ML16257A408

ANP-3105(NP), Revision 1, Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for Atrium 10XM Fuel for Mellla+ Operation.

ML16257A408
Person / Time
Site:	Brunswick
Issue date:	07/31/2015
From:	AREVA
To:	Office of Nuclear Reactor Regulation
Shared Package
ML16257A418	List: BSEP 16-0056, ANP-3108(NP), Revision 1, Applicability of Areva BWR Methods to Brunswick Extended Power Flow Operating Domain. ML16257A404 ML16257A406 ML16257A407 ML16257A408 ML16257A410 ML16257A411
References
BSEP 16-0056 ANP-3105NP, Rev 1
Download: ML16257A408 (95)

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ANP-3105NP, Revision 1, Brunswick Units 1and2 LOCA Break Spectrum Analysis for A TR/UM 1 OXM Fuel forMELLLA+

Operation, July 2015 BSEP 16-0056 Enclosure 25 Controlled Document A AREVA Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 1 OXM Fuel for MELLLA+ Operation July 2015 (c) 2015 AREVA Inc. ANP-3105NP Revision 1 AREVA Inc. Controlled Document Brunswick Units 1and2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation ANP-3105NP Revision 1 Controlled Document AREVA Inc. Copyright© 2015 AREVA Inc. All Rights Reserved ANP-3105NP Revision 1 Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation Nature of Changes Item Page Description and Justification

1. Page 2-1 Update the break size for the limiting case. 2. Page 6-1 Update the break size and the PCT for the limiting TLO case. 3. Tables 6.1-Update the results for the TLO cases. 6.9 4. Figures Update the plots for the limiting TLO case. 6.1-6.26 5. Page 7-2 Update the break size and the PCT for the limiting SLO case. 6. Tables 7.1-Update the results for the SLO cases. 7.3 ANP-3105NP Revision 1 Page i 7. Table 7.4 Update the summary results for the limiting TLO and SLO cases. 8. Figures Update the plots for the limiting SLO case. 7.1-7.26 9. Page 9-1 Update the results for the limiting case. AREVA Inc.

Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation ANP-3105NP Revision 1 Page ii Contents 1.0 lntroduction

..................................................................................................................

1-1 2.0 Summary of Results .....................................................................................................

2-1 3.0 LOCA Description

.........................................................................................................

3-1 3.1 Accident Description

.........................................................................................

3-1 3.2 Acceptance Criteria ...........................................................................................

3-2 4.0 LOCA Analysis Description

...........................................................................................

4-1 4.1 Slowdown Analysis ...........................................................................................

4-1 4.2 Refill/Reflood Analysis ......................................................................................

4-2 4.3 Heatup Analysis ................................................................................................

4-2 4.4 Plant Parameters

..............................................................................................

4-3 4.5 ECCS Parameters

............................................................................................

4-3 5.0 Break Spectrum Analysis Description

...........................................................................

5-1 5.1 Limiting Single Failure .......................................................................................

5-1 5.2 Recirculation Line Breaks .................................................................................

5-2 5.3 Non-Recirculation Line Breaks ..........................................................................

5-3 5.3.1 Main Steam Line Breaks .....................................................................

5-4 5.3.2 Feedwater Line Breaks .......................................................................

5-4 5.3.3 HPCI Line Breaks ...............................................................................

5-5 5.3.4 LPCS Line Breaks ...............................................................................

5-5 5.3.5 LPCI Line Breaks ................................................................................

5-5 5.3.6 RWCU Line Breaks .............................................................................

5-5 5.3. 7 Shutdown Cooling Line Breaks ...........................................................

5-6 5.3.8 Instrument Line Breaks .......................................................................

5-6 6.0 Recirculation Line Break LOCA Analyses .....................................................................

6-1 6.1 Limiting Break Analysis Results ........................................................................

6-1 6.2 Break Location Analysis Results .......................................................................

6-1 6.3 Break Geometry and Size Analysis Results ......................................................

6-1 6.4 Limiting Single-Failure Analysis Results ............................................................

6-2 6.5 Axial Power Shape Analysis Results .................................................................

6-2 6.6 State Point Analysis ..........................................................................................

6-2 7.0 Single-Loop Operation LOCAAnalysis

.........................................................................

7-1 7.1 SLO Analysis Modeling Methodology

................................................................

7-1 7.2 SLO Analysis Results .......................................................................................

7-2 8.0 Long-Term Coolability

..................................................................................................

8-1 9.0 Conclusions

..................................................................................................................

9-1 10.0 References

.................................................................................................................

10-1 AREVA Inc.

Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation Tables ANP-3105NP Revision 1 Page iii Table 4.1 Initial Conditions

......................................................................................................

4-5 Table 4.2 Reactor System Parameters

...................................................................................

4-6 Table 4.3 ATRIUM 10XM Fuel Assembly Parameters

.............................................................

4-7 Table 4.4 High-Pressure Coolant Injection Parameters

......................................... .................

4-8 Table 4.5 Low-Pressure Coolant Injection Parameters

............................................................

4-9 Table 4.6 Low-Pressure Core Spray Parameters

.................................................................

.4-10 Table 4.7 Automatic Depressurization System Parameters

..................................................

.4-11 Table 5.1 Available ECCS for Recirculation Line Break LOCAs ..............................................

5-7 Table 6.1 Results for Limiting TLO Recirculation Line Break 3.6 ft 2 Split Pump Discharge SF-LPCI Top-Peaked Axial 102% Power [ ] .....................

6-3 Table 6.2 Event Times for Limiting TLO Recirculation Line Break 3.6 ft 2 Split Pump Discharge SF-LPCI Top-Peaked Axial 102% Power [ ] .....................

6-4 Table 6.3 TLO Recirculation Line Break Spectrum Results for [ ] SF-BATT ......................................................................................................................

6-5 Table 6.4 TLO Recirculation Line Break Spectrum Results for [ ] SF-LPCI .......................................................................................................................

6-6 Table 6.5 TLO Recirculation Line Break Spectrum Results for [ ] Flow SF-BATT ...................................................................................

_ ...................................

6-7 Table 6.6 TLO Recirculation Line Break Spectrum Results for [ ] Flow SF-LPCI ............

6-8 Table 6. 7 TLO Recirculation Line Break Spectrum Results for [ ] Flow SF-BATT ......................................................................................................................

6-9 Table 6.8 TLO Recirculation Line Break Spectrum Results for [ ] Flow SF-LPCI ..........

6-10 Table 6.9 Summary of rLO Recirculation Line Break Results Highest PCT Cases ...............

6-11 Table 7.1 Results for Limiting SLO Line Break 0.6 DEG Pump Discharge SF-LPCI Top-Peaked Axial [ ] .....................

7-3 Table 7.2 Event Times for Limiting SLO Recirculation Line Break 0.6 DEG Pump Discharge SF-LPCI Top-Peaked Axial [ ] .....................

7-4 Table 7.3 SLO Recirculation Line Break Spectrum Results .....................................................

7-5 Table 7.4 Single-and Two-Loop Operation PCT Summary .....................................................

7-6 AREVA Inc.

Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation ANP-3105NP Revision 1 Page iv Figures Figure 1.1 Brunswick MELLLA+ Power I Flow Map .........................................*.......................

1-3 Figure 4.1 Flow Diagram for EXEM BWR-2000 ECCS Evaluation Model. ... : ........................

.4-12 Figure 4.2 RELAX System Model .........................................................................................

.4-13 Figure 4.3 RELAX Hot Channel Model Top-Peaked Axial ....................................................

.4-14 Figure 4.4 RELAX Hot Channel Model Mid-Peaked Axial ....................................................

.4-15 Figure 4.5 ECCS Schematic

................................................................................................

.4-16 Figure 4.6 Rod Average Power Distributions for 102%P and [ ] Mid-and Top-Peaked

..........................................................................................................

4-17 Figure 4.7 Rod Average Power Distributions for 102%P and [ ] Mid-and Top-Peaked .................................................................................................................

4-18 Figure 4.8 Rod Average Power Distributions for [ ] Mid-and Top-Peaked .................................................................................................................

4-19 Figure 6.1 Limiting TLO Recirculation Line Break Upper Plenum Pressure ...........................

6-12 Figure 6.2 Limiting TLO Recirculation Line Break Total Break Flow Rate ..............................

6-12 Figure 6.3 Limiting TLO Recirculation Line Break Core Inlet Flow Rate ................................

6-13 Figure 6.4 Limiting TLO Recirculation Line Break Core Outlet Flow Rate ..............................

6-13 Figure 6.5 Limiting TLO Recirculation Line Break Intact Loop Jet Pump Drive Flow Rate ......................................................................................................................

6-14 Figure 6.6 Limiting TLO Recirculation Line Break Intact Loop Jet Pump Suction Flow Rate ......................................................................................................................

6-14 Figure 6.7 Limiting TLO Recirculation Line Break Intact Loop Jet Pump Exit Flow Rate ......................................................................................................................

6-15 Figure 6.8 Limiting TLO Recirculation Line Break Broken Loop Jet Pump Drive Flow Rate ......................................................................................................................

6-15 Figure 6.9 Limiting TLO Recirculation Line Break Broken Loop Jet Pump Suction Flow Rate .............................................................................................................

6-16 Figure 6.10 Limiting TLO Recirculation Line Break Broken Loop Jet Pump Exit Flow Rate ......................................................................................................................

6-16 Figure 6.11 Limiting TLO Recirculation Line Break ADS Flow Rate ......................................

6-17 Figure 6.12 Limiting TLO Recirculation Line Break LPCS Flow Rate ....................................

6-17 Figure 6.13 Limiting TLO Recirculation Line Break Intact Loop LPCI Flow Rate ...................

