Text

Attachment 8 - NEDC-33576NP, Safety Analysis Report for Nine Mile Point Unit 2 Maximum Extended Load Line Limit Analysis Plus (Non-proprietary)
	ML13316B109
Person / Time
Site:	Nine Mile Point
Issue date:	11/01/2013
From:	; Constellation Energy Nuclear Group, EDF Group, Nine Mile Point
To:	; Office of Nuclear Reactor Regulation
Shared Package
ML13316B090	List: ML13316B107; ML13316B109; ML13316B110;
References
	DRF Section 0000-0138-0146, Rev. 6, NEDO-33576, Rev. 0
	Download: ML13316B109 (257)
	v • d • e

ATTACHMENT 8 NEDC-33576NP, SAFETY ANALYSIS REPORT FOR NINE MILE POINT UNIT 2 MAXIMUM EXTENDED LOAD LINE LIMIT ANALYSIS PLUS (NON-PROPRIETARY)

Nine Mile Point Nuclear Station, LLC November 1, 2013

GE Hitachi Nuclear Energy 0HITACHI NEDO-33576 Revision 0 DRF Section 0000-0138-0146 R6 October 2013 Non-ProprietaryInformation - Class I (Public)

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

INFORMATION NOTICE This is a non-proprietary version of the document NEDC-33576P, Revision 0, which has the proprietary information removed. Portions of the document that have been removed are indicated by an open and closed bracket as shown here ((

IMPORTANT NOTICE REGARDING CONTENTS OF THIS REPORT Please Read Carefully The design, engineering, and other information contained in this document is furnished for the purposes of supporting the Constellation Energy Nuclear Group (CENG) license amendment request for a Maximum Extended Load Line Limit Analysis Plus at Nine Mile Point Unit 2 in proceedings before the U.S. Nuclear Regulatory Commission. The only undertakings of GEH with respect to information in this document are contained in the contracts between GEH and its customers or participating utilities, and nothing contained in this document shall be construed as changing that contract. The use of this information by anyone for any purpose other than that for which it is intended, is not authorized; and with respect to any unauthorized use, GEH makes no representation or warranty, and assumes no liability as to the completeness, accuracy, or usefulness of the information contained in this document.

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TABLE OF CONTENTS Page Executive Sum m ary ..................................................................................................................... ix A cronym s ...................................................................................................................................... xi 1.0 Introduction .................................................................................................................... 1-1 1.1 Report Approach ........................................................................................................... 1-2 1.2 Operating Conditions and Constraints ........................................................................... 1-7 1.3 Summ ary and Conclusions ............................................................................................ 1-9 2.0 Reactor C ore and Fuel Perform ance ........................................................................... 2-1 2.1 Fuel Design and Operation ............................................................................................ 2-1 2.2 Therm al Lim its A ssessm ent .......................................................................................... 2-3 2.3 Reactivity Characteristics .............................................................................................. 2-6 2.4 Stability .......................................................................................................................... 2-8 2.5 Reactivity Control ....................................................................................................... 2-14 2.6 Additional Limitations and Conditions Related to Reactor Core and Fuel Perform ance ............................................................................................................ 2-15 3.0 Reactor C oolant and C onnected System s .................................................................... 3-1 3.1 N uclear System Pressure Relief and Overpressure Protection ...................................... 3-1 3.2 Reactor Vessel ............................................................................................................... 3-2 3.3 Reactor Internals ............................................................................................................ 3-3 3.4 Flow -Induced V ibration .............................................................................................. 3-10 3.5 Piping Evaluation ........................................................................................................ 3-13 3.6 Reactor Recirculation System ..................................................................................... 3-20 3.7 M ain Steam Line Flow Restrictors .............................................................................. 3-22 3.8 M ain Steam Isolation Valves ....................................................................................... 3-23 3.9 Reactor Core Isolation Cooling ................................................................................... 3-23 3.10 Residual Heat Rem oval System .................................................................................. 3-25 3.11 Reactor W ater Cleanup System ................................................................................... 3-26 4.0 Engineered Safety Features .......................................................................................... 4-1 4.1 Containm ent System Perform ance ................................................................................ 4-1 4.2 Em ergency Core Cooling System s ................................................................................ 4-6 4.3 Emergency Core Cooling System Perform ance .......................................................... 4-10 4.4 M ain Control Room Atm osphere Control System ...................................................... 4-17 4.5 Standby G as Treatm ent System ................................................................................... 4-17 4.6 M ain Steam Isolation Valve Leakage Control System ................................................ 4-18 4.7 Post-LO CA Combustible G as Control System ........................................................... 4-18 5.0 Instrum entation and C ontrol ........................................................................................ 5-1 5.1 N SSS M onitoring and Control ...................................................................................... 5-1 5.2 BO P M onitoring and Control ........................................................................................ 5-3 5.3 Technical Specification Instrum ent Setpoints ............................................................... 5-6 iii

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 6.0 Electrical Pow er and Auxiliary System s ...................................................................... 6-1 6.1 A C Pow er ...................................................................................................................... 6-I 6.2 D C Pow er ...................................................................................................................... 6-1 6.3 Fuel Pool ........................................................................................................................ 6-2 6.4 W ater System s ............................................................................................................... 6-3 6.5 Standby Liquid Control System .................................................................................... 6-4 6.6 H eating, Ventilation And A ir Conditioning .................................................................. 6-6 6.7 Fire Protection ............................................................................................................... 6-6 6.8 Other System s A ffected ................................................................................................. 6-7 7.0 Pow er C onversion System s ........................................................................................... 7-1 7.1 Turbine-G enerator ......................................................................................................... 7-1 7.2 Condenser and Steam Jet A ir Ejectors .......................................................................... 7-1 7.3 Turbine Steam Bypass ................................................................................................... 7-2 7.4 Feedw ater and Condensate Systems .............................................................................. 7-2 8.0 Radw aste System s and Radiation Sources .................................................................. 8-1 8.1 Liquid and Solid W aste M anagem ent ........................................................................... 8-1 8.2 Gaseous W aste M anagem ent ......................................................................................... 8-1 8.3 Radiation Sources in the Reactor Core .......................................................................... 8-3 8.4 Radiation Sources in Reactor Coolant ........................................................................... 8-3 8.5 Radiation Levels ............................................................................................................ 8-4 8.6 Norm al O peration O ff-Site D oses ................................................................................. 8-6 9.0 Reactor Safety Perform ance Evaluations .................................................................... 9-1 9.1 Anticipated Operational O ccurrences ............................................................................ 9-1 9.2 Design Basis Accidents and Events of Radiological Consequence .............................. 9-4 9.3 Special Events ............................................................................................................. 9-10 10.0 O ther Evaluations ........................................................................................................ 10-1 10.1 H igh Energy Line Break .............................................................................................. 10-1 10.2 M oderate Energy Line Break ...................................................................................... 10-2 10.3 Environm ental Q ualification ....................................................................................... 10-3 10.4 Testing ......................................................................................................................... 10-5 10.5 Individual Plant Exam ination ...................................................................................... 10-6 10.6 Operator Training and Hum an Factors ...................................................................... 10-11 10.7 Plant Life ................................................................................................................... 10-12 10.8 N RC and Industry Com m unications ......................................................................... 10-15 10.9 Em ergency and Abnorm al Operating Procedures ..................................................... 10-15 11.0 Licensing Evaluations .................................................................................................. 11-1 11.1 Effect on Technical Specifications .............................................................................. 11-1 11.2 Environm ental A ssessm ent ......................................................................................... 11-1 11.3 Significant Hazards Consideration A ssessm ent .......................................................... 11-2 12.0 References ..................................................................................................................... 12-1 iv

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Appendix A ............................................................................................................................ A -1 Appendix B ............................................................................................................................. B-1 A ppendix C ............................................................................................................................. C-1 V

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List of Figures Figure Title Page Figure 1-1 Power/Flow Operating Map for MELLLA+ ........................................................ 1-14 Figure 2-1 Power of Peak Bundle versus Cycle Exposure ..................................................... 2-22 Figure 2-2 Coolant Flow for Peak Bundle versus Cycle Exposure ........................................ 2-23 Figure 2-3 Exit Void Fraction for Peak Power Bundle versus Cycle Exposure ..................... 2-24 Figure 2-4 Maximum Channel Exit Void Fraction versus Cycle Exposure ........................... 2-25 Figure 2-5 Core Average Exit Void Fraction versus Cycle Exposure .................................... 2-26 Figure 2-6 Peak LHGR versus Cycle Exposure ..................................................................... 2-27 Figure 2-7 Dimensionless Bundle Power at BOC (200 MWd/ST) ........................................ 2-28 Figure 2-8 Dimensionless Bundle Power at MOC (10,000 MWd/ST) .................................. 2-29 Figure 2-9 Dimensionless Bundle Power at EOC (18,577 MWd/ST) .................................... 2-30 Figure 2-10 Bundle Operating LHGR (kW/ft) at BOC (200 MWd/ST) .................................. 2-31 Figure 2-11 Bundle Operating LHGR (kW/ft) at MOC (10,000 MWd/ST) ............................ 2-32 Figure 2-12 Bundle Operating LHGR (kW/ft) at EOC (18,577 MWd/ST) ............................. 2-33 Figure 2-13 Bundle Operating MCPR at BOC (200 MWd/ST) ............................................... 2-34 Figure 2-14 Bundle Operating MCPR at MOC (10,000 MWd/ST) ......................................... 2-35 Figure 2-15 Bundle Operating MCPR at EOC (18,577 MWd/ST) .......................................... 2-36 Figure 2-16 Bundle Operating LHGR (kW/ft) at 15,000 MWd/ST (Peak MFLPD Point) ...... 2-37 Figure 2-17 Bundle Operating MCPR at 1,500 MWd/ST (Peak MFLCPR Point) .................. 2-38 Figure 2-18 Bundle Average Void History for Bundles with Low CPRs ................................ 2-39 Figure 2-19 Required OPRM Armed Region ........................................................................... 2-40 Figure 5-1 NMP2 EPU/M+ Power/Flow Map with 5% Voiding at the TIP Exit B oun d ary ................................................................................................................ 5-9 Figure 9-1 L R NB P at ICF ...................................................................................................... 9-26 Figure 9-2 LRN BP at M ELLLA+ .......................................................................................... 9-27 Figure 9-3 ODYN ATWS Analysis - PRFO at EOC Short-Term Results ............................ 9-28 Figure 9-4 ODYN ATWS Analysis - MSIVC at EOC Long-Term Results .......................... 9-29 Figure 9-5 ODYN ATWS Analysis - PRFO at EOC PCT .................................................... 9-30 Figure 9-6 Single SLS Pump ODYN ATWS Analysis - PRFO at EOC Short-Term R e su lts .................................................................................................................. 9 -3 1 Figure 9-7 Single SLS Pump ODYN ATWS Analysis - MSIVC at EOC Long-Term R e su lts .................................................................................................................. 9 -3 2 Figure 9-8 Single SLS Pump ODYN ATWS Analysis - PRFO at EOC PCT ....................... 9-33 Figure 9-9 ATWS Instability from MELLLA+ Operating Domain - Turbine Trip with Fu ll Byp ass ........................................................................................................... 9-34 vi

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Figure 9-10 ATWS Instability from MELLLA+ Operating Domain - Turbine Trip with F u ll B yp ass ........................................................................................................... 9-35 Figure 9-11 ATWS Instability from MELLLA+ Operating Domain - Recirculation Pu m p T rip ............................................................................................................. 9-36 Figure 9-12 ATWS Instability from MELLLA+ Operating Domain - Recirculation P u mp T rip ............................................................................................................. 9-37 vii

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List of Tables Table Title Page Table 1-1 Computer Codes Used in the M+SAR Evaluations .............................................. 1-10 Table 1-3 Core Thermal Power to Core Flow Ratios ............................................................ 1-13 Table 2-1 Peak N odal Exposures .......................................................................................... 2-17 Table 2-2 Core Thermal Power to Core Flow Ratio at Steady-State and Off-Rated C on d ition s ............................................................................................................ 2 -18 Table 2-3 TLO and SLO DSS-CD Licensing Basis Generic Applicability Envelope Checklist C onfirm ation ........................................................................................ 2-19 Table 2-4 ((................. 2-20 Table 2-5 ((

)).................................................................................................... 2 -2 1 Table 3-1 K ey Results at 120% O LTP .................................................................................. 3-29 Table 9-1 AOO Event Results Sum m ary .............................................................................. 9-17 Table 9-2 Comparison of Slow Recirculation Flow Increase Results and MCPR Flow L im it ..................................................................................................................... 9 - 18 Table 9-3 Key Input Parameters for ATWS Analyses .......................................................... 9-19 Table 9-4 Key Results for Licensing Basis ODYN ATWS Analysis ................................... 9-20 Table 9-5 ODYN ATWS Analysis Limiting Event Results at MELLLA+ .......................... 9-21 Table 9-6 Key Input Parameters for Single SLS Pump ATWS Analyses ............................. 9-22 Table 9-7 Key Results for Single SLS Pump ODYN ATWS Analysis ................................ 9-23 Table 9-8 Single SLS Pump ODYN ATWS Analysis Limiting Event Results .................... 9-24 Table 9-9 Key Results for ATWS with Core Instability Analysis from MELLLA+

O perating D omain ................................................................................................ 9-25 viii

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EXECUTIVE

SUMMARY

This report summarizes the results of all significant safety evaluations (SEs) performed that justify the expansion of the core flow (CF) operating domain for the Nine Mile Point Unit 2 (NMP2) nuclear plant. The changes expand the operating domain in the region of operation with less than rated core flow (RCF), but do not increase the licensed power level or the maximum CF. The expanded operating domain is identified as Maximum Extended Load Line Limit Analysis Plus (MELLLA+).

The scope of evaluations required to support the expansion of the CF operating domain to the MELLLA+ boundary is contained in the Licensing Topical Report (LTR) NEDC-33006P-A, "Maximum Extended Load Line Limit Analysis Plus," referred to as the M+LTR (Reference 1).

This report provides a systematic disposition of the M+LTR subjects applied to NMP2, including performance of plant-specific assessments and confirmation of the applicability of generic assessments to support a MELLLA+ CF operating domain expansion.

It is not the intent of this report to address all the details of the analyses and evaluations reported herein. Only previously Nuclear Regulatory Commission (NRC)-approved or industry-accepted methods were used for the analyses of accidents and transients. Therefore, because the safety analysis methods have been previously addressed, the details of the methods are not presented for review and approval in this report. Also, event and analysis descriptions that are already provided in other licensing reports or the updated safety analysis report (USAR) are not repeated within this report.

The MELLLA+ operating domain expansion is applied as an incremental expansion of the operating boundary without changing the maximum licensed power or CF, or the current plant vessel dome pressure. This report supports operation of NMP2 at current licensed thermal power (CLTP) of 3,988 MWt with CF as low as 85% RCF following implementation of the extended power uprate (EPU) at NMP2. The terms CLTP and EPU are used interchangeably throughout this document, and refer to the same power level of 3,988 MWt. The MELLLA+ core operating domain expansion does not require major plant systems modifications. The core operating domain expansion involves changes to the operating power/core flow map, minor system modifications, procedure changes, and changes to a small number of instrument setpoints.

Because there are no increases in the operating pressure, power, steam flow rate, and feedwater (FW) flow rate, there are no significant effects on the plant systems outside of the nuclear steam supply system (NSSS). There is a potential increase in the steam moisture content at certain times while operating in the MELLLA+ operating domain. The effects of the potential increase in moisture content on plant systems have been evaluated and determined to be acceptable. The MELLLA+ operating domain expansion does not cause additional requirements to be imposed on any of the safety, balance-of-plant (BOP), electrical, or auxiliary systems. No changes to the power generation and electrical distribution systems are required as a result of the MELLLA+

operating domain expansion.

Evaluations of the reactor, engineered safety features (ESFs), power conversion, emergency power, support systems, environmental issues, and design basis accidents (DBAs) were ix

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) performed. The following conclusions summarize the results of the evaluations presented in this report.

All safety aspects of the plant that are affected by MELLLA+ operating domain expansion were evaluated.

There is no change in the existing design basis and licensing basis acceptance criteria of the plant.

Evaluations were performed using NRC-approved or industry-accepted analytical methods.

" Where applicable, more recent industry codes and standards were used.

No major hardware modifications to safety-related equipment are required to support MELLLA+ operating domain expansion.

" Systems and components affected by MELLLA+ were reviewed to ensure that there is no significant challenge to any safety system.

" Potentially affected commitments to the NRC were reviewed.

Planned changes not yet implemented have also been reviewed for the effects of MELLLA+.

This report summarizes the results of the SEs needed to justify a licensing amendment to allow the MELLLA+ operating domain expansion to a minimum CF rate of 85% of RCF at 100%

CLTP. These SEs demonstrate that the MELLLA+ operating domain expansion can be accommodated:

" without a significant increase in the probability or consequences of an accident previously evaluated;

without creating the possibility of a new or different kind of accident from any accident previously evaluated; and

" without exceeding any presently existing regulatory limits or acceptance criteria applicable to the plant that might cause a reduction in a margin of safety.

Therefore, the requested MELLLA+ operating domain expansion does not involve a significant hazards consideration.

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ACRONYMS Term Definition 1RPT One Recirculation Pump Trip 2RPT Two Recirculation Pump Trip ABSP Automated Backup Stability Protection AC Alternating Current ADS Automatic Depressurization System AL Analytical Limit ALARA As Low As Reasonably Achievable ANS American Nuclear Society ANSI American National Standards Institute AOO Anticipated Operational Occurrence AOP Abnormal Operating Procedure AOT Allowable Outage Time AP Annulus Pressurization APRM Average Power Range Monitor ARI Alternate Rod Insertion ARS Amplified Response Spectra ART Adjusted Reference Temperature ARTS APRM / RBM / Technical Specifications ASME American Society of Mechanical Engineers AST Alternate Source Term atom % Percentage of Atoms ATWS Anticipated Transient Without Scram AV Allowable Value BOC Beginning of Cycle BOP Balance-of-Plant BPV Boiler and Pressure Vessel BSP Backup Stability Protection BSW Biological Shield Wall BTU/Ibm BTU per Pounds Mass BWR Boiling Water Reactor BWRVIP Boiling Water Reactor Vessel and Internals Project CDA Confirmation Density Algorithm CDF Core Damage Frequency xi

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Term Definition cfmn Cubic Feet per Minute CENG Constellation Energy Nuclear Group CF Core Flow CFR Code of Federal Regulations CLTP Current Licensed Thermal Power CO Condensation Oscillation COLR Core Operating Limits Report CPR Critical Power Ratio ACPR Change in Critical Power Ratio CRD Control Rod Drive CRDA Control Rod Drop Accident CRGT Control Rod Guide Tube CS Core Spray CST Condensate Storage Tank DBA Design Basis Accident DC Direct Current DFFR Dynamic Forcing Functions Report D/G Diesel Generator DIR Design Input Request DOR Division of Responsibility DRF Design Record File DSS-CD Detect and Suppress Solution-Confirmation Density DSS-CD LTR DSS-CD Licensing Topical Report DSS-CD TRACG LTR DSS-CD TRACG Licensing Topical Report DTR Draft Task Report DW Drywell ECCS Emergency Core Cooling Systems EDG Emergency Diesel Generator EFPY Effective Full Power Year EOC End of Cycle EOOS Equipment Out-of-Service EOP Emergency Operating Procedure EPRI Electric Power Research Institute EPU Extended Power Uprate EQ Environmental Qualification xii

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Term Definition ESF Engineered Safety Feature OF Degrees Fahrenheit FAC Flow Accelerated Corrosion FCV Flow Control Valve FHA Fuel Handling Accident FIV Flow-Induced Vibration FTR Final Task Report FW Feedwater FWCF Feedwater Controller Failure (Maximum Demand)

FWHOOS Feedwater Heater(s) Out-of-Service GEH GE-Hitachi Nuclear Energy Americas LLC GESTAR General Electric Standard Application for Reactor Fuel GNF Global Nuclear Fuel - Americas LLC gpm Gallons Per Minute GWd/ST Gigawatt Days per Short Ton HCTL Heat Capacity Temperature Limit HELB High Energy Line Break HFCL High Flow Control Line HPCI High Pressure Coolant Injection HPCS High Pressure Core Spray HVAC Heating, Ventilation, and Air Conditioning IASCC Irradiated Assisted Stress Corrosion Cracking ICF Increased Core Flow ID Internal Diameter IGSCC Intergranular Stress Corrosion Cracking ILBA Instrument Line Break Accident IPE Individual Plant Examination IPEEE Individual Plant Examination of External Events IRM Intermediate Range Monitor ISI In-Service Inspection JPSL Jet Pump Sensing Line LAR License Amendment Request LCO Limiting Condition for Operation LCS Leakage Control System LERF Large Early Release Frequency xiii

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Term Definition LFWH Loss of Feedwater Heating LHGR Linear Heat Generation Rate LHGRFACf Linear Heat Generation Rate Flow Factor LOCA Loss-of-Coolant Accident LOFW Loss of Feedwater LOOP Loss of Off-Site Power LPCI Low Pressure Coolant Injection LPCS Low Pressure Core Spray LPRM Local Power Range Monitor LRNBP Generator Load Rejection Without Bypass LTR Licensing Topical Report MAPLHGR Maximum Average Planar Linear Heat Generation Rate MCO Moisture Carryover MCPR Minimum Critical Power Ratio MCPRr Flow-Dependent Minimum Critical Power Ratio MCPR, Power-Dependent Minimum Critical Power Ratio MCR Main Control Room MELB Moderate Energy Line Break MELC Moderate Energy Line Crack MELLLA Maximum Extended Load Line Limit Analysis MELLLA+ Maximum Extended Load Line Limit Analysis Plus MFLPD Maximum Fraction of Limiting Power Density MIP MCPR Importance Parameter M+LTR MELLLA+ Licensing Topical Report NEDC-33006P-A M+SAR MELLLA+ Safety Analysis Report (Plant Specific Safety Analysis Report)

M+LTR SER MELLLA+ Safety Evaluation Report Mlbm/hr Millions Of Pounds Mass per Hour MOC Middle of Cycle MOP Mechanical Overpower MOV Motor-Operated Valve MPC Maximum Permissible Concentration MS Main Steam MSIV Main Steam Isolation Valve MSIVC Main Steam Isolation Valve Closure MSIVF Main Steam Isolation Valve Closure with Scram on High Flux xiv

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Term Definition MSL Main Steam Line MSLBA Main Steam Line Break Accident MWd/ST Megawatt Days per Short Ton MWe Megawatt-Electric MWt Megawatt-Thermal NCL Natural Circulation Line NMP2 Nine Mile Point Unit 2 NMPNS Nine Mile Point Nuclear Station, LLC NPSH Net Positive Suction Head NRC Nuclear Regulatory Commission NSSS Nuclear Steam Supply System NTSP Nominal Trip Setpoint OBE Operating Basis Earthquake OLMCPR Operating Limit Minimum Critical Power Ratio OLTP Original Licensed Thermal Power OOS Out-of-Service OPRM Oscillation Power Range Monitor PCT Peak Cladding Temperature PDI Performance Demonstration Initiative ppm Parts per Million PRA Probabilistic Risk Assessment PRFO Pressure Regulator Failure - Open psi Pounds per Square Inch psia Pounds per Square Inch - Absolute psid Pounds per Square Inch - Differential psig Pounds per Square Inch - Gauge PWP Project Work Plan QA Quality Assurance QAP Quality Assurance Program RAI Request for Additional Information RBM Rod Block Monitor RCF Rated Core Flow RCIC Reactor Core Isolation Cooling RCPB Reactor Coolant Pressure Boundary RE Responsible Engineer xv

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Term Definition RG Regulatory Guide RHR Residual Heat Removal RIPD Reactor Internal Pressure Difference RIS Regulatory Issue Summary RLA Reload Licensing Analysis rpm Revolutions per Minute RPS Reactor Protection System RPT Recirculation Pump Trip RPTOOS Recirculation Pump Trip Out-of-Service RPV Reactor Pressure Vessel RRS Reactor Recirculation System RSLB Recirculation Suction Line Break RWCU Reactor Water Cleanup RWE Rod Withdrawal Error RWM Rod Worth Minimizer SAD Amplitude Discriminator Setpoint SAR Safety Analysis Report SBO Station Blackout SC Safety Communication SDC Shutdown Cooling SE Safety Evaluation SER Safety Evaluation Report SGTS Standby Gas Treatment System SLMCPR Safety Limit Minimum Critical Power Ratio SLO Single Loop Operation SLS Standby Liquid Control System SOP Special Operating Procedure SPC Suppression Pool Cooling SPDS Safety Parameter Display System SRLR Supplemental Reload Licensing Report SRM Source Range Monitor SRO Strong Rod Out SRP Standard Review Plan SRV Safety Relief Valve SRVDL Safety Relief Valve Discharge Line xvi

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Term Definition SRVOOS Safety Relief Valve - Out-of-Service SSE Safe Shutdown Earthquake STP Simulated Thermal Power TAF Top of Active Fuel TBVOOS Turbine Bypass Out-of-Service TFW Feedwater Temperature TIP Traversing Incore Probe TLO Two Loop Operation T-M Thermal-Mechanical TOP Thermal Overpower TR Topical Report TS Technical Specifications TSD Task Scoping Document TSTF Technical Specification Task Force TSV Turbine Stop Valve TTNBP Turbine Trip Without Bypass TTWBP Turbine Trip With Bypass UHS Ultimate Heat Sink USAR Updated Safety Analysis Report USE Upper Shelf Energy V&V Verification and Validation VPF Vane Passing Frequency wt.% Percent by Weight xvii

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1.0 INTRODUCTION

This report summarizes the results of all significant SEs performed that justify the expansion of the operating boundary to NMP2 operation at a CLTP of 3,988 MWt and with CF as low as 85%

of RCF. The terms CLTP and EPU are used interchangeably throughout this document, and refer to the same power level of 3,988 MWt. The changes expand the operating domain in the region of operation with less than RCF, but do not increase the licensed power level or the maximum CF. The expanded operating domain is identified as MELLLA+.

The scope of evaluations required to support the expansion of the CF operating domain to the MELLLA+ boundary is contained in the LTR NEDC-33006P-A, "Maximum Extended Load Line Limit Analysis Plus," referred to as the M+LTR (Reference 1). This report provides a systematic disposition of the M+LTR subjects applied to NMP2, including performance of plant-specific assessments and confirmation of the applicability of generic assessments to support a MELLLA+ CF operating domain expansion.

The MELLLA+ core operating domain expansion does not require major plant hardware modifications. In accordance with Limitation and Condition 12.2 of the NRC Safety Evaluation Report (SER) for MELLLA+ (Reference 1), referred to as the M+LTR SER, NMP2 will implement the Detect and Suppress Solution-Confirmation Density (DSS-CD) solution, with limitations and conditions as identified in the DSS-CD LTR SER (Reference 2), consistent with the M+LTR. DSS-CD requires a revision to the existing stability solution software. The operating domain expansion involves changes to the operating power/core flow map and changes to a small number of instrument setpoints. Because there are no increases in the operating pressure, power, steam flow rate, and FW flow rate, there are no significant effects on the plant hardware outside of the NSSS. There is a potential increase in the steam moisture content at certain times while operating in the MELLLA+ operating domain. The effects of the potential increase in moisture content on plant hardware have been evaluated and determined to be acceptable. The MELLLA+ operating domain expansion does not cause additional requirements to be imposed on any of the safety, BOP, electrical, or auxiliary systems. No changes to the power generation and electrical distribution systems are required due to the introduction of MELLLA+.

This report also addresses applicable limitations and conditions as described in the M+LTR SER and the NRC SER for the GE-Hitachi Nuclear Energy Americas LLC (GEH) LTR NEDC-33173P-A, "Applicability of GE Methods to Expanded Operating Domains," referred to as the Methods LTR SER (Reference 3).

The disposition of each limitation and condition is discussed along with the relevant section of this report. A complete listing of the required M+LTR SER, Methods LTR SER, and DSS-CD LTR SER limitations and conditions and the sections of this report which address them is presented in Appendices A, B, and C, respectively.

1-1

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 1.1 REPORT APPROACH The evaluations provided in this report demonstrate that the MELLLA+ operating domain expansion can be accomplished within the applicable safety design criteria. Many of the SEs and equipment assessments previously performed for the NMP2 EPU are unaffected because the MELLLA+ operating domain expansion effects are limited to the NSSS system.

This NMP2 MELLLA+ safety analysis report (M+SAR) follows the same structure and content as the M+LTR (Reference 1). Two dispositions of the evaluation topics are used to characterize the MELLLA+ evaluation scope. Topics are dispositioned as either "Generic" or "Plant-Specific" as described in Sections 1. 1.1 and 1.1.2, respectively.

1.1.1 Generic Assessments Generic assessments are those SEs that can be dispositioned by:

Providing or referencing a bounding analysis for the limiting conditions;

" Demonstrating that there is a negligible effect due to MELLLA+;

" Identifying the portions of the plant that are unaffected by the MELLLA+ power/flow map operating domain expansion; or

Demonstrating that the sensitivity to MELLLA+ is small enough that the required plant cycle-specific reload analysis process is sufficient and appropriate for establishing the MELLLA+ licensing basis in accordance with M+LTR SER Limitation and Condition 12.3.c and as defined in General Electric Standard Application for Reactor Fuel (GESTAR) (Reference 4).

As per M+LTR SER Limitation and Condition 12.4, the plant-specific MELLLA+

application shall provide the plant-specific thermal limits assessment and transient analysis results. Considering the timing requirements to support the reload, the fuel and cycle-dependent analyses including the plant-specific thermal limits assessment may be submitted by supplementing the initial M+SAR. Additionally, the Supplemental Reload Licensing Report (SRLR) for the initial MELLLA+ implementation cycle shall be submitted for NRC staff confirmation.

Some of the SEs affected by MELLLA+ are fuel operating cycle (reload) dependent.

Reload dependent evaluations require that the reload fuel design, core loading pattern, and operational plan be established so that analyses can be performed to establish core operating limits. The reload analysis demonstrates that the core design for MELLLA+

meets the applicable NRC evaluation criteria and limits documented in Reference 4.

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)) No plant can enter the MELLLA+ domain unless the appropriate reload core analysis is performed and all criteria and limits documented in Reference 4 are satisfied. Otherwise, the plant would be in an unanalyzed condition. Based on current requirements, the reload analysis results are documented in the SRLR, and the applicable core operating limits are documented in the plant-specific Core Operating Limits Report (COLR).

NMP2 will supplement this M+SAR with the fuel and cycle dependent analysis including the plant-specific thermal limits assessment. Additionally, NMP2 will submit the SRLR for the initial MELLLA+ implementation cycle for NRC staff confirmation.

As required by M+LTR SER Limitation and Condition 12.5.a, Nine Mile Point Nuclear Station, LLC (NMPNS) will modify NMP2 Technical Specification (TS) 3.4.1 to include a requirement that prohibits intentional single loop operation (SLO) while in the MELLLA+ operating domain, as defined in the COLR. This information is presented in the NMPNS MELLLA+ license amendment request (LAR) for NMP2.

As required by M+LTR SER Limitation and Condition 12.3.b, the applicability of the generic assessments to NMP2 is identified and confirmed in the applicable sections. In the event that the generic assessment presented in the M+LTR is not applicable to NMP2, a plant-specific evaluation per Section 1. 1.2 is completed to demonstrate the acceptability of the MELLLA+ operating domain expansion.

1.1.2 Plant-Specific Evaluation A NMP2-specific evaluation is provided for SEs not categorized as Generic. Where applicable, the assessment methodology in References 1, 4, 5, 6, or 7 is referenced. As required by M+LTR SER Limitation and Condition 12.3.a, the plant-specific evaluations performed and reported in this document use plant-specific values to model the actual plant systems, transient response, and current operating conditions.

1.1.3 Computer Codes and Methods NRC-approved or industry-accepted computer codes and calculational techniques are used in the evaluations for the MELLLA+ operating domain. The primary computer codes used for NMP2 evaluations are listed in Table 1-1. The application of these codes complies with the limitations, restrictions, and conditions specified in the approving NRC SER. Exceptions to the use of the code or special conditions of the applicable SER are included as notes to Table 1-1.

The Methods LTR NEDC-33173P-A (Reference 3) documents all analyses supporting the conclusions in this section that the application ranges of GEH codes and methods are adequate in the MELLLA+ operating domain. In accordance with the M+LTR SER Limitation and Condition 12. 1, the range of mass fluxes and power/flow ratios in the GEXL database covers the intended MELLLA+ operating domain. The database includes low flow, high qualities, and void fractions. There are no restrictions on the application of the GEXL-PLUS correlation in the MELLLA+ operating domain.

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As required by M+LTR SER Limitation and Condition 12.23.2, the NMP2-specific ODYN and TRACG calculations are provided to the NRC as required.

As discussed in Section 1.0, the specific limitations and conditions associated with the M+LTR, Methods LTR, DSS-CD LTR, and DSS-CD TRACG LTR are discussed along with the relevant section of this report. A complete listing of the required M+LTR SER, Methods LTR SER, and DSS-CD LTR SER limitations and conditions and the sections of this report which address them is presented in Appendices A, B, and C, respectively.

1.1.4 Scope of Evaluations Sections 2.0 through 11.0 provide evaluations of the MELLLA+ operating domain expansion on the respective topics. The scope of the evaluations is summarized in the following sections.

Section 2.0, Reactor Core and Fuel Performance: Core and fuel performance parameters are confirmed for each fuel cycle, and will be evaluated and documented in the SRLR and COLR for each fuel cycle that implements the MELLLA+ operating domain.

Section 3.0, Reactor Coolant and Connected Systems: Evaluations of the NSSS components and systems are performed in the MELLLA+ operating domain. Because the reactor operating pressure and the CF are not increased by MELLLA+, the effects on the Reactor Coolant and connected systems are minor. These evaluations confirm the acceptability of the MELLLA+

changes to process variables in the NSSS.

Section 4.0, Engineered Safety Features: The effects of MELLLA+ operating domain expansion on the containment, emergency core cooling systems (ECCS), standby gas treatment system (SGTS), and other ESFs are evaluated. The operating pressure for ESF equipment is not increased because operating pressure and safety relief valve (SRV) setpoints are unchanged as a result of MELLLA+.

Section 5.0, Instrumentation and Control: The instrumentation and control systems and analytical limits (ALs) for setpoints are evaluated to establish the effects of MELLLA+ operating domain expansion on process parameters. The scope of MELLLA+ effects on the controls and setpoints is limited because the MELLLA+ parameter variations are limited to the core.

Section 6.0, Electrical Power and Auxiliary Systems: Because the power level is not changed by MELLLA+, the electrical power and distribution systems are not affected. The auxillary systems have been previously evaluated to ensure they are capable of supporting safe plant operation at CLTP, which is unchanged by MELLLA+ operating domain expansion.

Section 7.0, Power Conversion Systems: Because the pressure, steam flow, and FW flow do not change as a result of MELLLA+ operating domain expansion, the power conversion systems are not affected by MELLLA+.

Section 8.0, Radwaste Systems and Radiation Sources: The liquid and gaseous waste management systems are not affected by the MELLLA+ operating domain changes. However, slightly higher loading of the condensate demineralizers is possible if the moisture carryover (MCO) in the reactor steam increases. The radiological consequences are evaluated to show that applicable regulations are met.

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Section 9.0, Reactor Safety Performance Evaluations: The USAR anticipated operational occurrences (AOOs), DBAs, and special events are reviewed as part of the MELLLA+

evaluation.

Section 10.0, Other Evaluations: High energy line break (HELB) and environmental qualification (EQ) evaluations for the MELLLA+ domain are confirmed to demonstrate the operability of plant equipment at MELLLA+ conditions. The effects on the individual plant examination (IPE) are evaluated to demonstrate there is no significant change to the NMP2 vulnerability to severe accidents.

Section 11.0, Licensing Evaluations: This section includes the effect on TS. The Environmental Assessment and the No Significant Hazards Consideration are provided as a part of the accompanying LAR.

1.1.5 Product Line Applicability The M+LTR describes processes, evaluations, and dispositions applicable to GE boiling water reactor (BWR) product lines BWR/3, BWR/4, BWR/5, and BWRI6. As such, the M+LTR process is applicable to NMP2, a BWR/5.

1.1.6 Report Generation and Review Process This M+SAR represents several years of project planning activities, engineering analysis, technical verification, and technical review. The final stages of the M+SAR preparation include M+SAR integration, additional review, on-site review committee review, and submittal to NRC.

The NMP2 MELLLA+ project relied on the generic M+LTR (Reference 1) submitted to and approved by the NRC (Reference 1).

The project began with the respective GEH and NMPNS Project Managers creating a Project Work Plan (PWP). This PWP, developed in accordance with GEH engineering procedures, was used to define the plant-specific work scope, inputs and outputs required for project activities. A division of responsibility (DOR) between NMPNS and GEH was used to further develop the work scope and assign responsible engineers (REs) from each organization. A task scoping document (TSD) applicable for each GEH task was created, reviewed, and approved by NMPNS prior to any technical work being performed. Each GEH task RE submitted a design input request (DIR) to the NMPNS task RE interface to define the correct plant information for use in the GEH task analysis and evaluation. Additional DIRs were submitted as the project continued.

A plant-specific M+SAR "shell" was created that contains the appropriate depth of information expected in the final M+SAR.

All pertinent information is captured in an individual task design record file (DRF) maintained by the GEH RE with oversight by the respective engineering manager. Each DRF contains the quality assurance records applicable to the task, which includes evidence of design verification.

A draft task report (DTR) was created for every GEH task. The DTR includes a description of the analysis performed, inputs, methods applied, results obtained and includes input to the applicable M+SAR section(s). The DTR with M+SAR input was verified, in accordance with the GEH quality assurance program (QAP), by a GEH technical verifier and a GEH Regulatory 1-5

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Affairs verifier, with oversight by the responsible GEH technical manager and GEH Project Manager. The DTR with M+SAR input was transmitted by the GEH Project Manager to NMPNS and reviewed by the NMPNS RE and other NMPNS engineers, as appropriate.

Subsequent comments were resolved between the GEH and the NMPNS REs and a final task report (FTR) with M+SAR input was developed. The FTR with M+SAR input was again verified (whether or not there were changes to the document), in accordance with the GEH QAP, by a GEH technical verifier and a GEH Regulatory Affairs verifier, with oversight by the responsible GEH technical manager and GEH Project Manager. The GEH Project Manager transmitted the FTR with M+SAR input to the NMPNS Project Manager.

For the NMP2 MELLLA+ project, NMPNS personnel:

1. Conducted multidisciplinary technical reviews of GEH evaluation reports (DTRs with M+SAR input and FTRs with M+SAR input) to ensure:

i. Appropriate use of design inputs; ii. Consistency with the M+LTR; and iii. Design basis and licensing basis requirements were addressed.

2. Provided technical review results, in the form of detailed comments, to GEH performers;

3. Participated in discussions with GEH REs to address and resolve comments; and

4. Controlled the application of the NMPNS off-site services process to GEH.

The Regulatory Affairs RE integrated the individual M+SAR sections creating a Draft M+SAR that was verified, in accordance with the GEH QAP, by another GEH Regulatory Affairs engineer, with oversight by the GEH Regulatory Affairs Services Licensing Manager and the GEH Project Manager. The GEH Project Manager transmitted the verified Draft M+SAR to NMPNS where it received another complete review by NMPNS's technical personnel, project staff, and Licensing staff.

NMPNS personnel generated questions and comments, which were responded to by GEH's technical and Regulatory Affairs personnel. The M+SAR was then presented to the NMPNS's on-site review committee. After resolution of any final comments, the Final M+SAR was submitted to the NRC.

A technical assessment of GEH's work was performed during reviews conducted at GEH offices in Wilmington, NC during January 2011. The scope of these assessments included work performed by GEH and Global Nuclear Fuel - Americas LLC (GNF) in support of the NMP2 MELLLA+ project. Participating in those activities were representatives of NMP2 mechanical/structural, nuclear, and reactor engineering disciplines, and project engineering. The NMP2 team reviewed design inputs, analysis methodologies, and results in the GEH DRFs. The reviews included discussion with GEH technical task performers to obtain a thorough understanding of GEH analysis methods.

1.1.7 Report Generation and Review Process As noted in Section 1.1.6 above, a DOR between NMPNS and GEH was used to further develop the work scope and assign REs from each organization. Tasks assigned to NMPNS REs were 1-6

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) performed under the NMPNS 10 Code of Federal Regulations (CFR) 50, Appendix B QAP, where applicable. The NMPNS assigned tasks were performed internally by NMPNS engineers or contracted out to engineering consulting firms on the NMPNS approved supplier list. Where applicable, the contractors applied a 10 CFR 50 Appendix B QAP.

NMPNS internal tasks were prepared, reviewed, and approved in accordance with applicable procedures.

For contracted tasks, a TSD applicable for each task was created, reviewed, and approved by NMPNS prior to any technical work being performed. This work scope formed the basis for the MELLLA+ task. The design inputs were then collected, reviewed, and forwarded to the engineering consultant, in accordance with applicable procedures.

FTRs, and other engineering products, when issued, are processed through the NMPNS engineering change process as a final verification of acceptability and retained as a quality record in the NMPNS nuclear records management system.

