-factor methodology was modified in response to the deficiencies found in the axial averaging process. An updated correlation for use in the Brunswick SLMCPR operability assessment calculations with ATRIUM 1OXM fuel is described in Reference 8.

The purpose of this report is to present results of an operability assessment for the BRK2-20 SLMCPR calculations presented in Reference 7 using the updated critical power correlation described in Reference 8 for the ATRIUM 1OXM fuel. The results of this analyses support a change in the list of approved methodologies in the Technical Specifications and also a change in the Technical Specification SLMCPR values for two-loop operation (TLO) and single-loop operation (SLO).

2.0 Methodology The analysis presented in this document used the methodology presented in Reference 1 and the operability assessment critical power correlation presented in Reference 8 for the ATRIUM 1OXM fuel.

The SLMCPR is defined as the minimum value of the critical power ratio which ensures that at least 99.9% of the fuel rods in the core are expected to avoid boiling transition during normal operation or an anticipated operational occurrence (AOO). The SLMCPR is determined using a statistical analysis that employs a Monte Carlo process that perturbs key input parameters used in the calculation of MCPR.

The set of uncertainties used in the statistical analysis include both fuel-related and plant-related uncertainties.

The SLMCPR analysis is performed with a power distribution that conservatively represents expected reactor operating states that could both exist at the operating limit MCPR (OLMCPR) and produce a MCPR equal to the SLMCPR during an AOO. [

ATRIUM is a trademark of AREVA NP.

Page 4

Co'itrol!ed Document 51-9177316-000 Brunswick Unit 2 Cycle 20 SLMCPR Analysis With SAFLIM3D Methodology - Operability Assessment (Nonproprietary Version)

In the AREVA methodology, the effects of channel bow on the critical power performance are accounted for in the SLMCPR analysis. Reference 1 discusses the application of a realistic channel bow model.

3.0 Analysis The core loading and cycle depletion from the BRK2-20 fuel cycle design report (Reference 9) was used as the basis of the SLMCPR analysis. Figure 1 presents the core loading including the assembly type, the cycle the fuel was originally loaded, and the number of assemblies. The BRK2-20 core is made up of ATRIUM 10XM, ATRIUM-10, and GE14 fuel. Analyses were performed [

] for the Brunswick power/flow map for MELLLA operation as shown in Figure 2. The BSP regions shown in the power/flow map are based on the methods discussed in Reference 10. The radial power distribution [

] is presented in Figure 3.

The operability assessment critical power correlation is used for the ATRIUM 1OXM fuel while the SPCB critical power correlation (Reference 11) is used for the ATRIUM-10 and GE14 fuel. The application of the SPCB critical power correlation to GE14 fuel follows the indirect process described in Reference 12.

The fuel- and plant-related uncertainties used in the BRK2-20 SLMCPR analysis are presented in Table 1. The radial and nodal power uncertainties used in the analysis include the effects of up to 40%

of the TIP channels out-of-service, up to 50% of the LPRMs out-of-service, and a 2500 effective full power hour (EFPH) LPRM calibration interval.

The BRK2-20 SLMCPR analysis supports a TLO SLMCPR of 1.06 and an SLO SLMCPR of 1.08.

Table 2 presents a summary of the analysis results including the SLMCPR and the percentage of rods expected to experience boiling transition. The percentages of the total number of fuel rods predicted to experience boiling transition in the overall Monte Carlo statistical evaluation associated with each nuclear fuel type are presented in Table 3. The results are for the [

I Page 5

51-9177316-000 Brunswick Unit 2 Cycle 20 SLMCPR Analysis With SAFLIM3D Methodology - Operability Assessment (Nonproprietary Version) 4.0 Discussion of Results Results from Reference 7 based on the currently approved ACE/ATRIUM 1OXM critical power correlation (Reference 4) are presented in Table 4. They are based on the same BRK2-20 design step-through and most of the same fuel- and plant-related uncertainties. The one exception is a slightly higher additive constant uncertainty associated with the currently approved correlation for the ATRIUM 1OXM fuel- [ ] . A comparison of results shows a decrease in the number of rods expected to experience boiling transition in both TLO and SLO with the use of the operability assessment correlation. The same SLMCPR limits are supported with both the currently approved ACE correlation (Reference 4) and the operability assessment correlation.