6-18 Figure 6.14 Limiting TLO Recirculation Line Break Broken Loop LPCI Flow Rate .................

6-18 Figure 6.15 Limiting TLO Recirculation Line Break Upper Downcomer Mixture Level ...........

6-19 Figure 6.16 Limiting TLO Recirculation Line Break Lower Downcomer Mixture Level ...........

6-19 AREVA Inc.

Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation ANP-3105NP Revision 1 Pagev Figure 6.17 Limiting TLO Recirculation Line Break Intact Loop Discharge Line Liquid Mass .....................................................................................................................

6-20 Figure 6.18 Limiting TLO Recirculation Line Break Upper Plenum Liquid Mass ....................

6-20 Figure 6.19 Limiting TLO Recirculation Line Break Lower Plenum Liquid Mass ....................

6-21 Figure 6.20 Limiting TLO Recirculation Line Break Hot Channel Inlet Flow Rate ..................

6-21 Figure 6.21 Limiting TLO Recirculation Line Break Hot Channel Outlet Flow Rate ................

6-22 . Figure 6.22 Limiting TLO Recirculation Line Break Hot Channel Coolant Temperature at the Hot Node at EOB ...................................................................

6-22 Figure 6.23 Limiting TLO Recirculation Line Break Hot Channel Quality at the Hot Node at EOB ........................................................................................................

6-23 Figure 6.24 Limiting TLO Recirculation Line Break Hot Channel Heat Transfer Coeff. at the Hot Node at EOB ........................................................................................

6-23 Figure 6.25 Limiting TLO Recirculation Line Break Hot Channel Reflood Junction Liquid Mass Flow Rate .........................................................................................

6-24 Figure 6.26 Limiting TLO Recirculation Line Break Cladding Temperatures ..........................

6-24 Figure 7.1 Limiting SLO Recirculation Line Break Upper Plenum Pressure .............................

7-7 Figure 7.2 Limiting SLO Recirculation Line Break Total Break Flow Rate ...............................

7-7 Figure 7.3 Limiting SLO Recirculation Line Break Core Inlet Flow Rate ..................................

7-8 Figure 7.4 Limiting SLO Recirculation Line Break Core Outlet Flow Rate ...............................

7-8 Figure 7.5 Limiting SLO Recirculation Line Break Intact Loop Jet Pump Drive Flow Rate ........................................................................................................................

7-9 Figure 7.6 Limiting SLO Recirculation Line Break Intact Loop Jet Pump Suction Flow Rate ........................................................................................................................

7-9 Figure 7.7 Limiting SLO Recirculation Line Break Intact Loop Jet Pump Exit Flow Rate ......................................................................................................................

7-10 Figure 7.8 Limiting SLO Recirculation Line Break Broken Loop Jet Pump Drive Flow Rate ......................................................................................................................

7-10 Figure 7.9 Limiting SLO Recirculation Line Break Broken Loop Jet Pump Suction Flow Rate .............................................................................................................

7-11 Figure 7.10 Limiting SLO Recirculation Line Break Broken Loop Jet Pump Exit Flow Rate ......................................................................................................................

7-11 Figure 7.11 Limiting SLO Recirculation Line Break ADS Flow Rate ......................................

7-12 Figure 7 .12 Limiting SLO Recirculation Line Break LPCS Flow Rate ....................................

7-12 Figure 7.13 Limiting SLO Recirculation Line Break Intact Loop LPCI Flow Rate ...................

7-13 Figure 7.14 Limiting SLO Recirculation Line Break Broken Loop LPCI Flow Rate .................

7-13 Figure 7 .15 Limiting SLO Recirculation Line Break Upper Downcomer Mixture Level ...........

7-14 Figure 7.16 Limiting SLO Recirculation Line Break Lower Downcomer Mixture Level. ..........

7-14 AREVA Inc.

Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation ANP-3105NP Revision 1 Page vi Figure 7.17 Limiting SLO Recirculation Line Break Intact Loop Discharge Line Liquid Mass .....................................................................................................................

7-15 Figure 7.18 Limiting SLO Recirculation Line Break Upper Plenum Liquid Mass ....................

7-15 Figure 7.19 Limiting SLO Recirculation Line Break Lower Plenum Liquid Mass ....................

7-16 Figure 7.20 Limiting SLO Recirculation Line Break Hot Channel Inlet Flow Rate ..................

7-16 Figure 7.21 Limiting SLO Recirculation Line Break Hot Channel Outlet Flow Rate ...............

7-17 Figure 7.22 Limiting SLO Recirculation Line Break Hot Channel Coolant Temperature at the Hot Node at EOB ...................................................................

7-17 Figure 7.23 Limiting SLO Recirculation Line Break Hot Channel Quality at the Hot Node at EOB ........................................................................................................

7-18 Figure 7.24 Limiting SLO Recirculation Line Break Hot Channel Heat Transfer Coeff. atthe Hot Node at EOB ........................................................................................

7-18 Figure 7.25 Limiting SLO Recirculation Line Break Hot Channel Reflood Junction Liquid Mass Flow Rate .........................................................................................

7-19 Figure 7.26 Limiting SLO Recirculation Line Break Cladding Temperatures

.........................

7-19 AREVA Inc.

Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation ADS ADSVOOS ANS BOL BWR CFR CHF CMWR DEG DG ECCS EOB FHOOS HPCI LOCA LPCI LPCS MAPLHGR MCPR MSIVOOS MWR NRC PCT RDIV SF-BATT SF-HPCI SF-LP Cl SLO TLO UFSAR AREVA Inc. Nomenclature automatic depressurization system ADS valve out-of-service American Nuclear Society beginning of life boiling-water reactor Code of Federal Regulations critical heat flux core average metal-water reaction double-ended guillotine diesel generator emergency core cooling system end of blowdown feedwater heaters out-of-service high-pressure coolant injection loss-of-coolant accident low-pressure coolant injection low-pressure core spray maximum average planar*linear heat generation rate minimum critical power ratio main steam isolation valve out-of-service metal-water reaction Nuclear Regulatory Commission, U.S. peak cladding temperature recirculation discharge isolation valve single failure of battery (DC) power single failure of the HPCI system single failure of an LPCI injection valve single-loop operation , two-loop operation updated final safety analysis report ANP-3105NP Revision 1 Page vii Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

1.0 Introduction

ANP-3105NP Revision 1 Page 1-1 The results of a loss-of-coolant accident (LOCA) break spectrum analysis for Brunswick Units 1 and 2 are documented in this report. The purpose of the break spectrum analysis is to identify the break characteristics that result in the highest calculated peak cladding temperature (PCT) during a postulated LOCA. Variation in the following LOCA parameters is examined:

• Break location

• Break type (double-ended guillotine (DEG) or split)

• Break size

• Limiting emergency core cooling system (ECCS) single failure

• Axial power shape (top-or mid-peaked)

The analyses documented in this report are performed with LOCA Evaluation Models developed by AREVA, and approved for reactor licensing analyses by the U.S. Nuclear Regulatory Commission (NRC). The models and computer codes used by AREVA for LOCA analyses are collectively referred to as the EXEM BWR-2000 Evaluation Model (References 1 -4). The EXEM BWR-2000 Evaluation Model and NRC approval are documented in Reference

1. The calculations described in this report are performed in conformance with 10 CFR 50 Appendix K requirements and satisfy the event acceptance criteria identified in 1 O CFR 50.46. Key model characteristics included in the report analyses are shown below. Other initial conditions used in the analyses are described in Section 4.0.

• Operation in the MELLLA+ domain of Figure 1.1 is supported.

[ . [ * ] ] Analyses support operation with one automatic depressurization system (ADS) valve out-of-service (ADSVOOS).

• ATRIUM is a trademark of AREVA Inc. AREVA Inc.

Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation ANP-3105NP Revision 1 Page 1-2

• A recirculation loop flow mismatch of 5% of rated core flow for operation greater than or equal to 75% rated core flow is supported.

A recirculation loop flow mismatch of 10% of rated core flow for operation less than 75% rated core flow is supported.

• The core is composed entirely of ATRIUM 10XM fuel at beginning-of-life (BOL) conditions.

• A 2.0% increase in initial core power to address the maximum uncertainty in monitoring reactor power, as per NRC requirements, is included.

• The limiting assembly in the core was assumed to be at a maximum average planar linear heat generation rate (MAPLHGR) limit of 13.1 kW/ft. The limiting break characteristics will be used in future analyses to determine the MAPLHGR limit versus exposure.

Even though the limiting break will not change with exposure or nuclear fuel design, the value of PCT calculated for any given set of break characteristics is dependent on exposure and local power peaking. Therefore, heatup analyses are performed to determine the PCT versus exposure for each nuclear design in the core. The heatup analyses are performed each cycle using the limiting boundary conditions determined in the break spectrum analysis.

The maximum PCT versus exposure from the heatup analyses are documented in the MAPLHGR report. This report also presents results for single-loop operation (SLO) and long term coolability.

AREVA Inc.

Contro!!ed Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

.. "' 0 c.. 120.0 110.0 100.0 90.0 80.0 70.0 60.0 50.0 40.0 30.0 20.0 10.0 0.0 0.0 0 AREVA Inc. 7.7 10 / / _ ...... , ... MELLLA+ .............

y , ... -... I ...... .........

