ML25315A008
| ML25315A008 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 10/22/2025 |
| From: | Bernhardt J Constellation Energy Generation |
| To: | Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML25316A017 | List: |
| References | |
| CCN 25-91 | |
| Download: ML25315A008 (1) | |
Text
Constellation Energy Generation - Nuclear Fuels COLR PEACH BOTTOM 3 Rev. 21 P3C26 Core Operating Limits Report Page 1 of 29 CORE OPERATING LIMITS REPORT FOR PEACH BOTTOM ATOMIC POWER STATION UNIT 3 RELOAD 25, CYCLE 26 Co-Prepared By:
J. Bernhardt - Cycle Management Date Co-Prepared By:
R. Olszewski - Cycle Management Date Reviewed By:
K. Witmer - Reactor Engineering Date Reviewed By:
J. Murphy - Engineering Safety Analysis Date Reviewed By:
K. McClure - Cycle Management Date Approved By:
K. McCoskey - NF Sr. Manager Date Station Qualified Reviewer:
J. Holley - SQR Date Bernhardt, Joseph Robert Digitally signed by Bernhardt, Joseph Robert Date: 2025.10.22 14:55:28 -04'00' Olszewski, Ryszard Digitally signed by Olszewski, Ryszard Date: 2025.10.22 15:18:39 -04'00' Witmer, Kyle T Digitally signed by Witmer, Kyle T Date: 2025.10.22 21:36:29 -04'00' Murphy, Jane-Erika Digitally signed by Murphy, Jane-Erika Date: 2025.10.23 10:44:17 -04'00' 2025.10.23 13:02:38
-04'00' Digitally signed by McCoskey, Kristin Date: 2025.10.23 13:37:58 -05'00' Digitally signed by Holley, Jeffrey W.
DN: cn=Holley, Jeffrey W.
Date: 2025.10.23 21:14:41 -04'00'
Constellation Energy Generation - Nuclear Fuels COLR PEACH BOTTOM 3 Rev. 21 P3C26 Core Operating Limits Report Page 2 of 29 Table of Contents REVISION HISTORY................................................................................................................................ 3 LIST OF TABLES...................................................................................................................................... 4 1.0 TERMS AND DEFINITIONS.......................................................................................................... 5 2.0 GENERAL INFORMATION........................................................................................................... 7 3.0 MAPLHGR LIMITS......................................................................................................................... 9 4.0 MCPR LIMITS............................................................................................................................. 10 5.0 LHGR LIMITS.............................................................................................................................. 14 6.0 ROD BLOCK MONITOR SETPOINTS........................................................................................ 17 7.0 TURBINE BYPASS VALVE PARAMETERS............................................................................... 18 8.0 EOC RECIRCULATION PUMP TRIP (EOC-RPT) OPERABILITY.............................................. 19 9.0 STABILITY PROTECTION.......................................................................................................... 20 10.0 ASYMMETRIC FEEDWATER TEMPERATURE OPERATION (AFTO)...................................... 22 11.0 MODES OF OPERATION........................................................................................................... 26 12.0 METHODOLOGY........................................................................................................................ 27
13.0 REFERENCES
............................................................................................................................ 27 APPENDIX A POWER/FLOW OPERATING MAP FOR MELLLA+ WITH TPO...................................... 29
Constellation Energy Generation - Nuclear Fuels COLR PEACH BOTTOM 3 Rev. 21 P3C26 Core Operating Limits Report Page 3 of 29 Revision History Revision Description Revision 21 Initial issuance for Cycle 26
Constellation Energy Generation - Nuclear Fuels COLR PEACH BOTTOM 3 Rev. 21 P3C26 Core Operating Limits Report Page 4 of 29 List of Tables Table 3-1 MAPLHGR Versus Average Planar Exposure......................................................................... 9 Table 3-2 MAPLHGR Single Loop Operation (SLO) Multiplier.................................................................... 9 Table 4-1 Operating Limit Minimum Critical Power Ratio (Symmetric Feedwater Heating)........................ 11 Table 4-2 Power Dependent MCPR(P) Limit Adjustments and Multipliers (Symmetric Feedwater Heating)