5.0 References

1. ANP-1 0307PA Revision 0, AREVA MCPR Safety Limit Methodology for Boiling Water Reactors, AREVA NP, June 2011.

2. ANF-524(P)(A) Revision 2 and Supplements 1 and 2, ANF CriticalPower Methodology for Boiling Water Reactors, Advanced Nuclear Fuels Corporation, November 1990.

3. ANP-10249PA Revision 1, ACE/ATRIUM-1O CriticalPower Correlation,AREVA NP, September 2009.

4. ANP-10298PA Revision 0, ACE/ATRIUM 1OXM Critical.PowerCorrelation,AREVA NP, March 2010.

5. BAW-1 0247PA Revision 0, Realistic Thermal-MechanicalFuel Rod Methodology for Boiling Water Reactors, AREVA NP, February 2008.

6. EMF-2158(P)(A) Revision 0, Siemens Power CorporationMethodology for Boiling Water Reactors: Evaluation and Validation of CASMO-4 / MICROBURN-B2, Siemens Power Corporation, October 1999.

7. 51-9175787-000, "Brunswick Unit 2 Cycle 20 SLMCPR Analysis With SAFLIM3D Methodology (Proprietary Version)," AREVA NP, February 2012.

8. ANP-3086(P), Brunswick Unit I and Unit 2 SLMCPR OperabilityAssessment Critical Power Correlationfor ATRIUM IOXM Fuel - Improved K-factor Model, AREVA NP, February 2012.

9. ANP-2920(P) Revision 0, Brunswick Unit 2 Cycle 20 Fuel Cycle Design, AREVA NP, May 2010.

10. 0G02-0119-260, Backup Stability Protection (BSP) for Inoperable Option Ill Solution, GE Nuclear Energy, July 17, 2002.

11. EMF-2209(P)(A) Revision 3, SPCB CriticalPower Correlation,AREVA NP, September 2009.

12. EMF-2245(P)(A) Revision 0, Application of Siemens Power Corporation'sCriticalPower Correlationsfor Co-Resident Fuel, Siemens Power Corporation, August 2000.

13. EMF-2493(P), MICROBURN-B2 Based Impact of Failed/BypassedLPRMs and TIPs, Extended LPRM CalibrationInterval, and Single Loop Operation on Measured RadialBundle Power Uncertainty,AREVA NP, December 2000.

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51-9177316-000 Brunswick Unit 2 Cycle 20 SLMCPR Analysis With SAFLIM3D Methodology - Operability Assessment (Nonproprietary Version)

14. NEDO-20340, Process ComputerPerformance Evaluation Accuracy, General Electric, June 1974.

15. NEDO-10958-A, General Electric BWR Thermal Analysis Basis (GETAB): Data, Correlationand Design Application, General Electric, January 1977.

16. NEDO-24344, Brunswick Steam Electric Plant Units I and 2 Single-Loop Operation, General Electric, September 1981.

17. Letter, H.D. Curet (AREVA) to H.J. Richings (NRC), "POWERPLEX Core Monitoring: Failed or Bypassed Instrumentation and Extended Calibration," HDC:96:012, May 6, 1996 (38-9043714-000).

18. 0B21-1305 Revision 1, "Core Monitoring LPRM Uncertainty and Sensitivity Decay," Progress Energy, March 2009 (NRC Accession Number ML092370285).

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51-9177316-000 Brunswick Unit 2 Cycle 20 SLMCPR Analysis With SAFLIM3D Methodology - Operability Assessment (Nonproprietary Version)

Table I Fuel- and Plant-Related Uncertainties for BRK2-20 SLMCPR Analyses Parameter Uncertainty Reference Fuel-Related Uncertainties

[

Plant-Related Uncertainties Feedwater flow rate 1.8%§ 15 Feedwater temperature 0.8%§ 15 Core pressure 0.8%- ** 14 Total core flow rate TLO 2.5% 15 SLO 6.0% 16

. []

Values from Reference 13 are a result of the application of the methodology discussed in Reference 17 to the base uncertainties presented in Reference 6. The uncertainties presented support operation with up to 50% of LPRMs out-of-service, up to 40% of the TIP channels out-of-service, and a 2500 EFPH LPRM calibration interval. The bases of these values include a core monitoring LPRM detector uncertainty of 4.3% from Reference 18.