1.2 OPERATING CONDITIONS AND CONSTRAINTS 1.2.1 Power/Flow Map The NMP2 power/flow map including the MELLLA+ operating domain expansion is shown in Figure 1-1. ((

All lines on the power/flow map in Figure 1-1, other than those associated with the MELLLA+

operating domain expansion, are unchanged by MELLLA+.

As required by M+LTR SER Limitation and Condition 12.5.c, NMP2 will include the power/flow map in the COLR after the MELLLA+ operating domain expansion is approved.

The MELLLA+ domain extends from 55% RCF at 77.6% EPU to 85% RCF at 100% EPU.

Normal core performance characteristics for plant power/flow maneuvers at near full power can be accomplished above 55% CF. Due to stability considerations at high power and low CF, the MELLLA+ domain was not extended below 55% RCF. The reactor operating conditions following an unplanned event could stabilize at a power/flow point outside the allowed operating domain. If this occurs the operator must reduce power or increase flow in accordance with plant procedures to place the plant back into the allowed operating domain.

The steady-state core thermal power to CF ratio for operation in the MELLLA+ domain is listed in Table 1-3. Each point listed is in compliance with the Methods LTR SER Limitation and Condition 9.3 of 50 MWt/Mlbmihr with the exception of the point of low flow/ high power, point

'M' (55% RCF / 77.6% EPU), on Figure 1-1. The point on the power/flow map is only marginally above the limit and is not used for extended periods of operation. Because the limitation is not intended to place operational restrictions on the plant (Reference 3.c), the NMP2 MELLLA+

power/flow map shall remain as shown in Figure 1-1, without any additional restrictions.

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As NMP2 exceeds the power-to-flow ratio of 50 MWt/Mlbm/hr at 55% RCF, an assessment of the limitation with respect to the conservatism of the power distribution uncertainties is performed. The results of this assessment are provided in Section 2.2.5.

1.2.2 Reactor Heat Balance The reactor heat balance is affected. Operation in the MELLLA+ domain, with lower CF, results in a decrease in recirculation pump heat and core inlet enthalpy.

1.2.3 Core and Reactor Conditions As mentioned previously, the MELLLA+ operating domain expansion results in changes to the core and reactor.

Table 1-2 compares Maximum Extended Load Line Limit Analysis (MELLLA) and MELLLA+

thermal-hydraulic operating conditions for NMP2. The differences shown in Table 1-2 are typical of other BWR plants analyzed for MELLLA+ operating domain expansion, and the core operating conditions listed in Table 1-3 represent the maximum allowed power-to-flow ratio statepoints within the boundaries of the MELLLA+ operating domain. ((

))

The decay heat is principally a function of the reactor power level and the irradiation time. The MELLLA+ operating domain expansion does not alter either of these two parameters, and therefore, there is no first order effect on decay heat. Enrichment, exposure, void fraction, power history, cycle length, and refueling batch fraction have a second order effect on decay heat.

1]

1.2.4 Operational Enhancements The following table provides the performance improvement and/or equipment out-of-service (EOOS) features applicable to NMP2 and whether they are allowed in the MELLLA+ operating domain. The table also dispositions other operational enhancements that were discussed in the M+LTR (Reference 1).

Operational Enhancements MELLLA+ NMP2 M+SAR Increased Core Flow (ICF) Allowed Included Single Loop Operation Not Allowed Not Included Safety Relief Valve - Out-of-Service (SRVOOS) (2 valves) Allowed Included Average Power Range Monitor (APRM) / Rod Block Allowed Included Monitor (RBM) / Technical Specifications (ARTS)

Recirculation Pump Trip Out-of- Service (RPTOOS) Allowed Included 1-8

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Turbine Bypass Out-of-Service (TBVOOS) Allowed Included Main Steam Isolation Valve (MSIV) Out-of-Service (OOS) Allowed Included Two Automatic Depressurization System (ADS) Valves Out- Allowed Included of-Service 20'F FW Operational Temperature Band Allowed Included 24 Month Cycle Allowed Included 60-Year Plant Life Allowed Included The evaluations performed in support of MELLLA+ operating domain expansion consider each of the operational enhancements listed as "Allowed." Because the operational enhancements are considered as a part of the design inputs for evaluations performed in support of MELLLA+

operating domain expansion, these operational enhancements are evaluated across the scope of this M+SAR and are therefore not dispositioned in a specific section.

The existing NMP2 License Condition 7 restricts operation with FW heating to within 20 degrees of the design FW temperature which satisfies M+LTR SER Limitation and Condition 12.5.b.

SLO in the MELLLA+ domain is not proposed. The present licensing basis for SLO remains applicable per plant TS.

As required by M+LTR SER Limitation and Condition 12.5.a, NMPNS will modify NMP2 TS 3.4.1 to include a requirement that prohibits intentional SLO operation while in the MELLLA+ operating domain as defined in the COLR. This information is presented in the NMPNS MELLLA+ LAR for NMP2.

1.3

SUMMARY

AND CONCLUSIONS This M+SAR documents the results of analyses necessary to expand the operating domain of the NMP2 plant to include the MELLLA+ domain. This document conforms to the scope, content and structure described in the M+LTR, which the NRC has determined "is acceptable for referencing in licensing applications for GE-designated boiling water reactors to the extent specified and under the limitations and conditions delineated in the TR [topical report] and in the enclosed final SE [safety evaluation]."

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Table 1-1 Computer Codes Used in the M+SAR Evaluations Task Computer Version or NRC Comments Code* Revision Approved Reactor Heat Balance ISCOR 09 Y(l) NEDE-2401 IP Rev. 0 SER Reactor Core and Fuel TGBLA 06 Y(2) NEDE-30130P-A Performance PANACEA 11 Y(2) NEDE-30130P-A ISCOR 09 Y(l) NEDE-240I P Rev. 0 SER PRIME 03 Y(17) NEDC-33256P-A Revision I, NEDC-33257P-A Revision 1, NEDC-33258P-A Revision 1 Thermal Hydraulic Stability ODYSY 05 Y NEDC-33213P-A TRACG 04 Y(14) NEDE-33147P-A Rev. 4 ISCOR 09 Y(l) NEDE-2401 IP Rev. 0 SER PANACEA II Y(3) NEDE-30130P-A Reactor Internal Pressure LAMB 07 (4) NEDE-20566P-A, September 1986 Differences TRACG 02 Y(5) NEDE-32176P, Rev. 0, February 1993 NEDE-32177P, Rev. 1, June 1993 NRC TAC No. M90270, Sept. 1994 ISCOR 09 Y(l) NEDE-2401 1P Rev. 0 SER Reactor Recirculation BILBO 04V (8) NEDE-23504, Feb. 1977 System (RRS)

Reactor Pressure Vessel TGBLA 06 Y(2) NEDE-30130P-A (RPV) Fluence DORTG 01 Y(l 1, 12) CCC-543 Containment System M3CPT 05 Y NEDO-10320, April 1971 (Reference 8)

Response and NUREG-0808 (Reference 9)

NEDE-20566P-A, September 1986 LAMB 08 (4) (Reference 10)

Break Flow Mass/Energy TRACG 04 N(I 5) NEDE-32176P Rev. 4, January 2008 Release Rates NEDE-32177P Rev. 3, August 2007 NEDO-33083-A Rev. 1, September 2010 Annulus Pressurization (AP) ISCOR 09 Y(l) NEDE-2401 IP Rev. 0 SER Loads GOTHIC 7.2b N(16)

AP Loads - RPV and SAP4G 07 N(8) NEDO-10909, Rev. 7, December 1979 Internals' Structural SPECA 05 N(8) NEDE-25181, August 1996 Analysis PDA 02 N(8) NEDE-10813A, February 1976 ECCS-Loss-of-Coolant LAMB 08 Y NEDE-20566P-A Accident (LOCA) PRIME 01 Y(17) NEDC-33256P-A, Rev. 1 01 Y NEDC-33257P-A, Rev. 1 01 Y NEDC-33258P-A, Rev. I SAFER 04 Y (9) (10)

ISCOR 09 Y(l) NEDE-2401 IP Rev. 0 SER TASC 03 Y NEDC-32084P-A 1-10

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Task Computer Version or NRC Comments Code* Revision Approved Transient Analysis PANACEA 11 Y NEDE-30130P-A (6)

ODYN 09 Y NEDE-24154P-A (Reference Ii)

NEDC-24154P-A, Vol. 4, Sup I (Reference 11)

ISCOR 09 Y(1) NEDE-2401 IP Rev. 0 SER TASC 03 Y NEDC-32084P-A Rev. 2 Anticipated Transient ODYN 09 Y NEDC-24154P-A, Vol. 4, Sup. I Without Scram (ATWS) STEMP 04 (7)

PANACEA 11 Y(6)

TASC 03A Y NEDC-32084P-A Rev. 2 ISCOR 09 Y(l) NEDE-2401 IP Rev. 0 SER TRACG 04 N(I 3) 1__

The application of these codes to the MELLLA+ analyses complies with the limitations, restrictions, and conditions specified in the approving NRC SER where applicable for each code. The application of the codes also complies with the SERs for the MELLLA+ programs.

Notes for Table 1-1:

(1) The ISCOR code is not approved by name. However, in the SER supporting approval of NEDE-2401 1P Revision 0 by the May 12, 1978 letter from D. G. Eisenhut (NRC) to R. Gridley (GE), the NRC finds the models and methods acceptable for steady-state thermal-hydraulic analysis, and mentions the use of a digital computer code. The referenced digital computer code is ISCOR. The use of ISCOR to provide core thermal-hydraulic information in reactor internal pressure differences (RIPDs), transient, ATWS, stability, and LOCA applications is consistent with the approved models and methods.

(2) The use of TGBLA Version 06 and PANACEA Version 11 was initiated following approval of Amendment 26 of GESTAR II by letter from S. A. Richards (NRC) to G. A. Watford (GE)

Subject:

"Amendment 26 to GE Licensing Topical Report NEDE-2401 1P-A, GESTAR II Implementing Improved GE Steady-State Methods (TAC NO. MA648 1)," November 10, 1999.

(3) The use of PANACEA Version 11 was initiated following approval of Amendment 26 of GESTAR II by letter from S. A. Richards (NRC) to G. A. Watford (GE)

Subject:

"Amendment 26 to GE Licensing Topical Report NEDE-24011P-A, GESTAR II Implementing Improved GE Steady-State Methods," (TAC NO. MA6481), November 10, 1999.

(4) The LAMB code is approved for use in ECCS-LOCA applications (NEDE-20566P-A), but no approving SER exists for the use of LAMB for the evaluation of RIPDs or containment system response. The use of LAMB for these applications is consistent with the model description of NEDE-20566P-A.

(5) NRC has reviewed and accepted the TRACG application for the flow-induced loads on the core shroud as stated in NRC SER TAC No. M90270.

(6) The physics code PANACEA (PANAC) provides inputs to the transient code ODYN. The use of PANACEA Version 11 in this application was initiated following approval of Amendment 26 of GESTAR II by letter from S. A. Richards (NRC) to G. A. Watford (GE)

Subject:

"Amendment 26 to GE Licensing Topical Report 1-11

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NEDE-2401 I P-A, GESTAR II Implementing Improved GE Steady-State Methods," (TAC NO. MA648 1),

November 10, 1999.

(7) The STEMP code uses fundamental mass and energy conservation laws to calculate the suppression pool heatup. The use of STEMP was noted in NEDE-24222, "Assessment of BWR Mitigation of ATWS, Volume I & II (NUREG-0460 Alternate No. 3) December 1, 1979." The code has been used in ATWS applications since that time. There is no formal NRC review and approval of STEMP or the ATWS TR.

(8) Not a safety analysis code that requires NRC approval. The code application is reviewed and approved by GEH for "Level-2" application and is part of GEH's standard design process. The application of this code has been used in other MELLLA+ and power uprate submittals.

(9) "SAFER Model for Evaluation of Loss-of-Coolant Accidents for Jet Pump and Non-Jet Pump Plants,"

NEDE-30996P-A, General Electric Company, October 1987.

(10) Letter, Richard E. Kingston (GEH) to NRC, "Transmittal of Revision 1 of NEDC-32950, Compilation of Improvements to GENE's SAFER ECCS-LOCA Evaluation Model," MFN 07-406, July 31, 2007.

(11) CCC-543, "TORT-DORT Two- and Three-Dimensional Discrete Ordinates Transport Version 2.8.14,"

Radiation Shielding Information Center (RSIC), January 1994.

(12) The use of DORTG was approved by the NRC through the letter from H. N. Berkow (NRC) to G. B.

Stramback (GE), "Final Safety Evaluation Regarding Removal of Methodology Limitations for NEDC-32983P-A, General Electric Methodology for Reactor Pressure Vessel Fast Neutron Flux Evaluations (TAC No. MC3788)," November 17, 2005.

(13) The TRACG04 code is not approved by the NRC for long-term ATWS calculations including ATWS with depressurization and ATWS with core instability. However, TRACG04 is used as a best-estimate code, while ODYN remains as the licensing basis code for ATWS consistent with the NRC SE for NEDC-33006P. The use of TRACG04 for the best-estimate TRACG ATWS analysis is also consistent with the NRC SE for NEDC-33006P. TRACG04 is approved by the NRC for application to ATWS overpressure transients in NEDE-32906P Supplement 3-A, "Migration to TRACGO4 / PANAC 1I from TRACG02 / PANAC1O for TRACG AOO and ATWS Overpressure Transients," April 2010.

(14) The TRACG04 application for DSS-CD is documented in NEDE-33147P-A Revision 4 (Reference 12).

(15) The TRACG break flow model and qualification basis is described in NEDE-32176P and NEDE-32177P.

The application of TRACG04 for the calculation of break flow mass/energy release rates has been approved for ESBWR LOCA application in NEDO-33083-A.

(16) GOTHIC quality assurance (QA) Version 7.2b has been applied in several NRC approved primary containment/subcompartment evaluation analyses including the NMP2 EPU peak pressure evaluations to address GEH Safety Communication (SC) 09-05 submitted on October 8, 2010 (Reference 13). The associated NRC SER for the NMP2 EPU LAR was issued on December 22, 2011 (Reference 14).

(17) Application of PRIME models and data to downstream methods is approved by NEDO-33173 Supplement 4-A, "Implementation of PRIME Models and Data in Downstream Methods," Revision 1, November 2012 (Reference 3).

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Table 1-2 Comparison of Thermal-Hydraulic Parameters MELLLA MELLLA+ MELLLA+

Parameter 100% CLTP, 100% CLTP, 77.6% CLTP, 99% Core Flow 85% Core Flow 55% Core Flow Thermal Power (MWt) 3988 3988 3095 Dome Pressure (psia) 1035 1035 1011 Steam Flow Rate (Mlbm/hr) 17.636 17.633 13.115 FW Flow Rate (Mlbm/hr) 17.604 17.601 13.083 FW Temperature ('F) 440.5 440.5 411.4 Core Flow (Mlbrn/hr) 107.4 92.2 59.7 Core Inlet Enthalpy (BTU/Ibm) 528.7 525.2 511.4 Core Pressure Drop (psi) 25.0 20.2 10.7 Core Average Void Fraction 0.504 0.531 0.532 Core Exit Void Fraction 0.723 0.755 0.766 Table 1-3 Core Thermal Power to Core Flow Ratios Point on the Core Thermal Core Flow Power-to-Flow Steady-State Operation Power/Flow Power Ratio Map (MWt/%CLTP) (Mlbm/hr/%rated) (MWt/Mlbm/hr)

Current Operating Domain E 3988 /100 108.5 /100 36.76 100% Rated Core Flow Current Operating Domain D 3988 / 100 107.4/99 37.13 99% Rated Core Flow MELLLA+

Operating Domain N 3988 /100 92.2 / 85 43.24 85% Rated Core Flow MELLLA+

Operating Domain M 3095 / 77.6 59.7 / 55 51.86 55% Rated Core Flow 1-13

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Core Flow (Mlbm/hr) 0 10 20 30 40 50 60 70 80 90 100 110 120 130 120 100% CLTP = 3988 MWt 4500 86.9% CLTP (Pre-EPU) 3467 MWt 110 100% Core Flo1 = 108.5 Mlbrn/hr 100 4000 90 3500 80 3000 f"70 2500 60 so 2000 Ei

"40 1500 30 1000 20 10 500 0

0 10 20 30 40 50 60 70 80 90 100 110 120 Core Flow (%)

Figure 1-1 Power/Flow Operating Map for MELLLA+

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 2.0 REACTOR CORE AND FUEL PERFORMANCE This section addresses the evaluations that are applicable to MELLLA+.

Because NMP2 currently uses only GE14 fuel, the following limitations and conditions from the Methods LTR SER and M+LTR SER are not applicable to the NMP2 M+SAR:

Methods LTR SER Limitations and Conditions:

APPLICATION OF 10 WEIGHT PERCENT GD: Limitation and Condition 9.13 MIXED CORE METHOD 1: Limitation and Condition 9.21 MIXED CORE METHOD 2: Limitation and Condition 9.22 M+LTR SER Limitations and Conditions:

CONCURRENT CHANGES: Limitations and Conditions 12.3.d, 12.3.e, and 12.3.f APPENDIX - A Request for Additional Information (RAI) 14-9: Limitation and Condition 12.23.6 APPENDIX - A RAI 14-10: Limitation and Condition 12.23.7 2.1 FUEL DESIGN AND OPERATION The effect of MELLLA+ on the fuel design and operation is described below. The topics addressed in this evaluation are:

M+LTR Topic Disposition NMP2 Result Fuel Product Line Design ((

Core Design Fuel Thermal Margin Monitoring Threshold ))

2.1.1 Fuel Product Line The fuel design limits are established for all new fuel product line designs as a part of the fuel introduction and reload analyses. The M+/-LTR establishes that there are no changes in fuel product line design as a consequence of MELLLA+. Because implementation of the MELLLA+

operating domain does not necessitate a new fuel design, no additional fuel and core design evaluation is required.

NMP2 currently operates with GEl4 fuel. The cycle in which MELLLA+ operating domain expansion is implemented shall contain GEl4 fuel. ((

)) no new fuel product line design is introduced, and there is no change to fuel design limits required by the MELLLA+ introduction at NMP2. Therefore, the SRLR will confirm that there are no new fuel products as a result of MELLLA+ and will validate the conclusion that no additional fuel and core design evaluation is required for NMP2.

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 2.1.2 Core Design and Fuel Thermal Monitoring Threshold

((

)) the maximum licensed power level and fuel design do not change as a result of MELLLA+. (( ))

there is no change to the average power density as a result of MELLLA+ operating domain expansion. Because the maximum licensed power level and fuel design do not change as a result of MELLLA+, there is no increase in the average bundle power. Because there is no change in average power density, there is no change required to the fuel thermal monitoring threshold.

(( )) there are no changes to the NMP2 fuel or fuel design limits as a result of MELLLA+. NMP2 continues to use GEl4 fuel. The CLTP remains at 3,988 MWt. This validates the conclusion that there are no changes needed to the fuel thermal monitoring threshold for NMP2.

Furthermore, because the MELLLA+ operating domain allows higher bundle power versus flow conditions, (( )) the range of void fraction, axial and radial power shape, and rod positions in the core may change slightly. The change in power distribution in the core is achieved, while the individual fuel bundles remain within the allowable thermal limits as defined in the COLR.

Also, (( )), and per Methods LTR SER Limitation and Condition 9.17, the range of void fraction, axial and radial power shape, and rod positions in the core does change slightly as a result of MELLLA+ operating domain expansion. For NMP2, the predicted bypass void fraction at the D-Level local power range monitor (LPRM) satisfied the

(( )) design requirement. The cycle-specific SRLR will confirm that the void fraction is

< 5% according to Methods LTR SER Limitation and Condition 9.17. The table below shows that steady-state bypass voiding is demonstrated on the MELLLA+ upper boundary at 100%

power.

Item % of Rated Core %of Rated Hot Channel Void Fraction in Bypass Region at Power Core Flow Instrumentation D Level (ISCOR Node 21) 1 100 99 1.6%

2 100 85 3.0%

As required by Methods LTR SER Limitation and Condition 9.24, the following core design and fuel monitoring parameters are plotted as indicated below in Table 2-1 and Figures 2-1 through 2-6 for each cycle exposure statepoint. The parameters are compared to the experience base reported in Reference 3:

Table 2-1 Peak Nodal Exposures Figure 2-1 Power of Peak Bundle versus Cycle Exposure Figure 2-2 Coolant Flow for Peak Bundle versus Cycle Exposure Figure 2-3 Exit Void Fraction for Peak Power Bundle versus Cycle Exposure 2-2

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

Figure 2-4 Maximum Channel Exit Void Fraction versus Cycle Exposure Figure 2-5 Core Average Exit Void Fraction versus Cycle Exposure Figure 2-6 Peak LHGR versus Cycle Exposure As part of the information requested for M+LTR SER Limitation and Condition 12.24.2, the exit void fraction for peak power bundle versus cycle exposure is provided in Figure 2-3.

Also, quarter core maps with mirror symmetry are plotted in Figure 2-7 through Figure 2-15 showing bundle power, bundle operating linear heat generation rate (LHGR), and minimum critical power ratio (MCPR) for beginning of cycle (BOC) (0.2 GWd/ST), middle of cycle (MOC) (10.0 GWd/ST), and end of cycle (EOC) (18.577 GWd/ST). The maximum fraction of limiting power density (MFLPD) occurs at 15.0 GWd/ST (Figure 2-16) and the largest maximum fraction of limiting critical power ratio (MFLCPR) occurs at 1.5 GWd/ST (Figure 2-17) for this core design. In Figure 2-7 through Figure 2-9, the bundle power is dimensionless. To obtain the bundle power in MWt, multiply each number by the average power per bundle. Prior to EOC, the average power per bundle is 5.2199; this factor equals 3,988/764, where 3,988 MWt is the RTP and 764 is the total number of fuel bundles in the core. At EOC, the average power per bundle is 4.6648.

Table 2-1 shows that NMP2's Peak Nodal Exposure are lower than the top four reference plants.

Figures 2-1 through 2-4 and Figure 2-6 show NMP2 MELLLA+ operation is in the expected range as compared to the reference plants. Figure 2-5 shows that NMP2 is higher than all the other plants. This is because of NMP2 MELLLA+ operating conditions, which are at full EPU power and 85% flow, while the available data for other plants are not at full EPU and/or MELLLA+ conditions. Figures 2-7 through 2-9 show the relative bundle power for BOC, MOC, and EOC, respectively. Figures 2-10 through 2-12 show the operating LHGR for BOC, MOC, and EOC, respectively. Figures 2-13 through 2-15 show the MCPR for BOC, MOC, and EOC, respectively. Figures 2-7 through 2-17 show general operational conditions for NMP2 in the MELLLA+ operating domain are well within expected parameters.

2.2 THERMAL LIMITS ASSESSMENT The effect of MELLLA+ on the MCPR safety and operating limits, maximum average planar linear heat generation rate (MAPLHGR), and LHGR limits is described below. As required by Limitation and Condition 9.6 of the Methods LTR SER, the GE14 fuel bundle R-factors generated for this project are consistent with GNF standard design practices, which use an axial void profile shape with 60% average in-channel voids. This is consistent with lattice axial void conditions expected for the hot channel operating state as shown in Figure 2-18. As required by Methods LTR SER Limitation and Condition 9.15, the nodal void reactivity biases applied in TRACG are applicable to the lattices representative of fuel loaded in the core.

The topics addressed in this evaluation are:

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Topic M+LTR Disposition NMP2 Result Safety Limit MCPR ((

Operating Limit MCPR MAPLHGR Limit LHGR Limit ))

2.2.1 Safety Limit Minimum Critical Power Ratio Er

)) the SLMCPR is calculated based on the actual core loading pattern for each reload core. In the event that the cycle-specific SLMCPR is not bounded by the current NMP2 TS value, NMP2 must implement a license amendment to change the TS.

(( )) the SLMCPR analysis for NMP2 reflects the actual plant core loading pattern and is performed for each reload core. The cycle-specific SLMCPR will be determined using the methods defined in Reference 4. As required by M+LTR SER Limitation and Condition 12.6, the SLMCPR will be calculated at the rated statepoint (100% CLTP / 100% CF), the upper right comer of the MELLLA+ upper boundary (100% CLTP / 85% CF), the lower left comer of the MELLLA+ upper boundary (77.6% CLTP /

55% CF), and the CLTP at the ICF statepoint (100% CLTP / 105% CF) (i.e., Figure 1-1 Statepoints E, N, M, and F, respectively). See Section 1.2.1 for further information on the power-to-flow statepoints. The currently approved off-rated CF uncertainty applied to the SLO operation is used for the minimum CF Statepoint N and at 55.0% CF Statepoint M. The calculated values will be documented in the SRLR.

As required by Methods LTR SER Limitation and Condition 9.5 and M+LTR SER Limitation and Condition 12.24.3, for MELLLA+ operation, a +0.02 adder will be added to the cycle-specific SLMCPR. The cycle-specific SLMCPR analysis will incorporate the +0.02 adder for MELLLA+ operation. The calculated values will be documented in the SRLR. A TS change will be requested if the current value is not bounding.

2.2.2 Operating Limit Minimum Critical Power Ratio

)) the OLMCPR is calculated by adding the change in MCPR due to the limiting AOO event to the SLMCPR. ((

)) The OLMCPR is determined on a cycle-specific basis from 2-4

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) the results of the reload transient analysis, as described in Reference 4. The cycle-specific analysis results are documented in the SRLR and included in the COLR. The MELLLA+ operating conditions do not change the methods used to determine this limit.

(( )) the OLMCPR for NMP2 is calculated by adding the change in MCPR due to the limiting AOO event to the SLMCPR.

)) if the Methods LTR SER and M+LTR SER penalties are ignored for NMP2. The OLMCPR for NMP2 is determined on a cycle-specific basis from the results of the reload transient analysis, as described in Reference 4. The NMP2 cycle-specific analysis results are documented in the SRLR and included in the COLR. The MELLLA+

operating conditions do not change the methods used to determine this limit. A +0.01 adder will be applied to the resulting OLMCPR as required by Limitation and Condition 9.19 of the Methods LTR SER. In the event that the cycle-specific reload analysis is based on TRACG rather than ODYN for AOO, no 0.01 adder to the OLMCPR is required.

((

2.2.3 Maximum Average Planar Linear Heat Generation Rate Limits

[R )) MAPLHGR limits ensure that the plant does not exceed regulatory limits established in 10 CFR 50.46. Section 4.3, Emergency Core Cooling System Performance, presents the evaluation to demonstrate that plants meet the regulatory limits in the MELLLA+ operating domain. ((

1))

Er )) the NMP2 MAPLHGR limits ensure that NMP2 does not exceed regulatory limits established in 10 CFR 50.46. Section 4.3 of this M+SAR presents the evaluation to demonstrate that NMP2 meets the regulatory limits in the MELLLA+ operating domain. ((

)) The MELLLA+ operating conditions do not change the methods used to determine this limit.

((

2.2.4 Linear Heat Generation Rate Limits Er )) LHGR limits ensure that the plant does not exceed fuel thermal-mechanical (T-M) design limits. The LHGR is determined by the fuel rod T-M design and is not affected by MELLLA+ operating domain expansion. No changes to the fuel rod are required as a part of MELLLA+. ((

2-5

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

)) the NMP2 LHGR limits ensure that the plant does not exceed fuel T-M design limits. There are no changes to the NMP2 fuel or fuel design limits as a result of MELLLA+. NMP2 continues to use GEl4 fuel. ((

)) The MELLLA+ operating conditions do not change the methods used to determine this limit.

((

2.2.5 Power-to-Flow Ratio Methods LTR SER Limitation and Condition 9.3 requires that plant-specific EPU and expanded operating domain applications confirm that the core thermal power to CF ratio does not exceed 50 MWt/Mlbm/hr at any statepoint in the allowed operating domain. For plants that exceed the power-to-flow value of 50 MWt/Mlbmihr, the application will provide a power distribution assessment to establish that axial and nodal power distribution uncertainties determined via neutronic methods have not increased.

The core thermal power to CF ratio at steady-state and off-rated conditions along the MELLLA+

boundary is reported in Table 2-2.

2.3 REACTIVITY CHARACTERISTICS The effect of MELLLA+ on hot excess reactivity, strong rod out (SRO) shutdown margin, and SLS shutdown margin is described below. The topics addressed in this evaluation are:

Topic M+LTR Disposition NMP2 Result Hot Excess Reactivity Strong Rod Out Shutdown Margin SLS Shutdown Margin 2.3.1 Hot Excess Reactivity operation in the MELLLA+ operating domain may change the hot excess reactivity during the cycle. This change in reactivity does not affect safety and is not expected to significantly affect the ability to manage power distribution through the cycle and to achieve the target power level.

)) The MELLLA+ operating conditions do not change the methods used to evaluate hot excess reactivity.

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)) NMP2 continues to operate on a 24-month cycle. The MELLLA+ operating conditions do not change the NMP2 methods used to evaluate that sufficient hot excess reactivity exists to match the 24 -month cycle conditions.

2.3.2 Strong Rod Out Shutdown Margin higher core average void fraction results in higher plutonium production, increased hot reactivity later in the operational cycle, and decreased hot-to-cold reactivity differences. Smaller cold shutdown margins may result from cores designed for operation with the MELLLA+ operating domain expansion. This potential loss in margin is offset through core design to maintain current design and TS cold shutdown margin requirements. All minimum SRO shutdown margin requirements apply to cold most reactive conditions and are maintained without change for MELLLA+ implementation. In order to account for reactivity uncertainties, including the effects of temperature and analysis methods, margin well in excess of the TS limits is included in the design requirements. ((

The MELLLA+ operating conditions do not change the methods used to evaluate SRO shutdown margin.

((I

)) NMP2 current design and TS cold shutdown margin limits are unchanged by MELLLA+. The MELLLA+ operating conditions do not change the NMP2 methods used to evaluate that SRO shutdown margin meets the current NMP2 design and TS cold shutdown limits.

2.3.3 SLS Shutdown Margin

)) higher core average void fraction results in higher plutonium production, increased hot reactivity later in the operational cycle, and decreased hot-to-cold reactivity differences. Smaller cold shutdown margins may result from cores designed for operation with the MELLLA+ operating domain expansion. This potential loss in margin is offset through core design to maintain current design and SLS TS requirements. All minimum SLS TS requirements apply to most reactive SLS conditions and are maintained without change for MELLLA+ implementation. In order to account for reactivity uncertainties, including the effects of temperature and analysis methods, margin in excess of the TS limits is included in the design 2-7

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) requirements. ((

)) The MELLLA+

operating conditions do not change the methods used to evaluate the SLS shutdown margin.

((i

)) NMP2 current design and SLS TS requirements for minimum natural boron equivalent are unchanged by the SLS performance modification or MELLLA+.

The MELLLA+ operating conditions do not change the NMP2 methods used to evaluate that SLS shutdown margin meets the current NMP2 design and SLS TS requirements. The SLS performance modifications are to increase the boron injection rate to support ATWS evaluations and do not affect the SLS shutdown margin evaluation.

2.4 STABILITY The DSS-CD stability solution (Reference 2) has been shown to provide an early trip signal upon instability inception prior to any significant oscillation amplitude growth and MCPR degradation for both core-wide and regional mode oscillations. NMP2 will implement the DSS-CD solution consistent with the M+LTR. DSS-CD implementation includes any limitations and conditions in the DSS-CD SER (Reference 2). In accordance with DSS-CD LTR SER Limitation and Condition 5.1 (Reference 2), because NMP2 is implementing DSS-CD using the NRC approved GEH Option III platform, a plant-specific review is not required. There were no changes proposed in the bounding uncertainty or in the process to bound the uncertainty in the MCPR.

Topic M+LTR Disposition NMP2 Result DSS-CD Setpoints ((

Armed Region Backup Stability Protection (BSP) ))

2.4.1 DSS-CD Setpoints

)) As a part of DSS-CD implementation, the applicability checklist is incorporated into the reload evaluation process and is documented in the SRLR.

DSS-CD implementation also includes incorporation of appropriate (( )) analyses to be performed if a specific reload analysis ((

)) DSS-CD is incorporated per the requirements of the DSS-CD LTR. This implementation requires that a process for reviewing the DSS-CD setpoints for each reload analysis is in place. ((

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)) no further review of MELLLA+ is necessary to evaluate the adequacy of the DSS-CD setpoints.

(( )) NMP2 will incorporate the DSS-CD solution consistent with the requirements of the DSS-CD LTR. Implementation of DSS-CD in accordance with the DSS-CD LTR ensures that NMP2 incorporates the applicability checklist into the reload evaluation process and documents the results of the applicability checklist review in the SRLR. DSS-CD implementation per the DSS-CD LTR also ensures that NMP2 incorporates appropriate (( )) analyses to be performed if a specific reload analysis ((

The generic DSS-CD licensing basis applicable to NMP2 is documented in Section 4.7 of Reference 2. ((

)) The step-by-step process summary for DSS-CD application of higher amplitude discriminator setpoint (SAD) is detailed in Table 4-17 of Reference 2. The results of the application of this process to NMP2 are summarized below.

((

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))

The CDA setpoint calculation formula and the adjustable parameter values are defined in the DSS-CD LTR (Reference 2). In accordance with DSS-CD LTR SER Limitation and Condition 5.2 (Reference 2), the DSS-CD LTR, or GESTAR II including the approved DSS-CD LTR, is referenced in the proposed TS changes for implementation of DSS-CD.

2.4.2 Armed Region 2-11

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))

The generic boundaries of the armed region were approved as part of the DSS-CD LTR.

((

)) no further review of MELLLA+ is necessary to evaluate the adequacy of the armed region.

Er no further review of MELLLA+ is necessary to evaluate the adequacy of the armed region.

Er 2.4.3 Backup Stability Protection Er )) the DSS-CD LTR defines the BSP along with a generic process for confirming that the BSP requirements are met in each reload analysis. This BSP may be used when the OPRM system is temporarily inoperable. Implementation of DSS-CD per the DSS-CD LTR requires that the alternate stability protection approach is confirmed on a cycle-specific basis to demonstrate adequacy for each reload cycle. ((

no further review of MELLLA+ is necessary to evaluate the adequacy of the BSP.

Er )) NMP2 will incorporate the DSS-CD solution in accordance with the requirements of the DSS-CD LTR. Implementation of DSS-CD in accordance with the DSS-CD LTR requires that NMP2 confirm the BSP approach is adequate as a part of the reload. ((

)) no further review of BSP is required.

Er 2-12

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 2.5 REACTIVITY CONTROL The control rod drive (CRD) system controls core reactivity by positioning neutron absorbing control rods within the reactor and scram the reactor by rapidly inserting control rods into the core. No change is made to the control rods or drive system due to MELLLA+. The topics addressed in this evaluation are:

Topic M+LTR Disposition NMP2 Result Scram Time Response CRD Positioning and Cooling CRD Integrity 2.5.1 Control Rod Scram

[ ))for BWR/3, BWR/4, and BWR/5 plants the hydraulic control unit accumulators supply the initial scram pressure and, as the scram continues, the reactor becomes the primary source of pressure to complete the scram.

)) the NMP2 hydraulic control unit accumulators supply the initial scram pressure and, as the scram continues, the reactor becomes the primary source of pressure to complete the scram. The NMP2 reactor dome pressure is 1,035 psia (1,020 psig) and does not change as a result of MELLLA+ operating domain expansion. ((

2.5.2 Control Rod Drive Positioning and Cooling

((I

)) As a result of MELLLA+, there is no increase in temperature and ((

)) Therefore, the CRD positioning and cooling functions are not affected by MELLLA+.

(( )) for NMP2, the reactor coolant temperature does not increase. ((

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 2.5.3 Control Rod Drive Integrity

[)) the postulated abnormal operating conditions for the CRD design assume a failure of the CRD system pressure-regulating valve that applies the maximum pump discharge pressure to the CRD mechanism internal components. This postulated abnormal pressure bounds the American Society of Mechanical Engineers (ASME) reactor overpressure limit. ((

no further evaluation of CRD integrity is required as result of MELLLA+.

ER )) the NMP2 CRD mechanism has been analyzed for an abnormal pressure operation (the application of the maximum CRD pump discharge pressure) that bounds the ASME RPV overpressure condition. ((

)) Also, as stated in Section 3.1.2, for the ASME RPV overpressure condition, the peak RPV bottom head pressure is unchanged and remains less than the limit of 1,375 psig. ((

)) and no further evaluation of CRD integrity is required as result of MELLLA+.

Er 2.6 ADDITIONAL LIMITATIONS AND CONDITIONS RELATED TO REACTOR CORE AND FUEL PERFORMANCE For that subset of limitations and conditions relating to Reactor Core and Fuel Design, which did not fit conveniently into the organizational structure of the M+LTR, the required information is presented here. The information is identified by either the M+LTR SER (Reference 1) limitation and condition or the Methods LTR SER (Reference 3) limitation and condition to which it relates.

2.6.1 TGBLA/PANAC Version In developing the NMP2 equilibrium core, the latest versions of TGBLA and PANAC were used.

Refer to Table 1-1 for the latest revisions to TGBLA and PANAC. Cycle-specific analyses will include the most recent TGBLA and PANAC versions. As required by Methods LTR SER Limitation and Condition 9.1, the most recent versions of TGBLA and PANAC are used.

2.6.2 M+LTR SER Limitation and Condition 12.24.1 2-15

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 2.6.3 LHGR and Exposure Qualification Methods LTR SER Limitation and Condition 9.12 states that once the PRIME LTR (Reference 15) and its application are approved, future license applications for EPU and MELLLA+ referencing LTR NEDC-33173P-A must utilize the PRIME T-M methods. The PRIME LTR was approved on January 22, 2010 (Reference 15) and implemented in GESTAR II in September 2010 (Reference 4). The NMP2 M+SAR has a PRIME T-M basis. PRIME fuel parameters have been used in all analyses requiring fuel performance parameters.

The T-M evaluation performed in support of the NMP2 M+SAR was performed using the PRIME T-M methodology.

2.6.4 GEXL-PLUS and Pressure Drop Database The applicability of the GE14 experimental GEXL-PLUS and pressure drop database is confirmed for operation in the MELLLA+ domain.

The Methods LTR NEDC-33173P-A (Reference 3) documents all analyses supporting the conclusions in this section that the application ranges of GEH codes and methods are adequate in the MELLLA+ operating domain. In accordance with M+LTR SER Limitation and Condition 12.1, the range of mass fluxes and power/flow ratios in the GEXL database covers the intended MELLLA+ operating domain. The database includes low flow, high qualities, and void fractions. There are no restrictions on the application of the GEXL-PLUS correlation in the MELLLA+ operating domain.

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Table 2-1 Peak Nodal Exposures Plant Cycle Peak (~IT Nodal Exposure (GWd/ST)

A 18 38.849 A 19 43.784 B 9 56.359 B 10 51.544 C 7 53.447 C 8 47.766 D 13 56.660 E 11 55.387 F EQ- 120% 51.174 NMP2 MELLLA+ 52.003 2-17

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Table 2-2 Core Thermal Power to Core Flow Ratio at Steady-State and Off-Rated Conditions Operating Domain Core Thermal Power Core Flow Power-to-Flow Ratio Statepoint* (MWt / %EPU) (Mlbm/hr / %rated) (MWt/MlbmI/hr)

M/M+ Boundary "D" 3,988/100 107.4/99 37.13 M+ Boundary "N" 3,988 / 100 92.2 / 85 43.24 M+ Boundary "M" 3,095 / 77.6 59.7/55 51.86 M/M+ Boundary "L" 2,727.8 / 68.4 59.7 / 55 45.71

"*" Statepoints D, N, M, and L are shown in Figure 1-1.

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Table 2-3 TLO and SLO DSS-CD Licensing Basis Generic Applicability Envelope Checklist Confirmation 2-19

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Table 2-4 [1 11 Note: ((

2-20

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Table 2-5 [1 11 Note: ((

2-21

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 8.0 7.5 '

7.0 ---- ------------

'6.5 5.5

--*-Plant A Cycle 18 m-Plant A Cycle 19 --.- Plant B Cycle 9 4.5 -o PlantBCyclelO1 Plant C Cycle 7 -- PlantCCydeB

-*-Plant D Cycle13 - PlantECyclell -PlantF 4.0, -*-NMP2 MELLLA+

0 2 4 6 8 10 12 14 16 18 Cycle Exposure (GWDYST)

Figure 2-1 Power of Peak Bundle versus Cycle Exposure 2-22

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 14 13

~12 E

-611 9) 71

-*-PlantA Cycle18 --- PlantA Cycle 19 - PlantB Cycle 9

-4Plant B Cycle 10 - Plant C Cycle 7 -Plant C Cycle 8

- PlantDCycle13 - PlantE Cycle 11 PPlantF

-.-- NM P2 MELLLA+

5 0 2 4 6 8 10 12 14 16 18 Cycle Exposure (GWDIST)

Figure 2-2 Coolant Flow for Peak Bundle versus Cycle Exposure 2-23

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 0.90 0.85 W

0.