................................................................................................................................................................ 12 Table 4-3 Flow Dependent MCPR Limits MCPR(F) (Symmetric Feedwater Heating)............................... 13 Table 4-4 SLO Flow Dependent MCPR Limits MCPR(F) (Symmetric Feedwater Heating)....................... 13 Table 4-5 Cycle-Specific SLMCPR (MCPR99.9%)....................................................................................... 13 Table 5-1 Linear Heat Generation Rate Limits - UO2 Rods................................................................... 14 Table 5-2 Linear Heat Generation Rate Limits - Gad Rods.................................................................... 14 Table 5-3 Power Dependent LHGR Multiplier LHGRFAC(P) (Symmetric Feedwater Heating).................. 15 Table 5-4 Power Dependent LHGR Multiplier LHGRFAC(P) (Asymmetric Loss of Feedwater Heating).... 16 Table 5-5 Flow Dependent LHGR Multiplier LHGRFAC(F) (Symmetric Feedwater Heating)..................... 16 Table 6-1 Rod Block Monitor Setpoints.................................................................................................... 17 Table 7-1 Turbine Bypass System Response Time.................................................................................. 18 Table 7-2 Minimum Required Bypass Valves to Maintain System Operability........................................... 18 Table 8-1 Recirculation Pump Trip Response Time................................................................................. 19 Table 9-1 Automated BSP Setpoints for the Scram Region...................................................................... 20 Table 9-2 Manual BSP Endpoints for Normal Feedwater Temperature.................................................... 21 Table 9-3 Manual BSP Endpoints for Reduced Feedwater Temperature................................................. 21 Table 10-1 AFTO MAPLHGR Reduction Factor (Asymmetric Feedwater Heating)................................... 22 Table 10-2 AFTO Operating Limit Minimum Critical Power Ratio 20°F < FWT DELTA 55°F (Asymmetric Feedwater Heating).................................................................................................................................. 23 Table 10-3 AFTO Power Dependent MCPR Limit Adjustments and Multipliers MCPR(P) 20°F < FWT DELTA 55°F (Asymmetric Feedwater Heating)................................................................................... 24 Table 10-4 AFTO Flow Dependent MCPR Limits MCPR(F) 20°F < FWT DELTA 55°F (Asymmetric Feedwater Heating).................................................................................................................................. 24 Table 10-5 AFTO Power Dependent LHGR Multiplier LHGRFAC(P) 20°F < FWT DELTA 55°F (Asymmetric Feedwater Heating)............................................................................................................. 25 Table 10-6 AFTO Flow Dependent LHGR Multiplier LHGRFAC(F) 20°F < FWT DELTA 55°F (Asymmetric Feedwater Heating)............................................................................................................. 25 Table 11-1 Modes of Operation............................................................................................................... 26 Table 11-2 EOOS Options Included in 'Base' Conditions....................................................................... 26 Table 11-3 Power Level Restrictions....................................................................................................... 26
Constellation Energy Generation - Nuclear Fuels COLR PEACH BOTTOM 3 Rev. 21 P3C26 Core Operating Limits Report Page 5 of 29 1.0 TERMS AND DEFINITIONS ABSP Automated Backup Stability Protection AFTO Asymmetric Feedwater Temperature Operation ALOFH Asymmetric Loss of Feedwater Heating APRM Average Power Range Monitor ARTS APRM, Rod Block and Technical Specification Improvement Program BASE The Base condition is for normal, steady state operation. See Section 11 for more details BSP Backup Stability Protection DLO Dual Loop Operation DSS-CD Detect and Suppress Solution - Confirmation Density ECCS-LOCA Emergency Core Cooling System - Loss of Coolant Accident EOC End of Cycle EOC-RPT End of Cycle Recirculation Pump Trip EOOS Equipment Out of Service. An analyzed option that assumes certain equipment to be non-operational EOR End of Rated. The cycle exposure at which reactor power is equal to 100% with recirculation system flow equal to 100%, all control rods fully withdrawn, all feedwater heating in service and equilibrium Xenon FW Feedwater FFWTR Final Feedwater Temperature Reduction FWHOOS Feedwater Heaters Out of Service FWT Feedwater Temperature HFCL High Flow Control Line HTSP Rod Block Monitor High Trip Setpoint INOP Inoperable ITSP Rod Block Monitor Intermediate Trip Setpoint KP Off-rated power dependent OLMCPR multiplier LHGR Linear Heat Generation Rate LHGRFAC(F)