§ References plant uncertainties were conservatively rounded up to the nearest 0.1% before use.

• • The core pressure uncertainty is taken in Reference 14 to be a more conservative value than accepted in Reference 15; therefore, the more conservative value is used.

Page 8

2~ThJfled L)&oum~n 51-9177316-000 Brunswick Unit 2 Cycle 20 SLMCPR Analysis With SAFLIM3D Methodology - Operability Assessment (Nonproprietary Version)

Table 2 BRK2-20 Results Summary for SLMCPR Analysis (Operability Assessment CPR Correlation for ATRIUM 1OXM)

Percentage of Rods SLMCPR in Boiling Transition TLO - 1.06 0.069 SLO - 1.08 0.069 Table 3 Contribution of Total Predicted Rods in BT by Nuclear Fuel Type Contribution of Total Rods Nuclear Predicted To Be Fuel Fuel Burnup in BT (%)

Type Design Status TLO SLO 14 GE14 Twice burned [

15 GE14 Twice burned 16 GE14 Twice burned 30 ATRIUM-10 Once burned 31 ATRIUM-10 Once burned 32 ATRIUM-10 Once burned 33 ATRIUM 1OXM Fresh 34 ATRIUM 1OXM Fresh ]

Table 4 BRK2-20 Results Summary for SLMCPR Analysis (Reference 4 ACEIATRIUM 10XM CPR Correlation)

Percentage of Rods SLMCPR in Boiling Transition TLO- 1.06 0.090 SLO - 1.08 0.088 Page 9

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51-9177316-000 Brunswick Unit 2 Cycle 20 SLMCPR Analysis With SAFLIM3D Methodology - Operability Assessment (Nonproprietary Version)

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1 0.318 0.395 0.447 0.468 0.456 2 0.429 0.638 0.726 0.776 0.803 0.820 3 0.276 0.373 0.511 0.672 0.880 1.098 0.969 1.169 1.175 4 0.312 0.496 0.696 0.841 0.964 1.209 1.280 1.309 1.318 1.105 5 0.278 0.496 0.695 1.021 1.010 1.274 1.336 1.152 1.369 1.152 1.359 6 0.380 0.693 1.019 1.026 1.313 1.375 1.164 1.365 1.132 1.328 1.132 7 0.507 0.835 1.002 1.310 1.383 1.187 1.404 1.139 1.075 0.896 1.291 8 0.401 0.661 0.953 1.263 1.367 1.188 1.421 1.194 1.347 0.914 1.062 1.073 9 0.309 0.624 0.865 1.190 1.318 1.152 1.404 1.196 1.399 1.132 1.313 1.099 1.316 10 0.380 0.709 1.076 1.255 1.119 1.341 1.126 1.338 1.121 1.340 1.097 1.292 1.081 11 0.436 0.757 0.952 1.279 1.327 1.093 1.025 0.879 1.284 1.064 1.069 0.889 1.248 12 0.458 0.785 1.144 1.285 1.111 1.282 0.853 1.013 1.066 1.265 0.879 1.028 0.994 13 0.447 0.803 1.150 1 .079 1.323 1.099 1.272 1.073 1.293 1.068 1.231 0.985 0.989 14 0.447 0.803 1.151 1.079 1.323 1.100 1.272 1.073 1.294 1.069 1.234 0.995 1.206 15 0.456 0.786 1.146 1.287 1.114 1.284 0.855 1.016 1.069 1.268 0.883 1.038 1.001 16 0.438 0.759 0.955 1.282 1.330 1.097 1.029 0.882 1.287 1.068 1.072 0.892 1.250 17 0.388 0.714 1.082 1.260 1.123 1 .345 1.130 1.342 1.126 1.343 1.100 1.294 1.081 18 0.316 0.633 0.872 1.197 1.324 1.156 1.408 1.199 1.402 1.134 1.316 1.100 1.317 19 0.451 0.681 0.960 1.269 1 .372 1.191 1.424 1.196 1.350 0.916 1.064 1.073 20 0.513 0.841 1.006 1 .314 1.387 1.189 1.408 1.142 1.078 0.898 1.293 21 0.375 0.695 1.022 1 .028 1.316 1.377 1.165 1.368 1.132 1.330 1.133 22 0.283 0.500 0.695 1 .023 1.011 1.275 1.338 1.153 1.372 1.154 1.361 23 0.310 0.497 0.696 0.841 0.956 1.211 1.282 1.312 1.320 1.107 24 0.284 0.373 0.513 0.674 0.882 1.100 0.970 1.172 1.177 25 0.431 0.645 0.726 0.777 0.806 0.823 26 0.319 0.390 0.448 0.471 0.460 1 2 3 4 5 6 9 10 11 12 13 J:14 15 16 17 18 19 20 21 22 23 24 25 26 I:

1 0.451 0.466 0.447 0.382 0.316 2 0.820 0.802 0.774 0.724 0.636 0.428 3 1.174 1.168 0.967 1.096 0.878 0.672 0.514 0.380 0.281 4 1.104 1.317 1.308 1.279 1.208 0.966 0.844 0.699 0.512 0.315 5 1.359 1.151 1.368 1.151 1.336 1.274 1.012 1.025 0.697 0.499 0.281 6 1.132 1.328 1.130 1.366 1 .162 1 .375 1.314 1.026 1.021 0.695 0.392 7 1.291 0.896 1.076 1.139 1.405 1.186 1.385 1.311 1.003 0.839 0.514 8 1.072 1.063 0.914 1 .348 1.195 1 .422 1.188 1.369 1.265 0.953 0.666 0.447 9 1.316 1.100 1.315 1.133 1 .401 1.198 1.406 1.151 1.320 1.192 0.869 0.631 0.328 10 1.082 1.294 1.099 1.343 1 .125 1.341 1.129 1.343 1.119 1.256 1.078 0.712 0.400 11 1.251 0.892 1.072 1.066 1.288 0.882 1.030 1.094 1.328 1.279 0.950 0.756 0.439 12 1.001 1.038 0.883 1.268 1.069 1.017 0.855 1.283 1.110 1.284 1.141 0.781 0.440 13 1.206 0.994 1.234 1 .068 1.293 1.072 1.271 1.098 1.321 1.075 1.147 0.798 0.438 14 0.989 0.984 1.230 1.066 1.291 1.070 1.269 1.098 1.320 1.076 1.147 0.799 0.446 15 0.994 1.027 0.878 1.264 1.064 1.011 0.850 1.279 1.109 1.283 1.141 0.782 0.457 16 1.247 0.887 1.068 1 .063 1.282 0.876 1.023 1.091 1.325 1.277 0.950 0.755 0.435 17 1.080 1.291 1.095 1.339 1.121 1.337 1.124 1.340 1.118 1.253 1.075 0.708 0.380 18 1.315 1.097 1.312 1.131 1.398 1.196 1.403 1.150 1.318 1.189 0.864 0.627 0.313 19 1.073 1.061 0.914 1.347 1.193 1.420 1.186 1.367 1.262 0.952 0.662 0.445 20 1.292 0.895 1.075 1 .139 1.404 1.185 1.384 1.310 1.001 0.835 0.509 21 1.132 1.329 1.130 1 .366 1.163 1.375 1.313 1.025 1.019 0.692 0.372 22 1.361 1.153 1.370 1.151 1.337 1.274 1.010 1.023 0.695 0.495 0.283 23 1.106 1.319 1.310 1.280 1.209 0.964 0.843 0.697 0.507 0.313 24 1.176 1.170 0.969 1.098 0.879 0.671 0.513 0.376 0.279 25 0.821 0.803 0.775 0.726 0.638 0.428 26 0.458 0.464 0.447 0.396 0.319 14 15 16 17 18 19 20 21 22 23 24 25 26 Figure 3 Radial Power Distribution for Brunswick Unit 2 Cycle 20 SLMCPR[ ]

With Operability Assessment CPR Correlation Page 12