0.80-LL 0

0.75 -

-Plant A Cycle 18 --U- PlantA Cycle 19 ý-Plant B Cycle 9

- Plant B Cycle 10 -- PlantC Cycle 7 Plant C Cycle 8

- Plant D Cycle 13 - PlantE Cycle 11 - Plant F

--4-NMP2 MELLLA+

0.70 I-0 2 4 6 8 10 12 14 16 18 Cycle Exposure (GWDWS-)

Figure 2-3 Exit Void Fraction for Peak Power Bundle versus Cycle Exposure 2-24

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 0.90 0.85 I-

.X0.85 Lo.N 0.75

--- Plant A Cycle 18 -u--Plant A Cycle 19

-4Plant B Cycle 10 -.-- Plant C Cycle 7

-- Plant D Cyclel3 -Plant E Cycle 11

-- NMP2 MELLLA+

0.70 0 2 4 6 8 10 12 14 16 18 Cycle Exposure (GWD/ST)

Figure 2-4 Maximum Channel Exit Void Fraction versus Cycle Exposure 2-25

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 0.80 0.78 0.76 t;

0.74 L-49 0.72 IN X

= 0.70 Uj 0

4) 0.68 -------------4--------

0, 0.66 -----------------

0 0.64 -- PlantA Cycle 18 -4w- Plant A Cycle 19

--- PlantB Cycle 10 -o-Plant C Cycle 7 0.62 PlantD Cycle 13 - Plant E Cycle 11

-- NMP2 MELLLA+

0.60 0 2 4 6 8 10 12 14 16 18 Cycle Exposure (GWDIST)

Figure 2-5 Core Average Exit Void Fraction versus Cycle Exposure 2-26

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 16 14 12

,=I

0

4.

PlantA Cycle 18 - PlantA Cycle 19 --- Plant B Cycle 9

lPlantBCycle10 -PlantC Cycle7 Plant C Cycle 8 2-

- Plant D Cycle 13 - Plant C Cycle 11 -Plant F L ]

--- NM P2 MELLLA+

0 0 2 4 6 8 10 12 14 16 18 Cycle Exposure (GWDP'ST)

Figure 2-6 Peak LHGR versus Cycle Exposure 2-27

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) ab lob go- U*

Imon j W4=

MFs fW

1 9 "Fl !

2 3 , S 1 1, , .t iQ 0 14 Figure 2-7 Dimensionless Bundle Power at BOC (200 MWd/ST) 2-28

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Sm

-W ab im

-I"

-,TiN coma t~p~m -,nou POWILf I~,r RX" $

7 I S U 5 1 U00d¶ M T~

Figure 2-8 Dimensionless Bundle Power at MOC (10,000 MWd/ST) 2-29

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

@doWWWAP WcW 00l of, i-j 2 46MSt

,o *as...4.. G .. I.. .; .!...

0my M Figure 2-9 Dimensionless Bundle Power at EOC (18,577 MWd/ST) 2-30

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) mlll it,_= ' ., *M I Dow-*-- Oft:--I mm- M _4-F.

.............. s O F1: 1 17" KY _j 4

I $ 40 Figure 2-10 Bundle Operating LHGR (kW/ft) at BOC (200 MWd/ST) 2-31

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) go 1***0- to PcW _j tpu I I*61

i F i ur B d 4 I $

M atU 0 UIST 4I Figure 2-11 Bundle Operating LHGR (kW/ft) at MOC (10,000 MWd/ST) 2-32

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

F3 osin -

Qfm t6 NNm Sm rvz o" 2 s P-0b.~ ~ ,

Figure 2-12 Bundle Operating LHGR (kW/ft) at EOC (18,577 MWd/ST) 2-33

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Ai';,'A-.'ý ! -' PR rub. oo, AI " ...j 2 nm*r CTP 22 come cw I

low[toit1 Figure 2-13 Bundle Operating MCPR at BOC (200 MWd/ST) 2-34

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WAG(.

F- Fof :

FOO 00"i

,_. 2sFnn

- m&* .Fr L

cow1 MT V I2 ) 4 I.

2 1 I

11 U 1 j~b~isd" MVM No Figure 2-14 Bundle Operating MCPR at MOC (10,000 MWd/ST) 2-35

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"eine mmo IM21*1 CAIJT

.....V' 09'4 Qolwm I 2 s 4 s

7 1 0 S z 1 1 4 is Figure 2-15 Bundle Operating MCPR at EOC (18,577 MWd/ST) 2-36

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I AVAIXIUý' I I'.' FqrF___m PcTV _- 4 As

-L"u 'Il mF FEW Kfur

- ,-F-m-F

'izmm m,Fo--n*m M*F*m m i 2 B O4W 1E00 WMM 14 3 6S I S I I U It 12 is 14 I Figure 2-16 Bundle Operating LHGR (kW/ft) at 15,000 MWdIST (Peak MFLPD Point) 2-37

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[ AFAIA-11,' I I'.' pqr__ý F3 OR1- m 1d

_1IVi 094" howI 2 9S 13FA Figure 2-17 Bundle Operating MCPR at 1,500 MWd/ST (Peak MFLCPR Point) 2-38

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) viil a11wl Ilio1111so IIUIII~3E~ruU~I*IhhIII~~huIIUIflhIIII~u~lhEIUI~t2

-c Z Itef 1111111ol 1111f:fi9sl vies 1:a411 u4 olil Uipol Figure 2-18 Bundle Average Void History for Bundles with Low CPRs 2-39

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

Core Flow (Mlbm/hr) 0 10 20 30 40 50 60 70 80 90 100 110 120 130 120 OPRM Armed Region 4500 110 100 4000 90 3500 80 .. ... - ----- --------.....

3000 70 2500 60 The OPRMArmed Region is 0 50

2000 defined by 75% drive flow. . "

However the use of 75% core flow is conservaive .

40 1500 30 1000 20 500 10 T..

7-__

0 0 0 10 20 30 40 50 60 70 80 90 100 110 120 Core Flow (%)

Figure 2-19 Required OPRM Armed Region 2-40

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 3.0 REACTOR COOLANT AND CONNECTED SYSTEMS This section addresses the evaluations that are applicable to MELLLA+.

3.1 NUCLEAR SYSTEM PRESSURE RELIEF AND OVERPRESSURE PROTECTION The topics addressed in this evaluation are:

Topic M+LTR Disposition NMP2 Result Flow-Induced Vibration i[

Overpressure Relief Capacity 3.1.1 Flow-Induced Vibration because there is no increase in the maximum main steam (MS) line flow for the MELLLA+

operating domain expansion, there is no effect on the flow-induced vibration (FIV) of the piping and SRVs during normal operation. ((

)) for NMP2, maximum MS line (MSL) flow in the MELLLA+ operating domain does not increase. The numerical values showing no increase in maximum steam flow rate are presented in Table 1-2. MELLLA+ does not result in any increase to the NMP2 maximum MSL flow, and there is no effect on the FIV experienced by the SRVs or piping during normal operation. ((

I]

3.1.2 Overpressure Relief Capacity The pressure relief system prevents overpressurization of the nuclear system during AOOs, the plant ASME upset overpressure protection event, and postulated ATWS events. The SRVs along with other functions provide this protection. For NMP2, the limiting overpressure event is the main steam isolation valve closure with scram on high flux (MSIVF) event. The peak RPV bottom head pressure is unchanged and remains less than the ASME limit of 1,375 psig.

The SRV setpoint tolerance is independent of the MELLLA+ operating domain expansion. The AOO, ASME overpressure, and ATWS response evaluations for MELLLA+ are performed using existing NMP2 SRV setpoint tolerances. The SRV setpoint tolerances are monitored at NMP2 for compliance to the TS requirements.

)) There are no changes made to the NMP2 licensing basis for the ASME overpressure event.

)) The SRV tolerance assumed in the NMP2 ASME overpressure event 3-1

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) analysis is 3%. The tolerance is consistent with the actual SRV performance testing conducted on the NMP2 SRVs per TS Surveillance Requirement 3.4.4.1.

Er

)) There are no changes to the existing licensing basis assumptions and code inputs used for the NMP2 ASME overpressure event analysis.

The ASME overpressure analysis for NMP2 was performed at the 105% ICF core flow statepoint, and at the 85% minimum CF statepoint using an approximate MELLLA+ equilibrium core. The analysis of the limiting overpressure event for NMP2 demonstrates that no change in overpressure relief capacity is required. ((

)) This process is unchanged by MELLLA+.

3.2 REACTOR VESSEL The RPV structure and support components form a pressure boundary to contain reactor coolant and form a boundary against leakage of radioactive materials into the drywell (DW). The topics addressed in this evaluation are:

Topic M+LTR Disposition NMP2 Result Fracture Toughness Reactor Vessel Structural Evaluation 3.2.1 Fracture Toughness The MELLLA+ operating domain expansion results in a slightly higher operating neutron flux in the upper portion of the core due to decreased water density. The effect of this water density reduction is (( )) in peak vessel and peak shroud flux. In accordance with M+LTR SER Limitation and Condition 12.8, the MELLLA+ flux is calculated using the GEH flux evaluation methodology contained in NEDC-32983P-A (Reference 16),

which is consistent with Regulatory Guide (RG) 1.190 (Reference 17) and was approved by the NRC in November 2005. The evaluation is based on an idealized equilibrium core loading which is not a bounding core design. This core loading is intended to show general trends for the purpose of comparison and demonstrating the anticipated effect on flux and fluence. The NMP2 RG 1.190 (Reference 17) fluence program monitors actual core operations to determine the effect on fracture toughness. The MELLLA+ operating domain flux distribution is assumed to be similar to that of current licensed operating domain flux distribution, whereas the magnitude of flux level is proportional to the thermal power. The change to the NMP2 54 effective full power years (EFPYs) vessel internal diameter (ID) peak fluence as a result of implementing MELLLA+ is (( 1]

Key flux/fluence comparisons at 120% OLTP are provided in Table 3-1.

Because there is no change to the NMP2 54 EFPY Vessel ID peak fluence as a result of MELLLA+, there is no change to the beltline adjusted reference temperature (ART). The 3-2

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) pressure/temperature curves do not require revision as a result of MELLLA+ operating domain expansion.

Because there is no change to the NMP2 54 EFPY Vessel ID peak fluence as a result of MELLLA+, there is no change to the upper shelf energy (USE). NMP2 continues to meet the 50 ft-lb requirement in 10 CFR 50, Appendix G Because there is no change to the NMP2 54 EFPY Vessel ID peak fluence as a result of MELLLA+, there is no change to the Weld Inspection Relief criteria for circumferential welds.

Therefore, the inspection relief request does not require revision as a result of MELLLA+

operating domain expansion.

As a result of MELLLA+ there is no change in the NMP2 54 EFPY Vessel ID peak fluence.

Therefore, there are no changes to the NMP2 ART, USE, or Weld inspection relief values as a result of MELLLA+.

3.2.2 Reactor Vessel Structural Evaluation

((

)) there are no changes in the reactor operating pressure, FW flow rate, or steam flow rates for the MELLLA+ operating domain expansion. Other applicable mechanical loads do not increase for the MELLLA+ operating domain expansion. ((

)) there is no change in the stress or fatigue for the reactor vessel components as a result of MELLLA+, and no further evaluation is required.

(( )) for NMP2, there are no increases in the reactor operating pressure, or maximum steam or FW flow rates for the MELLLA+

operating domain expansion. The numerical values showing no increases in reactor operating pressure, or maximum steam or FW flow rates are presented in Table 1-2. Other NMP2 mechanical loads do not increase as a result of the MELLLA+ operating domain expansion.

Therefore, there is no change in the stress and fatigue for the NMP2 reactor vessel components, and no further evaluation of NMP2 reactor vessel structural integrity is required.

3.3 REACTOR INTERNALS 3.3.1 Reactor Internal Pressure Differences The reactor internals include core support structure and non-core support structure components.

The topics addressed in this evaluation are:

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M+LTR Topic Disposition NMP2 Result Fuel Assembly and Control Rod Guide Tube Lift Forces ((

Reactor Internal Pressure Differences for Normal, Upset, Emergency and Faulted Conditions Reactor Internal Pressure Differences (Acoustic and Flow-Induced Loads) for Faulted Conditions Reactor Internals Structural Evaluation for Normal, Upset, and Emergency Conditions Reactor Internals Structural Evaluation for Faulted Conditions Steam Dryer Separator Performance Steam Line Moisture Performance Specification ))

3.3.1.1 Fuel Assembly and Control Rod Guide Tube Lift Forces

)) fuel assembly and CRGT lift forces are calculated for normal, upset, emergency, and faulted conditions consistent with the existing plant design basis. There are no increases in the core exit steam flow, reactor operating pressure, FW or steam flow rates for the MELLLA+ operating domain expansion. Because none of the preceding values change, the only remaining variable affecting the forces on the fuel assemblies and CRGTs for the normal, upset, emergency and faulted conditions in the MELLLA+ operating domain is the CF. Maximum CF is reduced in the MELLLA+ operating domain. ((

)) Therefore, no further evaluation of fuel assembly or CRGT lift forces is required.

(( )) for NMP2, the difference between the 100% CLTP / 105% core flow ICF operation point core exit steam flow and the 100% CLTP

/ 85% core flow MELLLA+ operation point core exit steam flow is essentially unchanged (less than a 0.4% increase). The differences between the vessel steam flow and FW flow rates for the two power-flow points are essentially unchanged, as well (both less than a 0.2% decrease). The dome pressures for the two power-flow points are identical. The small differences between the core exit steam flows, vessel steam flows and FW flow rates have a negligible effect on the fuel assembly and CRGT lift forces calculated for normal, upset, emergency and faulted conditions.

Therefore, because the NMP2 CF at the MELLLA+ statepoint at 85% CF is less than the current licensed operating domain statepoint at 105% CF, the normal, upset, emergency and faulted fuel assembly and CRGT lift forces for the MELLLA+ operating domain ((

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

)) and no further evaluation of these forces is required.

I]

3.3.1.2 Reactor Internal Pressure Differences for Normal, Upset, Emergency and Faulted Conditions

((

)) RIPDs (pressure differentials across the components) are calculated for normal, upset, emergency and faulted conditions consistent with the existing plant design basis. There are essentially no changes in the core exit steam flow, reactor operating pressure, FW or steam flow rates for the MELLLA+ operating domain expansion. Because none of the preceding values change, the only remaining variable affecting the RIPDs for the normal, upset, emergency and faulted conditions in the MELLLA+ operating domain is the CF.

Maximum CF is reduced in the MELLLA+ operating domain. ((

)) Therefore, no further evaluation of RIPDs for normal, upset, emergency and faulted conditions is required.

(( )) for NMP2, the difference between the 100% CLTP / 105% core flow ICF operation point core exit steam flow and the 100% CLTP

/ 85% core flow MELLLA+ operation point core exit steam flow is less than a 0.4% increase.

The differences between the vessel steam flow and FW flow rates for the two power-flow points are both less than a 0.2% decrease. The dome pressures for the two power-flow points are identical. The small differences between the core exit steam flows, vessel steam flows and FW flow rates have a negligible effect on the RIPDs for normal, upset, emergency and faulted conditions. Therefore, because the NMP2 CF at the MELLLA+ statepoint at 85% CF is less than the current licensed operating domain statepoint at 105% CF, the normal, upset, emergency and faulted condition RIPDs for the MELLLA+ operating domain ((

)) which includes ICF up to 105% RCF.

)) and no further evaluation of these pressure differentials is required for normal, upset, emergency and faulted conditions.

3.3.1.3 Reactor Internal Pressure Differences (Acoustic and Flow-Induced Loads) for Faulted Conditions As part of the RIPDs, the faulted acoustic and flow induced loads in the RPV annulus on jet pump, core shroud and core shroud support resulting from the recirculation line break LOCA have been considered in the NMP2 evaluation. ((

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

)) and NMP2 R[PDs for faulted conditions continue to be acceptable.

((

3.3.2 Reactor Internals Structural Evaluation Structural integrity evaluations for MELLLA+ operating domain expansion are performed consistent with the existing design basis of the components. ((

)) Therefore, no further structural evaluation of the reactor internals is required. An evaluation of the load categories applicable to the reactor internals under normal, upset, and emergency conditions is presented below:

MELLLA+ Results Load Category for Normal, Upset and Emergency Conditions Dead Weight Seismic (Operating Basis Earthquake (OBE))

RIPDs Fuel Assembly and CRGT Lift Forces Containment Dynamic Loads -

(LOCA and SRV)

Fuel Lift Loads Thermal Effects 3-6

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

MELLLA+ Results Load Category for Normal, Upset and Emergency Conditions Flow

((

3.3.2.1 Reactor Internals Structural Evaluation for Faulted Conditions

)) The M+LTR also defines that if the load conditions do not increase in the MELLLA+ operating domain, then the existing analysis results are bounding and no further evaluation is required. Applicable loads, load combinations, and service conditions are evaluated consistent with the plant design basis for each component. As shown below, ((

)) and thus no further evaluation is required.

MELLLA+ Results Load Category for Faulted Conditions Dead Weight Seismic (Safe Shutdown Earthquake (SSE))

RIPDs Fuel Assembly and CRGT Lift Forces Containment Dynamic Loads -

(LOCA and SRV)

Annulus Pressurization Jet Reaction Fuel Lift Loads Flow Acoustic and Flow-Induced Loads Due To Recirculation Line Break 3-7

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

The faulted condition loads for the NMP2 reactor internal components resulting from the MELLLA+ operating domain conditions ((

1] no further evaluation for Reactor Internals Structural Evaluation for faulted conditions is required.

3.3.3 Steam Separator and Dryer Performance The performance of the NMP2 steam separator-dryer has been evaluated to determine the moisture content of the steam leaving the RPV. Compared to the current licensed operating domain (100% CF statepoint), the average separator inlet flow decreases and the average separator inlet quality increases at MELLLA+ conditions. These factors, in addition to the core radial power distribution, affect the steam separator-dryer performance. Steam separator-dryer performance was evaluated at equilibrium cycle limiting conditions of high radial power peaking and 85% RCF to assess their capability to provide the quality of steam necessary to meet operational criteria at MELLLA+ operating conditions.

The evaluation of steam separator and dryer performance indicates that MCO increases at MELLLA+ conditions. This increase resulted in a MCO value above the original moisture performance specification of 0.10 wt.%. Section 3.3.4 identifies a plant-specific moisture performance specification based on as installed hardware.

3.3.4 Steam Line Moisture Performance Specification The effect of increased MCO on plant operation has been analyzed to verify acceptable steam separator-dryer performance under MELLLA+ operating conditions for a maximum moisture content of 0.25 wt.%. MCO is monitored during operation to ensure adequate operating limitations are implemented as required to maintain MCO within analyzed conditions. The amount of time NMP2 is operated with higher than the original design moisture content (0.10 wt.%) is minimized by operations. MCO monitoring periodicity is based upon results of startup testing, operating experience, control rod pattern and time in core life.

The ability of the steam dryer and separator to perform their design functions during MELLLA+

operation was evaluated. The NMP2 plant-specific evaluation concluded that the performance of the steam dryer and separator remains acceptable and the dryer skirt remains covered at L4, the low water level alarm in the MELLLA+ region.

MELLLA+ operation decreases the CF rate, resulting in an increase in separator inlet quality for constant reactor thermal power. These factors, in addition to core radial power distribution, influence steam separator-dryer performance. NMP2's steam separator/dryer performance was evaluated on a plant-specific basis to determine the influence of MELLLA+ on the steam dryer and separator operating conditions: (1) the entrained steam (i.e., carryunder) in the water returning from the separators to the reactor annulus region; (2) the moisture content in the steam leaving the RPV into the MSLs; and (3) the margin to dryer skirt uncovery.

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The moisture content of the steam leaving the RPV increases in the MELLLA+ domain. The effect of the increase has been analyzed in the tasks that use the MCO value from Sections 3.3.3 and 3.3.4. The effects of increased moisture are discussed in the following sections:

a. 3.5.1 Reactor Coolant Pressure Boundary Piping

[R 1] as discussed in Section 3.3.3, the MCO may increase during the cycle when a plant is operating at or near the MELLLA+ minimum CF rate.

R[ )) the MCO for NMP2 may increase to a maximum of 0.25 wt.% during the cycle when NMP2 is operating at or near the MELLLA+ minimum CF rate.

b. 8.1 Liquid and Solid Waste Management Although the volume of waste generated is not expected to increase, potentially higher MCO in the reactor steam would result in a slightly higher loading on the condensate demineralizers. Because the higher moisture content will occur infrequently, the MELLLA+ operating domain expansion will not cause the condensate demineralizer backwash frequency to be changed significantly as discussed in Section 8.1.2. The reactor water cleanup (RWCU) filter demineralizer backwash frequency is not affected because there is no effect on RWCU inlet conditions for MELLLA+, as discussed in Section 3.11.

c. 8.4.2 Fission and Activation Corrosion Products Steam separator and dryer performance for MELLLA+ operation is discussed in Section 3.3.3. The moisture content of the MS leaving the vessel may increase up to 0.25 wt.% at times while operating near the minimum CF in the MELLLA+ operating domain. The distribution of the fission and activated corrosion product activity between the reactor water and steam is affected by the increased moisture content. With increased MCO, additional activity is carried over from the reactor water with the steam. The maximum allowable moisture content leaving the reactor vessel is 0.25 wt.%.

d. 8.5 Radiation Levels As discussed in Section 8.4, the moisture content of the MS leaving the vessel may increase at certain times while operating in the MELLLA+ operating domain. However, the NMP2 MCO will be monitored and controlled to < 0.25 wt.%, which is within the analytical assumption of 0.35 wt.% used in the determination of normal operation radiation levels. The overall radiological effect of the increased moisture content is a function of the plant water radiochemistry and the levels of activated corrosion products maintained.

e. 10.7.2 Flow Accelerated Corrosion The EPU flow accelerated corrosion (FAC) evaluation for MS and extraction steam piping assumed a 0.25 wt.% MCO for mechanical thermal conditions. This 0.25 wt.%

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

MCO value bounds the maximum predicted MCO value of 0.236 wt.% for MELLLA+

based on equilibrium fuel cycle burnup assumptions. The predicted MCO is a function of fuel loading and rod patterns throughout the burnup history. The MSIVs allowable moisture content was found to be acceptable for MELLLA+ operation based on GEH engineering judgment, operating experience, and NMP2's MSIV inspection/maintenance program. The increased moisture content will not create a significant change in wear on MS piping and components based on the evaluations performed using CHECWORKSTM and design assessments for the components. MCO will be managed with monitoring to identify and track the duration of MCO above 0.1 wt.% based on taking chemical samples once per month. The FAC monitoring program was reviewed for potential changes to the program. No changes to the FAC program are required. The FAC related piping and component wear is managed by the FAC program and Maintenance Rule as discussed in Section 10.7.2.

f. 5.2.4 Main Steam Flow - FW Flow Mismatch Operation at the higher MCO performance specification is acceptable. With a dryer moisture performance specification up to 0.35 wt.%, the additional coolant removed from the RPV must be returned to the reactor in order to maintain correct water level. The FW system may be required to provide a slightly higher flow rate. The effect of the increased MSL MCO is to cause a slight imbalance in the FW control system control point. With a plant bias of 0.48 inches per percent this translates to z 0.12 inches of bias in the water level.

g 3.4.1 Piping Components with Flow-Induced Vibration - Safety Related Adequate margin exists to the FIV of the sample probes and thermowells due to the large margin available in the design.

3.4 FLOW-INDUCED VIBRATION The FIV evaluation addresses the influence of the MELLLA+ operating domain expansion on reactor coolant pressure boundary (RCPB) piping, RCPB piping components, and RPV internals.

The topics addressed in this evaluation are:

Topic M+LTR Disposition NMP2 Result Piping FIV Evaluation Recirculation System Piping Main Steam Piping Feedwater Piping Safety-Related Thermowells and Probes RPV Internals FIV Evaluation 3.4.1 FIV Influence on Piping

)) Flow rates in the recirculation system 3-10

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) piping, MS piping, and FW piping as well as associated MS and FW branch lines do not increase as a result of MELLLA+ operating domain expansion. ((

)) and no further evaluation of FIV influence on recirculation, MS, and FW piping is required.

)) For NMP2, there are no increases in the recirculation system, MS, or FW flow rates as a result of MELLLA+ operating domain expansion as compared to the current licensed operating domain. The numerical values showing no increases in recirculation system, MS, or FW flow rates are presented in Table 1-2.

)) and no further evaluation of FIV influence on recirculation, MS, and FW piping is required.

)) Because the flow rates in these piping systems do not increase for MELLLA+, there is no increase in FIV for the safety-related thermowells and probes. ((

)) and no further evaluation of FIV influence on safety-related thermowells and probes is required.

Also, [

)) For NMP2, there is no increase in flow in these systems for MELLLA+. Therefore, there is no increase in FIV for the safety-related thermowells and probes. ((

)) and no further evaluation of FIV influence on safety-related thermowells and probes is required.

((

3.4.2 FIV Influence on Reactor Internals Er

)) evaluates the effect of the MELLLA+ operating domain expansion on the following components: shroud, shroud head and steam separator-dryer, core spray (CS) line, low pressure coolant injection (LPCI) coupling, CRGT, in-core guide tubes, fuel channel, LPRM / intermediate range monitor (IRM) tubes, jet pumps, jet pump sensing lines (JPSLs), and FW sparger. The MELLLA+ operating domain expansion results in decreased core and recirculation flow as well as no increase in the MS and 3-11

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

FW flow rates. ((

)) the effect of the MELLLA+

operating domain expansion is presented for the following components:

Component(s) MELLLA+ Results Shroud Shroud Head and Steam Separator-Dryer CS Line LPCI Coupling CRGT In-Core Guide Tubes Fuel Channel LPRM/IRM Tubes Jet Pumps JPSLs FW Sparger For NMP2, the MELLLA+ operating domain expansion results in decreased core and recirculation flow as well as no increase in the MS and FW flow rates. The numerical values showing a decrease in core and recirculation flow as well as no increase in maximum steam or FW flow rates are presented in Table 1-2. As presented in the table above, ((

)) The reduced CF and recirculation flow 3-12

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) in the MELLLA+ domain ((

)) Therefore, no further evaluation of the FIV influence on reactor internals is required for the NMP2 MELLLA+ operating domain expansion.

Er 3.5 PIPING EVALUATION 3.5.1 Reactor Coolant Pressure Boundary Piping The RCPB piping systems evaluation consists of a number of safety-related piping subsystems that move fluid through the reactor and other safety systems. The topics addressed in this evaluation are:

Topic M+LTR Disposition NMP2 Result Main Steam and Feedwater (Inside Containment)

Recirculation and Control Rod Drive Reactor Core Isolation Cooling (RCIC)

High Pressure Core Spray (HPCS)

RWCU Low Pressure Core Spray (LPCS)

Standby Liquid Control Residual Heat Removal (RHR)

RPV Head Vent Line SRV Discharge Line (SRVDL)

Safety-Related Thermowells The piping systems are required to comply with the structural requirements of the ASME Boiler and Pressure Vessel (BPV) Code (or an equivalent Code) applicable at the time of construction or the governing code used in the stress analysis for a modified component.

3.5.1.1 Main Steam and Feedwater Piping Inside Containment Er

)) the system temperatures, pressures, and flows in the MELLLA+

operating domain are within the range of rated operating parameters for the MS and FW piping system (inside containment). ((

the temperatures, pressures, and flows in MS and FW systems for MELLLA+ operation are 1]

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) within the range of rated operating parameters for those systems, no further evaluation is required related to RCPB piping for MS and FW piping inside containment.

(( )) for NMP2, the MS and connected branch piping (i.e., RCIC steam lines) and FW temperatures, pressures, and flows are within the rated operating parameters for the MS and FW systems. MS and FW temperatures, flows, and pressures at MELLLA+ conditions are bounded by the EPU temperatures, flows, and pressures, and as such are within the design values used in the design of the piping and supports chosen for worst case conditions. NMP2 MS and FW piping inside containment is designed in accordance with the original code of record, ASME BPV Code,Section III, Subsection NB, 1974 Edition.

((

)) the temperatures, pressures, and flows in NMP2 MS and FW systems for MELLLA+ operation are within the range of rated operating parameters for those systems, and no further evaluation is required related to the NMP2 RCPB piping for MS and FW inside containment.

[I )) as discussed in Section 3.3.3, the MCO may increase during the cycle when a plant is operating at or near the MELLLA+

minimum CF rate. The generic disposition concludes that the change in erosion/corrosion rates as a result of increased carryover is adequately managed by the existing programs discussed in Section 10.7.2.

Er )), the MCO for NMP2 may increase to a maximum of 0.25 wt.% during the cycle when NMP2 is operating at or near the MELLLA+ minimum CF rate. NMP2 implements programs adequate to manage this change in the erosion/corrosion rate as described in Section 10.7.2.

The effect of MELLLA+ on the EPU AP load SC 09-01 evaluation has determined that the amplified response spectra (ARS) remains conservative for the rated power MELLLA+ Point N (Figure 1-1). The off-rated SC 09-01 methods show minor shifts in the ARS for selected nodes (power-flow map Points A and N in Figure 1-1) as compared to the EPU bounding spectrum.

The review of the EPU SC 09-01 AP load assessments show the minor shifts represent an insignificant change in the total load combination for these piping systems such that the conclusions reached for the EPU assessment remain unchanged.

3.5.1.2 Reactor Recirculation and Control Rod Drive Systems

)) there is no change in the maximum operating system temperatures, pressures, and flows in the MELLLA+ operating domain for the recirculation piping system and attached RHR piping system. ((

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

)) no further evaluation of the RCPB piping - reactor recirculation and CRD systems is required for MELLLA+ operating domain expansion.

(( )) for NMP2, the reactor recirculation and CRD system temperatures, flows, and pressures at MELLLA+ conditions are bounded by the EPU temperatures, flows, and pressures, and as such are within the design values used in the design of the piping and supports chosen for worst case conditions.

3.5.1.3 Other RCPB Piping Systems 3.5.1.3.1 Other RCPB Piping Systems - HPCS, LPCS, RHR/LPCI, and SLS

)) Because the piping systems meeting the criteria ((

)) their susceptibility to erosion/corrosion does not increase, and no further evaluation of these other RCPB piping systems is required.

(( )) MELLLA+ operating domain expansion for NMP2 does not change the maximum operating temperature, pressure, or flow rate of any of the following systems: HPCS, LPCS, RHR/LPCI, and SLS.

HPCS, LPCS, RHR/LPCI, and SLS temperatures, flows, and pressures at MELLLA+ conditions are bounded by the EPU temperatures, flows, and pressures, and as such are within the design values used in the design of the piping and supports chosen for worst case conditions.

Each of these NMP2 systems ((

)) their susceptibility to erosion/corrosion does not increase, and no further evaluation of these other RCPB piping systems is required for NMP2.

3.5.1.3.2 Other RCPB Piping Systems - RPV Head Vent Line and SRV Discharge Lines

((

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)) For the RPV head vent line and the SRVDL, there is no change in the temperature, pressure, or flows in these systems as a result of MELLLA+ operating domain expansion. Because the piping systems have no change in system temperature, pressure or flow as a result of MELLLA+ operating domain expansion, ((

)) Their susceptibility to erosion/corrosion does not increase, and no further evaluation of these other RCPB piping systems is required.

(( )) MELLLA+ operating domain expansion for NMP2 does not change the maximum operating temperature, pressure, or flow rate of any of the following piping systems: RPV head vent line and SRVDL.

RPV head vent line and SRVDL temperatures, flows, and pressures at MELLLA+ conditions are bounded by the EPU temperatures, flows, and pressures, and as such are within the design values used in the design of the piping and supports chosen for worst case conditions. Additionally, there is no flow through the SRVDL during normal operating conditions.

The RPV head vent line and the SRVDL are unaffected by MELLLA+ operating domain expansion. (( )) their susceptibility to erosion/corrosion does not increase, and no further evaluation of these other RCPB piping systems is required for NMP2.

3.5.1.3.3 Other RCPB Piping Systems - RWCU

((

)) Because the RWCU system has no change in system temperature, pressure or flow as a result of MELLLA+ operating domain expansion, ((

)) RWCU system susceptibility to erosion/corrosion does not increase, and no further evaluation of the RWCU system is required.

Er )) MELLLA+ operating domain expansion for NMP2 does not change the maximum operating temperature, pressure, or flow rate of the RWCU system. RWCU system temperatures, flows, and pressures at MELLLA+

conditions are bounded by the EPU temperatures, flows, and pressures, and as such are within the design values used in the design of the piping and supports chosen for worst case conditions.

The NMP2 RWCU system is unaffected by MELLLA+ operating domain expansion.

Er )) the RWCU system susceptibility to erosion/corrosion does not increase, and no further evaluation of the RWCU system is required.

3.5.1.3.4 Other RCPB Piping Systems - Safety-Related Thermowells

((

)) Because the RCPB piping systems evaluated for EPU do not experience any increase in pressure, temperature, or flow at MELLLA+, their susceptibility to erosion/corrosion does not increase, and no further evaluation of safety-related thermowells is required for NMP2.

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)) the NMP2 safety-related thermowells are unaffected by MELLLA+ as the evaluations performed for the currently licensed operating domain are bounding for MELLLA+ conditions. ((

Their susceptibility to erosion/corrosion does not increase and no further evaluation of safety-related thermowells is required for NMP2.

Because all of the piping systems in Section 3.5.1.3 meet the criteria listed ((

)) their susceptibility to erosion/corrosion does not increase, and no further evaluation of these other RCPB piping systems is required.

3.5.1.4 Other than Category "A" RCPB Material As required by M+LTR SER Limitation and Condition 12.9, the following discussion is presented regarding other than Category "A" materials that exist in the RCPB piping.

Category "A" is assumed to mean intergranular stress corrosion cracking (IGSCC) Category "A" that is a resistant material to IGSCC for BWR piping weldments in accordance with Generic Letter (GL) 88-01 (Reference 18). Other than Category "A" is assumed to mean non-resistant or cracked materials for IGSCC BWR piping weldments in accordance with GL 88-01 (IGSCC Categories B through G). USAR Section 5.2-5 is only a general RCPB list and is not specifically related to IGSCC. The SER for GL 88-01, along with the associated technical evaluation, establishes the IGSCC categories and initial IGSCC related bases. The current IGSCC program is located within the in-service inspection (ISI) program plan (CNG-NMP2-ISI-003).

CNG-NMP2-ISI-003, Section 6.1 specifically identifies 49 welds that are in the IGSCC other than Category "A" (Categories D and E shown in Tables 6-1 and 6-2 and summarized in Table 6-5 and Appendix E). CNG-NMP2-ISI-003-10 shows the implementation schedule and has the "ASME Section XI Category Item No." column as either "GLD" or "GL-E," which identifies the location of the weld.

The NMP2 ISI program for all ASME Code Class 1 and 2 RCPB piping is in accordance with an NRC staff approved alternate risk-informed inspection program utilizing the NRC approved Electric Power Research Institute (EPRI) methodology, Technical Report TR-1 12657, Revision B-A (Reference 19). In addition to the ASME Code,Section XI and the alternate risk-informed programs, NMP2 implements an augmented IGSCC inspection program in accordance with GL 88-01 (Reference 18), NUREG-0313 (Reference 20), and as modified by Boiling Water Reactor Vessel and Internals Project (BWRVIP)-75 (Reference 21) for IGSCC Category D weld examination frequency using normal water chemistry. NMP2 implements ASME Section XI, Appendix VIII for the performance demonstration for ultrasonic examination systems administrated through the EPRI performance demonstration initiative (PDI) program.

Appendix VIII provided the requirements for the performance demonstration for ultrasonic examination procedures, equipment, and personnel to detect and size flaws. All of the above 3-17

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) programs have been credited as an aging management program during the NMP2 license renewal process.

Continued implementation of the current program ensures the prompt identification of any degradation of RCPB components experienced during MELLLA+ operating conditions.

(( )) confirms that the augmented inspection program at NMP2 is adequate to address concerns related to other than Category "A" materials in the RCPB.

3.5.2 Balance-of-Plant Piping The BOP piping evaluation consists of a number of piping subsystems that move fluid through systems outside the RCPB. The topics considered in this section are:

Topic M+LTR Disposition NMP2 Result Main Steam and Feedwater (Outside Containment)

Reactor Core Isolation Cooling High Pressure Core Spray Low Pressure Core Spray Residual Heat Removal High Pressure Coolant Injection (HPCI)

Offgas System Containment Air Monitoring Neutron Monitoring System 3.5.2.1 Main Steam and Feedwater (Outside Containment)

((

)) for all MS and FW piping systems, including the associated branch piping, the temperature, pressure, flow, and mechanical loads do not increase due to the MELLLA+

operating domain expansion. ((

)) The susceptibility of these piping systems to erosion/corrosion increases only for the MS piping; however, that erosion/corrosion will be adequately managed as discussed in Sections 3.5.1.1 and 10.7.2. ((

no further evaluation is required for BOP Piping - MS and FW (outside containment).

[ MELLLA+ operating domain expansion for NMP2 does not change (no increase) the maximum operating temperature, pressure, flow rate, or mechanical loads for the MS and FW piping outside containment. MS and FW system temperatures, flows, and pressures at MELLLA+ conditions are bounded by the EPU temperatures, flows, and pressures, and as such are within the design values used in the design of 3-18

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) the piping and supports chosen for worst case conditions. The NMP2 MS and FW piping outside containment is unaffected by the MELLLA+ operating domain expansion. The NMP2 BOP piping outside containment was typically designed in accordance with American National Standards Institute (ANSI) B331.1 (Reference 22) and as such, there were no fatigue analyses required or performed. ((

)), the FW piping outside containment susceptibility to erosion/corrosion does not increase, and no further evaluation is required. The MS outside containment susceptibility to erosion/corrosion does increase; however, no further evaluation is required due to being adequately managed as discussed in Sections 3.5.1.1 and 10.7.2.

((i 3.5.2.2 Other BOP Piping Systems 3.5.2.2.1 Other BOP Piping Systems - RCIC, HPCS, LPCS, and RHR

)) the loads and temperatures used in the analyses depend on the containment hydrodynamic loads and temperature evaluation results (Section 4.1). ((

)) The design basis LOCA dynamic loads including the pool swell loads, vent thrust loads, condensation oscillation (CO) loads, and chugging loads have been defined and evaluated for EPU. The pool temperatures due to a design basis LOCA were also defined for EPU. The values for the MELLLA+ operating domain remain within these bounding values.

((

)) For these BOP piping systems, no further evaluation is required as a result of MELLLA+.

The effect of MELLLA+ on the EPU AP load SC 09-01 evaluation has determined that the ARS remains conservative for the rated power MELLLA+ Point N (Figure 1-1). The off-rated SC 09-01 methods show minor shifts in the ARS for selected nodes (power-flow map Points A and N in Figure 1-1) as compared to the EPU bounding spectrum. The review of the EPU SC 09-01 AP load assessments show the minor shifts represent an insignificant change in the total load combination for these piping systems such that the conclusions reached for the EPU assessment remain unchanged.

The MELLLA+ operating domain expansion for NMP2 does not change the maximum operating temperature, pressure, or flow rate, or increase mechanical loads for any of the following systems: RCIC, HPCS, LPCS, and RHR.

RCIC, HPCS, LPCS, and RHR system temperatures, flows, and pressures at MELLLA+

conditions are bounded by the EPU temperatures, flows, and pressures, and as such are within the design values used in the design of the piping and supports chosen for worst case conditions.

)) for each of the NMP2 systems described above, the loads and temperatures used in the analyses continue to be bounded by the loads and 3-19

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) temperatures used in the analyses performed for EPU. Section 4.1 shows that the NMP2 LOCA dynamic loads including the pool swell loads, vent thrust loads, CO loads, and chugging loads have been evaluated and are bounded by the current design basis. The NMP2 peak suppression pool temperatures due to a design basis LOCA are also bounded by the current design basis.

)) For these BOP piping systems, no further evaluation is required as a result of MELLLA+.

3.5.2.2.2 Other BOP Piping Systems - Offgas System, Containment Air Monitoring, and Neutron Monitoring System

)) For these BOP piping systems, no further evaluation is required as a result of MELLLA+.

(( )) there is no change to the NMP2 reactor operating pressure or power level as a result of MELLLA+ operating domain expansion.

The numerical values showing no increases in reactor operating pressure are presented in Table 1-2. ((

)) For these BOP piping systems, no further evaluation is required as a result of MELLLA+.

Because all of the piping systems in Section 3.5.2.2 meet the criteria listed ((

)) their susceptibility to erosion/corrosion does not increase, and no further evaluation of these other BOP piping systems is required.

I((

3.6 REACTOR RECIRCULATION SYSTEM The topics addressed in this evaluation are:

Topic M+LTR Disposition NMP2 Result System Evaluation ((

Net Positive Suction Head (NPSH)

Single Loop Operation Flow Mismatch _ E 3.6.1 System Evaluation

(( )) all of the RRS operating conditions for the MELLLA+ operating domain are within the operating conditions in the current licensed operating domain. SLO is not allowed in the MELLLA+

3-20

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) operating domain. ((

)) and no further evaluation of this topic is required.

)) the NMP2 RRS operating conditions in the MELLLA+ operating domain are within the operating conditions in the current licensed operating domain. For NMP2, there are no increases beyond design rated parameters in the RRS temperature, pressure, or flow rates as a result of MELLLA+ operating domain expansion as compared to the current licensed operating domain. RRS system temperature for the current licensed operating domain at 100% CF is 533.7°F and in the MELLLA+ operating domain at 85% CF is 530.7°F. RRS system pressures, at the discharge of the recirculation pump, will increase from 1,314.5 psia for the current licensed operating domain to 1,340.5 psia in the MELLLA+ operating domain. This slight increase in pressure is due to the adjustment of the FCV to approximately the 59% opened position and is within the design operating pressure of the RRS system components. The numerical values showing no increases in RRS system flow rates are presented in Table 1-2. For NMP2, SLO is not allowed in the MELLLA+ operating domain. ((

)) and no further evaluation of this topic is required.