Off-rated flow dependent LHGR multiplier LHGRFAC(P)
Off-rated power dependent LHGR multiplier LTSP Rod Block Monitor Low Trip Setpoint LUA Lead Use Assembly MAPLHGR Maximum Average Planar Linear Heat Generation Rate MCPR Minimum Critical Power Ratio MCPR99.9%
Limiting MCPR value such that 99.9% of the fuel in the core is not susceptible to boiling transition MCPR(F)
Off-rated flow dependent OLMCPR MCPR(P)
Off-rated power dependent OLMCPR MELLLA Maximum Extended Load Line Limit Analysis MELLLA+
Maximum Extended Load Line Limit Analysis Plus MSIVOOS Main Steam Isolation Valve Out of Service NCL Natural Circulation Line NRC Nuclear Regulatory Commission OLMCPR Operating Limit Minimum Critical Power Ratio
Constellation Energy Generation - Nuclear Fuels COLR PEACH BOTTOM 3 Rev. 21 P3C26 Core Operating Limits Report Page 6 of 29 PLUOOS Power Load Unbalance Out of Service PROOS Pressure Regulator Out of Service PR/PLUOOS Pressure Regulator and/or Power Load Unbalance Out of Service RBM Rod Block Monitor RDF Recirculation Drive Flow RPT Recirculation Pump Trip RPTOOS Recirculation Pump Trip Out of Service RTP Rated Thermal Power RWE Rod Withdrawal Error SAD Amplitude Discriminator Setpoint SFTO Symmetric Feedwater Temperature Operation SLMCPR Safety Limit Minimum Critical Power Ratio SLO Single Loop Operation SRVOOS Safety Relief Valve Out of Service Tau ()
A measure of scram time performance to notch position 36 throughout the cycle TBSOOS Turbine Bypass System Out of Service TBVOOS Turbine Bypass Valve Out of Service TCV Turbine Control Valve TCVSC Turbine Control Valve Slow Closure TCV/TSVOOS Turbine Control Valve and/or Turbine Stop Valve Out of Service TPO Thermal Power Optimization, also known as Measurement Uncertainty Recapture (MUR)
TSV Turbine Stop Valve
Constellation Energy Generation - Nuclear Fuels COLR PEACH BOTTOM 3 Rev. 21 P3C26 Core Operating Limits Report Page 7 of 29 2.0 GENERAL INFORMATION The Peach Bottom Unit 3 Cycle 26 core is comprised of GNF3 fuel and Westinghouse TRITON11 Lead Use Assemblies (LUAs). Although reload licensing was performed using solely a full core of GNF3 fuel, GNF performed evaluations to evaluate neutronic and thermal-hydraulic equivalency of the TRITON11 LUAs as documented in Reference 13. The LUAs are shown to maintain sufficient margin for normal operation, transients, and design basis accidents, including model, manufacturing, fuel type, material, and methodology uncertainties (Reference 16). This conclusion applies to the initial cycle operation of the LUAs (Cycle 26), as well as subsequent cycle operations, so long as the LUAs are operating in non-limiting core locations with similar or more margins to the initial cycle. Additionally, the TRITON11 LUAs should not be loaded into locations that are planned for control rod insertion during normal full-power operation over the life of the LUAs (Reference 16). This allows the reload licensing analyses performed by GNF under GESTAR and the core monitoring system model to assume a resident GNF3 assembly design in place of the TRITON11 LUAs in each of the eight LUA locations.
This report provides the following cycle-specific parameter limits for Peach Bottom Atomic Power Station Unit 3 Cycle 26 (Reload 25):
Maximum Average Planar Linear Heat Generation Rate (MAPLHGR)
Single Loop Operation (SLO) MAPLHGR multipliers Operating Limit Minimum Critical Power Ratio (OLMCPR)
ARTS MCPR thermal limits and multipliers SLO MCPR limits Cycle-specific SLMCPR (MCPR99.9%)
Linear Heat Generation Rate (LHGR)
ARTS LHGR thermal limit multipliers SLO LHGR multipliers Rod Block Monitor (RBM) Allowable Values and MCPR Limits Turbine Bypass Valve Parameters End-of-Cycle Recirculation Pump Trip (EOC-RPT) Parameters Stability Protection Setpoints Asymmetric Feedwater Temperature Operation (AFTO) thermal limit penalties Power Level Restrictions These values have been determined using NRC-approved methodology and are established such that all applicable limits of the plant safety analysis are met. SLO, FWHOOS operation, and FFWTR operation are not permitted in the MELLLA+ Region as controlled by station procedures. For the MELLLA+ Region, a specific definition of FWHOOS is provided in Facility Operating License Section 2.C(16). Operation in the MELLLA+ Region with up to a 10°F reduction in feedwater temperature below the design feedwater temperature is permitted.