MELLLA r-h. ...... ,,""' v ---.... / / ' \ I I I I Natural j I ""'-Circulation Line 1/ 15.4 20 23.1 30 __./ !/..--.---

35% Minimum Pump 30.8 40 I I 38.5 50 46.2 60 53.9 70 Core Flow Minimum) Power 61.6 80 69.3 90 Figure 1.1 Brunswick MELLLA+ Power I Flow Map ...... ...... \ \ I c F v / 77.0 84.7 100 110 ANP-3105NP Revision 1 Page 1-3 92.4 Mlbs/hr 120 (%)

[ Controlled Docun1ent Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

2.0 Summary

of Results ANP-3105NP Revision 1 Page 2-1 Based on analyses presented in this report, the limiting break characteristics are identified below. Limiting LOCA Break Characteristics Location Recirculation discharge pipe Type I size Split I 3.6 ft2 Single failure Low-pressure coolant injection valve Axial power shape Top-peaked The LOCA break spectrum analysis results presented in this report are for Brunswick Unit 2 which are conservatively applicable to Unit 1. Previous analysis results show that the limiting PCT for Unit 1 is bound by the limiting PCT for Unit 2. A more detailed discussion of results is provided in Sections 6.0 -7.0. ] The break characteristics identified in this report can be used in subsequent fuel type specific LOCA heatup analyses to determine the MAPLHGR limit appropriate for the fuel type. The SLO LOCA analyses support operation with an ATRIUM 10XM MAPLHGR multiplier of 0.80 applied to the normal two-loop operation MAPLHGR limit. The long-term coolability evaluation confirms that the ECCS capacity is sufficient to maintain adequate cooling in an ATRIUM 10XM core for an extended period after a LOCA. AREVA Inc.

Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation ANP-3105NP Revision 1 Page 2-2 All analyses support operation with one ADSVOOS. All analyses also support the required mismatch in the recirculation loop flows at the start of the LOCA -5% for core flows greater than or equal to 75% of rated and 10% for core flows less than 75% of rated. All analyses were performed assuming nominal feedwater temperature.

[ ] Therefore, this LOCA analysis supports FHOOS operation.

The analysis supports operation in the MELLLA+ domain of the Brunswick power/flow map shown in Figure 1.1. At Brunswick, operation with 1 MSIVOOS is limited to two-loop operation and power levels less than 70% of rated. For a given power level, 1 MSIVOOS can result in a higher reactor pressure at the initiation of a LOCA and a slightly higher break flow. [ ] Therefore, this LOCA analysis supports operation with 1 MSIVOOS. While the fuel rod temperatures in the limiting plane of the hot channel during a LOCA are dependent on exposure, the factors that determine the limiting break characteristics are primarily associated with the reactor system and are not dependent on fuel-exposure characteristics.

Fuel parameters that are dependent on exposure (e.g., stored energy, local peaking) have an insignificant effect on the reactor system response during a LOCA. The limiting break characteristics determined using BOL fuel conditions are applicable for exposed fuel. Fuel exposure effects are addressed in heatup analyses performed to determine or verify MAPLHGR limits versus exposure for each fuel design. AREVA Inc.

Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation 3.0 LOCA Description

3.1 Accident

Description ANP-3105NP Revision 1 Page 3-1 The LOCA is described in the Code of Federal Regulations 10 CFR 50.46 as a hypothetical accident that results in a loss of reactor coolant from breaks in reactor coolant pressure boundary piping up to and including a break equivalent in size to a double-ended rupture of the largest pipe in the reactor coolant system. There is not a specifically identified cause that results in the pipe break. However, for the purpose of identifying a design basis accident, the pipe break is postulated to occur inside the primary containment before the first isolation valve. For a boiling water reactor (BWR), a LOCA may occur over a wide spectrum of break locations and sizes. Responses to the break vary significantly over the break spectrum.

The largest possible break is a double-ended rupture of a recirculation pipe; however, this is not necessarily the most severe challenge to the emergency core cooling system (ECCS). A double-ended rupture of a main steam line causes the most rapid primary system depressurization, but because of other phenomena, steam line breaks are seldom limiting with respect to the event acceptance criteria (10 CFR 50.46). Because of these complexities, an analysis covering the full range of break sizes and locations is performed to identify the limiting break characteristics.

Regardless of the initiating break characteristics, the event response is conveniently separated into three phases: the blowdown phase, the refill phase, and the reflood phase. The relative duration of each phase is strongly dependent upon the break size and location.

The last two phases are often combined and will be discussed together in this report. During the blowdown phase of a LOCA, there is a net loss of coolant inventory, an increase in fuel cladding temperature due to core flow degradation, and for the larger breaks, the core becomes fully or partially uncovered.

There is a rapid decrease in pressure during the blowdown phase. During the early phase of the depressurization, the exiting coolant provides core cooling. Consistent with the discussion presented in Reference 6, [ ] The end of the blowdown phase is defined to occur when the system reaches the pressure corresponding to the rated LPCS flow. In the refill phase of a LOCA, the ECCS is functioning and there is a net increase of coolant inventory.

During this phase the core sprays provide core cooling and, along with low-pressure AREVA Inc.

Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation ANP-3105NP Revision 1 Page 3-2 and high-pressure coolant injection (LPCI and HPCI), supply liquid to refill the lower portion of the reactor vessel. In general, the core heat transfer to the coolant is less than the fuel decay heat rate and the fuel cladding temperature continues to increase during the refill phase. In the reflood phase, the coolant inventory has increased to the point where the mixture level reenters the core region. During the core reflood phase, cooling is provided above the mixture level by entrained reflood liquid and below the mixture level by pool boiling. Sufficient coolant eventually reaches the core hot node and the fuel cladding temperature decreases.

3.2 Acceptance

Criteria A LOCA is a potentially limiting event that may place constraints on fuel design, local power peaking, and in some cases, acceptable core power level. During a LOCA, the normal transfer of heat from the fuel to the coolant is disrupted.

As the liquid inventory in the reactor decreases, the decay heat and stored energy of the fuel cause a heatup of the undercooled fuel assembly.

In order to limit the amount of heat that can contribute to the heatup of the fuel assembly during a LOCA, an operating limit on the MAPLHGR is applied to each fuel assembly in the core. The Code of Federal Regulations prescribes specific acceptance criteria (10 CFR 50.46) for a LOCA event as well as specific requirements and acceptable features for Evaluation Models (10 CFR 50 Appendix K). The conformance of the EXEM BWR-2000 LOCA Evaluation Models to Appendix K is described in Reference

1. The ECCS must be designed such that the plant response to a LOCA meets the following acceptance criteria specified in 10 CFR 50.46:

• The calculated maximum fuel element cladding temperature shall not exceed 2200°F.

• The calculated local oxidation of the cladding shall nowhere exceed 0.17 times the local cladding thickness.

• The calculated total amount of hydrogen generated from the chemical reaction of the cladding with water or steam shall not exceed 0.01 times the hypothetical amount that would be generated if all of the metal in the cladding cylinders surrounding the fuel, except the cladding surrounding the plenum volume, were to react.

• Calculated changes in core geometry shall be such that the core remains amenable to cooling.

• After any calculated successful initial operation of the ECCS, the calculated core temperature shall be maintained at an acceptably low value and decay heat shall be removed for the extended period of time required by the long-lived radioactivity remaining in the core. AREVA Inc.

Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation ANP-3105NP Revision 1 Page 3-3 These criteria are commonly referred to as the peak cladding temperature (PCT) criterion, the local oxidation criterion, the hydrogen generation criterion, the coolable geometry criterion, and the long-term cooling criterion.

A MAPLHGR limit is established for each fuel type to ensure that these criteria are met.. LOCA PCT results are provided in Sections 6.0 -7.0 to determine the limiting LOCA event. LOCA analysis results demonstrating that the PCT, local oxidation, and hydrogen generation criteria are met are provided in follow-on MAPLHGR report and specific heatup analyses performed to determine MAPLHGR limits versus exposure for each fuel design. Compliance with these three criteria ensures that a coolable geometry is maintained.

Long-term coolability criterion is discussed in Section 8.0. AREVA Inc.

Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation 4.0 LOCA Analysis Description ANP-3105NP Revision 1 Page 4-1 The Evaluation Model used for the break spectrum analysis is the EXEM BWR-2000 LOCA analysis methodology described in Reference

1. The EXEM BWR-2000 methodology employs three major computer codes to evaluate the system and fuel response during all phases of a LOCA. These are the RELAX, HUXY, and RODEX2 computer codes. RELAX is used to calculate the system and hot channel response during the blowdown, refill, and reflood phases of the LOCA. The HUXY code is used to perform heatup calculations for the entire LOCA, and calculates the PCT and local clad oxidation at the axial plane of interest.

RODEX2 is used to determine fuel parameters (such as stored energy) for input to the other LOCA codes. The code interfaces for the LOCA methodology are illustrated in Figure 4.1. A complete analysis for a given break size starts with the specification of fuel parameters using RODEX2 (Reference 4). RODEX2 is used to determine the initial stored energy for both the blowdown analysis (RELAX hot channel) and the heatup analysis (HUXY). This is accomplished by ensuring that the initial stored energy in RELAX and HUXY is the same or higher than that calculated by RODEX2 for the power, exposure, and fuel design being considered.

4.1 Slowdown

Analysis The RELAX code (Reference

1) is used to calculate the system thermal-hydraulic response during the blowdown phase of the LOCA. For the system blowdown analysis, the core is represented by an average core channel. The reactor core is modeled with heat generation rates determined from reactor kinetics equations with reactivity feedback and decay heat as required by Appendix K of 10 CFR 50. The reactor vessel nodalization for the system analysis is shown in Figure 4.2. This nodalization is consistent with that used in the topical report submitted to the NRG (Reference 1 ). The RELAX blowdown analysis is performed from the time of the break initiation through the end of blowdown (EOB). The system blowdown calculation provides the upper and lower plenum transient boundary conditions for the hot channel analysis.