3.6.2 Net Positive Suction Head

)) Therefore, no further evaluation of the RRS NPSH topic is required.

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

)) flow rate and FW temperature and, as described above, they are not changed by MELLLA+. ((

)) The numerical values showing no significant changes in FW temperature and flow are presented in Table 1-2. Therefore, no further evaluation of the RRS NPSH topic is required.

3.6.3 Single Loop Operation

(( )) SLO is not allowed in the MELLLA+ operating domain.

(( )) SLO is not allowed in the MELLLA+ operating domain. NMP2 SLO operational limitations will be identified in TS 3.4.1. Therefore, SLO is not allowed in the MELLLA+ operating range and is not affected by the MELLLA+ domain expansion.

3.6.4 Flow Mismatch Flow mismatch is discussed in Section 4.3.8.

3.7 MAIN STEAM LINE FLOW RESTRICTORS The topics addressed in this evaluation are:

Topic " M+LTR Disposition NMP2 Result Structural Integrity

)) there is no increase in MS flow as a result of the MELLLA+ operating domain expansion. ((

)) and no further evaluation of this topic is required.

)) there is no increase in NMP2 MS flow as a result of MELLLA+ operating domain expansion. The numerical values showing that MS flow does not increase as a result of MELLLA+ are presented in Table 1-2. ((

)) and no further evaluation of this topic is required.

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 3.8 MAIN STEAM ISOLATION VALVES The topics addressed in this evaluation are:

Topic M+LTR Disposition NMP2 Result Isolation Performance Valve Pressure Drop ))

)) there is no increase in MS pressure, flow, or pressure drop as a result of the MELLLA+ operating domain expansion.

(( ))

and no further evaluation of this topic is required.

(( )) there is no significant change in NMP2 MS pressure, flow, or pressure drop as a result of MELLLA+ operating domain expansion. The MS pressure for the current licensed operating domain and in the MELLLA+ operating domain is 1,035 psia. The numerical values showing that MS flow does not increase as a result of MELLLA+ are presented in Table 1-2. The total MSL pressure drop at the TSVs is not significantly changed for MELLLA+; the MSIV pressure drop is also not significantly changed.

((i

)) and no further evaluation of this topic is required.

1]

3.9 REACTOR CORE ISOLATION COOLING The RCIC system provides inventory makeup to the reactor vessel when the vessel is isolated from the normal high pressure makeup systems. The topics addressed in this evaluation are:

Topic M+LTR Disposition NMP2 Result System Hardware ((

System Initiation Net Positive Suction Head Inventory Makeup Level Margin to Top of Active Fuel (TAF) F 3.9.1 System Hardware there are no changes to the RCIC system hardware as a result of MELLLA+ operating domain expansion.

(( )) there are no changes to the NMP2 RCIC system hardware as a result of MELLLA+.

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 3.9.2 System Initiation

(( )) there are no changes to the normal reactor operating pressure, decay heat, or SRV setpoints as a result of MELLLA+ operating domain expansion. ((

no further evaluation of this topic is required.

)) there are no changes to the normal reactor operating pressure, decay heat, or SRV setpoints as a result of MELLLA+ operating domain expansion. The NMP2 reactor operating pressure for the current licensed operating domain and in the MELLLA+ operating domain remain unchanged. The numerical values showing that reactor operating pressure does not increase as a result of MELLLA+ are presented in Table 1-2.

As described in Section 1.2.3, the generic disposition in the M+LTR concludes that there is no increase in decay heat as a result of MELLLA+ operating domain expansion. As discussed in Section 3.1.2, SRV setpoints are unchanged by MELLLA+ operating domain expansion.

Therefore, for NMP2, ((

)) No further evaluation of this topic is required.

3.9.3 Net Positive Suction Head

(( )) the NPSH available for the RCIC pump ((

)) For ATWS (Section 9.3) and fire protection (Section 6.7), operation of the RCIC system at suppression pool temperatures greater than the operational limit may be accomplished by using the CST volume as the source of water. Therefore, the specified operational temperature limit for the process water does not change with MELLLA+. The NPSH required by the RCIC pump ((

)) Therefore, no further evaluation is required for this topic.

)) for NMP2, there are no physical changes to the pump suction configuration. The NMP2 RCIC flow rate for the current licensed operating domain and in the MELLLA+ operating domain is 600 gpm. Minimum atmospheric pressure in 3-24

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) the suppression chamber and the CST for the current licensed operating domain and in the MELLLA+ operating domain does not change. The RCIC system has the capability of using the CST or the suppression pool as a suction source at EPU and MELLLA+ conditions. For ATWS (Section 9.3) and fire protection (Section 6.7), operation of the RCIC system at suppression pool temperatures greater than the operational limit may be accomplished by using the CST volume as the source of the water. Therefore, the specified operational temperature limit for the process water does not change with MELLLA+. In addition, the MELLLA+ suppression pool temperature following an ATWS is bounded by EPU.

The design basis function of the RCIC system is to provide coolant to the reactor vessel so that the core is not uncovered as a result of loss of off-site alternating current (AC) power or for a loss of feedwater (LOFW) event.

The NPSH required by the NMP2 RCIC pump ((

)) Therefore, no further evaluation is required for this topic.

3.9.4 Inventory Makeup Level Margin to TAF The makeup capacity of RCIC and the level margin to the TAF are evaluated in Section 9.1.3.

3.10 RESIDUAL HEAT REMOVAL SYSTEM The RHR system is designed to restore and maintain the reactor coolant inventory following a LOCA and remove reactor decay heat following reactor shutdown for normal, transient, and accident conditions. The topics addressed in this evaluation are:

Topic M+LTR Disposition NMP2 Result Low Pressure Coolant Injection Mode Suppression Pool and Containment Spray Cooling Modes Shutdown Cooling (SDC) Mode Steam Condensing Mode Fuel Pool Cooling Assist ))

The primary design parameters for the RHR system are the decay heat in the core and the amount of reactor heat discharged into the containment during a LOCA. The RHR system operates in various modes, depending on plant conditions. ((

))

3.10.1 Low Pressure Coolant Injection Mode The LPCI mode, as it supports the LOCA response, is discussed in Section 4.2.4, Low Pressure Coolant Injection.

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 3.10.2 Suppression Pool and Containment Spray Cooling Modes

)) the SPC mode is manually initiated to maintain the containment pressure and suppression pool temperature within design limits following isolation transients or a postulated LOCA. The short-term containment response, for the first 30 seconds of the event, does not credit the containment spray in the analyses. ((

)) Therefore, no further evaluation is required for this topic.

3.10.3 Shutdown Cooling Mode

[)) the SDC mode is designed to remove the sensible and decay heat from the reactor primary system during a normal reactor shutdown. This non-safety related mode allows the reactor to be cooled down within a certain time, so that the SDC mode of operation does not become a critical path during refueling operations. ((

)) Therefore, no further evaluation is required for this topic.

3.10.4 Steam Condensing Mode The steam condensing mode is not applicable to NMP2.

3.10.5 Fuel Pool Cooling Assist Mode The fuel pool cooling assist mode, using existing RHR heat removal capacity, provides supplemental fuel pool cooling in the event that the fuel pool heat load exceeds the capability of the fuel pool cooling and cleanup system. ((

)) Therefore, there is no effect on the fuel pool cooling assist mode.

3.11 REACTOR WATER CLEANUP SYSTEM The topics addressed in this evaluation are:

Topic M+LTR Disposition NMP2 Result System Performance ((

Containment Isolation 3-26

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 3.11.1 System Performance ER

)) the MELLLA+ operating domain expansion does not change the pressure or fluid thermal conditions experienced by the RWCU system. Operation in the MELLLA+ operating domain does not increase the quantity of fission products, corrosion products, and other soluble and insoluble impurities in the reactor water. Reactor water chemistry is within fuel warranty and TS limits on effluent conductivity and particulate concentration, and thus, no changes will be made in water quality requirements.

(( )) for NMP2, there is no total increase in the quantity of fission products, corrosion products, and other soluble and insoluble radionuclide impurities in the reactor water (see Section 8.4). Consistent with the generic disposition discussed above, for NMP2, there is no significant change in the FW line temperature, pressure, or flow rate. FW line temperature for the current licensed operating domain and in the MELLLA+ operating domain is 440.5'F (upstream of the RWCU return). As shown in Table 1-2, the FW flow rate in the MELLLA+ operating domain decreases slightly from the flow rate in the current licensed operating domain. As discussed in Section 1.2, reactor pressure for the current licensed operating domain and in the MELLLA+ operating domain does not change. Therefore, FW system resistance and operating conditions do not change and the pressure at the RWCU/FW system interface does not change. As discussed in Sections 1.2 and 3.6, reactor and recirculation system parameters are bounded by or unchanged from EPU conditions. Therefore, there is no effect on RWCU inlet conditions due to MELLLA+. Because there is no change to the pressure or fluid thermal conditions experienced by the RWCU system, and because there is no total increase in the quantity of fission products, corrosion products, and other soluble and insoluble radionuclide impurities in the reactor water, ((

)) Therefore, no further evaluation of this topic is required.

3.11.2 Containment Isolation

)) the RWCU system is a normally operating system with no safety-related functions other than containment isolation. ((

)) because there is no change in the FW line pressure, temperature, and flow rate.

(( )) for NMP2, there is no significant change in the FW line temperature, pressure, or flow rate. The FW line temperature for the current licensed operating domain and in the MELLLA+ operating domain is 440.5'F (upstream of the RWCU return). As shown in Table 1-2, the maximum FW flow rate in the MELLLA+

operating domain decreases slightly from the maximum flow rate in the current licensed operating domain. As such, the FW flow rates in the MELLLA+ operating domain remain 3-27

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) within the FW flow rates in the current licensed operating domain. As discussed in Section 1.2, reactor pressure for the current licensed operating domain and in the MELLLA+ operating domain does not change. Therefore, FW system resistance and operating conditions do not change and the pressure at the RWCU/FW system interface does not change for RWCU return lines. As discussed in Section 3.11.1 above, there is no change to RWCU inlet conditions.

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

Table 3-1 Key Results at 120% OLTP Item Parameter CLTP to M+

120% OLTP Comparison I Azimuthal flux distribution at RPV ID Ratio of M+/CLTP peak flux is 0.98 2 Relative axial flux distribution at RPV ID No significant change 3 Azimuthal flux distribution at shroud ID Ratio of M+/CLTP peak flux is 1.01 4 Relative axial flux distribution at shroud ID No significant change 5 54-EFPY axial fluence distribution at RPV ID Ratio of M+/CLTP peak fluence is 0.99 6 54-EFPY axial fluence at shroud H4 weld Ratio of M+/CLTP peak fluence is 1.02 7 Capsule (30 azimuth) flux Ratio of M+/CLTP flux is 1.02 8 Capsule lead factor Ratio of M+/CLTP lead factor is 1.05 9 Peak flux at top guide Ratio of M+/CLTP peak flux is 1.07 10 Peak flux at core plate Ratio of M+/CLTP peak flux is 0.94 11 54-EFPY peak fluence at top guide Ratio of M+/CLTP peak fluence is 1.06 12 54-EFPY peak fluence at core plate Ratio of M+/CLTP peak fluence is 0.94 3-29

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 4.0 ENGINEERED SAFETY FEATURES This section addresses the evaluations that are applicable to MELLLA+.

4.1 CONTAINMENT SYSTEM PERFORMANCE The topics addressed in this evaluation are:

Topic M+LTR Disposition NMP2 Result Short-Term Pressure and Temperature Response Long-Term Suppression Pool Temperature Response Containment Dynamic Loads Loss-of-Coolant Accident Loads Subcompartment Pressurization Safety Relief Valve Loads Safety Relief Valve Containment Dynamic Loads Safety-Relief Valve Piping Loads Containment Isolation Generic Letter 89-10 Generic Letter 95-07 Generic Letter 96-06 4.1.1 Short-Term Pressure and Temperature Response According to Section 4.1.1 of the M+LTR (Reference 1), operation in the MELLLA+ range may change the break energy for the DBA recirculation suction line break (RSLB). The break energy is derived from the break flow rate and enthalpy. ((

)) NMP2 short-term RSLB containment temperature and pressure responses are affected by the change in enthalpy as a result of MELLLA+ operating domain expansion.

The short-term RSLB analyses cases at MELLLA+ demonstrate that peak DW temperatures from the short-term RSLB for the current licensed operating domain and the MELLLA+

operating domain are bounded by the CLTP results reported in Reference 23 which remain below the design limit of 340'F.

For NMP2, there are two peak pressures; the first peak occurring -25 seconds (end of initial vessel inventory blowdown) and the second peak occurring -150 seconds (end of blowdown phase). The first peak is typically determined by standard short-term analysis, while the second peak is determined by the extended short-term analysis. The first peak is lower than the second peak; the difference is -0.5 psi for EPU. The extended short-term analysis is not sensitive to the subtle initial changes in vessel mass and energy associated with operation at various points in the operating domain. Due to the extended time frame until the DW reaches the second peak pressure conditions, it is recognized that the minor variability in the initial vessel inventory energy associated with various points in the operating range would have negligible effect in 4-1

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) comparison to the overall mass and energy contributions to the DW at the time of the second peak. Therefore, the effect of MELLLA+ is assessed from the results of the standard short-term analysis using more detailed LAMB break flow model, which captures the subcooling effect when operating in MELLLA+ operating domain. Several short-term cases are analyzed for MELLLA+ statepoints and results compared to EPU short-term results. The results show that EPU short-term peak pressure bounds the MELLLA+ peak pressures. The peak DW-to-wetwell differential pressures for operation in the MELLLA+ operating domain are bounded by those previously reported in Reference 23 for the current CLTP operation. ((

))

4.1.1.1 Long-Term Suppression Pool Cooling Temperature Response Therefore, no further evaluation of this topic is required.

(( )) the sensible and decay heat do not increase as a result of MELLLA+ operating domain expansion. ((

)) No further evaluation of this topic is required.

4.1.2 Containment Dynamic Loads 4.1.2.1 Loss-of-Coolant Accident Loads As described in the M+LTR, a (( )) evaluation is performed to determine the effect of MELLLA+ on the LOCA containment dynamic loads. Results from ((

)) are used to evaluate the effect of the MELLLA+ operating domain expansion on LOCA containment dynamic loads. The LOCA dynamic loads include vent clearing jet loads, pool swell, CO, and chugging.

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

These loads have been defined generically for Mark II plants as part of the Mark II containment program and are described in detail in the Mark II Containment Dynamic Forcing Functions Report (DFFR) (Reference 24). The DFFR was reviewed and approved by the NRC in NUREG-0808 and NUREG-0487 (References 9 and 25). The specific application of these loads to NMP2 is described in Section 6A.4 of the NMP2 USAR (Reference 26).

The results of the (( )) LOCA containment dynamic loads evaluation demonstrate that existing vent clearing jet loads, pool swell, CO, and chugging load definitions remain bounding for operation in the MELLLA+ operating domain. Therefore, the LOCA containment dynamic loads are not affected by the MELLLA+ operating domain expansion.

4.1.2.2 Subcompartment Pressurization Reduced FW temperature increases the subcooling in the FW and reactor recirculation lines, which increases the break flow rates for liquid line breaks. The current subcompartment pressurization loads evaluations consider the current licensed operating domain, which includes an operational band of-20'F (with a minimum FW temperature of 420.5°F at rated power). This analysis concludes that break flow rates for liquid line breaks such as FW and recirculation line breaks for the MELLLA+ expanded operating domain are bounded by the break flow rates for the current licensed operating domain. This operation band remains valid for the MELLLA+

operating domain.

4.1.2.2.1 Annulus Pressurization Load Evaluation The results from the updated dynamic analyses, including effects from both EPU and the non-conservative assumptions, were compared against those used as input to the component structural analyses of record. The effect of the increase in AP loads on the total component stresses is reduced when the AP loads are combined with the SSE seismic loads by the square root of the sum of the squares in the faulted load combination. The SSE seismic loads in the load combination are not affected by EPU. The effect of MELLLA+ on the EPU AP load SC 09-01 evaluation has determined that the ARS remains conservative for the rated power MELLLA+.

The off-rated SC 09-01 methods show minor changes in the sub compartment pressurization related to the updated methods associated with SC 09-01 when combined with the jet reaction loads and jet impingement loads using conservative assumptions. The minor changes in ARS frequency when combined in the faulted load combination with seismic show that the conclusions reached for the EPU assessment remain bounding with a few locations showing minor increases. The results of these evaluations show that all reactor vessel and internals, and associated vessel attachments and supports remain within design basis faulted allowable limits.

Because the MELLLA+ operating domain AP subcompartment pressurization are bound by the current licensed operating domain, no further evaluation of this topic is required.

The evaluation of the NMP2-specific AP subcompartment pressurization is determined to be acceptable for NMP2.

4-3

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 4.1.2.2.2 Drywell Head Subcompartment Pressurization Evaluation The pressure loading on the DW head refueling bulkhead plate to a postulated break in the RCIC head spray line in the DW head subcompartment is not affected by MELLLA+. The pressure and temperature/enthalpy for the RCIC is either not affected or may be slightly reduced in value compared to EPU. The postulated RSLB in the DW affects the upward pressure loading on the bulkhead plate and remains bounded by the EPU evaluation as the fluid enthalpy at the break location is not significantly affected (less than 1%), while the break location pressure is the same as at CLTP. Therefore, the DW head refueling bulkhead plate design margins is unchanged.

Because the MELLLA+ operating domain DW head subcompartment pressurization is bound by the current licensed operating domain, no further evaluation of this topic is required.

The evaluation of the NMP2-specific DW head subcompartment pressurization is determined to be acceptable for NMP2.

4.1.2.2.3 Biological Shield Wall Subcompartment Pressurization Evaluation The differential pressure loading on the biological shield wall (BSW) is not significantly affected by MELLLA+. The pressure and temperature/enthalpy for the high energy systems penetrating the BSW (recirculation, LPCS, HPCS, feedwater) are either not affected or may be slightly reduced in value compared to EPU. The peak BSW differential pressure load resulting from the limiting recirculation pump discharge line break at CLTP and MELLLA+ conditions remains bounded by the EPU evaluations and remains below the BSW design differential pressure. In addition, the EPU AP load SC 09-01 evaluation for the BSW remains conservative when considering MELLLA+ and the off-rated operating conditions.

Because the MELLLA+ operating domain BSW subcompartment pressurization is bound by the current licensed operating domain, no further evaluation of this topic is required.

The evaluation of the NMP2-specific BSW subcompartment pressurization is determined to be acceptable for NMP2.

4.1.2.3 SRV Piping - Containment Dynamic Loads because the sensible and decay heat do not change in the MELLLA+ operating domain, and because the SRV setpoints do not change, the SRV loads do not change. Therefore, no further evaluation of this topic is required.

(( )) the sensible and decay heat do not change as a result of MELLLA+ operating domain expansion. This response is discussed in Section 1.2.3. Also, there is no change to the NMP2 SRV setpoints as a result of MELLLA+

operating domain expansion. This topic is discussed in Section 3.1.2. Therefore, there is no change to the NMP2 SRV loads. No further evaluation of this topic is required.

4-4

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 4.1.2.4 SRV - Containment Dynamic Loads The basis for the M+LTR (Reference 1) generic SRV containment load disposition was confirmed to be applicable to NMP2.

Section 4.1 of the M+LTR (Reference 1) provides the following generic disposition for the effect of MELLLA+ on long-term suppression pool temperature response and SRV loads; 4.1.3 Containment Isolation

)) evaluation is required to demonstrate the adequacy of the containment isolation system.

)) Therefore, no containment isolation system evaluations are required for NMP2.

((

4.1.4 Generic Letter 89-10 Topic M+LTR Disposition NMP2 Result Generic Letter 89-10 ((

Generic Letter 89-16 Generic Letter 95-07 Generic Letter 96-06 ))

)) evaluation to evaluate changes to the GL 89-10 program is required.

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

)) Sections 6.6 and 10.1 confirm that other parameters with the potential to affect the capability of safety-related MOVs, such as the ambient temperature profile, are bounded by the current design basis. Therefore, a separate plant-specific GL 89-10 MOV program evaluation is not required.

4.1.5 Generic Letter 89-16 GL 89-16 (Reference 28) is not applicable to NMP2.

4.1.6 Generic Letter 95-07 evaluation of the GL 95-07 program is required.

)) Therefore, no GL 95-07 evaluation is required.

4.1.7 Generic Letter 96-06

((I evaluation of the GL 96-06 program is required.

((

)) Therefore, no GL 96-06 evaluation is required.

O((

4.2 EMERGENCY CORE COOLING SYSTEMS The ECCS includes HPCS, the LPCS system, the LPCI mode of the RHR system, and the ADS.

The topics addressed in this evaluation are:

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

Topic M+LTR Disposition NMP2 Result High Pressure Coolant Injection N/A to NMP2 N/A to NMP2 High Pressure Core Spray Low Pressure Core Spray Low Pressure Coolant Injection Mode of the Residual Heat Removal System Automatic Depressurization System Emergency Core Cooling System Net Positive Suction Head 4.2.1 High Pressure Coolant Injection The HPCI system is not applicable to NMP2.

4.2.2 High Pressure Core Spray

(( )) the HPCS system is designed to spray water into the reactor vessel over a wide range of operating pressures. In the event of a small break LOCA that does not immediately depressurize the reactor vessel, the HPCS system provides reactor vessel coolant inventory makeup to maintain reactor water level and help depressurize the reactor vessel. This system also provides spray cooling for long-term core cooling after a LOCA. In addition, the HPCS system serves as a backup to the RCIC system to provide makeup water in the event of a LOFW flow transient. For the MELLLA+ operating domain expansion, there is no change in the normal reactor operating pressure, decay heat, and the SRV setpoints. ((

no further evaluation of the HPCS system is required.

(( )) there is no change to the normal reactor pressure as a result of MELLLA+ operating domain expansion. The numerical values showing no increases in reactor operating pressure are presented in Table 1-2. The sensible and decay heat do not change as a result of MELLLA+ operating domain expansion. This response is discussed in Section 1.2.3. Also, there is no change to the NMP2 SRV setpoints as a result of MELLLA+

operating domain expansion. This topic is discussed in Section 3.1.2. ((

)) and no further evaluation of the HPCS system is required.

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 4.2.3 Low Pressure Core Spray

[I )) the LPCS system is automatically initiated in the event of a LOCA. The primary purpose of the LPCS system is to provide reactor coolant makeup for a large break LOCA and for any small break LOCA after the reactor vessel has depressurized. It also provides spray cooling for long-term core cooling in the event of a LOCA. ((

)) no further evaluation of the LPCS system for MELLLA+.

)) there is no change to the reactor pressure as a result of MELLLA+ operating domain expansion. The numerical values showing no increases in reactor operating pressure are presented in Table 1-2. ((

)) and no further evaluation of the LPCS system is required.

((

4.2.4 Low Pressure Coolant Injection

(( )) the LPCI mode of the RHR system is automatically initiated in the event of a LOCA. The primary purpose of the LPCI mode is to provide reactor coolant makeup for a large break LOCA and for any small break LOCA after the reactor vessel has depressurized. ((

)) no further evaluation of LPCI for MELLLA+.

(( )) there is no change to the reactor pressure as a result of MELLLA+ operating domain expansion. The numerical values showing no increases in reactor operating pressure are presented in Table 1-2. ((

]) and no further evaluation of the LPCI mode is required. In the event of a design basis 4-8

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

Appendix R event discussed in Section 6.7, the LPCI mode of RHR injects water into the reactor vessel to restore inventory and maintain core cooling following vessel depressurization.

((

4.2.5 Automatic Depressurization System R)) the ADS uses SRVs to reduce the reactor pressure following a small break LOCA, when it is assumed that the high pressure systems have failed. This allows the LPCS and LPCI systems to inject coolant into the reactor vessel. ((

)) no further evaluation of the ADS is required.

((

)) and no further evaluation of the ADS is required.

Er 4.2.6 ECCS Net Positive Suction Head Er )) the MELLLA+ operating domain expansion does not result in an increase in the heat addition to the suppression pool following a LOCA, station blackout (SBO), or Appendix R event. ((

)) There are no physical changes in the piping or system arrangement. There is no change in the operator actions to throttle the RHR and CS pumps.

Er )) there is no increase in the heat addition to the suppression pool following a LOCA, SBO, or Appendix R event (see Sections 4.1.2, 9.3.2, and 6.7, respectively). For NMP2, the most limiting case for ECCS NPSH is confirmed to occur at the long-term suppression pool temperature during a LOCA, ((

)) There are also no changes in NMP2 ECCS piping or system arrangement. There is no change in the operator actions to throttle the RHR and CS pumps. Therefore, all criteria related E[ )) of ECCS-NPSH are met, and no further evaluation is required.

The suppression pool temperature following an ATWS is bounded by EPU.

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

M+LTR SER Limitation and Condition 12.23.9 requires that plant-specific applications must review the safety system specifications to ensure that all of the assumptions used for the ATWS SE indeed apply to their plant-specific conditions including providing information on crucial systems like HPCI and physical limitations like NPSH and maximum vessel pressure that RCIC and HPCI can inject. NMP2 does not have a HPCI system. In response to an NRC RAI for the EPU LAR, NMP2 performed NPSH evaluation for ECCS pumps for variety of scenarios including DBA-LOCA and ATWS. The NPSH evaluation did not credit containment accident overpressure (Reference 31). As discussed above, MELLLA+ suppression pool temperature for DBA-LOCA is bounded by EPU. In addition, MELLLA+ ATWS suppression pool temperature is also bounded by EPU ATWS as shown in Table 9-4. Therefore, reduction in MELLLA+

containment pressure has no effect on the ECCS pump operability in regard to NPSH.

Therefore, NMP2 complies with M+LTR SER Limitation and Condition 12.23.9 related to NPSH and ECCS pump operability.

The EPU analysis of ECCS NPSH remains bounding for MELLLA+. The NRC reviewed the ECCS NPSH requirements as part of the EPU LAR, and stated in the NRC's SER for the NMP2 EPU LAR dated December 22, 2011 (Reference 14) that the NMP2 ECCS NPSH meets the guidance in RG 1.1 (Reference 32), does not credit containment accident pressure to ensure adequate NPSH, and meets NRC staff guidance on NPSH uncertainty and operation in maximum erosion zone.

4.3 EMERGENCY CORE COOLING SYSTEM PERFORMANCE The NMP2 ECCS is designed to provide protection against postulated LOCAs caused by ruptures in the primary system piping. The ECCS performance characteristics do not change for the MELLLA+ operating domain expansion.

The topics addressed in this evaluation are:

Topic M+LTR Disposition NMP2 Result Large Break Peak Clad Temperature Small Break Peak Clad Temperature Local Cladding Oxidation Core-Wide Metal Water Reaction Coolable Geometry Long-Term Cooling Flow Mismatch Limits These topics are described in Sections 4.3.2 through 4.3.8.

4.3.1 Break Spectrum Response and Limiting Single Failure

)) The break spectrum response is determined by the ECCS network design and is common to all BWRs. SAFER evaluation experience shows that the basic break spectrum 4-10

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) response is not affected by changes in CF (Reference 33). ((

M+LTR SER Limitation and Condition 12.14 requires that for plants that will implement MELLLA+, a sufficient number of small break sizes shall be analyzed at the rated EPU power level to ensure that the peak peak cladding temperature (PCT) break size is identified. ((

))

The factors influencing the selection of the limiting single failure for NMP2 are ((

)) The trends discussed in the M+LTR regarding the first and second clad temperature peaks of large breaks are applicable to NMP2. ((

))

The factors influencing the selection of the small break limiting single failure for NMP2 are 4.3.2 Large Break Peak Clad Temperature The effect of MELLLA+ operating domain expansion on the NMP2 LOCA performance is similar to that observed in the current licensed operating domain, which includes the MELLLA operating domain low CF region. The PCT response following a large recirculation line break has two peaks. The first peak is determined by the boiling transition during CF coastdown early in the event. The second peak is determined by the core uncovery and reflooding.

MELLLA+ operating domain expansion has two effects on the boiling transition and first peak PCT. First, the reduced CF causes the boiling transition to occur earlier and lower in the bundle.

Second, the reduced CF causes the initial subcooling in the downcomer to be higher so that the break flow is greater in the early phase of the LOCA event. For a given power level, the early boiling transition times (boiling transitions that occur before jet pump uncovery) for NMP2 occur earlier in the event and penetrate lower in the fuel bundle as the CF is reduced, but the effect of the early boiling transition on the LOCA PCT depends on the particular conditions.

Effect of MELLLA+ at Rated Power The PCT results are shown in the table at the end of this section. ((

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Effect of MELLLA+ at Less Than Rated Power M+LTR SER Limitation and Condition 12. 1O.a requires the M+SAR to provide a discussion on the power/flow combination scoping calculations that were performed to identify the limiting statepoints in terms of DBA-LOCA PCT response for the operation within the MELLLA+

boundary. As required by this limitation, ((

)) The PCT results summarized below show that there are no unusual trends in PCT in the MELLLA+ region and that there is margin to the 2,200'F PCT limit.

Effect of Axial Power Shave As required by M+LTR SER Limitation and Condition 12.11 (Reference 1) and Methods LTR SER Limitation and Condition 9.7 (Reference 3) for MELLLA+ applications, the small and large break ECCS-LOCA analyses shall include top-peaked and mid-peaked power shape in establishing the MAPLHGR and determining the PCT. This limitation is applicable to both the licensing basis PCT and the upper bound PCT. The plant-specific applications should report the limiting small and large break licensing basis and upper bound PCTs. ((

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 2 Appendix K PCT (OF) 2 Power/Flow' Nominal PCT (OF) 1st Peak 2nd Peak 1st Peak 2nd Peak Notes: 1 Power level shown is percent at EPU condition. Flow level shown is percent of RCF.

2 Results are for GE14 DBA large break.

4.3.3 Small Break Peak Clad Temperature I((

Effect of MELLLA+ at Rated Power The PCT results are shown in the table at the end of this section. ((

1))

M+LTR SER Limitation and Condition 12.13 requires that the MELLLA+ plant-specific SAR include calculations for the limiting small break at rated power/RCF and rated power/MELLLA+

boundary, if the small break PCT at rated power/RCF is within (( )) of the limiting Appendix K PCT. For NMP2, the small break PCT is limiting. Therefore, small break PCT calculations are performed for MELLLA+ flow, and the PCT results are shown in the table at the end of this section.

Effect of MELLLA+ at Less Than Rated Power M+LTR SER Limitation and Condition 12.1O.b requires that the M+SAR provide a justification as to why the transition statepoint ECCS-LOCA response bounds the 55% CF statepoint.

)) The PCT results 4-13

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) summarized below show that there are no unusual trends in PCT in the MELLLA+ region and that there is margin to the 2,200'F PCT limit.

Effect of Axial Power Shape As required by M+LTR SER Limitation and Condition 12.11 and Methods LTR SER Limitation and Condition 9.7 for MELLLA+ applications, the small and large break ECCS-LOCA analyses have included top-peaked and mid-peaked power shapes in establishing the MAPLHGR and determining the PCT. This limitation is applicable to both the licensing basis PCT and the upper bound PCT. The plant-specific applications have confirmed that the limiting small and large break with ((

))

Small Break Licensing Basis PCT Reference 34 provides justification for the elimination of the 1,600'F upper bound PCT limit and generic justification that the licensing basis PCT will be conservative with respect to the upper bound PCT. The NRC SER in Reference 34 accepted this position by noting that, because plant-specific upper bound PCT calculations have been performed for all plants, other means may be used to demonstrate compliance with the original SER limitations. These other means are acceptable provided there are no significant changes to a plant's configuration that would invalidate the existing upper bound PCT calculations. The changes in magnitude of the PCT due to MELLLA+ demonstrate that this plant configuration change does not invalidate the existing upper bound PCT calculations.

M+LTR SER Limitations and Conditions 12.12.a and 12.12.b and Methods LTR SER Limitation and Condition 9.8 also require that the ECCS-LOCA evaluation be performed for all statepoints in the upper boundary of the expanded operating domains. ((

)) The calculated GEl4 licensing basis PCT is 1,580'F, based on the limiting case scenario. ((

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 2 Power/Flow' Nominal PCT (*F)2 Appendix K PCT (OF)

Notes:

Power level shown is percent at EPU power level. Flow level shown is percent of RCF.

2 Results are for GEl4 limiting small break.

4.3.4 Local Cladding Oxidation Er

)) Sections 4.3.2 and 4.3.3 that determine the effect on the PCT. ((

)) and no further evaluation of this topic is required.

Er )) for NMP2, Sections 4.3.2 and 4.3.3 show acceptable PCT results that meet the 2,200'F limit. ((

)) and no further evaluation of this topic is required.

((

4.3.5 Core-Wide Metal Water Reaction

)) Sections 4.3.2 and 4.3.3 that determine the effect on the PCT. ((

)) and no further evaluation of this topic is required.

)) for NMP2, Sections 4.3.2 and 4.3.3 show acceptable PCT results that meet the 2,200'F limit. ((

)) and no further evaluation of this topic is required.

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 4.3.6 Coolable Geometry

)) NMP2's compliance with the coolable geometry acceptance criteria was generically demonstrated as a GEH BWR ((

4.3.7 Long-Term Cooling

)) NMP2's compliance with the long-term cooling acceptance criteria was generically demonstrated as a GEH BWR ((

4.3.8 Flow Mismatch Limits limits have been placed on recirculation drive flow mismatch over a range of CFs. For most plants, the limits on flow mismatch are more relaxed at lower CF rates. The drive flow mismatch affects the CF coastdown following the break. The effect of the drive flow mismatch on the LOCA evaluation is similar to a small change in the initial CF. ((

)) the discussion and trends in the M+LTR are applicable to NMP2. ((

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))

4.4 MAIN CONTROL ROOM ATMOSPHERE CONTROL SYSTEM The topics addressed in this evaluation are:

Topic M+LTR Disposition NMP2 Result Iodine Intake

(( )) the MELLLA+ operating domain expansion does not result in a change in the source terms or the release rates (Section 8.0). ((

)) Provided this criterion is met, no further evaluation of the Main Control Room (MCR) atmosphere control system is required.

(( )) there is no change in the NMP2 source term or release rates as a result of MELLLA+ operating domain expansion. This topic is discussed in Section 8.0. ((

)) No further evaluation of the MCR atmosphere control system is required.

I((

4.5 STANDBY GAS TREATMENT SYSTEM The topics addressed in this evaluation are:

Topic M+LTR Disposition NMP2 Result Flow Capacity Iodine Removal Capability 4.5.1 Flow Capacity

[ ))the SGTS is designed to maintain secondary containment at a negative pressure and to filter the exhaust air for removal of fission products potentially present during abnormal conditions. By limiting the release of airborne particulates and halogens, the SGTS limits off-site dose following a postulated DBA. ((

)) and no further evaluation of the SGTS flow is required.

(( )) the design flow capacity of the NMP2 SGTS was selected to maintain the secondary containment at the required negative pressure to minimize the potential for exfiltration of air from the Reactor Building. ((

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)) and no further evaluation is required.

4.5.2 Iodine Removal Capability

((

)) the SGTS is designed to maintain secondary containment at a negative pressure and to filter the exhaust air for removal of fission products potentially present during abnormal conditions. By limiting the release of airborne particulates and halogens, the SGTS limits off-site dose following a postulated DBA. ((

)) the core fission product inventory is not changed by the MELLLA+ operating domain expansion (Section 8.3), and coolant activity levels are defined by TS and do not change, so no change occurs in the SGTS adsorber iodine loading, decay heat rates, or iodine removal efficiency. ((

)) No further evaluation of this topic is required.

4.6 MAIN STEAM ISOLATION VALVE LEAKAGE CONTROL SYSTEM NMP2 does not use a MSIV leakage control system (LCS).

4.7 POST-LOCA COMBUSTIBLE GAS CONTROL SYSTEM The topics addressed in this evaluation are:

M+LTR Topic NMP2 Result Post-LOCA Combustible Gas Control ))

10 CFR 50.44 was revised in September 2003 and no longer defines a design basis LOCA hydrogen release. This new revision eliminates the requirements for hydrogen control systems to mitigate such a release. NMP2 has adopted the revised ruling per NMP2 license amendment Number 124, issued in April 2008, which relaxed the requirements for hydrogen and oxygen monitoring. This amendment also eliminated the requirements for hydrogen recombiners for the purpose of mitigating post-LOCA hydrogen release, although NMP2 has chosen to leave the recombiners in place and remain functional. NMPNS made commitments to maintain the hydrogen and oxygen monitoring systems capable of diagnosing beyond DBAs. MELLLA+

operating domain expansion has no effect on the design of these systems or on the ability of these systems to perform their intended functions. However, as this system is no longer required 4-18

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) to be maintained as a post-LOCA combustible gas control system, no further evaluation is necessary relative to the MELLLA+ operating domain expansion. The generic disposition of the system (under the M+LTR) is no longer applicable.

((

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 5.0 INSTRUMENTATION AND CONTROL This section addresses the evaluations that are applicable to MELLLA+.

5.1 NSSS MONITORING AND CONTROL Changes in process parameters resulting from the MELLLA+ operating domain expansion and their effects on instrument performance are evaluated in the following sections. The effect of the MELLLA+ operating domain expansion on the TS is addressed in Section 11.1 and the effect on the allowable values (AVs) in Section 5.3. The topics addressed in this evaluation are:

Topic M+LTR Disposition NMP2 Result Average Power Range, Intermediate Range, and Source Range Monitors Local Power Range Monitors Rod Block Monitor Rod Worth Minimizer Traversing Incore Probes 5.1.1 Average Power Range, Intermediate Range, and Source Range Monitors I((

)) the APRM output signals are calibrated to read 100% at the CLTP.

)) Using normal plant surveillance procedures, the IRMs may be adjusted to ensure adequate overlap with the SRMs and APRMs.

Therefore, no further evaluation of the APRMs, IRMs, or SRMs is required for MELLLA+.

(( )) there is no change in NMP2 core power as a result of MELLLA+ operating domain expansion. ((

)) The APRMs, IRMs, and SRMs are installed at NMP2 in accordance with the requirements established by the GEH design specifications. NMP2 uses normal plant procedures to adjust the IRMs to ensure adequate overlap with the SRMs and APRMs. Therefore, no further evaluation is required.

5.1.2 Local Power Range Monitors

(( )) there is no change in the neutron flux experienced by the LPRMs resulting from the MELLLA+ operating domain expansion. ((

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

)) No further evaluation of these topics is required for MELLLA+.

(( )) there is no change in the neutron flux experienced by the NMP2 LPRMs resulting from the MELLLA+ operating domain expansion. Analysis was performed to confirm that bypass voiding at the D Level LPRM does not exceed 5%. Therefore, ((

)) The LPRMs are installed at NMP2 in accordance with the requirements established by the GEH design specifications. No further evaluation of these topics is required for MELLLA+.

1))

5.1.3 Rod Block Monitors Er )) the RBM uses LPRM instrumentation inputs that are combined and referenced to an APRM channel. ((

)) and as described in Sections 5.1.1 and 5.1.2, the ((

)) No further evaluation of these topics is required for MELLLA+.

Section 9.1.1 evaluates the adequacy of the generic RBM setpoints.

Er 5.1.4 Rod Worth Minimizer

)) the function of the RWM is to support the operator by enforcing rod patterns until reactor power has reached appropriate levels. The RWM functions to limit the local power in the core to control the effects of the postulated control rod drop accident (CRDA) at low power.

E[r]

Therefore, no further evaluation is required.

(( )) the NMP2 RWM supports the operator by enforcing rod patterns until reactor power has reached appropriate levels.

E[r]

Therefore, no further evaluation is required.

E[

5-2

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 5.1.5 Traversing Incore Probes To address the M+LTR SER Limitation and Condition 12.15, bypass voiding above the D-Level, an analysis was performed to identify the region on the MELLLA+ power/flow map that has potentially unacceptable bypass voiding for the thermal traversing incore probes (TIPs) installed at NMP2. In the absence of bypass voiding greater than 5% no actions are required regarding the TIPs resulting from the MELLLA+ operating domain expansion. ((

Analysis shows that there is a small region of the MELLLA+ power flow domain near point M in Figure 5-1 where the hot channel voiding at the TIP exit exceeds 5% thus requiring specific attention per Limitation and Condition 12.15. ((

)) TIP operation and LPRM calibration in the remainder of the MELLLA+

domain are not adversely affected by the void conditions in the bypass region. NMPNS control room operators and Reactor Engineers will be trained on this requirement and station procedures will be modified accordingly.

(( )) there is no change in the neutron flux experienced by the NMP2 TIPs resulting from the MELLLA+ operating domain expansion.

(( )) The TIPs are installed at NMP2 in accordance with the requirements established by the GEH design specifications. No further evaluation of these topics is required for MELLLA+.

[ 1))

5.2 BOP MONITORING AND CONTROL Operation of the plant in the MELLLA+ domain has no effect on the BOP system instrumentation and control devices. The topics addressed in this evaluation are:

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

Topic M+LTR Disposition NMP2 Result Pressure Control System Turbine Steam Bypass System (Nomial Operation)

Turbine Steam Bypass System (Safety Analysis)

Feedwater Control System (Normal Operation)

Feedwater Control System (Safety Analysis)

Leak Detection System _]

5.2.1 Pressure Control System

)) Therefore, no further evaluation of this system is required as a result of MELLLA+.