This report provides cycle-specific OLMCPR, LHGR, and MAPLHGR thermal limits and related information for the following conditions:
All points in the operating region of the power/flow map including the MELLLA+ Region down to 85.2% of rated core flow during full power (4016 MWt) operation (Appendix A)
Increased Core Flow, up to 110% of rated core flow End-of-Cycle Power Coastdown to a minimum power level of 40% of rated power Feedwater Heaters Out of Service (FWHOOS) up to 55°F temperature reduction Final Feedwater Temperature Reduction (FFWTR) between End-of-Rated (EOR) and End-of-Cycle (EOC) up to 90°F temperature reduction (4th and 5th stage FWHOOS)
Asymmetric Feedwater Temperature Operation Equipment Out of Service Conditions per Section 11
Constellation Energy Generation - Nuclear Fuels COLR PEACH BOTTOM 3 Rev. 21 P3C26 Core Operating Limits Report Page 8 of 29 ARTS provides for power-and flow-dependent thermal limit adjustments and multipliers that allow for a more reliable administration of the MCPR and LHGR thermal limits. The off-rated limits assumed in the ECCS-LOCA analyses bound the cycle-specific off-rated limits calculated for MELLLA+ operation. Linear interpolation is to be used to find intermediate values unless otherwise indicated. The Allowable Values documented in Reference 5 for feedwater temperature as a function of thermal power for both FWHOOS and FFWTR are specified in the appropriate Peach Bottom procedures.
Constellation Energy Generation - Nuclear Fuels COLR PEACH BOTTOM 3 Rev. 21 P3C26 Core Operating Limits Report Page 9 of 29 3.0 MAPLHGR LIMITS 3.1 Technical Specification Section 3.2.1, 3.3.4.2, 3.4.1 and 3.7.6 3.2 Description The MAPLHGR limit as a function of average planar exposure is given in Table 3-1. For SLO, a multiplier is used, which is shown in Table 3-2. The impact of AFTO on MAPLHGR is addressed in Section 10.0. The power and flow dependent LHGR multipliers are sufficient to provide adequate protection for the off-rated conditions from an ECCS-LOCA analysis perspective. The MAPLHGR multipliers can either be set to one or set equal to the LHGR multipliers, which remain compliant with the basis of the ECCS-LOCA analysis with no loss of ECCS-LOCA margin.
Table 3-1 MAPLHGR Versus Average Planar Exposure (Reference 2)
Average Planar Exposure (GWD/ST)
MAPLHGR Limit (kW/ft) 0.0 14.36 21.22 13.01 40.82 10.75 57.60 8.00 63.50 6.00 Table 3-2 MAPLHGR Single Loop Operation (SLO) Multiplier (Reference 2)
SLO Multiplier 0.90
Constellation Energy Generation - Nuclear Fuels COLR PEACH BOTTOM 3 Rev. 21 P3C26 Core Operating Limits Report Page 10 of 29 4.0 MCPR LIMITS 4.1 Technical Specification Section 2.1.1.2, 3.2.2, 3.3.4.2, 3.4.1 and 3.7.6 4.2 Description The OLMCPR is provided in Table 4-1. These values are determined by the cycle-specific fuel reload analyses in Reference 2. Control rod scram time verification is required per Technical Specification 3.1.4, "Control Rod Scram Times". Tau (), a measure of scram time performance to notch position 36 throughout the cycle, is determined based on the cumulative scram time test results. The calculation of Tau shall be performed in accordance with site procedures. Linear interpolation shall be used to calculate the OLMCPR value if Tau is between 0.0 (Tau Option B) and 1.0 (Tau Option A). Table 4-1 is valid for the entire range of licensed flow and feedwater temperature unless specified otherwise (Reference 2).
The ARTS-based power-dependent MCPR limits (MCPR(P)) and multipliers (Kp) are provided in Table 4-2. Table 4-2 is valid for a maximum temperature reduction of 90F for FFWTR operation (bounding for FWHOOS operation) (Reference 2). The flow-dependent MCPR limits (MCPR(F))
are provided in Tables 4-3 through 4-4. Table 4-3 is valid for DLO conditions with SFTO, and Table 4-4 is valid for SLO conditions with SFTO.
The impact of AFTO on MCPR is addressed in Section 10. PR/PLUOOS + TBSOOS values were obtained by taking the most limiting values of the two EOOS conditions (Reference 11). For PR/PLUOOS + RPTOOS condition, the limits are listed in Section 10; these values are bounding for non-AFTO (i.e. SFTO) conditions.