Following the system blowdown calculation, another RELAX analysis is performed to analyze the maximum power assembly (hot channel) of the core. The RELAX hot channel blowdown calculation determines hot channel fuel, cladding, and coolant temperatures during the AREVA Inc.

Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation ANP-3105NP Revision 1 Page 4-2 blowdown phase of the LOCA. The RELAX hot channel nodalization is shown in Figure 4.3 for a top-peaked power shape, and in Figure 4.4 for a mid-peaked axial power shape. The hot channel analysis is performed using the system blowdown results to supply the core power and the system boundary conditions at the core inlet and exit. [ ] The initial average fuel rod temperature at the limiting plane of the hot channel is conservative relative to the average fuel rod temperature calculated by RODEX2 for operation of the ATRIUM 1 OXM assembly at the MAPLHGR limit. The heat transfer coefficients and fluid conditions in the hot channel from the RELAX hot channel calculation are used as input to the HUXY heatup analysis.

4.2 Refill/Reflood Analysis The RELAX code is also used to compute the system and hot channel hydraulic response during the refill/reflood phase of the LOCA. The RELAX system and RELAX hot channel analyses continue beyond the end of blowdown to analyze system and hot channel responses during the refill and reflood phases. The refill phase is the period when the lower plenum is filling due to ECCS injection.

The reflood phase is the period when some portions of the core and hot assembly are being cooled with ECCS water entering from the lower plenum. The purpose of the RELAX calculations beyond blowdown is to determine the time when the liquid flow via upward entrainment from the bottom of the core becomes high enough at the hot node in the hot assembly to end the temperature increase of the fuel rod cladding. This event time is called the time of hot node reflood. [ ] The RELAX calculations provide HUXY with the time of hot node reflood and the time when the liquid has risen in the bypass to the height of the axial plane of interest (time of bypass reflood).

4.3 Heatup

Analysis The HUXY code (Reference

2) is used to perform heatup calculations for the entire LOCA transient and provides PCT and local clad oxidation at the axial plane of interest.

The heat generated by metal-water reaction (MWR) is included in the HUXY analysis.

HUXY is used to calculate the thermal response of each fuel rod in one axial plane of the hot channel assembly.

These calculations consider thermal-mechanical interactions within the fuel rod. The clad swelling and rupture models from NUREG-0630 have been incorporated into HUXY AREVA Inc.

_, Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation ANP-3105NP Revision 1 Page 4-3 (Reference 3). The HUXY code complies with the 1 O CFR 50 Appendix K criteria for LOCA Evaluation Models. HUXY uses the EOB time and the times of core bypass reflood and core reflood at the axial plane of interest from the RELAX analysis.

[ ] Throughout the calculations, decay power is determined based on the ANS 1971 decay heat curve plus 20% as described in Reference

1. [ ] are used in the HUXY analysis.

The principal results of a HUXY heatup analysis are the PCT and the percent local oxidation of the fuel cladding, often called the %MWR. 4.4 Plant Parameters The LOCA break spectrum analysis is performed using the plant parameters provided by the utility. Table 4.1 provides a summary of reactor initial conditions used in the break spectrum analysis.

Table 4.2 lists selected reactor system parameters.

The break spectrum analysis is performed for a full core of ATRIUM 10XM fuel. Some of the key fuel parameters used in the break spectrum analysis are summarized in Table 4.3. 4.5 ECCS Parameters The ECCS configuration is shown in Figure 4.5. Table 4.4-Table

4.7 provide

the important ECCS characteristics assumed in the analysis.

The ECCS is modeled as fill junctions connected to the appropriate reactor locations:

LPCS injects into the upper plenum, HPCI injects into the upper downcomer, and LPCI injects into the recirculation lines. Although HPCI is expected to be available, no analysis mitigation credit is assumed for the HPCI system in any of the analyses discussed in this report. The flow through each ECCS valve is determined based on system pressure and valve position.

Flow versus pressure for a fully open valve is obtained by linearly interpolating the pump capacity data provided in Table 4.4 -Table 4.6. No credit for ECCS flow is assumed until the AREVA Inc.

Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation ECCS injection valves are fully open and the ECCS pumps reach rated speed. [ ANP-3105NP Revision 1 Page 4-4 ] The ADS valves are modeled as a junction connecting the reactor steam line to the suppression pool. The flow through the ADS valves is calculated based on pressure and valve flow characteristics.

The valve flow characteristics are determined such that the calculated flow is equal to the rated capacity at the reference pressure shown in Table 4.7. Only five ADS valves are assumed operable in the analyses to support operation with one ADSVOOS and the potential single failure of one ADS valve during the LOCA. In the AREVA LOCA analysis model, ECCS initiation is assumed to occur when the water level drops to the applicable level setpoint.

No credit is assumed for the start of LPCS or LPCI due to high drywell pressure.

[ ] AREVA Inc.

Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation Table 4.1 Initial Conditions Reactor power (% of rated) 102 [ Reactor power (MWt) 2981.5 [ [ Steam flow rate (Mlb/hr) 13.1 Steam dome pressure (psia) 1048.9 Core inlet enthalpy (Btu/lb) 527.7 ATRIUM 10XM hot assembly MAPLHGR (kW/ft) 13.1 [ Rod average power distributions Figure 4.6 * [ AREVA Inc. 102 2981.5 13.1 1048.7 522.4 13.1 Figure 4.7 ] ANP-3105NP Revision 1 Page 4-5 [ ] ] [ ] ]

] 11.6 1029.7 515.8 13.1 ] Figure 4.8 Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation AREVA Inc. Table 4.2 Reactor System Parameters Parameter Value Vessel ID (in) 220.5 Number of fuel assemblies 560 Recirculation suction pipe area (ft2) 3.67 1.0 DEG suction break area (ft 2) 7.33 Recirculation discharge pipe area (ft 2) 3.67 1.0 DEG discharge break area (ft 2) 7.33 ANP-3105NP Revision 1 Page 4-6 Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation AREVA Inc. Table 4.3 ATRIUM 10XM Fuel Assembly Parameters Parameter Fuel rod array Number of fuel rods per assembly Non-fuel rod type Fuel rod OD (in) Active fuel length (in) (including blankets)

Water channel outside width (in) Fuel channel thickness (in) Fuel channel internal width (in) Value 10x10 79 (full-length rods) 12 (part-length rods) Water channel replaces 9 fuel rods 0.4047 150.0 (full-length rods) 75.0 (part-length rods) 1.378 0. 075 (minimum wall) 0. 100 (corner) 5.278 ANP-3105NP Revision 1 Page 4-7 Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation Table 4.4 High-Pressure Coolant Injection Parameters Parameter Coolant temperature (maximum)

(°F) Initiating Signals and Setpoints Water level (in)* High drywell pressure (psig) Time Delays Time for HPCI pump to reach rated speed and injection Value 140 459 Not used valve wide open (sec) 60 Delivered Coolant Flow Rate Versus Pressure Vessel to Flow Torus AP Rate (psid) (gpm) 0 0 150 3825 1164 3825

• Relative to vessel zero. AREVA Inc. ANP-3105NP Revision 1 Page 4-8 Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation Table 4.5 Low-Pressure Coolant Injection Parameters Parameter Value Reactor pressure permissive for opening valves -analytical (psia) 41 O Coolant temperature (maximum)

(°F) 160 Water level (in)* Initiating Signals and Setpoints High drywell pressure (psig) Time Delays Time for LPCI pumps to reach rated speed (maximum) (sec) LPCI injection valve stroke time (sec) 358 Not used 31.8 37.5 Delivered Coolant Flow Rate Versus Pressure Flow Rate for Flow Rate for 1 Pump 2 Pumps Injecting Into Injecting Into Vessel to 1 Recirculation 1 Recirculation Torus L\P Loop Loop (psid) (gpm) (gpm) 0 8,690 14,420 20 7,000 12,000 202 0 0

• Relative to vessel zero. AREVA Inc. ANP-3105NP Revision 1 Page 4-9 Controlled Docun1ent Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation Table 4.6 Low-Pressure Core Spray Parameters Parameter Value Reactor pressure permissive for opening valves -analytical (psia) 410 Coolant temperature (maximum)

(°F) 160 Water level (in)* Initiating Signals and Setpoints High drywell pressure (psig) Time Delays Time for LPCS pumps to reach 358 Not used rated speed (maximum) (sec) 39.7 LPCS injection valve stroke time (sec) 14.0 Delivered Coolant Flow Rate Versus Pressure Vessel to Flow Rate for Torus AP 1 Pump (psid) (gpm) 0 5250 113 4000 265 0

• Relative to vessel zero. AREVA Inc. ANP-3105NP Revision 1 Page 4-10 Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation Table 4. 7 Automatic Depressurization System Parameters Parameter Value Number of valves installed 7 Number of valves available*

5 Minimum flow capacity of 4.15 at available valves 1112.4 (Mlbm/hr at psig) Initiating Signals and Setpoints Water level (in)t 358 High drywell pressure (psigfl: 2 Time Delays ADS timer (delay time from initiating signal to time valves are open (sec) 121 ANP-3105NP Revision 1 Page 4-11

• Only 5 valves are assumed operable in the analyses to support 1 ADSVOOS operation and the potential single failure of 1 ADS valve during the LOCA. t :t: [ Relative to vessel zero. AREVA Inc. ]

Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation I Fuel Data I: ... .... Neutronic Data ...