(( )) for NMP2, there are no increases in reactor operating pressure, MS or FW flow rates. The numerical values showing no increases in reactor operating pressure, MS or FW flow rates are presented in Table 1-2. The system dynamic characteristics of the NMP2 pressure control system are not changed. ((

)) Therefore, no further evaluation of this system is required as a result of MELLLA+.

5.2.2 Turbine Steam Bypass System (Normal Operation)

)) Therefore, no further evaluation of this system is required as a result of MELLLA+.

(( )) for NMP2, there are no increases in reactor operating pressure, MS or FW flow rates. The numerical values showing no increases in reactor operating pressure, MS or FW flow rates are presented in Table 1-2. The system dynamic characteristics of the NMP2 turbine steam bypass system under normal operation are not changed. ((

)) Therefore, no further evaluation of this system is required as a result of MELLLA+.

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 5.2.3 Turbine Steam Bypass System (Safety Analysis)

)) Therefore, no further evaluation of this system is required as a result of MELLLA+.

[R )) for NMP2, there are no increases in reactor operating pressure, MS or FW flow rates. The numerical values showing no increases in reactor operating pressure, MS or FW flow rates are presented in Table 1-2. The system dynamic characteristics of the NMP2 turbine steam bypass system in safety analysis conditions are not changed. ((

1))

Therefore, no further evaluation of this system is required as a result of MELLLA+.

((I 5.2.4 Feedwater Control System (Normal Operation)

((I

)) Therefore, no further evaluation of this system is required as a result of MELLLA+.

R)) for NMP2, there are no increases in reactor operating pressure, MS or FW flow rates. The numerical values showing no increases in reactor operating pressure, MS or FW flow rates are presented in Table 1-2. The system dynamic characteristics of the NMP2 FW control system under normal operation are not changed. ((

)) Therefore, no further evaluation of this system is required as a result of MELLLA+.

((I 5.2.5 Feedwater Control System (Safety Analysis)

)) Therefore, no further evaluation of this system is required as a result of MELLLA+.

(( )) for NMP2, there are no increases in reactor operating pressure, MS or FW flow rates. The numerical values showing no increases in reactor operating pressure, MS or FW flow rates are presented in Table 1-2. The system 5-5

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) dynamic characteristics of the NMP2 FW control system in safety analysis conditions are not changed. ((

)) Therefore, no further evaluation of this system is required as a result of MELLLA+.

((

5.2.6 Leak Detection System

)) Therefore, no further evaluation of this system is required as a result of MELLLA+.

(( )) for NMP2, there are no increases in reactor operating pressure, MS or FW flow rates. In addition, RWCU, RHR, HPCS, and RCIC pressures, temperatures, and flows are unchanged. The numerical values showing no increases in reactor operating pressure, MS or FW flow rates are presented in Table 1-2. In addition, as discussed in Section 4.1.2, suppression pool time history response temperatures in the MELLLA+ operating domain are bounded by the EPU results. Therefore, the system dynamic characteristics of the NMP2 leak detection system are not changed. ((

)) Therefore, no further evaluation of this system is required as a result of MELLLA+.

5.3 TECHNICAL SPECIFICATION INSTRUMENT SETPOINTS The TS instrument AVs and the nominal trip setpoints (NTSPs) are those sensed variables which initiate protective actions and are generally associated with the safety analysis. The determination of the AV and NTSP includes consideration of measurement uncertainty and are derived from the AL. Standard GEH setpoint methodology (Reference 35) is used to generate the AV and NTSPs from the related ALs.

The MELLLA+ operating domain expansion results in the development of two ALs.

GEH typically uses the approved simplified process to determine the instrument AVs and NTSPs for MELLLA+ applications. The NRC staff has previously reviewed and accepted the simplified approach in the review of NEDC-33004P-A (Reference 7). Consistent with that approval, for NMP2 the following criteria are satisfied for using the simplified process:

1. ((

2. NRC approved GEH or plant-specific methodologies are used (Reference 35).

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

3. ((

However, complete setpoint calculations, using the setpoint methodology described in Reference 35 have been performed for the APRM Flow Biased Scram and Rod Block for TLO, to better support NMP2 in implementing the guidance provided by Regulatory Issue Summary (RIS) 2006-17 (Reference 36) and Technical Specification Task Force (TSTF)-493 (Reference 37).

The topics addressed in this evaluation are:

Topic M+LTR Disposition NMP2 Result APRM Flow-Biased Scram ((

Rod Block Monitor 5.3.1 APRM Flow-Biased Scram The MELLLA+ APRM Flow Biased STP Scram AL line is established to ((

))

The MELLLA+ APRM Flow Biased STP AL expressions are:

ALM+ROD BLOCK = 0.61W + 60.1%, for the Rod Block, and ALM+sCRAM = 0.6 1W + 66.1%, for the Scram.

SLO is not applicable to the MELLLA+ operating domain as discussed in Section 3.6.3.

Therefore, the SLO setpoints are unchanged.

The evaluation of APRM Flow Biased STP Scram setpoints is consistent with the methods described for (( )) this topic in the M+LTR. The APRM Flow Biased STP Scram setpoints for the NMP2 (( are therefore acceptable.

5.3.2 Rod Block Monitor

[)) the RBM setpoints are established to mitigate the rod withdrawal error (RWE) event during power operation.

For plants with ARTS RBM systems, ((

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

)) Therefore, no further evaluation of the RBM TS values is required as a result of MELLLA+.

(( )) for NMP2, there is no change in reactor power level as a result of MELLLA+ operating domain expansion. NMP2 has an ARTS RBM system. ((

Therefore, no further evaluation of the RBM TS values is required as a result of MELLLA+.

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

I[

Figure 5-1 NMP2 EPUIM+ Power/Flow Map with 5% Voiding at the TIP Exit Boundary 5-9

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 6.0 ELECTRICAL POWER AND AUXILIARY SYSTEMS This section addresses the evaluations that are applicable to MELLLA+. Because there is no change in power output, most of the topics in this section are unaffected by the MELLLA+

operating domain expansion.

6.1 AC POWER The AC power supply includes both off-site and on-site power. The on-site power distribution system consists of transformers, buses, and switchgear. AC power to the distribution system is provided from the transmission system or from on-site D/Gs. The topics addressed in this evaluation are:

Topic M+LTR Disposition NMP2 Result AC Power (Normal or Degraded Voltage)

)) there is no change in the thermal power from the reactor or the electrical output from the station that results from the MELLLA+ operating domain expansion. ((

No further evaluation of the AC Power system is required.

(( )) there is no change in the NMP2 reactor thermal power or the electrical output from the station that results from the MELLLA+

operating domain expansion. ((

No further evaluation of the AC Power system is required.

))

6.2 DC POWER The direct current (DC) power distribution system provides control and motive power for various systems/components within the plant. The topics addressed in this evaluation are:

Topic M+LTR Disposition NMP2 Result DC Power Er )) the MELLLA+ operating domain expansion does not change system requirements for control or 6-1

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) motive power loads. (( )) Therefore, no further evaluation of this topic is required.

[R

)) as a result of MELLLA+ operating domain expansion. The MELLLA+

operating domain expansion does not change system requirements for control or motive power loads. Therefore, no further evaluation of the DC Power system is required.

6.3 FUEL POOL The topics addressed in this evaluation are:

Topic M+LTR Disposition NMP2 Result Fuel Pool Cooling:[

Crud Activity and Corrosion Products Radiation Levels Fuel Racks ]

6.3.1 Fuel Pool Cooling

_1

)) the MELLLA+ operating domain expansion does not increase the core power level. ((

)) No further evaluation of the fuel pool cooling systems are required for MELLLA+ operating domain expansion.

(( )) NMP2 reactor power level does not increase as a result of MELLLA+ operating domain expansion. ((

)) No further evaluation of the NMP2 fuel pool cooling systems is required for MELLLA+ operating domain expansion.

1]

6.3.2 Crud Activity and Corrosion Products

)) No further evaluation of the crud and corrosion products in the spent fuel pools is required for MELLLA+ operating domain expansion.

)) Therefore, no further evaluation of the crud and corrosion products in the spent fuel pools is required for the NMP2 MELLLA+ operating domain expansion.

6-2

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 6.3.3 Radiation Levels

((

)) No further evaluation of the radiation levels in the spent fuel pools is required for MELLLA+ operating domain expansion.

((

Therefore, no further evaluation of the radiation levels in the spent fuel pools is required for the NMP2 MELLLA+ operating domain expansion.

Er 6.3.4 Fuel Racks Er )) the MELLLA+

operating domain expansion does not increase the core power level. ((

)) No further evaluation of the fuel racks is required for MELLLA+ operating domain expansion.

(( )) the MELLLA+ operating domain expansion does not increase the NMP2 core power level. ((

)) No further evaluation of the fuel racks is required for MELLLA+ operating domain expansion.

6.4 WATER SYSTEMS The water systems are designed to provide a reliable supply of cooling water for normal operation and DBA conditions. The topics addressed in this evaluation are:

Topic M+LTR Disposition NMP2 Result]

Water Systems EE ))the performance of the safety-related service water system during and following the most limiting design basis event, the LOCA, is not affected by the MELLLA+ operating domain expansion.

Er

)) No further evaluation of water systems is required for MELLLA+.

6-3

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

)) for NMP2, the MELLLA+

operating domain expansion does not affect the performance of the safety-related emergency service water system or the RHR service water system during and following the most limiting design basis event, the LOCA, as discussed in Section 4.3. ((

)) No further evaluation of the NMP2 water systems is required for MELLLA+

operating domain expansion.

6.5 STANDBY LIQUID CONTROL SYSTEM The SLS is an automatic or manually operated system that pumps a sodium pentaborate solution into the vessel to provide neutron absorption and achieve a subcritical reactor condition in the situation where none of the control rods can be inserted. The topics addressed in this evaluation are:

Topic M+LTR Disposition NMP2 Result Shutdown Margin ((

System Hardware ATWS Requirements ))

6.5.1 Shutdown Margin I((

))An increase in the reactor boron concentration may be achieved by increasing, either individually or collectively, (1) the minimum solution volume, (2) the minimum specified solution concentration, or (3) the isotopic enrichment of the B 10 in the stored neutron absorber solution.

In order to account for reactivity variations between cycles, the USAR Section 9.3.5 limit for reactor coolant boron concentration has sufficient margin to accommodate most core design variations.

)) Because no new fuel product line designs are introduced for MELLLA+ operating domain expansion, the USAR Section 9.3.5 limit for minimum reactor coolant boron concentration of 780 ppm natural boron does not change as a result of MELLLA+ operating domain expansion. NMP2 calculates SLS shutdown margin as a part of the core reload analysis. Therefore, no further evaluation of SLS shutdown margin is required for MELLLA+.

6-4

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 6.5.2 System Hardware M+LTR describes that the SLS is typically designed for injection at a maximum reactor pressure equal to the upper analytical setpoint for the lowest group of SRVs operating in the relief mode.

1]

The NMP2 reactor operating pressure is unchanged by MELLLA+ operating domain expansion.

The numerical values showing no increases in reactor operating pressure are presented in Table 1-2. As discussed in Section 3.1.2, there are no changes to the NMP2 SRV setpoints as a result of MELLLA+ operating domain expansion. Because the reactor dome pressure and SRV setpoints are unchanged for MELLLA+, the SLS process parameters do not change. Therefore, the capability of the SLS to perform its shutdown function is not affected by MELLLA+. ((

)) Therefore, the NMP2 SLS remains capable of performing its shutdown function.

(( Er 6.5.3 ATWS Requirements As described in the M+LTR, the SLS ATWS performance is evaluated in Section 9.3.1 ((

)) The representative MELLLA+ evaluation shows that the SLS maintains the capability to mitigate an ATWS and that the current boron injection rate is sufficient relative to the peak suppression pool temperature. The ATWS analysis in Section 9.3.1 also demonstrates that there is no increase in the peak vessel dome pressure during the time the SLS is in operation.

Er

)) The pressure margin for the pump discharge relief valves remains above the minimum value needed to ensure that the SLS relief valves remain closed during system injection. Because NMP2 does not take credit for the operation of the SRVs in a power actuated relief mode during an ATWS, the peak reactor pressures for the loss of off-site power (LOOP) event would be the bounding ATWS event. The minimum reactor pressure, just prior to the time when SLS initiates, remains low enough to ensure SLS relief valve closure prior to the analyzed SLS initiation time in the event of an early initiation of the SLS during the initial ATWS transient pressure response. Consequently, the current NMP2 SLS process parameters associated with the minimum boron injection rate do not need to change. Therefore, SLS operation during an ATWS is not affected by the MELLLA+ operating domain expansion.

6-5

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 6.6 HEATING, VENTILATION AND AIR CONDITIONING The heating, ventilation, and air conditioning (HVAC) systems consist mainly of heating, cooling supply, exhaust and recirculation units in the Turbine Building, Reactor Building, DW, Control Building, and the Radwaste Building. The topics addressed in this evaluation are:

Topic I M+LTR Disposition NMP2 Result Heating, Ventilation, and Air Conditioning I))

[)) the process temperatures and heat load from motors and cables do not change due to MELLLA+ operating domain expansion. ((

)) No further evaluations of the HVAC system are required for MELLLA+

operating domain expansion.

)) for NMP2, HVAC systems, the process temperatures and heat load from motors and cables are bounded by the EPU process temperatures and heat loads and as such are within the design of the HVAC equipment chosen for worst case conditions. ((

)) No further evaluations of the NMP2 HVAC systems are required for MELLLA+ operating domain expansion.

6.7 FIRE PROTECTION This section addresses the fire protection program, fire suppression and detection systems, and safe shutdown system responses to postulated 10 CFR 50 Appendix R fire events. The topics addressed in this evaluation are:

Topic M+LTR Disposition NNMP2 Result Fire Protection

[)) because the decay heat does not change for the MELLLA+ operating domain expansion, there are no changes in vessel water level response, operator response time, PCT, and peak suppression pool temperature and containment pressure. ((

Provided the above criteria are met, no further evaluation of fire protection is required for MELLLA+ operating domain expansion.

(( )) for NMP2, these parameters do not change as a result of MELLLA+ operating domain expansion. As discussed in Section 1.2.3, decay heat does not change as a result of MELLLA+ operating domain expansion. Reactor 6-6

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) vessel water level response is unchanged by MELLLA+ operating domain expansion. Operator response times are not affected by MELLLA+ because: ((

)) The effect of MELLLA+ operating domain expansion on PCTs is evaluated to be acceptable in Section 4.3.

The effect of MELLLA+ operating domain expansion on peak suppression pool temperatures and containment pressure response are evaluated and concluded to be bounded by EPU conditions in Section 4.1. ((

)) and no further evaluation of fire protection is required for MELLLA+ operating domain expansion.

6.8 OTHER SYSTEMS AFFECTED The topics addressed in this evaluation are other systems that may be affected by the MELLLA+

operating domain expansion:

Topic M+LTR Disposition NMP2 Result Other Systems the systems typically found in a BWR power plant have been evaluated to establish those systems that are affected by the MELLLA+ operating domain expansion. Those systems that are significantly affected by the MELLLA+ operating domain expansion are addressed in this report.

Other systems not addressed by this report are not significantly affected by the MELLLA+

operating domain expansion.

)) the NMP2 systems evaluated ((

were reviewed for MELLLA+ operating domain expansion to ensure that all significantly affected systems were addressed. This topic confirms that those systems that are significantly affected by the MELLLA+ operating domain expansion are addressed in this report. Other systems not addressed by this report are not significantly affected by the MELLLA+ operating domain expansion.

6-7

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 7.0 POWER CONVERSION SYSTEMS This section addresses the evaluations that are applicable to MELLLA+. Because the pressure, steam and FW flow rates, and FW fluid temperature ranges are not significantly changed by the operating domain expansion, the power conversion systems are unaffected.

7.1 TURBINE-GENERATOR The turbine-generator converts the thermal energy in the steam into electrical energy. The topics addressed in this evaluation are:

Topic M+LTR Disposition NMP2 Result Turbine-Generator

[ ))the MELLLA+ operating domain expansion does not change the pressure, thermal energy, and steam flow from the reactor. Likewise, there is no change in the electrical output of the generator.

No further evaluation of this topic is required.

(( )) there is no change in the reactor power level as a result of MELLLA+ operating domain expansion. For NMP2, there are no increases in reactor operating pressure or MS flow rates. The numerical values showing no increases in reactor operating pressure and MS flow rates are presented in Table 1-2. The electrical output in the current licensed operating domain and in the MELLLA+ operating domain is approximately 1,368.9 MWe. Therefore, ((

)) No further evaluation of this topic is required.

7.2 CONDENSER AND STEAM JET AIR EJECTORS The condenser removes heat from the steam discharged from the turbine and provides liquid for the condensate and FW systems. The steam jet air ejectors remove non-condensable gases from the condenser to improve thermal performance. The topics addressed in this evaluation are:

Topic M+LTR Disposition NMP2 Result Condenser Steam Jet Air Ejectors

)) the MELLLA+ operating domain expansion does not change the steam flow rate or power level. ((

)) there is no change in the reactor power level as a result of MELLLA+ operating domain expansion. For NMP2, there are no 7-1

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) increases in reactor operating pressure or MS flow rates. The numerical values showing no increases in reactor operating pressure and MS flow rates are presented in Table 1-2.

((

)) MELLLA+ operating domain expansion does not affect the condenser, and no further evaluation is required.

MELLLA+ may increase the amount of moisture reaching the steam jet air ejectors motive steam inlet for short periods of time. The steam jet air ejectors would acceptably function because the maximum expected moisture at the steam jet air ejectors would be less than the typical industry guideline limit of 1 wt.% under the worst case moisture content at the inlet nozzles. The steam jet air ejectors will acceptably function in the MELLLA+ domain.

((

)) The evaluation of the NMP2 steam jet air ejector is acceptable for MELLLA+ operation.

7.3 TURBINE STEAM BYPASS The turbine steam bypass system provides a means of accommodating excess steam generated during normal plant maneuvers and transients. The topics addressed in this evaluation are:

Topic M+LTR Disposition NMP2 Result]

Turbine Steam Bypass there is no change in the power level, pressure or steam flow for the MELLLA+ operating domain expansion. Therefore, MELLLA+ operating domain expansion does not affect the turbine steam bypass system, and no further evaluation is required.

Er )) there is no change in the reactor power level as a result of the MELLLA+ operating domain expansion. For NMP2, there are no increases in the reactor operating pressure or MS flow rates. The numerical values showing no increases in the reactor operating pressure and MS flow rates are presented in Table 1-2.

Therefore, MELLLA+ operating domain expansion does not affect the NMP2 turbine steam bypass system, and no further evaluation is required.

7.4 FEEDWATER AND CONDENSATE SYSTEMS The FW and condensate systems provide the source of makeup water to the reactor to support normal plant operation. The topics addressed in this evaluation are:

Topic M+LTR Disposition NMP2 Result Feedwater and Condensate Systems

((

)) there is no change in the FW pressure, temperature, or flow for the MELLLA+ operating 7-2

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) domain expansion. The performance requirements for the FW and condensate systems are not changed by MELLLA+ operating domain expansion, and no further evaluation is required.

(( )) there is no change in the NMP2 FW pressure, temperature, and flow rates. Because FW flow is unchanged in the MELLLA+

domain, system resistance and therefore operating pressures in the MELLLA+ operating domain are not changed. The numerical values showing no increases in FW temperature and flow rates are presented in Table 1-2. Therefore, MELLLA+ operating domain expansion does not affect the NMP2 FW and condensate systems, and no further evaluation is required.

((

7-3

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 8.0 RADWASTE SYSTEMS AND RADIATION SOURCES This section addresses the evaluations that are applicable to MELLLA+.

8.1 LIQUID AND SOLID WASTE MANAGEMENT The Liquid radwaste system collects, monitors, processes, stores and returns processed radioactive waste to the plant for reuse or discharge. The topics addressed in this evaluation are:

Topic M+LTR Disposition I NMP2 Result Coolant Fission and Corrosion Product Levels Waste Volumes 8.1.1 Coolant Fission and Corrosion Product Levels A discussion of the coolant activation products as well as fission and activated corrosion products levels in the coolant is presented in Section 8.4.

8.1.2 Waste Volumes R)) because the power level, FW flow, and steam flow do not change for the MELLLA+ operating domain expansion, the volume of liquid radwaste and the coolant concentrations of fission and corrosion products will be unchanged. The largest source of liquid and wet solid waste is from the backwash of the condensate demineralizers. Although the volume of waste generated is not expected to increase, potentially higher MCO in the reactor steam could result in slightly higher loading on the condensate demineralizers. Because the higher moisture content will occur infrequently, the MELLLA+ operating domain expansion will not cause the condensate demineralizer backwash frequency to be changed significantly. The RWCU filter demineralizer backwash frequency is not affected, as discussed in Section 3.11. Therefore, the waste volumes will not be affected by the MELLLA+ operating domain expansion, and no further evaluation of this topic is required.

(( )) there is no change in the reactor power level as a result of MELLLA+ operating domain expansion. For NMP2, there are no increases in the MS or FW flow rates. The numerical values showing no increases in MS and FW flow rates are presented in Table 1-2. The NMP2 MCO will be monitored and controlled to

< 0.25 wt.% within the analytical assumption of 0.35 wt.% used in the determination of post-shutdown radiation levels.

((I 8.2 GASEOUS WASTE MANAGEMENT The primary function of the gaseous waste management (offgas) system is to process and control the release of gaseous radioactive effluents to the site environs so that the total radiation exposure of persons in off-site areas is as low as reasonably achievable (ALARA) and does not exceed applicable guidelines. The topics addressed in this evaluation are:

8-1

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

Topic M+LTR Disposition NMP2 Result Off-Site Release Rate Recombiner Performance 8.2.1 Off-Site Release Rate

(( ))the radiological release rate is administratively controlled to remain within existing limits and is a function of fuel cladding performance, main condenser air inleakage, charcoal adsorber inlet dew point, and charcoal adsorber temperature. [

)) No further evaluation of this topic is required.

)) the NMP2 radiological release rate is administratively controlled to remain within existing release rate limits. In addition, none of the applicable identified parameters are affected by MELLLA+ operating domain expansion.

There is no change to the offgas system. Therefore, it can be concluded that the generic discussion in the M+LTR is applicable to NMP2. ((

)), and no further evaluation is required.

((

8.2.2 Recombiner Performance Er

)) Therefore, recombiner performance is unaffected by the MELLLA+ operating domain expansion, and no further evaluation is required.

Er )) the NMP2 radiolytic gas flow rate, the catalytic recombiner temperature, and the offgas condenser heat load, as well as components downstream of the offgas condenser does not change as a result of MELLLA+ operating domain expansion. Therefore, the NMP2 recombiner performance is unaffected by the MELLLA+

operating domain expansion, and no further evaluation is required.

Er

))

8-2

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 8.3 RADIATION SOURCES IN THE REACTOR CORE During power operation, the radiation sources in the core are directly related to the fission rate.

These sources include radiation from the fission process, accumulated fission products, and neutron activation reactions. The topics addressed in this evaluation are:

Topic M+LTR Disposition NMP2 Result Post-Operational Radiation Sources for Radiological and Shielding Analysis

)) the post-operation radiation sources in the core are primarily the result of accumulated fission products. ((

)) Therefore, no further evaluation of radiation sources in the reactor core is required.

(( )) the reactor power does not increase as a result of MELLLA+ operating domain expansion. NMP2 core average exposure is No further evaluation of radiation sources in the reactor core is required.

8.4 RADIATION SOURCES IN REACTOR COOLANT Radiation sources in the reactor coolant include activation products, activation corrosion products, and fission products. The topics addressed in this evaluation are:

Topic M+LTR Disposition NMP2 Result Coolant Activation Products ((

Fission and Activated Corrosion Products 8.4.1 Coolant Activation Products

((

)) during reactor operation, the coolant passing through the core region becomes radioactive as a result of nuclear reactions. The coolant activation process is the dominant source resulting in the production of short-lived radionuclides of N-16 and other activation products. These coolant activation products are the primary source of radiation in the turbines during operation. The M+LTR states that if ((

)) no further evaluation of this topic is required.

)) the reactor power does not increase as a result of MELLLA+ operating domain expansion. The NMP2 steam flow rate does 8-3

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) not change as a result of MELLLA+ operating domain expansion. Numerical values demonstrating that the MS flow does not increase are provided in Table 1-2. ((

)) No further evaluation of this topic is required.

((I 8.4.2 Fission and Activated Corrosion Products The reactor coolant contains fission products and activated corrosion products. For the MELLLA+ operating domain, there is no change in the FW flow, steam flow, or power.

However, ((

For NMP2, reactor power does not change as a result of the MELLLA+ operating domain expansion. The NMP2 MS and FW flow rates do not change as a result of the MELLLA+

operating domain expansion. Numerical values demonstrating that the MS and FW flow rates do not increase are provided in Table 1-2. Therefore, the MELLLA+ operating domain expansion does not affect the total activity concentration in the reactor coolant.

Steam separator and dryer performance for MELLLA+ operation is discussed in Section 3.3.3.

The moisture content of the MS leaving the vessel is assumed to increase up to 0.35 wt.% at times while operating near the minimum CF in the MELLLA+ operating domain. The distribution of the fission and activated corrosion product activity between the reactor water and steam is affected by the increased moisture content. With increased MCO, additional activity is carried over from the reactor water with the steam. For NMP2, certain individual activation product concentrations were observed to exceed design basis levels at 0.35 wt.% moisture content. However, total activation product activity was below 30% of the total design basis activation product activity for water and below 95% of the total design basis activation product activity for steam. There are no individual design basis requirements for individual activation products. No fission product concentrations exceeded the design basis.

8.5 RADIATION LEVELS Radiation levels during operation are derived from coolant sources. The topics addressed in this evaluation are:

Topic M+LTR Disposition NMP2 Result Normal Operational Radiation Levels [_

Post-Shutdown Radiation Levels Post-Accident Radiation Levels ))

8-4

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 8.5.1 Normal Operational Radiation Levels The M+LTR describes that plant radiation levels for normal and post-shutdown operation are directly dependent upon radiation levels and radionuclide species in the reactor coolant (steam and water) except where the core is directly involved. ((

))

For NMP2, reactor power does not change as a result of the MELLLA+ operating domain expansion. The NMP2 MS flow rate does not change as a result of the MELLLA+ operating domain expansion. Numerical values demonstrating the MS flow rate does not increase are provided in Table 1-2. Because there is no change in power or steam flow rate for the MELLLA+ expanded operating domain, the radiation levels from the coolant activation products do not vary significantly. As discussed in Section 8.4, the moisture content of the MS leaving the vessel may increase at certain times while operating in the MELLLA+ operating domain.

However, the NMP2 MCO will be monitored and controlled to < 0.25 wt.% within the analytical assumption of 0.35 wt.% used in the determination of normal operation radiation levels. The overall radiological effect of the increased moisture content is a function of the plant water radiochemistry and the levels of activated corrosion products maintained. NMP2 maintains appropriate health physics and ALARA controls to address any increase in the normal operation levels.

8.5.2 Post-Shutdown Radiation Levels The M+LTR describes that plant radiation levels for normal and post-shutdown operation are directly dependent upon radiation levels and radionuclide species in the reactor coolant (steam and water) except where the core is directly involved. ((

))

For NMP2, reactor power does not change as a result of the MELLLA+ operating domain expansion. The NMP2 MS flow rate does not change as a result of the MELLLA+ operating domain expansion. Numerical values demonstrating the MS flow rate does not increase are provided in Table 1-2. The shutdown radiation levels are dominated by the accumulated contamination of some fission and activated corrosion products. As discussed in Section 8.4, the moisture content of the MS leaving the vessel may increase at certain times while operating in the MELLLA+ operating domain. However, the NMP2 MCO will be monitored and controlled to < 0.25 wt.% within the analytical assumption of 0.35 wt.% used in the determination of post-shutdown radiation levels. The overall radiological effect of the increased moisture content is a function of the plant water radiochemistry and the levels of activated corrosion products maintained. NMP2 maintains appropriate health physics and ALARA controls to address any increase in the shutdown radiation levels.

8-5

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 8.5.3 Post-Accident Radiation Levels The M+LTR describes that the post-accident radiation levels depend primarily upon the core inventory of fission products and TS levels of radionuclides in the coolant, neither of which is affected by MELLLA+. ((

)) Section 9.2 discusses DBA radiological consequences.

8.6 NORMAL OPERATION OFF-SITE DOSES The primary source of normal operation off-site doses is: (1) airborne releases from the offgas system; and (2) gamma shine from the plant turbines. The topics addressed in this evaluation are:

Topic M+LTR Disposition NMP2 Result Plant Gaseous Emissions ((

Gamma Shine from the Turbine 8.6.1 Plant Gaseous Emissions for the MELLLA+ operating domain expansion, there is no change in the core power and the steam flow rate. (( )) No further evaluation of plant gaseous emissions is required.

Er )) the reactor power does not change as a result of the MELLLA+ operating domain expansion. The NMP2 steam flow rate does not change as a result of the MELLLA+ operating domain expansion. Numerical values demonstrating that the MS flow does not increase are provided in Table 1-2. ((

)) Therefore, no further evaluation of plant gaseous emissions is required.

8.6.2 Gamma Shine from the Turbine

)) Provided these conditions are met, no further evaluation of gamma shine from the turbine is required.

(( )) and as discussed in Section 3.2.1, the change in flux as a result of the MELLLA+ operating domain expansion is insignificant. The NMP2 steam flow rate does not change as a result of the MELLLA+ operating domain expansion. Numerical values demonstrating the MS flow does not increase are provided in 8-6

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

Table 1-2. ((

8-7

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 9.0 REACTOR SAFETY PERFORMANCE EVALUATIONS This section addresses the evaluations that are applicable to MELLLA+.

9.1 ANTICIPATED OPERATIONAL OCCURRENCES The NMP2 USAR defines the licensing basis AOOs. Table 9-1 of the M+LTR provides an assessment of the effect of the MELLLA+ operating domain expansion on each of the Reference 4 limiting AOO events and key non-limiting events. Table 9-1 of the M+LTR includes fuel thermal margin, overpressure, and loss of water level events. The overpressure protection analysis events are addressed in Section 3.1. The topics addressed in this evaluation are as follows:

Topic M+LTR Disposition NMP2 Result Fuel Thermal Margin Events ((

Power and Flow Dependent Limits Non-Limiting Events ))

9.1.1 Fuel Thermal Margin Events

((i

)) The limiting thermal margin events defined in Reference 4 include:

Generator Load Rejection Without Bypass (LRNBP) or Turbine Trip Without Bypass (TTNBP),

Loss of Feedwater Heating (LFWH),

" RWE, and

Feedwater Controller Failure (Maximum Demand) (FWCF).

The fuel loading error is categorized as an Infrequent Incident. However, if the licensee does not meet the requirements of GESTAR II (Reference 4), the fuel loading error event would be analyzed as an AOO. NMP2 does not meet the requirements of Reference 4. Therefore, the fuel loading error event is evaluated as an AOO for each reload. ((

9-1

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

))

The thermal margin event analysis is performed as part of the reload process for each reload core and results are documented in the SRLR. From M+LTR SER Limitation and Condition 12.4,

)) In accordance with Methods LTR SER Limitation and Condition 9.19, an additional 0.01 will be added to the OLMCPR for conditions above the stretch power uprate power level or above the MELLLA boundary (MELLLA+ conditions), until such time that GEH expands the experimental database supporting the Findlay-Dix void-quality correlation to demonstrate the accuracy and performance of the void-quality correlation based on experimental data representative of the current fuel designs and operating conditions during steady-state, transient, and accident conditions. In the event that the cycle-specific reload analysis is based on TRACG rather than ODYN for AOO, no 0.01 adder to the OLMCPR is required.

In accordance with M+LTR SER Limitation and Condition 12.16, an RWE analysis was performed to confirm the adequacy of the generic RBM setpoints. The RWE was simulated using the three-dimensional core simulator PANACEA. The analysis was performed with an approximate equilibrium core at the MELLLA+ 100% power, 85% CF statepoint for a comprehensive set of RBM setpoints. The results of this RWE analysis confirmed the validity of the generic RBM setpoints. The RWE results also meet the 1% cladding circumferential plastic strain acceptance criterion.

In accordance with Methods LTR SER Limitations and Conditions 9.9, 9.10, and 9.11, acceptable fuel rod T-M performance for both U0 2 and GdO 2 fuel rods was demonstrated.

Results for all AOO pressurization transient events analyzed, including EOOS, showed at least 10% margin to the fuel centerline melt and the 1% cladding circumferential plastic strain acceptance criteria. The minimum calculated margin to the fuel centerline melt criterion for AOO pressurization transient events was 19.2%. The minimum calculated margin to the cladding strain criterion was 18.2%. Fuel rod T-M performance will be evaluated as part of the RLAs performed for the cycle-specific core. Documentation of acceptable fuel rod T-M response will be included in the SRLR or COLR.

9-2

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 9.1.2 Power and Flow Dependent Limits The operating MCPR., LHGR, and/or MAPLHGR thermal limits are modified by a flow factor when the plant is operating at less than 100% CF. The MCPR flow factor (MCPRf) and the LHGR flow factor (LHGRFACf) are primarily based upon an evaluation of the slow recirculation flow increase event. ((

)) Table 9-2 summarizes the results of the slow recirculation flow increase analysis and compares them with the MCPR flow limit. The reference limits bound the slow recirculation flow results performed for the MELLLA+

operating domain. ((

Similarly, the thermal limits are modified by a power factor (MCPRp) when the plant is operating at less than 100% power. ((

1))

9.1.3 Non-Limiting Events

((E )) provides an assessment of the effect of the MELLLA+ operating range expansion for each of the Reference 4 limiting AOO events and key non-limiting events. Provided these evaluations are applicable to NMP2, no further evaluations are required for non-limiting events. The results of the M+LTR assessment are presented in the table below:

Event Discussion Fuel Thermal Margin Events Inadvertent HPCI Start The inadvertent HPCI start event is not applicable for NMP2.

Slow Recirculation Increase (Kf, MCPRf) (Reference 4 event -

bounds recirculation event AOOs)

Fast Recirculation Increase 9-3

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 1]

9.2 DESIGN BASIS ACCIDENTS AND EVENTS OF RADIOLOGICAL CONSEQUENCE 9.2.1 Design Basis Events This section addresses the radiological consequences of a DBA. The topics addressed in this evaluation are:

Topic M+LTR Disposition NMP2 Result Control Rod Drop Accident ((

Instrument Line Break Accident (ILBA)

Main Steam Line Break Accident (MSLBA) (Outside Containment)

Loss-of-Coolant Accident (Inside Containment)

Large Line Break (Feedwater or Reactor Water Cleanup)

Liquid Radwaste Tank Failure Fuel Handling Accident (FHA)

Offgas System Failure Cask Drop 9.2.1.1 Control Rod Drop Accident

(( )) the radiological consequences of this DBA are evaluated to determine off-site doses as well as control room operator doses. DBA calculations are generally based on core inventory sources or TS source terms, [R

)) For Event 1, the source term is based on fission products from failed fuel and the instantaneous transport to the condenser remains conservative for MELLLA+, therefore Event 1 is unchanged for MELLLA+. The source term for Event 2 is based on the maximum activity allowed under the MSL radiation monitor safety limit, therefore the analyzed condition in Event 2 is bounding for MELLLA+.

The CRDA release is dependent on the source terms and maximum peaking factor. Operation in the MELLLA+ operating domain does not affect the alternate source term (AST) CRDA source 9-4

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) term and the peaking factor remains bounding. ((

)) and no further evaluation is required.

9.2.1.2 Instrument Line Break Accident

(( )) the radiological consequences of a DBA are evaluated to determine off-site doses as well as control room operator doses. DBA calculations are generally based upon core inventory sources or TS source terms, ((

)) Table 9-4 of the M+LTR provides a detailed evaluation of each of the above events. ((

)) then no further review is required.

Therefore the ILBA evaluation is not affected by the MELLLA+ operating domain expansion and no further evaluation is required.

9.2.1.3 Main Steam Line Break Accident (Outside Containment)

)) the radiological consequences of this DBA are evaluated to determine off-site doses as well as control room operator doses. DBA calculations are generally based on core inventory sources or TS source terms, ((

)) Table 9-4 of the 9-5

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

M+LTR provides a detailed evaluation of the MSLBA events. ((

)) then no further review is required.

)) In addition, the analysis of record for the worst-case MSLBA radiological consequences is at hot standby conditions, which is outside of the MELLLA+ operating domain.

Therefore the NMP2 MSLBA evaluation is not affected by the MELLLA+ operating domain expansion and no further evaluation is required.

9.2.1.4 Loss-of-Coolant Accident (Inside Containment)

((

))the radiological consequences of this DBA are evaluated to determine off-site doses as well as control room operator doses. DBA calculations are generally based on core inventory sources or TS source terms, ((

The design input and assumptions for suppression pool pH were previously evaluated. The source term assumptions are not changing for MELLLA+. In addition, the acid production terms are not changing for MELLLA+ conditions. The use of Sodium Pentaborate as a buffer per USAR Section 15.8.3.5 continues to be appropriate.

Table 9-4 of the M+LTR provides a detailed evaluation of each of the above events. ((

)) then no further review is required.

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)) Therefore, the NMP2 LOCA evaluation is not affected by the MELLLA+ operating domain expansion and no further evaluation is required.

9.2.1.5 Feedwater Line Break E[ )) the radiological consequences of a DBA are evaluated to determine off-site doses as well as control room operator doses. DBA calculations are generally based upon core inventory sources or TS source terms, ((

)) Table 9-4 of the M+LTR provides a detailed evaluation of each of the above events. ((

)) then no further review is required.

)) Therefore the NMP2 FW Line Break evaluation is not affected by the MELLLA+ operating domain expansion and no further evaluation is required.

((

9.2.1.6 Liquid Radwaste Tank Failure The M+LTR discussion of the liquid radwaste tank failure describes in Table 9-4 of the M+LTR Er 9-7

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

)) The moisture content of the MS increases in a small area of the MELLLA+ operating domain near the minimum CF and 100% CLTP (see Sections 3.3.4 and 8.4). Section 8.5 discusses the analysis of the radioactive nuclide inventory in the radwaste tank. ((

)) Therefore, the liquid radwaste tank failure accident does not present a radiological concern at NMP2 for operation in the MELLLA+ operating domain.

Er 9.2.1.7 Fuel Handling Accident E[r]

the radiological consequences of this DBA are evaluated to determine off-site doses as well as control room operator doses. DBA calculations are generally based on core inventory sources or TS source terms, ((

)) Table 9-4 of the M+LTR provides a detailed evaluation of each of the above events. ((

))

then no further review is required.

Er Therefore, the NMP2 FHA evaluation for the MELLLA+ operating domain is bounded by the analysis for the current licensed operating domain, and no further evaluation is required.

Er 1]

9.2.1.8 Offgas System Failure Er )) the radiological consequences of a DBA are evaluated to determine off-site doses as well as control room operator doses. DBA calculations are generally based upon core inventory sources or TS source terms, E[

)) Table 9-4 of the M+LTR provides a 9-8

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) detailed evaluation of each of the above events. ((

)) then no further review is required.

)) Therefore the NMP2 offgas system failure evaluation is not affected by the MELLLA+ operating domain expansion and no further evaluation is required.

1))

9.2.1.9 Cask Drop

(( )) the radiological consequences of a DBA are evaluated to determine off-site doses as well as control room operator doses. DBA calculations are generally based upon core inventory sources or TS source terms, ((

)) Table 9-4 of the M+LTR provides a detailed evaluation of each of the above events. ((

)) then no further review is required.

)) Therefore the NMP2 cask drop evaluation for the MELLLA+ operating domain is bounded by the analysis for the current licensed operating domain, and no further evaluation is required.

((I 9.2.2 Other Events with Radiological Consequences This section addresses the radiological consequences of other events as described in the M+LTR.

The topics addressed in this evaluation are:

Topic M+LTR Disposition I NMP2 Result None N/A 9-9

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 9.3 SPECIAL EVENTS This section considers three special events: ATWS, SBO, and ATWS with Core Instability. The operator actions required as a result of ATWS are reviewed and discussed as a part of Section 10.9. The topics addressed in this evaluation are:

Topic M+LTR Disposition NMP2 Result ATWS (Overpressure) ((

ATWS (Suppression Pool Temperature and Containment Pressure)

ATWS (Peak Cladding Temperature and Oxidation)

Station Blackout ATWS with Core Instability 9.3.1 Anticipated Transients Without Scram There is no change in core power, decay heat, pressure, or steam flow as a result of the MELLLA+ operating range expansion. ((

)) The ATWS evaluation acceptance criteria are to:

Maintain reactor vessel integrity (i.e., peak vessel bottom pressure less than the ASME Service Level C limit of 1,500 psig)

" Maintain containment integrity (i.e., maximum containment pressure lower than the design pressure of the containment structure and maximum suppression pool temperature lower than the pool temperature limit)

Maintain coolable core geometry Plant-specific ATWS analyses are performed to demonstrate that the ATWS acceptance criteria are met for operation in the MELLLA+ operating domain. NMP2 meets the ATWS mitigation requirements in 10 CFR 50.62 for an alternate rod insertion (ARI) system, SLS boron injection equivalent to 86 gpm, and automatic RPT logic (i.e., ATWS-RPT). The plant-specific ATWS analyses take credit for the ATWS-RPT and SLS. However, ARI is not credited.