.. RPF,APF (CASMO, System MICROBURN)

Analysis i (RELAX) ,____/ Fuel Parameters (RODEX2) I Fuel Stored -Energy -Boundary Conditions (power, upper & lower plenum conditions)

Gap, Fuel Stored Energy Gap Coefficient, Fission Gas + ir Hot Assembly Analysis* (RELAX) I Boundary Conditions (Pressure, Temperature, Power, Quality, Heat Transfer Coefficient)

Time of Hot Node Reflood ... ANP-3105NP Revision 1 Page 4-12 : I Plant Data 11 SS CoreT/H (XCOBRA) Heatup Analysis End of Slowdown, _ Time of Bypass Reflood AREVA Inc. *The hot assembly calculation may be combined with the system calculation or executed separately (HUXY) Peak Cladding Temperature, Metal Water Reaction + Figure 4.1 Flow Diagram for EXEM BWR-2000 ECCS Evaluation Model Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

[ Figure 4.2 RELAX System Model AREVA Inc. ANP-3105NP Revision 1 Page 4-13 l Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

[ AREVA Inc. Figure 4.3 RELAX Hot Channel Model Top-Peaked Axial ] ANP-3105NP Revision 1 Page 4-14 Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

[ AREVA Inc. Figure 4.4 RELAX Hot Channel Model Mid-Peaked Axial ] ANP-3105NP Revision 1 Page 4-15 Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation U) DG-3 1A LPCI Injection Valve 1A AREVA Inc. (i) DG-1 Discharge Valve 1A 1A Loop-A Figure 4.5 ECCS Schematic 1B Loop-B (i) DG-2 Discharge Valve 1B ANP-3105NP Revision 1 Page 4-16 1D (j) DG-4 1B LPCI Injection Valve 1B Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

[ Figure 4.6 Rod Average Power Distributions for 102%P and [ ] Mid-and Top-Peaked AREVA Inc. ANP-3105NP Revision 1 Page 4-17 ]

Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

[ Figure 4. 7 Rod Average Power Distributions for 102%P and [ ] Mid-and Top-Peaked AREVA Inc. ANP-3105NP Revision 1 Page 4-18 ]

Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

[ Figure 4.8 Rod Average Power Distributions for [ ] Mid-and Top-Peaked AREVA Inc. ANP-3105NP Revision 1 Page 4-19 ]

Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

5.0 Break

Spectrum Analysis Description ANP-3105NP Revision 1 Page 5-1 The objective of these LOCA analyses is to ensure that the limiting break location, break type, break size, and ECCS single failure are identified.

The LOCA response scenario varies considerably over the spectrum of break locations.

Potential break locations have been separated into two groups: recirculation line breaks and non-recirculation line breaks. The basis for the break locations and potentially limiting single failures analyzed in this report is described in the following sections.

5.1 Limiting

Single Failure Regulatory requirements specify that the LOCA analysis be performed assuming that all offsite power supplies are lost instantaneously and that only safety grade systems and components are available.

In addition, regulatory requirements also specify that the most limiting single failure of ECCS equipment must be assumed in the LOCA analysis.

The term "most limiting" refers to the ECCS equipment failure that produces the greatest challenge to event acceptance criteria.

The limiting single failure can be a common power supply, an injection valve, a system pump, or system initiation logic. The most limiting single failure may vary with break size and location.

The potential limiting single failures identified in the UFSAR (Reference

9) are shown below:

• DC power (i) (SF-BATT}

• DC power (j)

• Diesel generator ( i)

• Diesel generator (j)

• LPCI injection valve (SF-LPCI)

• High-pressure coolant injection system (SF-HPCI}

The single failures and the available ECCS for each failure assumed in these analyses are summarized in Table 5.1. Other potential failures are not specifically considered because they result in as much or more ECCS capacity.

As indicated earlier, no analysis mitigation credit is assumed for the HPCI system in any of the LOCA analyses presented in this report. A review of Table 5.1 shows that the DC power (i) and LPCI injection valve failures are the two potential limiting failures as the other single failures result in as much or more ECCS capacity.

Only five ADS valves are assumed operable in the AREVA Inc.

Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation ANP-3105NP Revision 1 Page 5-2 analyses to support operation with one ADSVOOS and the potential single failure of one ADS valve during the LOCA. 5.2 Recirculation Line Breaks The response during a recirculation line LOCA is dependent on break size. The rate of reactor vessel depressurization decreases as the break size decreases.

The high-pressure ECCS and ADS will assist in reducing the reactor vessel pressure to the pressure where the LPCI and LPCS flows start. For large breaks, rated LPCS and LPCI flow is generally reached before or shortly after the time when the ADS valves open so the ADS system is not required to mitigate the LOCA. ADS operation is an important emergency system for small breaks where it assists in depressurizing the reactor system faster, and thereby reduces the time required to reach rated LPCS and LPCI flow. The two largest flow resistances in the recirculation piping are the recirculation pump and the jet pump nozzle. For breaks in the discharge piping, there is a major flow resistance in both flow paths from the reactor vessel to the break. For breaks in the suction piping, the major flow resistances are in the same flow path from the vessel to the break. As a result, pump suction side breaks experience a more rapid blowdown, which tends to make the event more severe. For suction side breaks, the recirculation discharge isolation valve on the broken loop closes which allows the LPCI flow to fill the discharge piping and supply flow to the lower plenum and core. For discharge side breaks, the LPCI flow in the broken loop is assumed to exit the system through the break resulting in a decrease in available LPCI flow to the core, thereby increasing the severity of the event. Both suction and discharge recirculation pipe breaks are considered in the break spectrum analysis.

Two break types (geometries) are considered for the recirculation line break. The two types are the double-ended guillotine (DEG) break and the split break. For a DEG break, the piping is assumed to be completely severed resulting in two independent flow paths to the containment.

The DEG break is modeled by setting the break area (at both ends of the pipe) equal to the full pipe cross-sectional area and varying the discharge coefficient between 1.0 and 0.4. The range of discharge coefficients is used to cover uncertainty in the actual geometry at the break. Discharge coefficients below 0.4 are unrealistic and not AREVA Inc.

Controlled Document Brunswick.Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation ANP-3105NP Revision 1 Page 5-3 considered in the EXEM BWR-2000 methodology.

The most limiting DEG break is determined by varying the discharge coefficient.

A split type break is assumed to be a longitudinal opening or hole in the piping that results in a single break flow path to the containment.

Appendix K of 10 CFR 50 defines the cross-sectional area of the piping as the maximum split break area required for analysis.

Break types, break sizes, and single failures are analyzed for both suction and discharge recirculation line breaks. Section 6.0 provides a description and results summary for breaks in the recirculation line. 5.3 Non-Recirculation Line Breaks In addition to breaks in the recirculation line, breaks in other reactor coolant system piping must be considered in the LOCA break spectrum analysis.

Although the recirculation line large breaks result in the largest coolant inventory loss, they do not necessarily result in the most severe challenge to event acceptance criteria.

The double-ended rupture of a main steam line is expected to result in the fastest depressurization of the reactor vessel. Special consideration is required when the postulated break occurs in ECCS piping. Although ECCS piping breaks are small relative to a recirculation pipe DEG break, the potential to disable an ECCS system increases their severity.

The following sections address potential LOCAs due to breaks in non-recirculation line piping. Non-recirculation line breaks outside containment are inherently less challenging to fuel limits than breaks inside containment.

For breaks outside containment, isolation or check valve closure will terminate break flow prior to the loss of significant liquid inventory and the core will remain covered. If high-pressure coolant inventory makeup cannot be reestablished, ADS actuation may become necessary.

[ ] Although analyses of breaks outside containment may be required to address non-fuel related regulatory requirements, these breaks are not limiting relative to fuel acceptance criteria such as PCT. AREVA Inc.

[ [ Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation 5.3.1 Main Steam Line Breaks ANP-3105NP Revision 1 Page 5-4 A steam line break inside containment is assumed to occur between the reactor vessel and the inboard main steam line isolation valve (MSIV) upstream of the flow limiters.

The break results in high steam flow out of the broken line and into the containment.

Prior to MSIV closure, a steam line break also results in high steam flow in the intact steam lines as they feed the break via the steam line manifold.

A steam line break inside containment results in a rapid . depressurization of the reactor vessel. Initially the break flow will be high quality steam; however, the rapid depressurization produces a water level swell that results in liquid discharge at the break. For steam line breaks, the largest break size is most limiting because it results in the most level swell and liquid loss out of the break. 1 5.3.2 Feedwater Line Breaks 1 AREVA Inc.

[ [ Control Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation 5.3.3 HPCI Line Breaks ment The HPCI injection line is connected to the feedwater line outside containment.

1 ANP-3105NP Revision 1 Page 5-5 The HPCI steam supply line is connected to the main steam line inside containment.

1 5.3.4 LPCS Line Breaks A break in the LPCS line is expected to have many characteristics similar to [ ] However, some characteristics of the LPCS line break are unique and are not addressed in other LOCA analyses.

Two important differences from other LOCA analyses are that the break flow will exit from the region inside the core shroud and the break will disable one LPCS system. The LPCS line break is assumed to occur just outside the reactor vessel. [ 1 5.3.5 LPCI Line Breaks The LPCI injection lines are connected to* the larger recirculation discharge lines. [ 1 5.3.6 RWCU Line Breaks The RWCU extraction line is connected to a recirculation suction line with an additional connection to the vessel bottom head. [ 1 The RWCU return line is connected to the feedwater line; [ 1 AREVA Inc.

[ Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation 5.3. 7 Shutdown Cooling Line Breaks ANP-3105NP Revision 1 Page 5-6 The shutdown cooling suction piping is connected to a recirculation suction line and the shutdown cooling return line is connected to a recirculation discharge line. [ ] 5.3.8 Instrument Line Breaks ] AREVA Inc.

Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation ANP-3105NP Revision 1 Page 5-7

• t § Assumed Failure* DC power (i) (SF-BATT)

DC power (j) Diesel generator ( i) Diesel generator (j) LPCI injection valve (SF-LPCI)

HPCI system (SF-HPCI)

Table 5.1 Available ECCS for Recirculation Line Break LOCAs Recirculation Recirculation Suction Break Discharge Break Systems Remaining

t. +. § Systems Remaining

+. § 1 LPCS + 3LPCI + ADS 1 LPCS + 1 LPCI + ADS 2 LPCS + 2LPCI + HPCI +ADS 2LPCS + HPCI + ADS 1 LPCS + 3LPCI + HPCI +ADS 1 LPCS + 1 LPCI + HPCI + ADS 2LPCS + 2LPCI + HPCI + ADS 2LPCS + HPCI + ADS 2LPCS + 2LPCI + HPCI +ADS 2LPCS + HPCI +ADS 2LPCS + 4LPCI + ADS 2LPCS + 2LPCI + ADS Failure of either DC power ( i) or diesel generator ( i) will result in the loss of one diesel generator (DG-1 or DG-2). The loss of DC power ( i) will also result in the loss of the HPCI. The loss of DC power (j) or diesel generator (j) will result in the loss of one diesel generator (DG-3 or DG-4). Systems remaining, as identified in this table for recirculation suction line breaks, are applicable to other non-ECCS line breaks. For a LOCA from an ECCS line break, the systems remaining are those listed for recirculation suction breaks, less the ECCS in which the break is assumed. 1LPCI (1 pump into 1 loop) means one RHR pump operating in one LPCI loop, 2LPCI (2 pumps into 1 loop) means two RHR pumps operating in one loop, 3LPCI (3 pumps into 2 loops) means three RHR pumps operating in two loops, 4LPCI (4 pumps into 2 loops) means four RHR pumps operating in two loops. Although HPCI is expected to be available for some events, no accident analysis mitigation credit is assumed for this system. AREVA Inc.

[ Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

6.0 Recirculation

Line Break LOCA Analyses ANP-3105NP Revision 1 Page 6-1 The largest diameter recirculation system pipes are the suction line between the reactor vessel and the recirculation pump and the discharge line between the recirculation pump and the riser manifold ring. LOCA analyses are performed for breaks in both of these locations with consideration for both DEG and split break geometries.

The break sizes considered included DEG breaks with discharge coefficients from 1.0 to 0.4 and split breaks with areas ranging between the full pipe area and 0.05 ft2. As discussed in Section 5.0, the single failures considered in the recirculation line break analyses are SF-BATT and SF-LPCI. 1 6.1 Limiting Break Analysis Results The analyses demonstrate that the limiting (highest PCT) recirculation line break is the 3.6 ft 2 split break in the pump discharge piping with an SF-LPCI single failure and a top-peaked axial power shape when operating at 102% rated core power and [ ] The PCT is 1925°F. The key results and event times for this limiting break are provided in Tables 6.1 and 6.2, respectively.

Figures 6.1 -6.25 provide plots of key parameters from the RELAX system and hot channel analyses.

A plot of cladding temperature versus time in the hot assembly from the HUXY heatup analysis is provided in Figure 6.26. Tables 6.3 -6.8 present the detailed break spectrum PCT results for each of the single failures and state points considered in this LOCA analyses.

Table 6.9 provides a summary of the highest PCT recirculation line break calculations for each of the single failures, state points, and axial power shapes. The results of the break analyses are discussed in the following sections.

6.2 Break

Location Analysis Results Table 6.9 shows that the maximum PCT calculated for a recirculation line break occurs in the pump discharge piping. 6.3 Break Geometry and Size Analysis Results Recirculation line break PCT results versus break geometry (DEG or split) and size are presented in Tables 6.3 -6.8. The maximum PCT calculated for a recirculation line break occurs for a 3.6 ft 2 split break. AREVA Inc.

Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

6.4 Limiting

Single-Failure Analysis Results The results in Table 6.9 show that the limiting single-failure is SF-LPCI. 6.5 Axial Power Shape Analysis Results ANP-3105NP Revision 1 Page 6-2 The results in Table 6.9 show that the top-peaked axial power shape is limiting compared to the mid-peaked shape analyses for the limiting break size. 6.6 State Point Analysis Table 6.9 shows that 102% rated core power and [ state point for the recirculation line breaks. AREVA Inc. ] was the limiting Controlled Document ANP-3105NP Brunswick Units 1 and 2 LOCA Break Spectrum Analysis Revision 1 for ATRIUM 10XM Fuel for MELLLA+ Operation Page 6-3 AREVA Inc. Table 6.1 Results for Limiting TLO Recirculation Line Break 3.6 ft 2 Split Pump Discharge SF-LPCI Top-Peaked Axial 102% Power [ ] PCT 1925°F Maximum local MWR 1.25% Maximum planar average MWR 0.60%

Controlled Document ANP-3105NP Brunswick Units 1 and 2 LOCA Break Spectrum Analysis Revision 1 for ATRIUM 10XM Fuel for MELLLA+ Operation Page 6-4 .. AREVA Inc. Table 6.2 Event Times for Limiting TLO Recirculation Line Break 3.6 ft 2 Split Pump Discharge SF-LPCI Top-Peaked Axial 102% Power [ ] Event Time (sec) Initiate break 0.0 Initiate scram 0.6 Low-low liquid level, L2 (459 in) 5.5 Low-low-low liquid level, L 1 (358 in) 8.2 Jet pump uncovers 9.3 Recirculation suction uncovers 15.8 Diesel generators started 15.0 LPCS high-pressure cutoff 60.5 Power at LPCS injection valves 27.8 LPCS valve pressure permissive 48.3 LPCS valve starts to open 49.3 LPCS valve open 63.3 LPCS pump at rated speed 39.7 LPCS flow starts 63.4 LPCS permissive for ADS 39.7 RDIV pressure permissive 57.2 RDIV starts to close 58.2 RDIV closed 95.2 Rated LPCS flow 90.0 ADS valves open 129.2 Slowdown ends 90.0 Bypass reflood 176.7 Core reflood 175.7 PCT 175.7 Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

[ * [ AREVA Inc. ] Table 6.3 TLO Recirculation Line Break Spectrum Results for [ ] SF-BATT ANP-3105NP Revision 1 Page 6-5 ]

Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

[ * [ AREVA Inc. ] Table 6.4 TLO Recirculation Line Break Spectrum Results for [ ] SF-LPCI ANP-3105NP Revision 1 Page 6-6 ]

Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

[ * [ AREVA Inc. ] Table 6.5 TLO Recirculation Line Break Spectrum Results for [ ] Flow SF-BATT ANP-3105NP Revision 1 Page 6-7 ]

Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

[ * [ AREVA Inc. ] Table 6.6 TLO Recirculation Line Break Spectrum Results for [ ] Flow SF-LPCI ANP-3105NP Revision 1 Page 6-8 ]

Controlled Docun1ent Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

[ * [ AREVA Inc. ] Table 6. 7 TLO Recirculation Line Break Spectrum Results for [ ] Flow SF-BATT ANP-3105NP Revision 1 Page 6-9 ]

Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

[ * [ AREVA Inc. 1 Table 6.8 TLO Recirculation Line Break Spectrum Results for [ ] Flow SF-LPCI ANP-3105NP Revision 1 Page 6-10 ]

Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

[ AREVA Inc. Table 6.9 Summary of TLO Recirculation Line Break Results Highest PCT Cases ANP-3105NP Revision 1 Page 6-11 ]

Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

[ [ AREVA Inc. Figure 6.1 Limiting TLO Recirculation Line Break Upper Plenum Pressure Figure 6.2 Limiting TLO Recirculation Line Break Total Break Flow Rate ANP-3105NP Revision 1 Page 6-12 l l Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

[ [ AREVA Inc. Figure 6.3 Limiting TLO Recirculation Line Break Core Inlet Flow Rate Figure 6.4 Limiting TLO Recirculation Line Break Core Outlet Flow Rate ANP-3105NP Revision 1 Page 6-13 ] ]

Controlled Docurnent Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

[ [ AREVA Inc. Figure 6.5 Limiting TLO Recirculation Line Break Intact Loop Jet Pump Drive Flow Rate Figure 6.6 Limiting TLO Recirculation Line Break Intact Loop Jet Pump Suction Flow Rate ANP-3105NP Revision 1 Page 6-14 ] ]

Controlled Docurnent Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

[ [ AREVA Inc. Figure 6.7 Limiting TLO Recirculation Line Break Intact Loop Jet Pump Exit Flow Rate Figure 6.8 Limiting TLO Recirculation Line Break Broken Loop Jet Pump Drive Flow Rate ANP-3105NP Revision 1 Page 6-15 ] ]

Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

[ [ AREVA Inc. Figure 6.9 Limiting TLO Recirculation Line Break Broken Loop Jet Pump Suction Flow Rate Figure 6.10 Limiting TLO Recirculation Line Break Broken Loop Jet Pump Exit Flow Rate ANP-3105NP Revision 1 Page 6-16 ] ]

Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation AREVA Inc. IT w 0 g 0 g 0 .. ..J u.. Cf) 0 <( 0 d N 0 d 20 40 50 BO 1 00 120 140 150 180 200 TIME(SEC)

Figure 6.11 Limiting TLO Recirculation Line Break ADS Flow Rate g 0 g " 0 d 20 40 60 80 100 120 140 1 50 180 200 TIME(SEC)

Figure 6.12 Limiting TLO Recirculation Line Break LPCS Flow Rate ANP-3105NP Revision 1 Page 6-17 Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation AREVA Inc. ! '5i q oo _J L1. 0 a. _J = 6 w :;:!. "' 9 "' ci _J L1. 0 a. _J _J []J "' 9 20 40 60 80 100 120 140 150 180 200 TIME(SEC)