In accordance with M+LTR SER Limitations and Conditions 12.18.e and 12.18.f, the key input parameters to the plant-specific ATWS analyses are provided in Table 9-3. For key input parameters that are important to simulating the ATWS analysis and are specified in the TS (e.g., SLS parameters and ATWS-RPT), the calculation assumptions are consistent with the allowed NMP2 TS values and plant configuration. Although conservative inputs consistent with the NMP2 TS values were used, this does not imply that ATWS is part of the TS Bases. In some instances, nominal input parameters are used consistent with the approach in Reference 38.

Reference 38 contained sensitivity studies on key parameters for information. However, there was no specific uncertainty treatment applied. In addition, the EOOS assumptions for ATWS are consistent with TS requirements. M+LTR SER Limitation and Condition 12.23.2 requires that the plant-specific automatic settings be modeled for ATWS. For NMP2, the plant automatic 9-10

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) settings, which include the ATWS-RPT, low pressure isolation, and SRV actuation, are modeled based on the input parameters in Table 9-3. As required by M+LTR SER Limitation and Condition 12.23.8, the plant-specific ATWS analyses account for plant- and fuel-design-specific features including debris filters.

9.3.1.1 Anticipated Transients Without Scram (Licensing Basis)

The plant-specific ATWS analysis is performed using the approved ODYN methodology documented in Section 5.3.4 of ELTRI (Reference 5). The ATWS analysis using the ODYN methodology is the plant's licensing basis for this application.

A licensing basis ODYN ATWS analysis was performed to demonstrate the effect of MELLLA+

on the ATWS acceptance criteria. ((

The results of the licensing basis ODYN ATWS analysis are provided in Tables 9-4 and 9-5.

The tabulated peak value and time trace for reactor power, reactor dome pressure, PCT and suppression pool temperature is provided in Table 9-5 for the limiting event in the ODYN ATWS analysis. For reactor power, analysis results are provided for the limiting event with respect to peak reactor vessel pressure. The limiting event is the PRFO at EOC.

)) The peak vessel bottom pressure response is dependent on several inputs, including the SRV upper tolerances assumed in the ATWS analysis. In accordance with M+LTR SER Limitation and Condition 12.23.3, ((

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)) NMP2 as-found SRV lift setpoint tests do not show a propensity for setpoint drift higher than the 3% drift tolerance. Therefore, the SRV upper tolerances used in the ATWS analysis are consistent with the plant-specific performance.

The suppression pool temperature following an ATWS is bounded by EPU. Therefore, MELLLA+ does not affect the NPSH available for the ECCS pumps. ((

)) M+LTR SER Limitation and Condition 12.23.11 requires that the use of suppression pool temperature limits higher than the heat capacity temperature limit (HCTL) for emergency depressurization must be justified. The containment design limit is the ATWS acceptance criteria. ((

)) Per M+LTR SER Limitation and Condition 12.18.b, a best estimate TRACG analysis modeling emergency depressurization is not required if the plant increases boron-10 concentration/enrichment so that the integrated heat load to containment calculated by the licensing ODYN calculation does not change with respect to a reference OLTP / 75% flow ODYN calculation.

The peak containment pressure is 6.5 psig, which is below the NMP2 design limit of 45 psig. In accordance with M+LTR SER Limitation and Condition 12.23.10, the increase in containment pressure resulting from ATWS events with MELLLA+ operation does not adversely affect operation of the safety-grade equipment. As discussed in Sections 4.2.6 and 10.3, safety-grade equipment has been evaluated for operation at DBA LOCA conditions; these conditions bound the containment pressure increase following an ATWS event. Therefore, operation of safety-grade equipment is not adversely affected by the MELLLA+ operating domain expansion.

A coolable core geometry is ensured by meeting the 2,200'F PCT and 17% local cladding oxidation acceptance criteria of 10 CFR 50.46. ((

))

The results of the licensing basis ODYN ATWS analysis meet the ATWS acceptance criteria.

Therefore, the NMP2 response to an ATWS event initiated in the MELLLA+ operating domain is acceptable.

9-12

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 9.3.1.1.1 Anticipated Transients Without Scram (Single SLS Pump)

An additional plant-specific ATWS analysis is performed using the same approved ODYN methodology as the licensing basis calculation. The purpose of the additional analysis is to show that all ATWS acceptance criteria are met with only a single SLS pump operating. Input parameters specific to this analysis are provided in Table 9-6. All other input parameters are consistent with Table 9-3.

The results of the single SLS pump ODYN ATWS analysis are provided in Tables 9-7 and 9-8.

The tabulated peak value and time trace for reactor power, reactor dome pressure, PCT, and suppression pool temperature is provided in Table 9-8 for the limiting event in the ODYN ATWS analysis. For reactor power, analysis results are provided for the limiting event with respect to peak reactor vessel pressure. The limiting event is the PRFO at EOC.

All ATWS acceptance criteria are met at MELLLA+ conditions with only a single SLS pump operating.

9.3.1.2 Anticipated Transients Without Scram (Best-Estimate Calculation)

The HCTL is provided in the NMP2 EOPs. The HCTL is a function of operating reactor pressure and suppression pool water level. For normal suppression pool water level, the HCTL is approximately 140'F near the SRV opening pressure. At the extreme upper suppression pool water level covered by EOPs, the HCTL is approximately 90'F near the SRV opening pressure.

NMP2 EOPs require depressurization during an ATWS event when the suppression pool temperature reaches the HCTL. As a result, M+LTR SER Limitation and Condition 12.18.a requires that a best-estimate TRACG ATWS analysis must be performed for NMP2 because hot shutdown was not achieved prior to reaching the HCTL based on the licensing basis ODYN calculation. M+LTR SER Limitation and Condition 12.18.c further requires that PCT be evaluated for both the initial overpressure and depressurization phases for the TRACG ATWS calculation. However, M+LTR SER Limitation and Condition 12.18.b states that the TRACG calculation is not required if the plant increases the boron-10 concentration/enrichment so that the integrated heat load to containment calculated by the licensing ODYN calculation does not change with respect to a reference OLTP/75% flow ODYN calculation.

For NMP2, the boron-10 enrichment is increased from 25 atom % to 92 atom % at MELLLA+

operating conditions. The results of the MELLLA+ licensing ODYN calculation are compared to a reference OLTP/75% flow ODYN calculation. ((

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))

As a result of the increased boron-10 enrichment at MELLLA+, the best-estimate TRACG ATWS analysis is not required to meet the ATWS acceptance criteria.

9.3.2 Station Blackout

(( )) there is no significant change in core power, decay heat, pressure, or steam flow as a result of the MELLLA+ operating domain expansion. ((

)) there is no change in the reactor power level as a result of the MELLLA+ operating domain expansion. As discussed in Section 1.2.3, there is no significant change in decay heat as a result of the MELLLA+ operating domain expansion. For NMP2, there are no increases in reactor operating pressure as result of MELLLA+ operating domain expansion. For NMP2, there are no significant changes in the MS flow rate. The numerical values showing no significant changes to reactor operating power and MS flow rate are presented in Table 1-2. ((

)) No further evaluation is required.

9.3.3 ATWS with Core Instability The NRC has reviewed and accepted GEH's disposition of the effect of large coupled thermal-hydraulic/neutronic core oscillations during a postulated ATWS event, which is presented in NEDO-32047-A (Reference 39). The companion report, NEDO-32164 (Reference 40) was approved by the same NRC SER. The NRC review concluded that the GEH TRACG code is an adequate tool to estimate the behavior of operating reactors during transients that may result in large power oscillations. The review also concluded that ATWS criteria, which are listed below, were met:

1. Radiological consequences must be maintained within 10 CFR 100 guidelines;

2. Primary system integrity to be maintained;

3. Fuel damage limited so as not to significantly distort the core, impede core cooling, or prevent safe shutdown;

4. Containment integrity to be maintained; and

5. Long-term shutdown and cooling capability to be maintained.

Furthermore, the NRC review concluded that the specified operator actions are sufficient to mitigate the consequences of an ATWS event with large core power oscillations. ((

9-14

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))

M+LTR SER Limitation and Condition 12.19 requires that a plant-specific ATWS instability calculation be performed to demonstrate that NMP2 EOP actions, including boron injection and water level control strategy, effectively mitigate an ATWS event with large power oscillations in the MELLLA+ operating domain. The plant-specific ATWS instability calculation was (1) based on the limiting of BOC, peak reactivity exposure condition (MOC), and EOC; (2) modeled the plant-specific configuration important to the ATWS instability response; and (3) used the limiting of the regional mode or core-wide mode nodalization scheme. M+LTR SER Limitation and Condition 12.23.5 requires that the power density be less than 52.5 MWt/Mlbm/hr. For NMP2, the plant-specific maximum power-to-flow ratio at rated power and minimum CF is 43.3 MWt/Mlbm/hr and meets the requirement. The plant-specific TRACG calculation modeled in-channel water rod flow in accordance with M+LTR SER Limitation and Condition 12.24.1. The plant-specific ATWS instability calculation was performed using the latest NRC-approved neutronic and thermal-hydraulic codes TGBLA06/PANAC 11 and TRACG04 (Reference 41).

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The results of the plant-specific TRACG ATWS instability calculation are provided in Table 9-9.

Figures 9-9, 9-10, 9-11, and 9-12 show the mitigating effect of decreasing water level and boron injection on the core and bundle response to both the TTWBP (for limiting pressure) and RPT (for limiting PCT) ATWS instability events.

The results of the plant-specific TRACG ATWS instability calculation meet the ATWS acceptance criteria. Therefore, the NMP2 response to an ATWS with core instability event initiated in the MELLLA+ operating domain is acceptable. NMP2 EOP actions, including boron injection and water level control strategy, effectively mitigate an ATWS event with large power oscillations in the MELLLA+ operating domain.

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Table 9-1 AOO Event Results Summary Flow Peak Dome Peak Vessel Peak Neutron Peak Heat GE14

(% of Rated) Event Pressure Pressure Flux Flux (psig) (psig) (%) (%Initial) ACPR (')

105 LRNBP 1,255 1,283 520 133 0.30 85 LRNBP 1,253 1,275 402 125 0.26 105 TTNBP 1,253 1,280 511 130 0.30 85 TTNBP 1,251 1,273 367 122 0.25 105 FWCF 1,229 1,257 474 131 0.28 85 FWCF 1,228 1,249 338 123 0.23 85 LFWH (2) - (3) - (3) - (3) - (3) 0.14 100 RWE _ (3) _ (3) _ (3) _ (3) 0.29 85 RWE _(3) _(3) _(3) - (3) 0.29 Notes:

(1) For the pressurization events, the uncorrected ACPR values are presented.

(2) The LFWH is most limiting at low CF, and therefore, it was not analyzed at CLTP/MELLLA conditions.

The event is non-limiting with respect to ACPR.

(3) The PANACEA code is used to analyze slow events; therefore, system response parameters are not applicable.

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Table 9-2 Comparison of Slow Recirculation Flow Increase Results and MCPR Flow Limit Flow (%) Slow Recirculation Flow MCPR Flow Limit Increase MCPR 112 1.13 1.25 110 1.14 1.25 100 1.17 1.25 90 1.21 1.25 80 1.25 1.30 70 1.29 1.37 60 1.32 1.45 55 1.34 1.48 9-18

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Table 9-3 Key Input Parameters for ATWS Analyses Parameter CLTP MELLLA+ Basis Reactor Power (MWt) 3,988 3,988 Analyzed Power (MWt) 3,988 3,988 Analyzed Core Flow (Mlbm/hr / % Rated) 107.4 / 99.0 92.2 / 85.0 Reactor Dome Pressure (psia) 1,035 1,035 MSIV Closure Time (sec) 4.0 4.0 High Pressure ATWS-RPT Setpoint (psig) 1,095.0 1,095.0 Low Pressure Isolation Setpoint (psig) 720.0 720.0 RCIC Flow Rate (gpm) 600.0 600.0 Number of SRVs / SRVOOS 18/2 18/2 Each SRV Capacity at 1,145 psig (lbm/hr) 890,371 890,371 SRV Analytical Opening Setpoints (psig) 1,121 - 1,161 1,121 - 1,161 SLS Injection Location HPCS HPCS SLS Injection Rate (gpm) 82.4 80.01 Boron-10 Enrichment (atom %) 25.0 92.0 Sodium Pentaborate Concentration (% by Weight) 13.6 13.6 SLS Liquid Transport Time (sec) 120.0 124.0' 3

Initial Suppression Pool Liquid Volume (ft ) 145,200 145,200 Initial Suppression Pool Temperature (°F) 90.0 90.0 Number of RHR Suppression Pool Cooling Loops 2 2 RHR Heat Exchanger Effectiveness Per Loop 249.0 265.02 (BTU/sec-°F)

RHR Heat Exchanger Effectiveness Per Loop 249.0 265.02 during LOOP Event (BTU/sec-°F)

RHR Service Water Temperature ('F) 84.0 84.0 Notes:

1. ((

2. This value is consistent with the EPU LOCA long-term suppression pool temperature analysis.

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Table 9-4 Key Results for Licensing Basis ODYN ATWS Analysis ATWS Acceptance Criteria CLTP MELLLA+ Design Limit Peak Vessel Pressure (psig) (( _1,500 Peak Suppression Pool Temperature ('F) 190 Peak Containment Pressure (psig) 45.0 Peak Cladding Temperature ('F) 2,200 Peak Local Cladding Oxidation (%) 2 17 Peak Upper Plenum Pressure After SLS Pump Startup (psia) ))_--

Notes:

1. ((

))

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Table 9-5 ODYN ATWS Analysis Limiting Event Results at MELLLA+

Parameter Limiting Event Peak Value Time Trace Reactor Power (Neutron Flux) PRFO at EOC 968% Rated Figure 9-3 Reactor Dome Pressure PRFO at EOC 1,370 psia Figure 9-3 Suppression Pool Temperature MSIVC at EOC 160°F Figure 9-4 Peak Cladding Temperature PRFO at EOC 1,437°F Figure 9-5 9-21

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Table 9-6 Key Input Parameters for Single SLS Pump ATWS Analyses Parameter MELLLA+ Basis SLS Injection Rate (gpm) 40.0 ' ((

SLS Liquid Transport Time (sec) 236.0' Notes:

1. ((

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Table 9-7 Key Results for Single SLS Pump ODYN ATWS Analysis ATWS Acceptance Criteria MELLLA+ Design Limit Peak Vessel Pressure (psig) 1,500 Peak Suppression Pool Temperature (°F) 190 Peak Containment Pressure (psig) 45.0 0

Peak Cladding Temperature ( F) 2,200 Peak Local Cladding Oxidation (%) 17 Peak Upper Plenum Pressure After SLS Pump Startup (psia) --

Notes:

1. ((

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Table 9-8 Single SLS Pump ODYN ATWS Analysis Limiting Event Results Parameter Limiting Event Peak Value Time Trace Reactor Power (Neutron Flux) PRFO at EOC 968% Rated Figure 9-6 Reactor Dome Pressure PRFO at EOC 1,370 psia Figure 9-6 0

Suppression Pool Temperature MSIVC at EOC 166 F Figure 9-7 Peak Cladding Temperature PRFO at EOC 1,437°F Figure 9-8 9-24

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Table 9-9 Key Results for ATWS with Core Instability Analysis from MELLLA+

Operating Domain ATWS Acceptance Criteria MELLLA+ Design Limit Peak Vessel Pressure (psig) 1 (( 1,500 Peak Cladding Temperature (°F) 2,200 Peak Local Cladding Oxidation (%) 2 )) 17 Notes:

1. The TRACG calculation of peak vessel pressure is based on two SRVs OOS.

2. ((

I]

9-25

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 275 [ Ne1-1-Fs HW 55F 70 --- Vessel DomePre..u. 1350

-- AweragesSurface Heat Film Safety Val'e Flow Core Inlet Flow -- ReliefVale Flow 250 500 re- Turbine Btass Steam Flow 60 1300 225 450 200 400 501250 175 300 S150 40 - 1200 250 S125 _ E 30 1150 100 2002Z 75 150 20 10 50 100 10 1050 25 50 0 0 010 N I q i F q 1000 0 1 2 3 4 5 6 70 1 2 3 4 5 6 7 Time (s) Time (5) 125 Vese Le 60 10 VoidReactl

-A&- Vessel LreamFlow - S- .nram Readlly

-S- FeedweterFlow -- Doppler ReactMt"

_GT'urbine Steam Flow Total React"~t 50 75 40 50 so 25 20~. .

S -20 0 10

-25 0

-50 4 -10 -40 I a 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 Time (s) Time (s)

PID:50163 Figure 9-1 LRNBP at ICF 9-26

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 70 1350 200 60 1300 175 50 1250 150 40 12002~

125 30 115501 150 20 1100 15 1050 25 0 0 10S0 Time(s) Time (S) 125 100 0

125 75 10 so RD:50163 Figure 9-2 LRNBP at MELLLA+

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Figure 9-3 ODYN ATWS Analysis - PRFO at EOC Short-Term Results 9-28

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Figure 9-4 ODYN ATWS Analysis - MSIVC at EOC Long-Term Results 9-29

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[R Figure 9-5 ODYN ATWS Analysis - PRFO at EOC PCT 9-30

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Figure 9-6 Single SLS Pump ODYN ATWS Analysis - PRFO at EOC Short-Term Results 9-31

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 11 1]

Figure 9-7 Single SLS Pump ODYN ATWS Analysis - MSIVC at EOC Long-Term Results 9-32

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Figure 9-8 Single SLS Pump ODYN ATWS Analysis - PRFO at EOC PCT 9-33

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Figure 9-9 ATWS Instability from MELLLA+ Operating Domain - Turbine Trip with Full Bypass 9-34

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]

Figure 9-10 ATWS Instability from MELLLA+ Operating Domain - Turbine Trip with Full Bypass 9-35

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I]

Figure 9-11 ATWS Instability from MELLLA+ Operating Domain - Recirculation Pump Trip 9-36

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((I Figure 9-12 ATWS Instability from MELLLA+ Operating Domain - Recirculation Pump Trip 9-37

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 10.0 OTHER EVALUATIONS This section addresses the evaluations in Section 10 of the M+LTR.

10.1 HIGH ENERGY LINE BREAK HELBs are evaluated for their effects on equipment qualification. The topics addressed in this evaluation are:

Topic M+LTR Disposition NMP2 Result Steam Lines Balance-of-Plant Liquid Lines Other Liquid Lines 1]

10.1.1 Steam Lines MELLLA+ operating domain expansion has no effect on the steam pressure or enthalpy at the postulated steam line break locations. The MS enthalpy will be slightly lower for MELLLA+

and hence the EPU HELB subcompartment analyses are bounding for MELLLA+. ((

)) a review of the heat balances produced for NMP2 MELLLA+ operating domain expansion confirms that there is no significant effect on the steam pressure or enthalpy at the postulated break locations (e.g., MS and RCIC).

10.1.2 Balance-of-Plant Liquid Lines

(( 1]

MELLLA+ operating domain expansion has no effect on the steam pressure or enthalpy at the postulated FW line break locations. ((

)) a review of the heat balances produced for MELLLA+ confirms that there is no effect on the liquid line conditions at the postulated FW break locations. ((

10-1

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 10.1.3 Other Liquid Lines

)) The scope of these evaluations includes MELLLA+ operating domain expansion effects on subcompartment pressures and temperatures, pipe whip, jet impingement, and flooding, consistent with the plant licensing basis.

(( )) a review of the heat balances produced for the NMP2 MELLLA+ operating domain confirms that there is no effect on the liquid line conditions (excluding FW addressed in Section 10.1.2) at the postulated break locations. ((

)) The scope of these evaluations includes MELLLA+ operating domain expansion effects on subcompartment pressures and temperatures, pipe whip, jet impingement, and flooding, consistent with the plant licensing basis. ((

))

10.2 MODERATE ENERGY LINE BREAK Moderate energy line breaks (MELBs) are evaluated for their effects on equipment qualification.

NMP2 uses the MELB equivalent term moderate energy line crack (MELC). The topics addressed in this evaluation are:

Topic M+LTR Disposition NMP2 Result Flooding Environmental Qualification 10.2.1 Flooding

)) a review of the NMP2 auxiliary flow rates and system inventories shows that MELLLA+ operating domain expansion does not affect the flow rates of moderate energy piping systems. Also, for NMP2, no operational modes evaluated for MELB are affected by MELLLA+ operating domain expansion. ((

10-2

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10.2.2 MELB Environmental Qualification

)) a review of the NMP2 auxiliary flow rates and system inventories shows that MELLLA+ operating domain expansion does not affect the flow rates of moderate energy piping systems. Also, for NMP2, no operational modes evaluated for MELB are affected by MELLLA+ operating domain expansion. ((

10.3 ENVIRONMENTAL QUALIFICATION Safety-related components are required to be qualified for the environment in which they operate. The topics addressed in this evaluation are:

Topic M+LTR Disposition NMP2 Result Electrical Equipment ((I___________

Mechanical Equipment with Non-Metallic Co Mechanical Component Design Oualification 11 10.3.1 Electrical Equipment there is no change or increase in core power, radiation levels, decay heat, pressure, steam flow, or FW flow as a result of the MELLLA+ operating domain expansion. ((

)) No further evaluation is required for EQ of electrical equipment as a result of MELLLA+ operating domain expansion.

(( )) the reactor power does not increase as a result of MELLLA+ operating domain expansion. There is no change in normal 10-3

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) operation radiation levels (see Section 8.5). There is also no change in decay heat (see Section 1.2.3). For NMP2, there are no increases in reactor operating pressure, MS or FW flow rates. The numerical values showing no increases in reactor operating pressure, MS or FW flow rates are presented in Table 1-2. ((

)) No further evaluation is required for EQ of electrical equipment as a result of MELLLA+ operating domain expansion.

((

10.3.2 Mechanical Equipment With Non-Metallic Components

[r

)) operation in the MELLLA+ operating domain does not increase any of the normal process temperatures. ((

)) No further evaluation is required for EQ of mechanical equipment with non-metallic components as a result of the MELLLA+ operating domain expansion.

(( )) for NMP2, normal process temperatures are not affected by MELLLA+. ((

)) No further evaluation is required for EQ of mechanical equipment with non-metallic components as a result of the MELLLA+ operating domain expansion.

Er 10.3.3 Mechanical Component Design Qualification

((

)) operation in the MELLLA+ operating domain does not affect any of the normal process temperatures, pressures, or flow rates. ((

)) The change in fluid induced loads on safety-related components is discussed in Sections 3.2.2, 3.5, and 4.1.2. ((

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)) for NMP2, normal process temperatures, pressures, and flow rates are not affected by MELLLA+. There is no change in radiation levels (see Section 8.5). ((

10.4 TESTING When the MELLLA+ operating domain expansion is implemented, testing is recommended to confirm operational performance and control aspects of the MELLLA+ changes. The topics addressed in this evaluation are:

Topic M+LTR Disposition NMP2 Result Steam Separator-Dryer Performance ((

APRM Calibration Core Performance Pressure Regulator Water Level Setpoint Changes Neutron Flux Noise Surveillance 10.4.1 Steam Separator-Dryer Performance The performance of the steam separator-dryer (i.e., MCO) is determined by a test similar to that performed in the original startup test program. Testing will be performed near the CLTP and the MELLLA+ minimum CF statepoint of 85% as well as other statepoints that may be deemed valuable for the purpose of defining the MCO magnitude and trend.

10.4.2 Average Power Range Monitor Calibration The APRM system is calibrated and functionally tested. The APRM STP scram and rod block are calibrated with the MELLLA+ equations and the APRM trips and alarms tested. This test will confirm that the APRM trips, alarms, and rod blocks perform as intended in the MELLLA+

operating domain.

10.4.3 Core Performance The core performance test will evaluate the core thermal power, fuel thermal margin, and CF performance to ensure a monitored approach to CLTP in the MELLLA+ operating domain.

Measurements of reactor parameters are taken in the MELLLA+ operating domain. Core thermal power and fuel thermal margin are calculated using accepted methods. After steady-state conditions are established, measurements will be taken, core thermal power and fuel thermal margin calculated, and evaluated against projected values and operational limits.

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 10.4.4 Pressure Regulator The pressure regulator test will confirm that the pressure control system settings established for operation at CLTP are adequate in the MELLLA+ operating domain. The pressure regulator should not require any changes from the settings established for the current licensed operating domain. The pressure control system response to pressure setpoint changes is determined by making a down setpoint step change and, after conditions stabilize, an upward setpoint step change.

10.4.5 Water Level Setpoint Changes The water level setpoint changes test verifies that the FW control system can provide acceptable reactor water level control in the MELLLA+ operating domain. Reactor water level setpoint step changes are introduced into the FW control system, while the plant response is monitored.

10.4.6 Neutron Flux Noise Surveillance The neutron flux noise surveillance test verifies that the neutron flux noise level in the reactor is within expectations in the MELLLA+ operating domain. The noise will be recorded by monitoring the LPRMs and APRMs at steady-state conditions in the MELLLA+ operating domain.

10.5 INDIVIDUAL PLANT EXAMINATION This section provides an assessment of the risk increase, including core damage frequency (CDF) and large early release frequency (LERF), associated with operation in the MELLLA+ range.

The topics addressed in this evaluation are:

M+LTR Topic Disposition NMP2 Result Initiating Event Categories and Frequency [I Component Reliability Operator Response Success Criteria External Events Shutdown Risk PRA Quality ))

In accordance with M+LTR SER Limitation and Condition 12.21, a plant-specific probabilistic risk assessment (PRA) evaluation was performed, which included CDF and LERF effects associated with operation in the MELLLA+ operating domain. The evaluation scope included all of the elements of Section 10.5, Individual Plant Examination, of the M+LTR (Reference 1).

The associated PRA report is provided as Attachment 4 to the NMPNS MELLLA+ LAR.

The proposed MELLLA+ operating region for NMP2 has been reviewed to determine the effect on the PRA. The PRA is based on the EPU MELLLA operating region and includes internal events as well as fire and seismic initiating events. The effect of MELLLA+ on the PRA is very 10-6

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) low and meets NRC guidelines in RG 1.174 (Reference 43) for CDF and LERF. MELLLA+ has no effect on the risk associated with accidents initiated during shutdown conditions.

The estimated risk increase for at-power events due to MELLLA+ is a delta CDF of 1E-8 and delta LERF of 3E-9. This represents a very small risk change in RG 1.174 (Reference 43).

Based on these results, the proposed MELLLA+ operating region is acceptable on a risk basis.

Risk Metric NMP2 EPU MELLLA+ Risk Increase CDF 3.77E-6 3.78E-6 IE-8 LERF 3.92E-7 3.95E-7 3E-9 Sensitivity analyses results also demonstrate a low risk with CDF and LERF changes no more than 1E-7.

10.5.1 Initiating Event Categories and Frequency The MELLLA+ core operating range expansion involves changes to the operating power/core flow map and a small number of setpoints. There is no change in the operating pressure, power, steam flow rate, and FW flow rate. MELLLA+ implementation does not include changes to plant hardware or operating procedures that would create additional event categories or have a significant effect on initiating event frequencies.

))

As noted in Section 2.4, the BSP, which is considered a part of the DSS-CD stability solution, may be used when the OPRM system is temporarily inoperable. ((

1]

10.5.2 Component and System Reliability

((

)) There is no change in the operating pressure, power, steam flow rate, and FW flow rate. The MELLLA+ core operating range expansion does not require major plant hardware modifications. ((

)) The TS ensure that plant and system performance parameters are maintained within the values 10-7

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) assumed in the safety analyses. The TS setpoints, AVs, operating limits, and the like are selected such that the equipment parameter values are equal to or more conservative than the values used in the safety analyses. ((

))

10.5.3 Operator Response The operator responses to anticipated occurrences, accidents, and special events for EPU with MELLLA+ conditions are basically the same as for EPU conditions. Minor changes to ATWS operator response in the PRA has occurred due to small reductions in timing for operator actions during an ATWS event. ((

1]

Because decay heat is unchanged, the time for boil-off is unchanged. Therefore, long-term core cooling is not affected by the MELLLA+ operating range expansion.

)) The minimum operator action time to initiate SLS is 2 minutes and the minimum operator action time to inhibit ADS and start water level reduction, if necessary, (i.e., motor-driven FW pump nuclear power plants) is 90 seconds in ATWS analyses (Section 9.3.1). SLS initiation is automatic at NMP2, thus critical operator action to initiate SLS is not required in the NMP2 PRA. The minimum operator action time to inhibit ADS and start water level reduction is potentially reduced, but this was found to have an insignificant effect on risk.

((I 10.5.4 Success Criteria Systems success criteria credited in a PRA to perform the critical safety functions were analyzed based on MELLLA+. Reactor thermal power, operating pressure, steam flow, and FW flow are not changed by MELLLA+. The power conversion systems, electrical systems, and other auxiliary systems are not changed as a result of MELLLA+ operation. Also, MELLLA+ does not change the operating conditions of systems modeled in the PRA. There is no effect on the success criteria provided for the critical safety functions in the PRA; reactivity control, pressure control, inventory control at high pressure, emergency depressurization, inventory control at low pressure and containment heat removal; the following summarizes:

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1) Reactivity Control - The number of control rods and reactor protection system (RPS) success criteria is unchanged. One of two SLS pumps as a successful alternate shutdown system is unchanged, and in fact, this success criterion is further supported by the MELLLA+

evaluations and the increase in boron-10 enrichment. Although MELLLA+ has no effect on the probability of scram failure, the plant may be at a slightly higher power during ATWS until SLS is injected. This can affect the timing of operator response as described in Section 3.2.5 of Attachment 4 to the NMPNS MELLLA+ LAR.

2) Pressure Control (RPV Overpressure Protection) - There is no effect on the number of SRVs required for success. RPV dome operating pressure is not increased and there is no effect for non-ATWS events. The higher power condition during ATWS was evaluated and the assumed success criteria (16 of 18 SRVs required) in the PRA is still met with MELLLA+ conditions. GEH analysis indicates margin in over pressure protection with two SRVs OOS; therefore, the probability of overpressure due to failure of several SRVs is still dominated by common cause failure of the SRVs, which is unchanged in the PRA.

3) Pressure Control (SRVs Reclose) - The success criteria is that all SRVs reclose, which is unchanged. There is no effect on the number of SRV challenges for non-ATWS events as operating pressure and power is not changed. However, the SRVs are likely open for a longer time during ATWS due to higher initial power level. The NMP2 turbine bypass is rated at approximately 18.5% of rated steam flow. Thus, until power level is reduced to the equivalent bypass flow rate, SRVs will be open. In the case of a more severe transient such as closure of all MSIVs, SRVs will be open until SLS is injected; however, the increased boron-10 enrichment ensures that the time to reactor shutdown is not increased due to MELLLA+. The potential increase in probability of a stuck open SRV in the ATWS model is considered with regard to PRA model change (see Section 3.3 of Attachment 4 to the NMPNS MELLLA+ LAR).

4) High Pressure Injection - There is no change in the number of pumps required for success.

The MELLLA+ plant changes do not result in changes to injection systems, and reactor power and pressure are unchanged. Thus, there is no effect on injection system success criteria for non-ATWS events. The potential for higher power level during ATWS until SLS injection does not affect the systems credited for initial level control. The timing associated with operator response is evaluated (see Sections 3.2.5 and 3.3 of Attachment 4 to the NMPNS MELLLA+ LAR).

5) Emergency Depressurization - There is no change in the number of SRVs required to support low pressure injection success. MELLLA+ does not involve changes to the ADS and does not change reactor power or pressure. Although ATWS power is potentially higher until SLS is injected, there is no effect on success criteria. The timing associated with operator response is evaluated (see Sections 3.2.5 and 3.3 of Attachment 4 to the NMPNS MELLLA+ LAR).

6) Low Pressure Injection - There is no change in the systems and number of pumps required for success. The MELLLA+ plant changes do not result in changes to injection systems, and reactor power and pressure are unchanged. Thus, there is no effect on injection system 10-9

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) success criteria for non-ATWS events. The potential for slightly higher power level during initial stages of ATWS does not affect the systems credited for level control after emergency depressurization and during SLS injection.

7) Containment Heat Removal - There is no change to the systems and success criteria for this function. Plant changes for MELLLA+ do not result in changes to containment heat removal systems, and reactor power and pressure are unchanged. Thus, there is no effect on heat removal success criteria for non-ATWS events. Also, for mitigated ATWS events (SLS injection), the RHR success criteria are unchanged. The potential reduction in time to align RHR is considered in Section 3.2.5 of Attachment 4 to the NMPNS MELLLA+ LAR.

Although the suppression pool heat-up could be initially faster during ATWS due to potentially higher power level, the SLS increased boron-10 enrichment maintains the integrated containment heat up unchanged.

8) Containment Response - Containment analysis for LOCA and ATWS under MELLLA+

conditions indicate the dynamic loads and containment conditions remain acceptable. No effect on the PRA was identified (see Section 3.2.7 "Level 2 Model" of Attachment 4 to the NMPNS MELLLA+ LAR).

The operating range expansion involves changes to the operating power/core flow map and a small number of setpoints. There is no change in the operating pressure, power, steam flow rate, and FW flow rate. The MELLLA+ operating range expansion does not impose any additional requirements on any of the safety, BOP, electrical, or auxiliary systems. Adequate SRV capacity is provided to ensure that the ATWS overpressure requirement for MELLLA+ is satisfied.

Therefore, MELLLA+ operating range expansion will not affect the PRA success criteria.

10.5.5 External Events The operating range expansion is not expected to affect the elements of an internal event PRA, as discussed in Sections 10.5.1 to 10.5.4. Therefore, there is no effect on the external events PRA.

10.5.6 Shutdown Risks The operating range expansion does not change the shutdown conditions; therefore, it has no effect on the plant PRA shutdown risks.

10.5.7 PRA Quality MELLLA+ does not have a significant effect on any PRA elements. The NMP2 PRA underwent an Internal Events and Internal Flooding industry peer review in August 2009 utilizing ASME/ANS RA-Sa-2009 and RG 1.200 Revision 2 (Reference 44). Subsequent post-peer review updates to the PRA have resolved most observations as well as incorporated the effect of EPU. The remaining open observations were reviewed with respect to this application and were found to have a negligible risk effect.

Besides including EPU, the NMP2 PRA scope also includes the results of the individual plant examination of external events (IPEEE) for fires and seismic initiating events at power. The quality of the External Events modeling has not been peer reviewed against RG 1.200 Revision 2 (Reference 44) and ASME/ANS RA-Sa-2009; however, the quality was found acceptable for the 10-10

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

NMP2 emergency diesel generator (EDG) allowable outage time (AOT) application approved by the NRC in 2011 (Reference 45). Also, the risk effect associated with the MELLLA+ operating range on external events risk is minimal.

10.6 OPERATOR TRAINING AND HUMAN FACTORS Some additional training is required to prepare for NMP2 operation in the MELLLA+ operating domain. The topics addressed in this evaluation are:

Topic I M+LTR Disposition NMP2 Result Operator Training and Human Factors 1 ))

The description of the Operator Training and Human Factors topic in the M+LTR describes that the operator training program and plant simulator will be evaluated to determine the specific changes required. The selection of training topics, operator training, the control room modifications, and simulator modifications are within the scope of the Licensee. Required changes are part of the MELLLA+ implementation plan and will be made consistent with the Licensee's current plant training program requirements. These changes will be made consistent with similar changes made for other plant modifications and include any changes to TS, EOPs, and plant systems.

The operator responses to anticipated occurrences, accidents, and special events are not significantly affected by operation in the MELLLA+ domain. Significant events result in automatic plant shutdown (scram). Some events result in automatic RCPB pressure relief, ADS actuation and/or automatic ECCS actuation (for low water level events). MELLLA+ operating domain expansion does not cause changes in any of the automatic safety functions. After the automatic responses have initiated, the operator actions for plant safety (e.g., maintaining safe shutdown, core cooling, and containment cooling) do not change for MELLLA+ operating domain expansion.

As part of the NMPNS MELLLA+ LAR, the SLS has been modified by increasing the isotopic enrichment of boron-10 in the sodium pentaborate solution as described in Section 6.5. This results in an effect in the ATWS response and is evaluated in Section 9.3. 1.

Consistent with the requirements for the plant-specific analysis as described in the M+LTR, the operator training program and plant simulator will be evaluated to determine the specific changes required. Simulator changes and fidelity validation will be performed in accordance with applicable ANSI standards currently being used at the training simulator. Section 10.9 addresses the MELLLA+ operating domain effects on the EOPs and the abnormal operating procedures (AOPs). Operators will be trained regarding changes to procedures, including the limitation to not perform LPRM calibrations in the prohibited region to the left of the line illustrated on Figure 5-1.

The primary effects of MELLLA+ operating domain expansion on MCR operation involve changes to the power/flow map. Other than the changes to the computer display for the power/flow map, there are no major physical changes to the MCR controls, displays, or alarms as a result of MELLLA+ operating domain expansion. Some changes are required to MCR panel 10-11

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) board alarm settings and automatic actuation setpoints to accommodate changes due to MELLLA+ operating domain expansion. The SLS modification to increase the isotopic enrichment of boron-10 in the sodium pentaborate solution (as described in Section 6.5) results in a reduction in solution storage tank minimum required volume and associated alarm level.

These changes do not affect human factors.

The APRM STP scram and rod block AVs are also being changed as a result of MELLLA+

operating domain expansion. These changes are described in Section 5.3.

The SLS is modified by: (1) increasing the boron-10 enrichment in the sodium pentaborate solution in the SLS; (2) decreasing the sodium pentaborate solution volume stored in the SLS storage tank; (3) reducing the injection flow requirement for ATWS response from two SLS pumps to one pump required to meet 10 CFR 50.62 for ATWS mitigation, though both SLS pumps would actually operate during an event; and (4) modifying instrumentation setpoints.

The changes required to adopt the MELLLA+ power/flow map, DSS-CD (including automatic actuation setpoints), and the modifications to SLS are implemented as design changes in accordance with the NMP2 approved change control procedures. The change control process includes a review by operations and training personnel. Training and implementation requirements are identified and tracked, including effects on the simulator. Verification of training is required as part of the design change closure process.

There are no planned upgrades of controls, displays, or alarms from analog to digital instruments as part of MELLLA+ operating domain expansion. There are no changes to the analog and digital inputs for the safety parameter display system (SPDS) for MELLLA+ operating domain expansion.

Training required to operate NMP2 following the MELLLA+ operating domain expansion will be conducted prior to operation in the MELLLA+ domain. Training for the MELLLA+ startup testing program will be performed using "just in time" training of plant operation personnel where appropriate. Data obtained during operation in the MELLLA+ domain will be incorporated into additional training, as needed. The classroom training will cover various aspects of MELLLA+ operating domain expansion, including changes to the power/flow map, changes to important setpoints, changes to plant procedures, and startup test procedures. The classroom training may be combined with simulator training for normal operational sequences unique to operation in the MELLLA+ domain. The plant dynamics do not change substantially for operation in the MELLLA+ domain. Enhanced training on ATWS event mitigation in the MELLLA+ domain, FW pump trip transient, and RPT transient will be conducted.

The evaluation of the NMP2 operator training and human factors is consistent with the guidance presented in the M+LTR and meets current industry standards.

10.7 PLANT LIFE The plant life evaluation identifies degradation mechanisms influenced by increases in fluence and flow rate. The topics addressed in this evaluation are:

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Topic M+LTR Disposition NMP2 Result Irradiated Assisted Stress Corrosion Cracking (IASCC)

Flow Accelerated Corrosion 10.7.1 Irradiated Assisted Stress Corrosion Cracking With regard to IASCC, the M+LTR states that the longevity of most equipment is not affected by the MELLLA+ operating domain expansion. The peak fluence experienced by the reactor internals may increase, representing a minor increase in the potential for IASCC. Therefore, the current inspection strategy for the reactor internal components is adequate to manage any potential effects of MELLLA+.

Section 3.2.1 provides an evaluation of the change in fluence experienced by the reactor internals. The change in fluence is minor, resulting in an insignificant change in the potential for IASCC. Therefore, the current inspection strategy based on the BWRVIP (Reference 46) is sufficient to address the small increase in fluence.

Fluence calculations performed at MELLLA+ conditions as required by M+LTR SER Limitation and Condition 12.22 indicate that only the top guide and shroud exceed the 5E20 n/cm 2 threshold value for IASCC. The core plate fluence was calculated to be 5.95E20 n/cm 2, however, while this value is slightly above the IASCC threshold, it is actually a decrease from the permitted CLTP value, thus it has no effect. In-core instrumentation dry tubes and guide tubes are included in the evaluation due to an existing identification as being susceptible to IASCC in BWRVIP-47 (Reference 47).

The increase in fluence due to MELLLA+ does cause an increased potential for IASCC.

However, the inspection strategies and inspections recommended by BWRVIP-25, 26, 47, and 76 (References 48, 49, 47, and 46, respectively) are based on component configuration and field experience and this inspection program is considered adequate to address the increase in potential for IASCC in the top guide, shroud, and in core instrumentation dry tubes and guide tubes.