Figure 6.13 Limiting TLO Recirculation Line Break Intact Loop LPCI Flow Rate 20 40 60 80 100 120 140 160 180 200 TIME(SEC)

Figure 6.14 Limiting TLO Recirculation Line Break Broken Loop LPCI Flow Rate ANP-3105NP Revision 1 Page 6-18 Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation AREVA Inc. E' 0 ci N -o Jiri > x a: w q 0 z 5 0 a: wq $"' 9 0 0 20 40 60 BO 100 120 140 160 1BO 200 TIME(SEC)

Figure 6.15 Limiting TLO Recirculation Line Break Upper Downcomer Mixture Level 20 40 60 BO 100 120 140 1GO 180 200 TIME(SEC)

Figure 6.16 Limiting TLO Recirculation Line Break Lower Downcomer Mixture Level ANP-3105NP Revision 1 Page 6-19 Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation AREVA Inc. mo --' 0 ::;; Cl So 0 ci _o --' g w-a: J!'. (.) en o oo --' g -"' 0 ci 0 ci 20 40 60 100 100 180 200 TIME(SEC)

Figure 6.17 Limiting TLO Recirculation Line Break Intact Loop Discharge Line Liquid Mass 20 40 60 80 I 00 120 140 160 180 200 TIME(SEC)

Figure 6.18 Limiting TLO Recirculation Line Break Upper Plenum Liquid Mass ANP-3105NP Revision 1 Page 6-20 Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation AREVA Inc.

ci 0 ci _g c:J ... 2. D" 50 Q ci _J 0 :;;; fil ::>"' z CL g a: g w"' Do _J d 0 :il ., 20 40 60 BO 100 120 140 160 180 200 TIME(SEC)

Figure 6.19 Limiting TLO Recirculation Line Break Lower Plenum Liquid Mass 0 20 40 60 80 100 120 140 150 180 200 TIME(SEC)

Figure 6.20 Limiting TLO Recirculation Line Break Hot Channel Inlet Flow Rate ANP-3105NP Revision 1 Page 6-21 Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

[ AREVA Inc. 20 40 60 BO 100 120 140 160 180 200 TIME(SEC)

Figure 6.21 Limiting TLO Recirculation Line Break Hot Channel Outlet Flow Rate Figure 6.22 Limiting TLO Recirculation Line Break Hot Channel Coolant Temperature at the Hot Node at EOB ANP-3105NP Revision 1 Page 6-22 ]

Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

[ [ AREVA Inc. Figure 6.23 Limiting TLO Recirculation Line Break Hot Channel Quality at the Hot Node at EOB Figure 6.24 Limiting TLO Recirculation Line Break Hot Channel Heat Transfer Coeff. at the Hot Node at EOB ANP-3105NP Revision 1 Page 6-23 ] ]

Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

[ 1500 500 AREVA Inc. Figure 6.25 Limiting TLO Recirculation Line Break Hot Channel Reflood Junction Liquid Mass Flow Rate 0 -PCTRod(Rod II) G-----0 Water Channel G----O Fuel Channel 50 100 150 Time (sec) 200 250 Figure 6.26 Limiting TLO Recirculation Line Break Cladding Temperatures 300 ANP-3105NP Revision 1 Page 6-24 ]

[ Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation 7.0 Single-Loop Operation LOCA Analysis ANP-3105NP Revision 1 Page 7-1 During SLO, the pump in one recirculation loop is not operating.

A break may occur in either loop, but results from a break in the inactive loop would be similar to those from a two-loop operation break. If a break occurs in the inactive loop during SLO, the intact active loop flow to the reactor vessel would continue during the recirculation pump coastdown period and would provide core cooling similar to that which would occur in breaks during TLO. The system response would be similar to that resulting from an equal-sized break during two-loop operation.

A break in the active loop during SLO results in a more rapid loss of core flow and earlier degraded core conditions relative to those from a break in the inactive loop. Therefore, only breaks in the active recirculation loop are analyzed.

A break in the active recirculation loop during SLO will result in an earlier loss of core heat transfer relative to a similar break occurring during two-loop operation.

This occurs because there will be an immediate loss of jet pump drive flow. Therefore, fuel rod surface temperatures will increase faster in an SLO LOCA relative to a TLO LOCA. Also, the early loss of core heat transfer will result in higher stored energy in the fuel rods at the start of the heatup. The increased severity of an SLO LOCA can be reduced by applying an SLO multiplier to the two-loop MAPLHGR limits. [ 1 7 .1 SLO Analysis Modeling Methodology 1 AREVA Inc.

[ [ Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation 7 .2 SLO Analysis Results ] ] ANP-3105NP Revision 1 Page 7-2 The SLO analyses are performed with a 0.80 multiplier applied to the two-loop.

MAPLHGR limit resulting in an SLO MAPLHGR limit of 10.48 kW/ft. The analyses are performed at BOL fuel conditions.

The limiting SLO LOCA is the 3. 7 ft 2 pump discharge line break with SF-LPCI and a top-peaked axial power shape. The PCT for this case is 1867°F. Other key results and event times for the limiting SLO LOCA are provided in Tables 7.1 and 7.2, respectively.

Figures 7.1 -7.25 show important RELAX system and hot channel results from the SLO limiting LOCA analysis.

Figure 7.26 shows the cladding surface temperature for the limiting rod as calculated by HUXY. Table 7.3 shows the spectrum of SLO analyses and the PCT for each case. A comparison of the limiting SLO and the limiting two-loop results is provided in Table 7.4. The results in Table 7.4 show that the limiting two-loop LOCA results bound the limiting SLO results when a 0.80 multiplier is applied to the two-loop MAPLHGR limit. AREVA Inc.

Controlled Document ANP-3105NP Brunswick Units 1 and 2 LOCA Break Spectrum Analysis Revision 1 for ATRIUM 10XM Fuel for MELLLA+ Operation Page 7-3 AREVA Inc. Table 7.1 Results for Limiting SLO Recirculation Line Break 3.7 ft 2 Split Pump Discharge SF-LPCI Top-Peaked Axial [ ] PCT 1867°F Maximum local MWR 1.14% Maximum planar average MWR 0.59%

Controlled Docurnent ANP-3105NP Brunswick Units 1 and 2 LOCA Break Spectrum Analysis Revision 1 for ATRIUM 10XM Fuel for MELLLA+ Operation Page 7-4 AREVA Inc. Table 7.2 Event Times for Limiting SLO Recirculation Line Break 3. 7 ft 2 Pump Discharge SF-LPCI Top-Peaked Axial [ ] Event Time (sec) Initiate break 0.0 Initiate scram 0.6 Low-Low liquid level, L2 (459 in) 5.7 Low-Low-Low liquid level, L 1 (358 in) 8.5 Jet pump uncovers 9.8 Recirculation suction uncovers 16.8 Diesel generators started 15.0 LPCS high-pressure cutoff 60.4 Power at LPCS injection valves 27.8 LPCS valve pressure permissive 48.1 LPCS valve starts to open 49.1 LPCS valve open 63.1 LPCS pump at rated speed 39. 7 LPCS flow starts 63.1 LPCS permissive for ADS 39. 7 RDIV pressure permissive 57.0 RDIV starts to close 58.0 RDIV closed 95.0 Rated LPCS flow 87.9 ADS valves open 129.5 Slowdown ends 87.9 Bypass reflood 172. 7 Core reflood 179.1 PCT 179.1 Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

[ * [ AREVA Inc. ] Table 7.3 SLO Recirculation Line Break Spectrum Results ANP-3105NP Revision 1 Page 7-5 ]

Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation Operation Single-loop Two-loop AREVA Inc. Table 7.4 Single-and Two-Loop Operation PCT Summary Limiting Case 3.7 ft 2 split pump discharge top-peaked SF-LPCI 3.6 ft 2 split pump discharge top-peaked SF-LPCI ANP-3105NP Revision 1 Page 7-6 PCT (oF) 1867 1925 Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

[ [ AREVA Inc. Figure 7.1 Limiting SLO Recirculation Line Break Upper Plenum Pressure Figure 7.2 Limiting SLO Recirculation Line Break Total Break Flow Rate l l ANP-3105NP Revision 1 Page 7-7 Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

[ [ AREVA Inc. Figure 7.3 Limiting SLO Recirculation Line Break Core Inlet Flow Rate Figure 7.4 Limiting SLO Recirculation Line Break Core Outlet Flow Rate 1 1 ANP-3105NP Revision 1 Page 7-8 Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

[ [ AREVA Inc. Figure 7.5 Limiting SLO Recirculation Line Break Intact Loop Jet Pump Drive Flow Rate Figure 7.6 Limiting SLO Recirculation Line Break Intact Loop Jet Pump Suction Flow Rate ] ] ANP-3105NP Revision 1 Page 7-9 Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

[ [ AREVA Inc. Figure 7.7 Limiting SLO Recirculation Line Break Intact Loop Jet Pump Exit Flow Rate Figure 7.8 Limiting SLO Recirculation Line Break Broken Loop Jet Pump. Drive Flow Rate ANP-3105NP Revision 1 Page 7-10 ]. ]

Controlled Docurnent Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

[ [ AREVA Inc. Figure 7.9 Limiting SLO Recirculation Line Break Broken Loop Jet Pump Suction Flow Rate Figure 7.10 Limiting SLO Recirculation Line Break Broken Loop Jet Pump Exit Flow Rate ] ] ANP-3105NP Revision 1 Page 7-11 Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation AREVA Inc. 20 40 60 80 100 120 140 160 180 TIME(SEC)

Figure 7.11 Limiting SLO Recirculation Line Break ADS Flow Rate 0.---.---.--.---.---.---.---,--,,--,,--,,--,--,--,--,--,--,--,--,--,--,--, g 1\1 0 § 0 ci 20 40 60 80 100 120 140 160 180 TIME(SEC)