The BWRVIP evaluated the failure modes and effects of reactor vessel internals and published the results in BWRVIP-06 (Reference 50). This evaluation for the shroud concluded that the inspections and evaluations performed in response to Generic Letter (GL) 94-03 (Reference 51) provided conservative assurance that the shroud is able to perform its safety function. The inspections of the shroud and top guide are conducted using the guidance of BWRVIP-26, 76, and 183 (References 49, 46, and 52, respectively). These guidelines in the areas of detection, inspection, repair or mitigation ensure the long-term function of these components.

10.7.2 Flow Accelerated Corrosion

((

)) for MELLLA+, there is no increase in the MS flow rate and temperature, and the FW flow rate and temperature. As described in Section 3.3.3, the MCO may increase in the MSLs.

If this occurs, it may slightly increase the FAC rates for a small period of time during the cycle when the plant is operating at or near the MELLLA+ minimum CF. ((

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The Maintenance Rule also provides oversight for the other mechanical and electrical components important to plant safety, to guard against age-related degradation. Therefore, no further evaluation of this topic is required per the M+LTR.

[I )) for NMP2, there are no significant changes in MS or FW temperatures and MS or FW flow rates. As discussed in Section 3.3.3, there is an increase in MCO during the cycle for a short duration. This increase in MCO has no significant effect on FAC parameters. Therefore, there is no significant change in the potential for FAC in the MS system.

The evaluation of and inspection for flow-induced erosion/corrosion in piping systems affected by FAC is addressed by compliance with NRC GL 89-08. The requirements of GL 89-08 are implemented at NMP2 by utilization of the Electric Power Research Institute generic program, "CHECWORKSTM. NMP2-specific parameters are entered into this program to develop requirements for monitoring and maintenance of specific system piping. No changes are required to the NMP2-specific parameters that are entered into the CHECWORKSTM program.

The FAC monitoring programs are adequate to manage potential effects of MELLLA+ operating domain expansion.

In addition to FAC, a periodic non-destructive examination program was established to inspect safety-related piping and heat exchangers at known or suspected high corrosion, biofouling or silt buildup areas in response to GL 89-13. This program is supplemented by visual inspections of opened piping and heat exchangers whenever possible.

The Maintenance Rule also provides oversight for other mechanical and electrical components important to plant safety, to monitor performance and guard against age-related degradation.

The longevity of NMP2 equipment is not affected by the MELLLA+ operating domain expansion.

(( )), and Section 3.3.4.e, the MCO for NMP2 may increase to a maximum value of 0.25 wt.% for a period of time during the cycle when NMP2 is operating at or near the MELLLA+ minimum CF rate. The EPU FAC evaluation for steam piping assumed a 0.25 wt.% MCO, which bounds the maximum predicted 0.236 wt.% MCO in the MELLLA+ operating domain. NMP2 implements programs adequate to manage this change in the erosion/corrosion rate. ((

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 10.8 NRC AND INDUSTRY COMMUNICATIONS The topic addressed in this evaluation is:

Topic M+LTR Disposition NMP2 Result Plant Disposition of NRC and Industry Communications

)) NRC and industry communications could affect the plant design and safety analyses. As discussed in Section 1.0, the MELLLA+ operating domain expansion has a limited effect on the safety evaluations and system assessments. Because the maximum thermal power and CF rate do not change for MELLLA+ operating domain expansion, the effect of the changes is limited to the NSSS, primarily within the core. The evaluations and calculations included in this M+SAR, along with any supplements, demonstrate that the MELLLA+ operating domain expansion can be accomplished within the applicable design criteria. Because these evaluations of plant design and safety analyses inherently include any effect as a result of NRC and industry communications, it is not necessary to review prior communications and no additional information is required in this area.

1]

10.9 EMERGENCY AND ABNORMAL OPERATING PROCEDURES EOPs and AOPs can be affected by MELLLA+ operating domain expansion. The topics addressed in this evaluation are:

Topic M+LTR Disposition NMP2 Result Emergency Operating Procedures ((

Abnormal Operating Procedures 10.9.1 Emergency Operating Procedures EOPs include variables and limit curves which define conditions where operator actions are indicated. The EOPs remain symptom-based and thus the operator actions remain unchanged.

MELLLA+ operating domain expansion is not expected to affect the NMP2 EOPs. However, in accordance with M+LTR SER Limitation and Condition 12.23.4, the EOPs will be reviewed for any effect and revised as necessary prior to implementation of MELLLA+ operating domain expansion. Any changes identified to the EOPs will be included in the operator training to be conducted prior to implementation of MELLLA+. The ATWS calculation performed for MELLLA+ was based on the NMP2 operator actions from the EOPs.

10.9.2 Abnormal Operating Procedures NMP2 refers to AOPs as special operating procedures (SOPs). SOPs include event based operator actions. No significant SOP revisions are expected as a result of MELLLA+ operating domain expansion. However, the SOPs will be reviewed for any effect and revised as necessary prior to implementation of MELLLA+ operating domain expansion. Any changes identified to 10-15

NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) the SOPs will be included in the operator training to be conducted prior to implementation of MELLLA+.

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 11.0 LICENSING EVALUATIONS The licensing evaluations addressed in this section include:

Effect on TS

" Environmental Assessment

Significant Hazards Consideration Assessment 11.1 EFFECT ON TECHNICAL SPECIFICATIONS The NMP2 TS that are affected by a MELLLA+ operating domain expansion are provided in the NMPNS MELLLA+ LAR. The implementation of MELLLA+ requires revision of a limited number of the NMP2 TS, including a prohibition on the intentional operation with only a single recirculation loop in operation while in the MELLLA+ operating domain, as defined in the COLR. In addition, changes to the NMP2 TS are required to incorporate the DSS-CD stability solution option and changes to the SLS (including increasing the boron-10 isotopic enrichment in the sodium pentaborate solution, decreasing the minimum net volume stored in the SLS tank, and increasing the SLS pump discharge pressure requirements).

11.2 ENVIRONMENTAL ASSESSMENT The environmental effects of MELLLA+ operating domain expansion are controlled at the same limits as the current analyses. None of the present limits for plant environmental releases are increased as a consequence of MELLLA+ operating domain expansion. MELLLA+ has no effect on the non-radiological elements of concern, and the plant will be operated in an environmentally acceptable manner as documented by the Environmental Assessment for NMP2's current licensed operating domain. Existing federal, state, and local regulatory permits presently in effect accommodate the MELLLA+ operating domain expansion without modification.

The evaluation of the effects of MELLLA+ operating domain expansion on normal radiological effluents is included in Section 8.0. There will be no change in the radiological effluents released to the environment due to the MELLLA+ operating domain expansion. The normal effluents and doses remain well within the 10 CFR 20 limits and the 10 CFR 50 Appendix I guidance. There is no change to the predicted doses from postulated accidents and the 10 CFR 50.67 dose criteria continue to be met. In addition, the quantity of spent fuel does not increase as a result of MELLLA+ operating domain expansion.

The environmental evaluations also demonstrate that the MELLLA+ changes qualify for a categorical exclusion not requiring an environmental assessment in accordance with 10 CFR 51.22(c)(9). See the NMPNS MELLLA+ LAR for an evaluation of the 10 CFR 51.22(c)(9) criteria.

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 11.3 SIGNIFICANT HAZARDS CONSIDERATION ASSESSMENT Increasing the operating domain can be done safely within plant-specific limits, and is a highly cost effective way to provide needed flexibility in the generating capacity. The M+SAR provides the safety analyses and evaluations to justify expanding the CF rate operating domain.

DSS-CD introduces an enhanced detection algorithm, the CDA, which reliably detects the inception of power oscillations and generates an early power suppression trip signal prior to any significant oscillation amplitude growth and MCPR degradation.

The SLS is used to mitigate the consequences of an ATWS event and is used to limit the radiological dose during a LOCA. The proposed changes do not affect the capability of the SLS to perform these two functions in accordance with the assumptions of the associated analyses.

The ATWS evaluation with the proposed changes incorporated demonstrated that all the ATWS acceptance criteria are met. The ability of the SLS to mitigate radiological dose in the event of a LOCA is not affected by these changes. The increase in the boron-10 enrichment in the sodium pentaborate solution for the SLS is sufficient to reduce the injection flow requirement from two SLS pumps to one. This result represents an increase in SLS redundancy. In the event of a single SLS pump failure during a postulated ATWS, a single SLS pump will be capable of providing the design sodium pentaborate solution flow, thereby increasing safety margin.

NMPNS currently requires two SLS pumps and is not proposing any changes to Limiting Condition for Operation (LCO) 3.1.7 or to the completion time of Required Action A.1 of TS 3.1.7 to reflect this additional margin A complete Significant Hazards Consideration Assessment is provided in the NMPNS MELLLA+ LAR.

11.3.1 Modification Summary The MELLLA+ core operating domain expansion does not require major plant hardware modifications. The core operating domain expansion involves changes to the operating power/core flow map, minor system modifications, procedure changes, and changes to a small number of instrument setpoints. Because there is no change in the operating pressure, power, steam flow rate, and FW flow rate, there are no major modifications to other plant equipment.

The stability solution is being changed from Option III to the DSS-CD solution. The DSS-CD solution algorithm, licensing basis, and application procedures are generically described in NEDC-33075P (Reference 2), and are applicable to NMP2. The DSS-CD solution uses the same hardware as the current Option III solution. To support this change, a new computer (i.e., the NUMAC interfacing computer) will be installed to convert the proprietary encrypted signal from the PRNM system, and supply the converted signal to NMP2's current processing computer.

The boron-10 enrichment in the sodium pentaborate solution in the SLS is increased from

> 25 atom percent to > 92 atom percent. The increase in the boron-10 enrichment in the sodium pentaborate solution for the SLS is sufficient to: (1) decrease the sodium pentaborate solution volume stored in the SLS storage tank; and (2) maintain the ATWS margin equivalent to the OLTP/75% flow basis and address the GEH SC 10-13 dilution flow safety communication (Reference 53). The higher enrichment also increases margin by meeting 10 CFR 50.62 for 11-2

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ATWS mitigation based on a single SLS pump, although TS requirements and LCO are not relaxed. In addition, SLS tank level instrument setpoints will be changed to account for the reduced SLS tank minimum volume related to the change to > 92 atom percent boron-10 enrichment.

11.3.2 Discussion of MELLLA+ Issues Plant performance and responses to hypothetical accidents and transients have been evaluated for the MELLLA+ operating domain expansion license amendment. This section summarizes the plant reactions to events evaluated for licensing the plant, and the potential effects on various margins of safety, and thereby concludes that no significant hazards consideration will be involved.

11.3.2.1 MELLLA+ Analysis Basis The MELLLA+ safety analyses are based on a RG 1.49 (Reference 54) power factor times the rated power level, except for some analyses that are performed at nominal rated power, either because the RG 1.49 power factor is already accounted for in the analysis methods or RG 1.49 does not apply.

11.3.2.2 Fuel Thermal Limits No change is required in the mechanical fuel design to meet the plant licensing limits while operating in the MELLLA+ domain. No increase in allowable peak bundle power is needed and fuel thermal design limits will be met in the MELLLA+ domain. The analyses for each fuel reload are required to meet the criteria accepted by the NRC as specified in Reference 4 or otherwise approved in an associated TS amendment request. In addition, future fuel designs will meet acceptance criteria approved by the NRC.

11.3.2.3 Makeup Water Sources The BWR design concept includes a variety of ways to pump water into the reactor vessel to deal with all types of events. There are numerous safety-related and non-safety related cooling water sources. The safety-related cooling water sources alone can maintain core integrity for all postulated events by providing adequate cooling water. There are high and low pressure, high and low volume, safety and non-safety grade means of delivering water to the vessel. These means include at least:

" FW and Condensate Pumps

" LPCS System

" HPCS System

" LPCI of the RHR System

" RCIC System

SLS

" CRD Pumps 11-3

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Many of these diverse water supply means are redundant in both equipment and systems.

The MELLLA+ operating domain expansion does not result in an increase or decrease in the available water sources, nor does it change the selection of those assumed to function in the safety analyses. NRC-approved methods were used to evaluate the performance of the ECCS during postulated LOCAs.

11.3.2.4 Design Basis Accidents DBAs are very low probability hypothetical events whose characteristics and consequences are used in the design of the plant, so that the plant can mitigate their consequences to within acceptable regulatory limits. For BWR licensing evaluations, capability is demonstrated for coping with: (1) the range of hypothetical pipe break sizes in the largest recirculation, steam, and FW lines; (2) a postulated break in one of the ECCS lines; and (3) the most limiting small lines.

This break range bounds the full spectrum of large and small, high and low energy line breaks and demonstrates the ability of plant systems to mitigate the accidents while accommodating a single active equipment failure in addition to the postulated LOCA. Several of the significant licensing assessments are based on the LOCA and include:

Challenges to Fuel (ECCS Performance Analyses) in accordance with the rules and criteria of 10 CFR 50.46 and Appendix K where the limiting criterion is the fuel PCT.

Challenges to the Containment wherein the primary criteria of merit are the maximum containment pressure calculated during the course of the LOCA and maximum suppression (cooling) pool temperature for long-term cooling.

DBA Radiological Consequences calculated and compared to the criteria of 10 CFR 50.67.

11.3.2.5 Challenges to Fuel The evaluation of the ECCS performance is provided in Section 4.3. With MAPLHGR setdowns as indicated for low flow conditions, the PCT calculated for a LOCA from the MELLLA+

domain is bounded by the licensing basis PCT that was calculated based on rated flow.

However, the ECCS performance evaluation (Section 4.3) demonstrates significant margin to criteria of 10 CFR 50.46 at the reduced flow of MELLLA+ domain. Therefore, the ECCS safety margin is not significantly affected by MELLLA+ operating domain expansion.

11.3.2.6 Challenges to the Containment The peak values for containment pressure and temperature for events initiated in the MELLLA+

domain meet design requirements and confirm the suitability of the plant for operation in the MELLLA+ domain. The containment dynamic and structural loads for events initiated in the MELLLA+ domain continue to meet design requirements. The containment pressure and temperature remains below the design limits following any DBA. Therefore, the containment and its cooling systems are satisfactory for operation in the MELLLA+ domain.

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 11.3.2.7 Design Basis Accident Radiological Consequences The magnitude of the potential radiological consequences depends on the quantity of fission products released to the environment, the atmospheric dispersion factors, and the dose exposure pathways. The atmospheric dispersion factors and the dose exposure pathways do not change.

The quantity of activity released to the environment is a function of the activity released from the core and the transport mechanisms between the core and the effluent release point. The radiological releases for events initiated in the MELLLA+ domain do not increase.

The radiological consequences of LOCA inside containment, MSLBA, ILBA, CRDA, and FHA are bounded by the evaluation at the current licensed operating domain and need not be reevaluated for the MELLLA+ domain. The radiological results for all accidents remain below the applicable regulatory limits for the plant.

11.3.2.8 Anticipated Operational Occurrence Analyses AOOs are evaluated to demonstrate consequences that meet the SLMCPR. The SLMCPR is determined using NRC-approved methods. The limiting transients are core specific and are analyzed for each reload fuel cycle to meet the licensing acceptance criteria (Section 2.2.1).

Therefore, the margin of safety to the SLMCPR is not affected by operation in the MELLLA+

domain.

11.3.2.9 Combined Effects DBAs are postulated using deterministic regulatory criteria to evaluate challenges to the fuel, containment, and off-site radiation dose limits. The off-site dose evaluation performed in accordance with RG 1.3 (Reference 55) and Standard Review Plan (SRP) 15.6.5 calculates more severe radiological consequences than the combined effects of bounding DBAs that produce the greatest challenge to the fuel and containment. In contrast, the DBA that produces the highest PCT does not result in damage to the fuel equivalent to the assumptions used in the off-site dose evaluation, and the DBA that produces the maximum containment pressure, does not result in leak rates to the atmosphere equivalent to the assumptions used in the off-site dose evaluation.

Thus, the off-site doses calculated in conformance with RG 1.3 (Reference 55) and SRP 15.6.5 are conservative compared to the combined effect of the bounding DBA evaluations.

11.3.2.10 Non-LOCA Radiological Release Accidents The limiting non-LOCA events were reviewed for the effect of MELLLA+. The dose consequences for the non-LOCA radiological release accident events are shown in Section 9.0 to remain below regulatory limits.

11.3.2.11 Equipment Qualification Plant equipment and instrumentation have been evaluated against the applicable criteria. The qualification envelope either does not change due to the MELLLA+ operating domain expansion or is bounded by the current licensed operating domain.

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC) 11.3.2.12 Balance-of-Plant Because the power, pressure, steam and FW flow rate, and FW temperature do not change for MELLLA+ operating domain expansion, there are no significant changes to the BOP systems/equipment. MELLLA+ may increase the moisture content in BOP MS piping and components. The increased moisture content affects FAC, which is discussed in Section 10.7.2.

11.3.2.13 Environmental Consequences For operation in the MELLLA+ domain, the environmental effects will be controlled to the same limits as for the current operating power/flow map. None of the present environmental release limits are increased as a result of MELLLA+ operating domain expansion.

As a result, it is concluded that the NMP2 MELLLA+ operating domain expansion does not constitute an unreviewed environmental question and is eligible for categorical exclusion as provided by 10 CFR 51.22(c)(9).

11.3.2.14 Technical Specifications Changes The TS ensure that plant and system performance parameters are maintained within the values assumed in the safety analyses. The TS setpoints, AVs, operating limits, and the like are selected such that the equipment parameter values are equal to or more conservative than the values used in the safety analyses. NMP2 TS changes are provided in the NMPNS MELLLA+ LAR.

Instrument uncertainties were properly considered for the setpoint changes associated with MELLLA+ operating domain expansion.

The TS also address equipment operability (availability) and put limits on EOOS (not available for use) times such that the plant can be expected to have the complement of equipment available to mitigate abnormal plant events assumed in the safety analyses. Because the safety analyses for the MELLLA+ operating domain expansion show that the results are within regulatory limits, there is no undue risk to public health and safety.

The implementation of MELLLA+ requires revision of a limited number of the NMP2 TS, including a prohibition on the intentional operation with only a single recirculation loop in operation while in the MELLLA+ operating domain as defined in the COLR. In addition, changes to the NMP2 TS are required to incorporate the DSS-CD stability solution option and changes to the SLS (including increasing the boron-10 isotopic enrichment in the sodium pentaborate solution, decreasing the minimum net volume stored in the SLS tank, and increasing the SLS pump discharge pressure requirements).

TS changes will provide a level of protection comparable to previously issued TS.

11.3.2.15 Assessment of 10 CFR 50.92 Criteria The assessment of significant hazards consideration is included in the NMPNS MELLLA+ LAR.

11.3.3 Discussion of DSS-CD Stability Solution Issues For the NMP2 MELLLA+ operating domain expansion, the long-term stability solution is being changed from the currently approved Option III solution to DSS-CD. The DSS-CD solution algorithm, licensing basis, and application procedures are generically described in 11-6

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NEDC-33075P (Reference 2) and NEDE-33147P-A (Reference 12), and are applicable to NMP2 including any limitations and conditions associated with their use and approval.

The DSS-CD solution is designed to identify the power oscillation upon inception and initiate control rod insertion to terminate the oscillations prior to any significant amplitude growth.

DSS-CD provides protection against violation of the SLMCPR for anticipated oscillations.

DSS-CD is based on the same hardware design as Option III. However, it introduces an enhanced detection algorithm that detects the inception of power oscillations and generates an earlier power suppression trip signal exclusively based on successive period confirmation recognition. The existing Option III algorithms are retained (with generic setpoints) to provide defense-in-depth protection for unanticipated reactor instability events.

11.3.4 Discussion of SLS Changes The SLS is described in Section 9.3.5 of the NMP2 USAR. The system provides a backup capability for shutting down the reactor. The SLS is needed only in the event that sufficient control rods cannot be inserted into the reactor core to accomplish shutdown and cooldown in the normal manner. To accomplish this function, the SLS injects a sodium pentaborate solution into the reactor.

The specified neutron absorber solution is sodium pentaborate. It is prepared by dissolving granularly-enriched sodium pentaborate in demineralized water (NMP2 USAR Section 9.3.5.2).

The boron absorbs thermal neutrons and thereby terminates the nuclear fission chain reaction in the uranium fuel. The sodium pentaborate also acts as a buffer to maintain the pool pH at or above 7.0 to prevent the re-evolution of iodine, when mixed in the suppression pool following a LOCA accompanied by significant fuel damage (NMP2 USAR Section 9.3.5.1).

The NMPNS MELLLA+ LAR contains an evaluation utilizing a method provided in NRC-approved LTR NEDE-31096P-A (Reference 56) that demonstrates the boron equivalency requirement of 10 CFR 50.62(c)(4) is met, when the changes to the SLS flow rate and the boron-10 isotope enrichment are included. In the event of a single SLS pump failure during a postulated ATWS, a single SLS pump will be capable of injecting sufficient negative reactivity, thereby increasing safety margin.

The proposed boron-10 enrichment changes do not affect the capability to achieve and maintain a pH above 7.0 in the suppression pool following a LOCA, because the chemical properties and concentration of the sodium pentaborate solution injected into the suppression pool will remain the same. Given the reduced volume of solution that will be available, there will be a two hour reduction in the time available to add boron to the suppression pool to maintain the pH above 7.0 (the nominal time based on a low level alarm is within 22 hours2.546296e-4 days 0.00611 hours 3.637566e-5 weeks 8.371e-6 months versus the current requirement of within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months ). The 22 hours2.546296e-4 days 0.00611 hours 3.637566e-5 weeks 8.371e-6 months remains within the guideline of less than 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months with a large margin to the minimum requirements for a manual operator action of 30 minutes.

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12.0 REFERENCES

1. GE Hitachi Nuclear Energy, "General Electric Boiling Water Reactor Maximum Extended Load Line Limit Analysis Plus," NEDC-33006P-A, Revision 3, June 2009.

2. GE Hitachi Nuclear Energy, "GE Hitachi Boiling Water Reactor Detect and Suppress Solution - Confirmation Density," NEDC-33075P, Revision 7, June 2011; and Anthony J. Mendiola (NRC) to Jerald G. Head (GEH), "Revised Draft Safety Evaluation for GE-Hitachi Nuclear Energy Americas, LLC Topical Report NEDC-33075P, Revision 7, 'GE Hitachi Boiling Water Reactor Detect and Suppress Solution - Confirmation Density' (TAC No. ME6577)," MFN-13-045, August 6, 2013.

3. a. GE Hitachi Nuclear Energy, "Applicability of GE Methods to Expanded Operating Domains," NEDC-33173P-A, Revision 4, November 2012.

b. Letter, Richard E. Kingston (GEH) to NRC, "Clarification of Stability Evaluations-NEDC-33173P," MFN 08-541, June 25, 2008.

c. Letter, James F. Harrison (GEH) to NRC, "Implementation of Methods Limitations-NEDC-33173P," MFN 08-693, September 18, 2008.

d. Letter, James F. Harrison (GEH) to NRC, "NEDC-33173P - Implementation of Limitation 12," MFN 09-143, February 27, 2009.

e. GE Hitachi Nuclear Energy, "Implementation of PRIME Models and Data in Downstream Methods," NEDO-33173 Supplement 4-A, Revision 1, November 2012.

4. GE Hitachi Nuclear Energy, "General Electric Standard Application for Reactor Fuel,"

NEDE-2401 1-P-A- 19 and NEDE-2401 1-P-A- 19-US, May 2012.

5. GE Nuclear Energy, "Generic Guidelines for General Electric Boiling Water Reactor Extended Power Uprate," NEDC-32424P-A, February 1999.

6. GE Nuclear Energy, "Generic Evaluations of General Electric Boiling Water Reactor Extended Power Uprate," NEDC-32523P-A, February 2000, Supplement 1, Volume I, February 1999, and Supplement 1, Volume II, April, 1999.

7. GE Nuclear Energy, "Constant Pressure Power Uprate," NEDC-33004P-A, Revision 4, July 2003.

8. GE Nuclear Energy, "The GE Pressure Suppression Containment System Analytical Model," NEDM- 10320, March 1971.

9. NUREG-0808, U.S. Nuclear Regulatory Commission, "Mark II Containment Program Load Evaluation and Acceptance Criteria," August 1981.

10. GE Nuclear Energy, "General Electric Model for LOCA Analysis in Accordance with 10 CFR 50 Appendix K," NEDE-20566-P-A, Revision 2, September 1986.

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11. GE Nuclear Energy, "Qualification of the One-Dimensional Core Transient Model (ODYN) for Boiling Water Reactors (Supplement 1 - Volume 4)," NEDC-24154P-A, Revision 1, Supplement 1, February 2000.

12. GE Hitachi Nuclear Energy, "DSS-CD TRACG Application," NEDE-33147P-A, Revision 4, August 2013.

13. Letter, Thomas Lynch (NMPNS) to Document Control Desk (NRC), "Nine Mile Point Nuclear Station Unit No. 2: Docket No. 50-410, Supplemental Information Regarding Nine Mile Point Nuclear Station, Unit No. 2 - Re: The License Amendment Request for Extended Power Uprate Operation (TAC No. ME1476) - Update to License Amendment Request," October 8, 2010.

14. Letter, NRC to Ken Langdon (NMPNS), "Nine Mile Point Nuclear Station, Unit No. 2 -

Issuance of Amendment Re: Extended Power Uprate (TAC No. ME1476),"

December 22, 2011.

15. Global Nuclear Fuel, "The PRIME Model for Analysis of Fuel Rod Thermal-Mechanical Performance," NEDC-33256P-A, NEDC-33257P-A and NEDC-33258P-A, Revision 1, September 2010.

16. GE Nuclear Energy, "General Electric Methodology for Reactor Pressure Vessel Fast Neutron Flux Evaluations," NEDC-32983P-A, Revision 2, January 2006.

17. Regulatory Guide 1.190, "Calculational and Dosimetry Methods for Determining Pressure Vessel Neutron Fluence," U.S. NRC, March 2001.

18. NRC Generic Letter 88-01, "NRC Position on IGSCC in BWR Austenitic Stainless Steel Piping," January 25, 1988.

19. "Revised Risk-Informed In-Service Inspection Evaluation Procedure," EPRI TR-1 12657, Revision B, W03230, Final Report, July 1999.

20. Nuclear Regulatory Commission, "Technical Report on Material Selection and Processing Guidelines for BWR Coolant Pressure Boundary Piping," NUREG-0313, Revision 2, January 1988.

21. BWRVIP-75, "BWR Vessel and Internals Project Technical Basis for Revisions to Generic Letter 88-01 Inspection Schedules," October 1999.

22. American National Standards Institute, ANSI B31.1-1977, including 1978 Winter Addenda, "Power Piping."

23. GE Hitachi Nuclear Energy, "Safety Analysis Report for Nine Mile Point Nuclear Station Unit 2 Constant Pressure Power Uprate," NEDC-33351 P, Revision 0, May 2009.

24. GE Nuclear Energy, "Mark II Containment Dynamic Forcing Functions Information Report," NEDO-21061, Revision 4, November 1981.

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25. NUREG-0487, U.S. Nuclear Regulatory Commission, "Mark II Containment Lead Plant Program Load Evaluation and Acceptance Criteria," October 1978, Supplement 1, September 1980, and Supplement 2, February 1981.

26. Section 6A.4 of the NMP2 USAR.

27. NRC Generic Letter 89-10, "Safety-Related Motor-Operated Valve Testing and Surveillance," June 28, 1989.

28. NRC Generic Letter 89-16, "Installation of a Hardened Wetwell Vent," September 1, 1989.

29. NRC Generic Letter 95-07, "Pressure Locking and Thermal Binding of Safety-Related Power-Operated Gate Valves," August 17, 1995.

30. NRC Generic Letter 96-06, "Assurance of Equipment Operability and Containment Integrity During Design-Basis Accident Conditions," September 30, 1996.

31. Letter, Sam Belcher (NMPNS) to Document Control Desk (NRC), "Nine Mile Point Nuclear Station Unit No. 2; Docket No. 50-410, Response to Request for Additional Information Regarding Nine Mile Point Nuclear Station, Unit No. 2- Re: The License Amendment Request for Extended Power Uprate Operation (TAC No. ME1476) -

Containment Accident Pressure, Combustible Gas Control, Pipe Stress Analysis, and Boral Monitoring Program," May 9, 2011.

32. Regulatory Guide 1.1, "Net Positive Suction Head for Emergency Core Cooling and Containment Heat Removal System Pumps," U.S. NRC, November 2, 1970.

33. GE Nuclear Energy, "Compilation of Improvements to GENE's SAFER ECCS-LOCA Evaluation Model," NEDC-32950P, Revision 1, July 2007.

34. GE Nuclear Energy, "GESTR-LOCA and SAFER Models for Evaluation of Loss-of-Coolant Accident Volume III, Supplement 1, Additional Information for Upper Bound PCT Calculation," NEDE-23785P-A, Volume III, Supplement 1, Revision 1, March 2002.

35. GE Nuclear Energy, "General Electric Instrument Setpoint Methodology,"

NEDC-31336P-A, September 1996.

36. NRC Regulatory Issue Summary 2006-17, "NRC Staff Position on the Requirements of 10 CFR 50.36, 'Technical Specifications,' Regarding Limiting Safety System Settings During Periodic Testing and Calibration of Instrument Channels," August 24, 2006.

37. Letter, Technical Specifications Task Force (TSTF) to NRC, "Transmittal of Revised TSTF-493 Revision 4," TSTF-09-29, dated January 5, 2010; and Letter, TSTF to NRC, "Transmittal of TSTF-493 Revision 4, Errata," TSTF- 10-07, dated April 23, 2010.

38. GE Nuclear Energy, "Assessment of BWR Mitigation of ATWS, Volume II (NUREG-0460 Alternate No. 3)," NEDE-24222, December 1979.

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39. GE Nuclear Energy, "ATWS Rule Issues Relative to BWR Core Thermal-Hydraulic Stability," NEDO-32047-A, June 1995, (SER includes approval for: "Mitigation of BWR Core Thermal-Hydraulic Instabilities in ATWS," NEDO-32164, December 1992.).

40. GE Nuclear Energy, "Mitigation of BWR Core Thermal-Hydraulic Instabilities in ATWS," NEDO-32164, December 1992.

41. GE Hitachi Nuclear Energy, "Migration to TRACG04 / PANAC 11 from TRACG02 /

PANACIO for TRACG AOO and ATWS Overpressure Transients," NEDE-32906P, Supplement 3-A, Revision 1, April 2010.

42. Letter from James F. Harrison (GEH) to NRC, "Use of the Shumway Tmin Correlation with Zircaloy for TRACG Analyses," MFN 13-073, September 9, 2013.

43. Regulatory Guide 1.174, "An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis," U.S. NRC, Revision 2, May 2011.

44. Regulatory Guide 1.200, "An Approach for Determining the Technical Adequacy of Probabilistic Risk Assessment Results for Risk-Informed Activities," U.S. NRC, Revision 2, March 2009.

45. Letter, Richard V. Guzman (NRC) to Kenneth Langdon (NMPNS), "Nine Mile Point Nuclear Station, Unit No. 2 - Issuance of Amendment Regarding Extension of Completion Time for an Inoperable Division 1 or Division 2 Diesel Generator (TAC No. ME3736)," October 31, 2011.

46. "BWR Core Shroud Inspection and Flaw Evaluation Guidelines," BWRVIP-76, EPRI TR- 114232, November 1999.

47. BWRVIP-47, "BWR Lower Plenum Inspection and Flaw Evaluation Guidelines,"

November 2004.

48. BWRVIP-25, "BWR Core Plate Inspection and Flaw Evaluation Guidelines,"

December 1996.

49. BWRVIP-26, "BWR Top Guide Inspection and Flaw Evaluation Guidelines,"

November 2004.

50. BWRVIP-06-A, "Safety Assessment of BWR Reactor Internals," March 2002.

51. NRC Generic Letter 94-03, "Intergranular Stress Corrosion Cracking of Core Shrouds in Boiling Water Reactors," July 25, 1994.

52. BWRVIP-183, "Top Guide Grid Beam Inspection and Flaw Evaluation Guidelines,"

December 2007.

53. GE Hitachi Nuclear Energy Safety Communication, "Standby Liquid Control System Dilution Flow," SC 10-13, October 11, 2010.

54. Regulatory Guide 1.49, "Power Levels of Nuclear Power Plants," U.S. NRC, Revision 1, December 1973 (Withdrawn July 2007).

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55. Regulatory Guide 1.3, "Assumptions Used for Evaluating the Potential Radiological Consequences of a Loss of Coolant Accident for Boiling Water Reactors," U.S. NRC, Revision 2, June 1974.

56. GE Nuclear Energy, "Anticipated Transients Without Scram Response to NRC ATWS Rule, 10CFR50.62," NEDE-31096P-A, February 1987.

57. Regulatory Guide 1.99, "Radiation Embrittlement of Reactor Vessel Materials," U.S.

NRC, Revision 2, May 1988.

58. GE Hitachi Nuclear Energy, "General Electric Boiling Water Reactor Detect and Suppress Solution-Confirmation Density," NEDC-33075P-A, Revision 6, January 2008.

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Appendix A Disposition of additional limitations and conditions related to the final SE for NEDC-33173P, "Applicability of GE Methods to Expanded Operating Domains" There are 24 limitations and conditions listed in Section 9 of the Methods LTR SER. The table below lists each of the 24 limitations and conditions. The table also shows that NMP2 complies with 14 of the limitations and conditions. The table identifies which section of this M+SAR discusses compliance with each limitation and condition. Ten limitations and conditions are not applicable to NMP2 for the following reasons.

9.2 NMP2 MELLLA+ based on TGBLA06/PANACl1, not TGBLA 04/PANAC 10.

9.4 This penalty is specific for EPU applications. Limitation and Condition 9.5 addresses MELLLA+ SLMCPR penalty.

9.13 NMP2 MELLLA+ is less than 10 weight percent Gd.

9.14 NMP2 MELLLA+ has a PRIME T-M and PRIME fuel temperature basis.

9.15 NMP2 MELLLA+ licensing basis is not based on TRACG for the void reactivity coefficient bias and uncertainties relative to lattice designs.

9.16 NMP2 MELLLA+ licensing basis is not based on TRACG for the void coefficient biases and uncertainties for known dependencies.

9.18 Stability Setpoints Adjustment to DSS-CD because the significant conservatisms in the current licensing methodology and associated MCPR margins are more than sufficient to compensate for the overall uncertainty in the OPRM instrumentation.

9.20 NMP2 MELLLA+ licensing basis is not based on TRACG for the Void-Quality Correlation.

9.21 NMP2 MELLLA+ is not based on a mixed core.

9.22 NMP2 MELLLA+ is not based on unapproved fuel product lines.

There is one remaining limitation and condition, Limitation and Condition 9.23 that relates to MELLLA+ eigenvalue tracking. If NMP2 is the first implementation of MELLLA+, then NMP2 intends to comply with that limitation and condition. The required data will be collected and evaluated in accordance with Limitation and Condition 9.23. This information will be submitted to the NRC in accordance with the limitation and condition following the implementation of the MELLLA+ expanded operating domain at NMP2.

Note that Reference 3.c clarifies the implementation of Limitations and Conditions 9.3, 9.8, 9.17, and 9.19.

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Appendix A (continued)

Disposition of additional limitations and conditions related to the final SE for NEDC-33173P, "Applicability of GE Methods to Expanded Operating Domains" Limitation Section of NMP2 and Condition Limitation andM+A M+SAR which whc NubrCondition Lmtion Te Limitation and Condition Description Disposition Number Condition Title addresses the Lmtto n from NRC Limitation and SER Condition The neutronic methods used to simulate the reactor core response and that feed into the TGBLA/PANAC downstream safety analyses supporting Comply Table 1-1 and 9.1 Version operation at EPU/MELLLA+ will apply Section 2.6.1 TGBLA06/PANAC 11 or later NRC-approved version of neutronic method.

For EPU/MELLLA+ applications, relying on TGBLA04/PANAC 10 methods, the bundle RMS difference uncertainty will be established from plant-specific core-tracking data, based Table 1-1 9.2 3D Monicore on TGBLA04/PANACI0. The use of plant- N/A specific trendline based on the neutronic (1) method employed will capture the actual bundle power uncertainty of the core monitoring system.

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Limitation Section of NMP2 and Condition Limitation andM+A M+SAR which whh NubrCondition Lmtion Te Limitation and Condition Description Disposition Number Condition Title addresses the Lmtto n from NRC Limitation and SER Condition Plant-specific EPU and expanded operating domain applications will confirm that the core thermal power to core flow ratio will not Sections 1.2.1 and 2.2.5 exceed 50 MWt/Mlbrn/hr at any statepoint in 93 Power/Flow the allowed operating domain. For plants that Comply (2)

Ratio exceed the power-to-flow value of 50 MWtiMlbm/hr, the application will provide Consistent with power distribution assessment to establish that Reference 3.c neutronic methods axial and nodal power distribution uncertainties have not increased.

For EPU operation, a 0.02 value shall be added 9.4 SLMCPR 1 to the cycle-specific SLMCPR value. This adder is applicable to SLO, which is derived N/A (3) from the dual loop SLMCPR value.

This Limitation has been revised according to Appendix I of this SE.

For operation at MELLLA+, including operation at the EPU power levels at the 9.5 SLMCPR 2 achievable CF statepoint, a 0.01 value shall be Comply Sections 2.2.1 and 2.2.5 added to the cycle-specific SLMCPR value for power-to-flow ratios up to 42 MWt/Mlbm/hr, and a 0.02 value shall be added to the cycle-specific SLMCPR value for power-to-flow ratios above 42 MWt/Mlbm/hr.

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Limitation Section of NMP2 and M+SAR which Condition NubrCondition Limitation and Lmtion Te Limitation and Condition Description Disposition addresses the Number Condition Title Lmtto and n from NRC Limitation SER Condition The plant specific R-factor calculation at a bundle level will be consistent with lattice axial void conditions expected for the hot 9.6 R-Factor channel operating state. The plant-specific Comply Section 2.2 EPU/MELLLA+ application will confirm that the R-factor calculation is consistent with the hot channel axial void conditions.

For applications requesting implementation of EPU or expanded operating domains, including MELLLA+, the small and large break ECCS-LOCA analyses will include top-peaked and mid-peaked power shape in 9.7 ECCS-LOCA 1 establishing the MAPLHGR and determining Comply Sections 4.3.2 and 4.3.3 the PCT. This limitation is applicable to both the licensing bases PCT and the upper bound PCT. The plant-specific applications will report the limiting small and large break licensing basis and upper bound PCTs.

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Limitation Section of NMP2 and Condition Limitation andMSA M+SAR which whc NubrCondition Lmtion Te Limitation and Condition Description Number Condition Title Disposition addresses the Lmtto n from NRC Limitation and SER Condition The ECCS-LOCA will be performed for all statepoints in the upper boundary of the expanded operating domain, including the minimum CF statepoints, the transition Section 4.3.3 statepoint, as defined in Reference 1 and the 9.8 ECCS-LOCA 2 55 percent CF statepoint. The plant-specific Comply (2) application will report the limiting ECCS-LOCA results as well as the rated Consistent with power and flow results. The SRLR will Reference 3.c include both the limiting statepoint ECCS-LOCA results and the rated conditions ECCS-LOCA results.

Plant-specific EPU and MELLLA+

applications will demonstrate and document that during normal operation and core-wide AOOs, the T-M acceptance criteria as specified in Amendment 22 to GESTAR II will be met. Specifically, during an AOO, the 9.9 Transient LHGR licensing application will demonstrate that the: Comply Section 9.1.1 1 (1) loss of fuel rod mechanical integrity will not occur due to fuel melting and (2) loss of fuel rod mechanical integrity will not occur due to pellet-cladding mechanical interaction.

The plant-specific application will demonstrate that the T-M acceptance criteria are met for the both the U0 2 and the limiting GdO 2 rods.

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Limitation and Section of NMP2 Condition Limitation and M+SAR which Number Condition Title Limitation and Condition Description Disposition addresses the from NRC Limitation and SER Condition Each EPU and MELLLA+ fuel reload will document the calculation results of the Transient LHGR analyses demonstrating compliance to 9.10 transient T-M acceptance criteria. The plant Comply Section 9.1.1 T-M response will be provided with the SRLR or COLR, or it will be reported directly to the NRC as an attachment to the SRLR or COLR.

To account for the effect of the void history bias, plant-specific EPU and MELLLA+

applications using either TRACG or ODYN will demonstrate an equivalent to 10 percent margin to the fuel centerline melt and the 1 percent cladding circumferential plastic strain acceptance criteria due to pellet-cladding mechanical interaction for all of Transient LHGR limiting AOO transient events, including 9.11 3 EOOS. Limiting transients in this case, refers Comply Section 9.1.1 to transients where the void reactivity coefficient plays a significant role (such as pressurization events). If the void history bias is incorporated into the transient model within the code, then the additional 10 percent margin to the fuel centerline melt and the 1 percent cladding circumferential plastic strain is no longer required.

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Limitation Section of NMIP2 and M+SAR which Condition Number Limitation and Condition Title Limitation and Condition Description Disposition addresses the fombR C o o TLimitation and from NRC SER Condition In MFN 06-481, GE committed to submit plenum fission gas and fuel exposure gamma scans as part of the revision to the T-M licensing process. The conclusions of the plenum fission gas and fuel exposure gamma scans of GE 1Oxl 0 fuel designs as operated will be submitted for NRC staff review and LHGR and approval. This revision will be accomplished Section 2.6.3 9.12 Exposure through Amendment to GESTAR II or in a Comply Qualification T-M licensing LTR. PRIME (a newly (4) developed T-M code) has been submitted to the NRC staff for review (Reference 15).