Figure 7.12 Limiting SLO Recirculation Line Break LPCS Flow Rate ANP-3105NP Revision 1 Page 7-12 Controlled Document Bfunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 1 OXM Fuel for MELLLA+ Operation AREVA Inc. u w :::!. _J u.. u 0.. _J _J CD "' 9 20 40 60 80 100 120 140 160 180 TIME(SEC)

Figure 7.13 Limiting SLO Recirculation Line Break Intact Loop LPCI Flow Rate 20 40 60 80 100 120 140 1150 180 TIME(SEC)

Figure 7.14 Limiting SLO Recirculation Line Break Broken Loop LPCI Flow Rate ANP-3105NP Revision 1 Page 7-13 Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation AREVA Inc. 0 g f -o J LO w-ru _, x a: WC! :;; 0 u z 5: 0 0 a: wq 5: "' g 0 0 20 40 60 80 100 120 140 160 180 TIME(SEC)

Figure 7.15 Limiting SLO Recirculation Line Break Upper Downcomer Mixture Level 20 40 60 80 100 120 140 160 180 TIME(SEC)

Figure 7.16 Limiting SLO Recirculation Line Break Lower Downcomer Mixture Level ANP-3105NP Revision 1 Page 7-14 Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation AREVA Inc.

ci "'0 _J 0 -o CJ) 0 So gg _J g CJ a: () _J g -"' 0 ci 20 40 00 80 100 120 140 HW 180 TIME(SEC)

Figure 7.17 Limiting SLO Recirculation Line Break Intact Loop Discharge Line Liquid Mass ci 0 ci 20 40 60 80 100 120 140 160 180 TIME(SEC)

Figure 7.18 Limiting SLO Recirculation Line Break Upper Plenum Liquid Mass ANP-3105NP Revision 1 Page 7-15 Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

[ AREVA Inc.

ci 0 g ::!. 0 ... 50 Qo _J 0 z a. g a: g w"' :,;: Oo -1 g :I! "' 0 g 20 40 60 80 100 120 140 160 180 TIME(SEC)

Figure 7.19 Limiting SLO Recirculation Line Break Lower Plenum Liquid Mass Figure 7.20 Limiting SLO Recirculation Line Break Hot Channel Inlet Flow Rate ANP-3105NP Revision 1 Page 7-16 l Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

[ [ AREVA Inc. Figure 7.21 Limiting SLO Recirculation Line Break Hot Channel Outlet Flow Rate Figure 7.22 Limiting SLO Recirculation Line Break Hot Channel Coolant "Femperature at the Node at EOB ANP-3105NP Revision 1 Page 7-17 ] ]

Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

[ [ AREVA Inc. Figure 7.23 Limiting SLO Recirculation Line Break Hot Channel Quality at the Hot Node at EOB Figure 7.24 Limiting SLO Recirculation Line Break Hot Channel Heat Transfer Coeff. at the Hot Node at EOB ANP-3105NP Revision 1 Page 7-18 ] ]

Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

[ AREVA Inc. Figure 7.25 Limiting SLO Recirculation Line Break Hot Channel Reflood Junction Liquid Mass Flow Rate 1500 500 0 -PCT Rod (Rod 11) G----0 Water Channel G-EJ Fuel Channel 50 100 150 Time (sec) 200 250 300 Figure 7.26 Limiting SLO Recirculatfon Line Break Cladding Temperatures ANP-3105NP Revision 1 Page 7-19 ]

Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation 8.0 Long-Term Coolability ANP-3105NP Revision 1 Page 8-1 Long-term coolability addresses the issue of reflooding the core and maintaining a water level adequate to cool the core and remove decay heat for an extended time period following a LOCA. For non-recirculation line breaks, the core can be reflooded to the top of the active fuel and be adequately cooled indefinitely.

For recirculation line breaks, the core will initially remain covered following reflood due to the static head provided by the water filling the jet pumps to a level of approximately two-thirds core height. Eventually, the heat flux in the core will not be adequate to maintain a two-phase water level over the entire length of the core. Beyond this time, the upper third of the core will remain wetted and adequately cooled by core spray. Maintaining water level at two-thirds core height with one core spray system operating is sufficient to maintain long-term coolability as demonstrated by the NSSS vendor (Reference 10). Since fuel temperatures during long-term cooling are low relative to the PCT and are not significantly affected by fuel design, this conclusion is applicable to ATRIUM 10XM fuel. AREVA Inc.

Controlled Document Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation

9.0 Conclusions

The major conclusions of this LOCA break spectrum analysis are: ANP-3105NP Revision 1 Page 9-1

• The limiting recirculation line break is a 3.6 ft 2 split break in the pump discharge piping with single failure SF-LPCI and a top-peaked axial shape when operating at 102% rated core power and [ ] . .

• The limiting break analysis identified above satisfies all the acceptance criteria specified in 10 CFR 50.46. The analysis is performed in accordance with 10 CFR 50.46 Appendix K requirements.

• The MAPLHGR limit multiplier for SLO is 0.80 for ATRIUM 10XM fuel. This multiplier ensures that a LOCA from SLO is less limiting than a LOCA from two-loop operation.

The limiting break characteristics determined in this report can be referenced and used in future Brunswick Units 1 and 2 LOCA analyses to establish the MAPLHGR limit versus exposure for ATRIUM 10XM fuel. AREVA Inc.

Do cu Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation 10.0 References ANP-3105NP Revision 1 Page 10-1 1. EMF-2361 (P)(A) Revision 0, EXEM BWR-2000 EGGS Evaluation Model, Framatome ANP, May 2001. 2. XN-CC-33(A)

Revision 1, HUXY: A Generalized Multirod Heatup Code with 10 CFR 50 Appendix K Heatup Option Users Manual, Exxon Nuclear Company, November 1975. 3. XN-NF-82-07(P)(A)

Revision 1, Exxon Nuclear Company EGGS Cladding Swelling and Rupture Model, Exxon Nuclear Company, November 1982. 4. XN-NF-81-58(P)(A)

Revision 2 and Supplements 1 and 2, RODEX2 Fuel Rod Thermal -Mechanical Response Evaluation Model, Exxon Nuclear Company, March 1984. 5. Safety Evaluation by the Office of Nuclear Reactor Regulation, Licensing Topical Report NEDC-33006P, "General Electric Boiling Water Reactor Maximum Extended Load Line Limit Analysis Plus," General Electric Hitachi Nuclear Energy America, LLC, October 2008 (ML081130008).

6. Letter, P. Salas (AREVA) to Document Control Desk (USNRC), "Proprietary Viewgraphs and Meeting Summary for Closed Meeting on Application of the EXEM BWR-2000 ECCS Evaluation Methodology," NRC:11 :096, September 22, 2011. 7. Letter, T.J. McGinty (USNRC) to P. Salas (AREVA), "Response to AREVA NP, Inc. (AREVA) Proposed Analysis Approach for Its EXEM Boiling Water Reactor Emergency Core Cooling System (ECCS) Evaluation Model," July 5, 2012. 8. EMF-2292(P)(A)

Revision 0, ATRIUMŽ-10:

Appendix K Spray Heat Transfer Coefficients, Siemens Power Corporation, September 2000. 9. Updated FSAR Brunswick Steam Electric Plant, Units 1and2, Revision 22. 10. NED0-20566A, General Electric Company Analytical Model for Loss of Coolant Analysis in Accordance with 10CFR50 Appendix K, September 1986. I AREVA Inc.

AREVA NP Affidavit Regarding Withholding ANP-3105P, Revision 1, Brunswick Units 1and2 LOCA Break Spectrum Analysis for A TR/UMŽ 1 OXM Fuel for MELLLA+ Operation, July 2015 BSEP 16-0056 Enclosure 26 AFFIDAVIT COMMONWEAL TH OF VIRGINIA ) ) SS. CITY OF LYNCHBURG ) 1. My name is Gayle Elliott. I am Manager, Product Licensing, for AREVA Inc. (AREVA) and as such I am authorized to execute this Affidavit.

2. I am familiar with the criteria applied by AREVA to determine whether certain AREVA information is proprietary.

I am familiar with the policies established by AREVA to ensure the proper application of these criteria.

3. I am familiar with the AREVA information contained in Licensing Report ANP-3105P, Revision 1, entitled, "Brunswick Units 1 and 2 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel for MELLLA+ Operation," dated July 2015 and referred to herein as "Document." Information contained in this Document has been classified by AREVA as proprietary in accordance with the policies established by AREVA Inc. 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 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 1 O CFR 2.390. The information for which withholding from disclosure is re.quested qualifies under 10 CFR 2.390(a)(4) "Trade secrets and commercial or financial information." 6. The following criteria are customarily applied by AREVA to determine whether information should be classified as proprietary: (a) The information reveals details of AREVA'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. (d) The information reveals certain distinguishing aspects of a process, methodology, or component, the exclusive use of which provides a competitive advantage for AREVA in product optimization or marketability. (e) The information is vital to a competitive advantage held by AREVA, would be helpful to competitors to AREVA, and would likely cause substantial harm to the competitive position of AREVA. The information in this Document is considered proprietary for the reasons set forth in paragraphs 6(c), 6(d) and 6{e) above. 7. In accordance with AREVA's policies governing the protection and control of information, proprietary information contained in this Document has made available, on a limited basis, to others outside AREVA only as required and under suitable agreement providing for nondisclosure and limited use of the information.

8. AREVA 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 JtJ day of 9"+ , 2015.

Danita R. Kidd . NOTARY PUBLIC, COMMONWEALTH OF VIRGINIA MY COMMISSION EXPIRES: 12/31/16 Reg. # 205569