Once the PRIME LTR and its application are approved, future license applications for EPU and MELLLA+ referencing LTR NEDC-33173P must utilize the PRIME T-M methods.

Before applying 10 weight percent Gd to licensing applications, including EPU and expanded operating domain, the NRC staff Application of needs to review and approve the T-M LTR Section 2.0 9.13 10 Weight demonstrating that the T-M acceptance criteria N/A Percent Gd specified in GESTAR II and Amendment 22 to (5)

GESTAR II can be met for steady-state and transient conditions. Specifically, the T-M application must demonstrate that the T-M acceptance criteria can be met for thermal A-7

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Limitation Section of NMP2 and M+SAR which Condition Number Limitation and Condition Title Limitation and Condition Description Disposition addresses the fombR C o o TLimitation and from NRC Condition SER II overpower (TOP) and mechanical overpower (MOP) conditions that bounds the response of plants operating at EPU and expanded operating domains at the most limiting statepoints, considering the operating flexibilities (e.g., EOOS).

Before the use of 10 weight percent Gd for modem fuel designs, NRC must review and approve TGBLA06 qualification submittal.

Where a fuel design refers to a design with Gd-bearing rods adjacent to vanished or water rods, the submittal should include specific information regarding acceptance criteria for the qualification and address any downstream effects in terms of the safety analysis. The 10 weight percent Gd qualifications submittal can supolement this report.

Any conclusions drawn from the NRC staff Part 21 evaluation of the GE's Part 21 report will be Evaluation of applicable to the GESTR-M T-M assessment 9.14 GESTR-M Fuel of this SE for future license application. GE N/A (6) submitted the T-M Part 21 evaluation, which is Calculation currently under NRC staff review. Upon completion of its review, NRC staff will inform GE of its conclusions.

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Limitation Section of NMP2 and Condition Limitation andM+A M+SAR which whh NubrCondition Lmtion Te Limitation and Condition Description Disposition Number Condition Title addresses the Lmtto n from NRC Limitation and SER Condition The void reactivity coefficient bias and Section 2.2 9.15 Void Reactivity uncertainties in TRACG for EPU and N/A 1 MELLLA+ must be representative of the (7) lattice designs of the fuel loaded in the core.

A supplement to TRACG /PANAC 1I for AOO is under NRC staff review (Reference 41). TRACG internally models the response surface for the void coefficient biases and uncertainties for known dependencies due to the relative moderator density and exposure on nodal basis. Therefore, the void history bias determined through the methods review can be incorporated into the response surface "known" bias or through changes in lattice Void Reactivity physics/core simulator methods for 9.16 2 establishing the instantaneous cross-sections. N/A (7)

Including the bias in the calculations negates the need for ensuring that plant-specific applications show sufficient margin. For application of TRACG to EPU and MELLLA+

applications, the TRACG methodology must incorporate the void history bias. The manner in which this void history bias is accounted for will be established by the NRC staff SE approving NEDE-32906P, Supplement 3, "Migration to TRACG04/PANAC 11 from TRACG02/PANAC 10," May 2006 A-9

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Limitation Section of NMP2 and M+SAR which Condition Limitation and Limitation and Condition Description Disposition addresses the Number Condition Title Limitation and from NRC Condition Condition SER (Reference 41). This limitation applies until the new TRACG/PANAC methodology is approved by the NRC staff.

The instrumentation specification design bases limit the presence of bypass voiding to 5 percent (LRPM (sic) levels). Limiting the bypass voiding to less than 5 percent for long-term steady operation ensures that Section 2.1.2 instrumentation is operated within the Steady-State 5 specification. For EPU and MELLLA+

9.17 Percent Bypass operation, the bypass voiding will be evaluated Comply (2)

Voiding on a cycle-specific basis to confirm that the void fraction remains below 5 percent at all Consiste wit LPRM levels when operating at steady-state conditions within the MELLLA+ upper boundary. The highest calculated bypass voiding at any LPRM level will be provided with the plant-specific SRLR.

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Limitation Section of NMP2 and M+SAR which Condition Number Limitation and Condition Title Limitation and Condition Description Disposition addresses the Limitation and from NRC Condition Condition SER The NRC staff concludes that the presence bypass voiding at the low-flow conditions where instabilities are likely can result in calibration errors of less than 5 percent for Stability OPRM cells and less than 2 percent for APRM Stabiity 98 signals. These calibration errors must be 9.18 Setpoints accounted for while determining the setpoints N/A Section 2.4.1 Adjustment for any detect and suppress long-term methodology. The calibration values for the different long-term solutions are specified in the associated sections of this SE, discussing the stability methodology.

For applications involving PANCEA/ODYN/ISCOR/TASC for operation at EPU and MELLLA+, an additional 0.01 will be added to the OLMCPR, until such time Sections 2.2.2 and 9.1.1 that GE expands the experimental database Void-Quality supporting the Findlay-Dix void-quality (2),(10) 9.19 Correlation 1 correlation to demonstrate the accuracy and Comply performance of the void-quality correlation Consistent with based on experimental data representative of Reference 3.c the current fuel designs and operating conditions during steady-state, transient, and accident conditions.

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Limitation Section of NMP2 and Condition Limitation andM+ M+SAR which Rwih NubrCondition Lmtion Te Limitation and Condition Description Disposition Number Condition Title addresses the Lmtto n from NRC Limitation and SER Condition The NRC staff is currently reviewing Supplement 3 to NEDE-32906P, "Migration to TRACG04/PANAC1 1 from TRACG02/PANAC 10," dated May 2006 0

Void-Quality (Reference 41). The adequacy of the TRACG 9.20 Correlation 2 interfacial shear model qualification for N/A (7) application to EPU and MELLLA+ will be addressed under this review. Any conclusions specified in the NRC staff SE approving Supplement 3 to LTR NEDC-32906P (Reference 41) will be applicable as approved.

Plants implementing EPU or MELLLA+ with mixed fuel vendor cores will provide plant-specific justification for extension of GE's analytical methods or codes. The content of Section 2.0 9.21 Mixed Core the plant-specific application will cover the N/A Method 1 topics addressed in this SE as well as subjects (8) relevant to application of GE's methods to legacy fuel. Alternatively, GE may supplement or revise LTR NEDC-33173P (Reference 3) for mixed core application.

For any plant-specific applications of TGBLA06 with fuel type characteristics not Section 2.0 9.22 Mixed Core covered in this review, GE needs to provide N/A Method 2 assessment data similar to that provided for the (8)

GE fuels. The Interim Methods review is applicable to all GE lattices up to GEl4. Fuel A-12

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Limitation Section of NMP2 and M+SAR which Condition Limitation and Number Condition Title Limitation and Condition Description Disposition addresses the fombR C o o TLimitation and from NRC Condition SER lattice designs, other than GE lattices up to GE14, with the following characteristics are not covered by this review:

square internal water channels water crosses

Gd rods simultaneously adjacent to water and vanished rods

1lxii lattices

MOX fuel The acceptability of the modified epithermal slowing down models in TGBLA06 has not been demonstrated for application to these or other geometries for expanded operating domains.

Significant changes in the Gd rod optical thickness will require an evaluation of the TGBLA06 radial flux and Gd depletion modeling before being applied. Increases in the lattice Gd loading that result in nodal reactivity biases beyond those previously established will require review before the GE methods may be applied.

MELLLA+ In the first plant-specific implementation of 9.23 Eigenvalue MELLLA+, the cycle-specific eigenvalue Comply (9)

Tracking tracking data will be evaluated and submitted A-13

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Limitation Section of NMP2 and M+SAR which Condition Number Limitation and Condition Title Limitation and Condition Description Disposition addresses the fombR C o o TLimitation and from NRC SER Condition to NRC to establish the performance of nuclear methods under the operation in the new operating domain. The following data will be analyzed:

Hot critical eigenvalue,

Cold critical eigenvalue,

Nodal power distribution (measured and calculated TIP comparison),

Bundle power distribution (measured and calculated TIP comparison),

Thermal margin,

CF and pressure drop uncertainties, and

The MCPR importance parameter (MIP)

Criterion (i.e., determine if core and fuel design selected is expected to produce a plant response outside the prior experience base).

Provision of evaluation of the core-tracking data will provide the NRC staff with bases to establish if operation at the expanded operating domain indicates: (1) changes in the performance of nuclear methods outside the EPU experience base; (2) changes in the available thermal margins; (3) need for changes in the uncertainties and NRC-A-14

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Limitation Section of NMP2 and M+SAR which Condition Number Limitation and Condition Title Limitation and Condition Description Disposition addresses the fombR C o o TLimitation and from NRC SER Condition approved criterion used in the SLMCPR methodology; or (4) any anomaly that may require corrective actions.

The plant-specific applications will provide prediction of key parameters for cycle exposures for operation at EPU (and MELLLA+ for MELLLA+ applications). The plant-specific prediction of these key parameters will be plotted against the EPU Reference Plant experience base and 4

Plant-Specific MELLLA+ operating experience, if available.

9.24 plant-pionc For evaluation of the margins available in the Comply Section 2.1.2 Application fuel design limits, plant-specific applications will also provide quarter core map (assuming core symmetry) showing bundle power, bundle operating LHGR, and MCPR for BOC, MOC, and EOC. Because the minimum margins to specific limits may occur at exposures other than the traditional BOC, MOC, and EOC, the data will be provided at these exposures.

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Appendix A (continued)

Disposition of additional limitations and conditions related to the final SE for NEDC-33173P, "Applicability of GE Methods to Expanded Operating Domains" Notes:

1. As shown in Table 1-1, NMP2 used TGBLA06 and PANAC 11.

2. Correspondence concerning implementation of this limitation and condition is docketed in Reference 3.c.

3. This limitation and condition relates to EPU applications and as such is not applicable to the M+SAR.

4. The PRIME LTR and its application (Reference 3.a) was approved on January 22, 2010 and implemented in GESTAR II in September 2010 (Reference 4). PRIME fuel parameters will be used in all analyses requiring fuel performance parameters.

5. NMP2 uses GEl4 fuel, and as such does not seek to apply 10 wt.% Gd to this licensing application.

6. This limitation and condition relates to GEH's treatment of the NRC staff review of the 10 CFR Part 21 report related to the GESTR-M T-M evaluation. The NMP2 M+SAR has a PRIME T-M and PRIME fuel temperature basis included. Therefore, this limitation is no longer applicable.

7. The NMP2 M+SAR licensing basis is not based on TRACG for: (1) the void reactivity coefficient bias and uncertainties relative to lattice designs; (2) the void coefficient biases and uncertainties for known dependencies; and (3) the Void-Quality Correlation. The NMP2 M+SAR analysis uses ODYN as the licensing basis code, and as such, this limitation and condition is not applicable to the NMP2 M+SAR.

8. The NMP2 M+SAR is not based on a mixed core, nor is it based on unapproved fuel product lines. NMP2 uses GE14, therefore, this limitation and condition is not applicable to the NMP2 M+SAR.

9. If NMP2 is a first plant application of MELLLA+ then GEH will provide the required information. This limitation and condition relates to a GEH commitment to submit cycle-specific eigenvalue tracking data to the NRC to establish performance of GEH methods under operation in the MELLLA+ operating domain. As such, this requirement specifies information to be supplied at a later date by GEH.

10. In the event that the cycle specific reload analysis is based on TRACG rather than ODYN for AOO, no 0.01 adder to the OLMCPR is required.

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Appendix B Disposition of additional limitations and conditions related to the final SE for NEDC-33006P, "Maximum Extended Load Line Limit Analysis Plus" There are 54 limitations and conditions listed in Section 12 of the M+LTR SER. The table below lists each of the 54 limitations and conditions. The table also shows that NMP2 complies with 47 of the limitations and conditions. The table identifies which section of this M+SAR discusses compliance with each limitation and condition. The remaining seven limitations and conditions are not applicable to NMP2 for the following reasons.

12.3d NMP2 MELLLA+ is not based on unapproved fuel product lines.

12.3e NMP2 MELLLA+ is not based on unapproved fuel product lines.

12.3f NMP2 MELLLA+ is not based on unapproved fuel product lines.

12.1 O.c NMP2 MELLLA+ takes credit for off-rated limits at the minimum CF statepoint. Core monitoring is required.

12.20 NMP2 MELLLA+ is based on plant specific ATWS Instability (12.19).

12.23.6 NMP2 MELLLA+ is not based on unapproved fuel product lines.

12.23.7 NMP2 MELLLA+ is not based on unapproved fuel product lines.

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Appendix B (continued)

Disposition of additional limitations and conditions related to the final SE for NEDC-33006P, "Maximum Extended Load Line Limit Analysis Plus" Limitation Section of NMP2 Cnd Limitation and M+SAR which number Condition Limitation and Condition Description Disposition Number addresses the Title Limitation and SER Condition The plant-specific application will confirm that for operation within the boundary defined by the MELLLA+ upper boundary and maximum CF range, the GEXL-PLUS experimental database covers the thermal-hydraulic conditions the fuel bundles will experience, including, bundle power, mass flux, void fraction, pressure, and subcooling.

If the GEXL-PLUS experimental database does not cover the within bundle thermal-hydraulic conditions, during steady-state, transient conditions, 12.1 GEXL-PLUS and DBA conditions, GHNE will inform the NRC Comply Sections 1.1.3 and at the time of submittal and obtain the necessary 2.6.4 data for the submittal of the plant-specific MELLLA+ application. In addition, the plant-specific application will confirm that the experimental pressure drop database for the pressure drop correlation covers the pressure drops anticipated in the MELLLA+ range.

With subsequent fuel designs, the plant-specific applications will confirm that the database supporting the CPR correlations covers the powers, B-2

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Limitation Section of NMP2 and Cnd Limitation and M+SAR which Condition Number Condition Limitation and Condition Description Disposition addresses the from NRC Title Limitation and Condition SER flows and void fractions BWR bundles will experience for operation at and within the MELLLA+ domain, during steady-state, transient, and DBA conditions. The plant-specific submittal will also confirm that the NRC staff reviewed and approved the associated CPR correlation if the changes in the correlation are outside the GESTAR I1(Amendment 22) process. Similarly, the plant-specific application will confirm that the experimental pressure drop database does cover the range of pressures the fuel bundles will experience for operation within the MELLLA+ domain.

Plant-specific MELLLA+ applications must comply with the limitations and conditions specified in and 12.2 Related LTRs be consistent with the purpose and content covered Comply Section 1.0 in the NRC staff SEs approving the latest version of the following LTRs: NEDC-33173P, NEDC-33075P-A, and NEDC-33147-A.

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Limitation Section of NMP2 Cnd Limitation and M+SAR which number Condition Limitation and Condition Description Disposition addresses the frmbNr Title Limitation and SER Condition The plant-specific analyses supporting MELLLA+

operation will include all operating condition changes that are implemented at the plant at the time of MELLLA+ implementation. Operating condition changes include, but are not limited to, those changes that affect, an increase in the dome pressure, maximum CF, fuel cycle length, or any Concurrent changes in the licensed operational enhancements. Comply Section 1.1.2 Changes For example, with an increase in dome pressure, the following analyses must be analyzed: the ATWS analysis, the ASME overpressure analyses, the transient analyses, and the ECCS-LOCA analysis.

Any changes to the safety system settings or any actuation setpoint changes necessary to operate with the increased dome pressure must be included in the evaluations (e.g., SRV setpoints).

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Limitation Section of NMP2 Cnd Limitation and M+SAR which number Condition Limitation and Condition Description Disposition addresses the frmbNr Title Limitation and from NRC SER Condition For all topics in LTR NEDC-33006P that are reduced in scope or generically dispositioned, the plant-specific application will provide justification that the reduced scope or generic disposition is applicable to the plant. If changes that invalidate 12.3.b the LTR dispositions are to be implemented at the Comply Section 1.1 1 time of MELLLA+ implementation, the plant-specific application will provide analyses and evaluations that demonstrate the cumulative effect with MELLLA+ operation. For example, if the dome pressure is increased, the ECCS performance will be evaluated on a plant-specific basis.

Any generic bounding sensitivity analyses provided in LTR NEDC-33006P will be evaluated to ensure that the key plant-specific input parameters and assumptions are applicable and bounded. If these generic sensitivity analyses are not applicable or additional operating condition changes affect the 12.3.c generic sensitivity analyses, a plant-specific Comply Section 1.1.1 evaluation will be provided. For example, with an increase in the dome pressure, the ATWS sensitivity analyses that model operator actions (e.g., depressurization if the HCTL is reached) needs to be reanalyzed, using the bounding dome pressure condition.

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Limitation and Section of NMP2 Cnd Limitation and M+SAR which number Condition Limitation and Condition Description Disposition addresses the frmbNr Title Limitation and SER Condition If a new GE fuel product line or another vendor's fuel is loaded at the plant, the applicability of any generic sensitivity analyses supporting the MELLLA+ application shall be justified in the plant-specific application. If the generic sensitivity analyses cannot be demonstrated to be applicable, Section 2.0 the analyses will be performed including the new 12.3.d N/A fuel. For example, the ATWS instability analyses supporting the MELLLA+ condition are based on (1) the GEl4 fuel response. New analyses that demonstrate the ATWS instability performance of the new GE fuel or another vendor's fuel for MELLLA+ operation shall be provided to support the plant-specific application.

If a new GE fuel product line or another vendor's fuel is loaded at the plant prior to a MELLLA+

application, the analyses supporting the plant-specific MELLLA+ application will be based on a specific core configuration or bounding core Section 2.0 12.3.e conditions. Any topics that are generically N/A dispositioned or reduced in scope in LTR (1)

NEDC-33006P will be demonstrated to be applicable, or new analyses based on the specific core configuration or bounding core conditions will be provided.

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Limitation Section of NMP2 and Limitation and M+SAR which Condition Condition Limitation and Condition Description Disposition addresses the Number frmbNr Title Limitation and from NRC Condition SER If a new GE fuel product line or another vendor's fuel is loaded at the plant prior to a MELLLA+

application, the plant-specific application will reference an NRC-approved stability method supporting MELLLA+ operation, or provide Section 2.0 12.3.f sufficient plant-specific information to allow the N/A NRC staff to review and approve the stability (1) method supporting MELLLA+ operation. The plant-specific application will demonstrate that the analyses and evaluations supporting the stability method are applicable to the fuel loaded in the core.

For MELLLA+ operation, core instability is possible in the event a transient or plant maneuver places the reactor at a high power/low-flow condition. Therefore, plants operating at MELLLA+ conditions must have a NRC-approved 12.3.g instability protection method. In the event the instability protection method is inoperable, the Comply Section 2.4 applicant must employ an NRC-approved backup instability method. The licensee will provide TS changes that specify the instability method operability requirements for MELLLA+ operation, including any BSP methods.

The plant-specific MELLLA+ application shall 12.4 Reload analysis provide the plant-specific thermal limits assessment Comply Sections 1.1.1 and submittal and transient analysis results. Considering the 9.1.1 timing requirements to support the reload, the fuel B-7

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Limitation Section of NMP2 and Cnd Limitation and M+SAR which number Condition Limitation and Condition Description Disposition addresses the Number from NRC Title Limitation and SER Condition and cycle-dependent analyses including the plant-specific thermal limits assessment may be submitted by supplementing the initial M+SAR.

Additionally, the SRLR for the initial MELLLA+

implementation cycle shall be submitted for NRC staff confirmation.

The licensee will amend the TS LCO for any EOOS Sections 1.1.1 and 12.5.a (i.e., SLO) or operating flexibilities prohibited in Comply 1.2.4 the plant-specific MELLLA+ application.

For an operating flexibility, such as Feedwater Heater(s) Out-of-Service (FWHOOS), that is 12.5.b prohibited in the MELLLA+ plant-specific application but is not included in the TS LCO, the Comply Section 1.2.4 licensee will propose and implement a license Operating condition.

Flexibility The power flow map is not specified in the TS; however, it is an important licensed operating domain. Licensees may elect to be licensed and operate the plant under plant-specific-expanded 12.5.c domain that is bounded by the MELLLA+ upper Comply Section 1.2.1 boundary. Plant-specific applications approved for operation within the MELLLA+ domain will include the plant-specific power/flow map specifying the licensed domain in the COLR.

SLMCPR Until such time when the SLMCPR methodology 12.6 Statepoints and (References 10 and 25) for off-rated SLMCPR Comply Section 2.2.1 CF Uncertainty calculation is approved by the staff for MELLLA+

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Limitation Section of NMP2 and Cnd Limitation and M+SAR which number Condition Limitation and Condition Description Disposition addresses the frmbNr Title Limitation and from NRC SER Condition operation, the SLMCPR will be calculated at the rated statepoint (120 percent P/100 percent CF), the plant-specific minimum CF statepoint (e.g., 120 percent P /80 percent CF), and at the 100 percent OLTP at 55 percent CF statepoint. The currently approved off-rated CF uncertainty will be used for the minimum CF and 55 percent CF statepoints. The uncertainty must be consistent with the CF uncertainty currently applied to the SLO operation or as NRC-approved for MELLLA+

operation. The calculated values will be documented in the SRLR.

Manual operator actions are not adequate to control the consequences of instabilities when operating in the MELLLA+ domain. If the primary stability protection system is declared inoperable, a non-12.7 Stability manual NRC-approved backup protection system Comply Section 2.4 must be provided, or the reactor core must be operated below a NRC-approved backup stability boundary specifically approved for MELLLA+

operation for the stability option employed.

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Limitation Section of NMP2 and Cnd Limitation and M+SAR which number Condition Limitation and Condition Description Disposition addresses the frmbNr Title Limitation and SER Condition The applicant is to provide a plant-specific Fluence evaluation of the MELLLA+ RPV fluence using the 8Methodology most up-to-date NRC-approved fluence 12.8 and Fracture methodology. This fluence will then be used to Comply Section 3.2.1 Toughness provide a plant-specific evaluation of the RPV fracture toughness in accordance with RG 1.99, Revision 2 (Reference 57).

MELLLA+ applicants must identify all other than Reactor Category "A" materials, as defined in 12.9 Coolant NUREG-0313 (Reference 20), Revision 2, that Pressure exist in its RCPB piping, and discuss the adequacy Comply Section 3.5.1.4 Boundary of the augmented inspection programs in light of the MELLLA+ operation on a plant-specific basis.

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Limitation Section of NMIP2 and Cnd Limitation and M+SAR which number Condition Limitation and Condition Description Disposition addresses the frmbNr Title Limitation and from NRC Condition SER The plant-specific application will provide the 10 CFR Part 50, Appendix K, and the nominal PCTs calculated at the rated EPU power/rated CF, rated EPU power/minimum CF, at the low-flow MELLLA+ boundary (Transition Statepoint). For the limiting statepoint, both the upper bound and the licensing PCT will be reported. The M+SAR will justify why the transition statepoint ECCO - Ca ECCS-LOCA response bounds the 55 percent CF Comply Section 4.3.2 12.10.a Off-rated statepoint. The M+SAR will provide discussion on Multiplier what power/flow combination scoping calculations were performed to identify the limiting statepoints in terms of DBA-LOCA PCT response for the operation within the MELLLA+ boundary. The M+SAR will justify that the upper bound and licensing basis PCT provided is in fact the limiting PCT considering uncertainty applications to the non-limiting statepoints.

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Limitation Section of NMP2 and Cnd Limitation and M+SAR which number Condition Limitation and Condition Description Disposition addresses the frmbNr Title Limitation and SER Condition LOCA analysis is not performed on cycle-specific basis; therefore, the thermal limits applied in the M+SAR LOCA analysis for the 55 percent CF MELLLA+ statepoint and/or the transition statepoint must be either bounding or consistent with cycle-specific off-rated limits. The COLR and the SRLR will contain confirmation that the off- Sections 4.3.2 and 12.10.b rated limits assumed in the ECCS-LOCA analyses Comply 4.3.3 bound the cycle-specific off-rated limits calculated for the MELLLA+ operation. Every future cycle reload shall confirm that the cycle-specific off-rated thermal limits applied at the 55 percent CF and/or the transition statepoints are consistent with those assumed in the plant-specific ECCS-LOCA analyses.

12. 1Ox Off-rated limits will not be applied to the minimum N/A (2)

CF statepoint.

If credit is taken for these off-rated limits, the plant 12.0O.d will be required to apply these limits during core Comply Section 4.3.2 1 monitoring.

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

Limitation Section of NMP2 Cnd Limitation and M+SAR which number Condition Limitation and Condition Description Disposition addresses the frmbNr Title Limitation and SER Condition For MELLLA+ applications, the small and large break ECCS-LOCA analyses will include top-ECCS-LOCA peaked and mid-peaked power shape in establishing 12.11 Axial Power the MAPLHGR and determining the PCT. This Comply Sections 4.3.2 and Distribution limitation is applicable to both the licensing bases 4.3.3 Evaluation PCT and the upper bound PCT. The plant-specific applications will report the limiting small and large break licensing basis and upper bound PCTs.

12. 12.a Both the nominal and Appendix K PCTs should be Comply Section 4.3.3 reported for all of the calculated statepoints, and The plant-variable and uncertainties currently Reporting applied will be used, unless the NRC staff 12.12.b specifically approves a different plant variable Comply Section 4.3.3 uncertainty method for application to the non-rated statepoints.

Small break LOCA analysis will be performed at the MELLLA+ minimum CF and the transition Small Break statepoints for those plants that: (1) are small break 12.13 LOCA LOCA limited based on small break LOCA analysis Comply Section 4.3.3 performed at the rated EPU conditions; or (2) have margins of less than or equal to (( )) relative to the Appendix K or the licensing basis PCT.

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

Limitation Section of NMP2 Cnd Limitation and M+SAR which number Condition Limitation and Condition Description Disposition addresses the rTitle Limitation and from NRC Title SER Condition The scope of small break LOCA analysis for MELLLA+ operation relies upon the EPU small Break break LOCA analysis results. Therefore, the NRC 12.14 Spectrum staff concludes that for plants that will implement Comply Section 4.3.1 MELLLA+, sufficient small break sizes should be analyzed at the rated EPU power level to ensure that the peak PCT break size is identified.

Plant-specific MELLLA+ applications shall identify where in the MELLLA+ upper boundary the bypass voiding greater than 5 percent will occur above the D-level. The licensee shall provide in the plant-specific submittal the operator actions and Bypass Voiding procedures that will mitigate the effect of the 12.15 Above the D- bypass voiding on the TIPs and the core simulator Comply Section 5.1.5 Abve used to monitor the fuel performance. The plant-specific submittal shall also provide discussion on what effect the bypass voiding greater than 5 percent will have on the NMS as defined in Section 5.1.1.5. The NRC staff will evaluate on plant-specific bases acceptability of bypass voiding above D level.

Plants operating at the MELLLA+ operating domain shall perform RWE analyses to confirm the 12.16 RWE adequacy of the generic RBM setpoints. The Comply Section 9.1.1 M+SAR shall provide a discussion of the analyses

_performed and the results.

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

Limitation Section of NMP2 Cnd Limitation and M+SAR which number Condition Limitation and Condition Description Disposition addresses the rTitle Limitation and from NRC Title SER Condition As specified in LTR NEDC-33006P, at least two plant-specific ATWS calculations must be performed: MSIVC and PRFO. In addition, if RHR capability is affected by LOOP, then a third plant-specific ATWS calculation must be performed that includes the reduced RHR capability. To evaluate the effect of reduced RHR capacity during LOOP, the plant-specific ATWS 12.17 ATWS LOOP calculation must be performed for a sufficiently Comply Section 9.3.1.1 large period of time after HSBW injection is complete to guarantee that the suppression pool temperature is cooling, indicating that the RHR capacity is greater than the decay heat generation.

The plant-specific application should include evaluation of the safety system performance during the long-term cooling phase, in terms of available NPSH.

For plants that do not achieve hot shutdown prior to reaching the HCTL based on the licensing ODYN ATWS code calculation, plant-specific MELLLA+

12.18.a TRACG implementations must perform best-estimate TRACG calculations on a plant-specific basis. The Comply Section 9.3.1.2 Analysis TRACG analysis will account for all plant parameters, including water-level control strategy and all plant-specific EOP actions.

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

Limitation Section of NMP2 and Cnd Limitation and M+SAR which number Condition Limitation and Condition Description Disposition addresses the frmbNr Title Limitation and SER Condition The TRACG calculation is not required if the plant increases the boron- 10 concentration/enrichment so 12.18.b that the integrated heat load to containment Comply Sections 9.3.1.1 and calculated by the licensing ODYN calculation does 9.3.1.2 not change with respect to a reference OLTP/75 percent flow ODYN calculation.

PCT for both phases of the transient (initial 12.18.c overpressure and emergency depressurization) must Comply Section 9.3.1.2 be evaluated on a plant-specific basis with the TRACG ATWS calculation.

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

Limitation Section of NMP2 and Condition Limitation and M+SAR which Number Condition Limitation and Condition Description Disposition addresses the from NRC mTitle Titleio Limitation and SER Condition In general, the plant-specific application will ensure that operation in the MELLLA+ domain is consistent with the assumptions used in the ATWS analysis, including EOOS (e.g., FWHOOS, SLO, SRVs, SLS pumps, and RHR pumps, etc.). If assumptions are not satisfied, operation in MELLLA+ is not allowed. The SRLR will specify the prohibited flexibility options for plant-specific MELLLA+ operation, where applicable. For key input parameters, systems and engineering safety 12.18.d features that are important to simulating the ATWS Comply Section 9.3.1.1 analysis and are specified in the TS (e.g., SLS parameters, ATWS RPT, etc.), the calculation assumptions must be consistent with the allowed TS values and the allowed plant configuration. If the analyses deviate from the allowed TS configuration for long-term equipment out- of-service (i.e., beyond the TS LCO), the plant-specific application will specify and justify the deviation. In addition, the licensee must ensure that all operability requirements are met (e.g., NPSH) by equipment assumed operable in the calculations.

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

Limitation Section of NMP2 and Cnd Limitation and M+SAR which number Condition Limitation and Condition Description Disposition addresses the frmbNr Title Limitation and from NRC SER Condition Nominal input parameters can be used in the ATWS analyses provided the uncertainty treatment and selection of the values of these input parameters are consistent with the input methods used in the original GE ATWS analyses in 12.18.e NEDE-24222. Treatment of key input parameters Comply Section 9.3.1 in terms of uncertainties applied or plant-specific TS value used can differ from the original NEDE-24222 approach, provided the manner in which it is used yields more conservative ATWS results.

The plant-specific application will include 12.18.f tabulation and discussion of the key input Comply Section 9.3.1 parameters and the associated uncertainty treatment.

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

Limitation Section of NMP2 and Limitation and M+SAR which Condition number Lmtto n Condition Limitation and Condition Description Disposition addresses the frmbNr Title Limitation and from NRC SER Condition Until such time that NRC approves a generic solution for ATWS instability calculations for MELLLA+ operation, each plant-specific MELLLA+ application must provide ATWS instability analysis that satisfies the ATWS acceptance criteria listed in SRP Section 15.8. The plant-specific ATWS instability calculation must:

Plant-Specific (1) be based on the peak-reactivity exposure 12.19 ATWS conditions, (2) model the plant-specific Comply Section 9.3.3 Instability configuration important to ATWS instability response including mixed core, if applicable, and (3) use the regional-mode nodalization scheme. In order to improve the fidelity of the analyses, the plant-specific calculations should be based on latest NRC-approved neutronic and thermal-hydraulic codes such as TGBLA06/PANAC 11 and TRACG04.

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

Limitation Section of NMP2 and Cnd Limitation and M+SAR which number Condition Limitation and Condition Description Disposition addresses the rTitle Limitation and from NRC Condition SER Once the generic solution is approved, the plant-specific applications must provide confirmation that the generic instability analyses are relevant and applicable to their plant. Applicability confirmation includes review of any differences in plant design or operation that will result in significantly lower stability margins during ATWS such as:

12.20 Generic ATWS

turbine bypass capacity, N/A (3)

Instability 0 fraction of steam-driven feedwater pumps, 9 any changes in plant design or operation that will significantly increase core inlet subcooling during ATWS events,

significant differences in radial and axial power distributions, o hot-channel power-to-flow ratio, 0 fuel design changes beyond GE14.

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

Limitation Section of NMP2 and Cnd Limitation and M+SAR which number Condition Limitation and Condition Description Disposition addresses the frmbNr Title Limitation and from NRC SER Condition Licensees that submit a MELLLA+ application should address the plant-specific risk effects associated with MELLLA+ implementation, consistent with approved guidance documents (e.g., NEDC-32424P-A, NEDC-32523P-A, and Individual Plant NEDC-33004P-A) and the Matrix 13 of RS-001 12.21 Evaluation and re-address the plant-specific risk effects Comply Section 10.5 consistent with the approved guidance documents that were used in their approved EPU application and Matrix 13 ofRS-001. If an EPU and MELLLA+ application come to the NRC in parallel, the expectation is that the EPU submittal will have incorporated the MELLLA+ effects.

The applicant is to provide a plant-specific IASCC evaluation when implementing MELLLA+, which includes the components that will exceed the IASCC threshold of 5xl 02 0 n/cm 2 (E> 1MeV), the effect of failure of these components on the 12.22 IASCC integrity of the reactor internals and core support Comply Section 10.7.1 structures under licensing design bases conditions, and the inspections that will be performed on components that exceed the IASCC threshold to ensure timely identification of IASCC, should it occur.

Limitations Section 9.3.1.1 12.23.1 from the See limitation 12.18.d. Comply ATWS RAI (4)

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Limitation Section of NM.P2 and Cnd Limitation and M+SAR which number Condition Limitation and Condition Description Disposition addresses the rTitle Limitation and from NRC Condition SER Evaluations The plant-specific ODYN and TRACG key 12.23.2 calculation parameters must be provided to the staff Comply Sections 1.1.3 and so they can verify that all plant-specific automatic 9.3.1 settings are modeled properly.

The ATWS peak pressure response would be dependent upon SRVs upper tolerances assumed in the calculations. For each individual SRV, the tolerances used in the analysis must be consistent with or bound the plant-specific SRV performance.

The SRV tolerance test data would be statistically treated using the NRC's historical 95/95 approach 12.23.3 or any new NRC-approved statistical treatment Comply Section 9.3.1.1 method. In the event that current EPU experience base shows propensity for valve drift higher than pre-EPU experience base, the plant-specific transient and ATWS analyses would be based on the higher tolerances or justify the reason why the propensity for the higher drift is not applicable the plant's SRVs.

EPG/SAG parameters must be reviewed for applicability to MELLLA+ operation in a plant-12.23.4 specific basis. The plant-specific MELLLA+ Sections 9.3.1.1 and application will include a section that discusses the Comply 10.9.1 plant-specific EOPs and confirms that the ATWS calculation is consistent with the operator actions.

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

Limitation Section of NMP2 and Cnd Limitation and M+SAR which number Condition Limitation and Condition Description Disposition addresses the frmbNr Title Limitation and SER Condition The conclusions of this LTR and associated SE are limited to reactors operating with a power density lower than 52.5 MW/MLBM/hr for operation at the Sections 1.2.3 and 12.23.5 minimum allowable CF at 120 percent OLTP. Comply 9.3.3 Verification that reactor operation will be maintained below this analysis limit must be performed for all plant-specific applications.

For MELLLA+ applications involving GE fuel types beyond GE 14 or other vendor fuels, bounding Section 2.0 12.23.6 ATWS Instability analysis will be provided to the N/A staff. Note: this limitation does not apply to (1) special test assemblies.

Section 2.0 12.23.7 See limitation 12.23.6. N/A (1)(5)

The plant-specific ATWS calculations must account 12.23.8 for all plant- and fuel-design-specific features, such Comply Section 9.3.1 as the debris filters.

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

Limitation Section of NMP2 Limitation and M+SAR which Condition Condition Limitation and Condition Description Disposition addresses the Number frmbNr Title Limitation and from NRC SER Condition Plant-specific applications must review the safety system specifications to ensure that all of the assumptions used for the ATWS SE indeed apply to their plant-specific conditions. The NRC staff review will give special attention to crucial safety 12.23.9 systems like HPCI, and physical limitations like NPSH and maximum vessel pressure that RCIC and Comply Section 4.2.6 HPCI can inject. The plant-specific application will include a discussion on the licensing bases of the plant in terms of NPSH and system performance. It will also include NPSH and system performance evaluation for the duration of the event.

Plant-specific applications must ensure that an increase in containment pressure resulting from 12.23.10 ATWS events with EPU/MELLLA+ operation does Comply Section 9.3.1.1 not affect adversely the operation of safety-grade equipment.

The plant-specific applications must justify the use of plant-specific suppression pool temperature 12.23.11 limits for the ODYN and TRACG calculations that Comply Section 9.3.1.1 are higher than the HCTL limit for emergency

_depressurization.

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Section of NMP2 Limitation and M+SAR which Condition Limitation and Condition Description Disposition addresses the Title Limitation and Condition For EPU/MELLLA+ plant-specific applications that use TRACG or any code that has the capability Comply Sections 2.6.2 and to model in-channel water rod flow, the supporting 9.3.3 analysis will use the actual flow configuration.

Limitations The EPU/MELLLA+ application would provide the from Fuel exit void fraction of the high-powered bundles in Dependent the comparison between the EPU/MELLLA+ and Comply Section 2.1.2 Analyses RAI the pre-MELLLA+ conditions.

Evaluations Section 2.2.1 See limitation 12.6. Comply (6)

See limitation 12.18.d. Comply (7)

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Appendix B (Continued)

Disposition of additional limitations and conditions related to the final SE for NEDC-33006P, "Maximum Extended Load Line Limit Analysis Plus" Notes:

1. NMP2 uses GE14 fuel, therefore, this limitation and condition is not applicable to the NMP2 M+SAR.

2. Because NMP2 takes credit for off-rated condition at the minimum CF statepoint, the M+LTR requires implementation of Limitation and Condition 12.10.d. Therefore, Limitation and Condition 12.1 O.c is not applicable.

3. This requirement relates to implementation of a generic ATWS Instability Solution, which is not yet approved by the NRC. NMP2 MELLLA+ is based on a plant-specific ATWS instability analysis.

4. This is a repeat of Limitation and Condition 12.18.d.

5. This is a repeat of Limitation and Condition 12.23.6.

6. This is a repeat of Limitation and Condition 12.6.

7. This is a repeat of Limitation and Condition 12.18.d.

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Appendix C Disposition of additional limitations and conditions related to the draft SE for NEDC-33075P, Revision 7, "General Electric Boiling Water Reactor Detect and Suppress Solution -

Confirmation Density" There are four limitations and conditions listed in Section 5 of the DSS-CD LTR SER. The table below lists each of the four limitations and conditions. The table also shows that NMP2 complies with all four of the limitations and conditions. The table identifies which section of this M+SAR discusses compliance with each limitation and condition.

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Appendix C (continued)

Disposition of additional limitations and conditions related to the draft SE for NEDC-33075P, Revision 7, "General Electric Boiling Water Reactor Detect and Suppress Solution - Confirmation Density" Limitation and Section of NMP2 M+SAR Condition Limitation and Condition Description Disposition which addresses the Limitation Number from NRC and Condition SER The NRC staff previously reviewed and approved the implementation of DSS-CD using the approved GEH Option III hardware and software. The DSS-CD solution is not approved for use with non-GEH hardware. The hardware components Section 2.4 5.1 required to implement DSS-CD are expected to be Comply those currently used for the approved Option III. If (1) the DSS-CD hardware implementation deviates from the approved Option III solution, a hardware review by the NRC staff will be required.

Implementations on other Option III platforms will require plant-specific reviews.

The CDA setpoint calculation formula and the adjustable parameters values are defined in NEDC-33075P, Revision 7 (Reference 2).

Deviation from the stated values or calculation formulas is not allowed without NRC review. To Scin24 5.2 this end, the subject TR, when approved and Comply implemented by a licensed nuclear power plant, (2) must be referenced in the plant TSs, so that these values become controlled and part of the licensing bases.

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NEDO-33576 REVISION 0 NON-PROPRIETARY INFORMATION - CLASS I (PUBLIC)

Limitation and Condition Section of NMP2 M+SAR Nditio Limitation and Condition Description Disposition which addresses the Limitation from NRC and Condition SER The NRC staff previously concluded that the plant-specific settings for eight of the FIXED parameters and three of the ADJUSTABLE 53 parameters, as stated in section 3.6.3 of the NRC Comply (3) staff's SE for NEDC-33075P, Revision 5 (Reference 58), are licensing basis values. The process by which these values will be controlled must be addressed by licensees.

If plants other than Brunswick Steam Electric Plant, Units 1 and 2, use the DSS-CD trip function, those 5.4 plant licensees must ensure the DSS-CD trip function is applicable in their plant licensing bases, Comply (4) including the optional BSP trip function, if it is to be installed.

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Appendix C (continued)

Disposition of additional limitations and conditions related to the draft SE for NEDC-33075P, Revision 7, "General Electric Boiling Water Reactor Detect and Suppress Solution -

Confirmation Density" Notes:

1. The DSS-CD solution is implemented on GEH hardware that is currently installed and approved by the NRC for the Option III solution.

2. The subject TR, or GESTAR II, is referenced in the NMP2 TSs.

3. The values of the FIXED and ADJUSTABLE parameters are established by GEH and will be documented in a DSS-CD Settings Report.

4. Verification and validation (V&V) of the DSS-CD trip function code was performed for transportability considerations.

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ML13316B109

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ML13316B109

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