The cycle-specific exposure-dependent SLMCPRs, known as MCPR99.9%, can be found in Table 4-5 for dual loop and single loop operating conditions. The values in Table 4-5 or more conservative values were used to calculate the MCPR limits and off-rated limits in this section and Section 10.
Constellation Energy Generation - Nuclear Fuels COLR PEACH BOTTOM 3 Rev. 21 P3C26 Core Operating Limits Report Page 11 of 29 Table 4-1 Operating Limit Minimum Critical Power Ratio (Symmetric Feedwater Heating)
(References 2 and 11)
EOOS Combination SCRAM Time Option(1)
Cycle Exposure 8124 MWd/ST
> 8124 MWd/ST Base B
1.40 1.39 A
1.42 1.42 Base SLO B
1.43 1.42 A
1.45 1.45 TBSOOS B
1.48 1.48 A
1.48 1.48 TBSOOS SLO B
1.51 1.51 A
1.51 1.51 RPTOOS B
1.40 1.39 A
1.42 1.42 RPTOOS SLO B
1.43 1.42 A
1.45 1.45 PR/PLUOOS B
1.40 1.39 A
1.42 1.42 PR/PLUOOS SLO B
1.43 1.42 A
1.45 1.45 PR/PLUOOS +
TBSOOS B
1.48 1.48 A
N/A N/A (1) When Tau does not equal 0 or 1, use linear interpolation.
Constellation Energy Generation - Nuclear Fuels COLR PEACH BOTTOM 3 Rev. 21 P3C26 Core Operating Limits Report Page 12 of 29 Table 4-2 Power Dependent MCPR(P) Limit Adjustments and Multipliers (Symmetric Feedwater Heating)
(References 2 and 11)
EOOS Combination Core Flow
(% of rated)
Core Thermal Power (% of rated) 22.6 26.3
> 26.3 40 55 65
< 85
> 85 100 MCPR(P)
OLMCPR Multiplier, Kp Base
< 60 2.47 2.31 1.405 1.285 1.210 1.130 1.056 1.056 1.000
> 60 2.47 2.37 Base SLO
< 60 2.50 2.34 1.405 1.285 1.210 1.130 1.056 1.056 1.000
> 60 2.50 2.40 TBSOOS
< 60 2.90 2.63 1.405 1.285 1.210 1.130 1.061 1.061 1.000
> 60 2.90 2.85 TBSOOS SLO
< 60 2.93 2.66 1.405 1.285 1.210 1.130 1.061 1.061 1.000
> 60 2.93 2.88 RPTOOS
< 60 2.47 2.31 1.405 1.285 1.210 1.130 1.056 1.056 1.000
> 60 2.47 2.37 RPTOOS SLO
< 60 2.50 2.34 1.405 1.285 1.210 1.130 1.056 1.056 1.000
> 60 2.50 2.40 PR/PLUOOS
< 60 2.47 2.31 1.405 1.285 1.210 1.170 1.119 1.066 1.000
> 60 2.47 2.37 PR/PLUOOS SLO
< 60 2.50 2.34 1.405 1.285 1.210 1.170 1.119 1.066 1.000
> 60 2.50 2.40 PR/PLUOOS +
TBSOOS
< 60 2.90 2.63 1.405 1.285 1.210 1.170 1.119 1.066 1.000
> 60 2.90 2.85
Constellation Energy Generation - Nuclear Fuels COLR PEACH BOTTOM 3 Rev. 21 P3C26 Core Operating Limits Report Page 13 of 29 Table 4-3 Flow Dependent MCPR Limits MCPR(F)
(Symmetric Feedwater Heating)
(Reference 2)
Core Flow
(% rated)
MCPR(F)
Limit 30.0 1.56 90.4 1.20 110.0 1.20 Table 4-4 SLO Flow Dependent MCPR Limits MCPR(F)
(Symmetric Feedwater Heating)
(Reference 2)
Core Flow
(% rated)
MCPR(F)
Limit 30.0 1.59 90.4 1.23 110.0 1.23 Table 4-5 Cycle-Specific SLMCPR (MCPR99.9%)
(Reference 2)
Loop Operation MCPR99.9%
DLO 1.10 SLO 1.10
Constellation Energy Generation - Nuclear Fuels COLR PEACH BOTTOM 3 Rev. 21 P3C26 Core Operating Limits Report Page 14 of 29 5.0 LHGR LIMITS 5.1 Technical Specification Section 3.2.3, 3.3.4.2, 3.4.1 and 3.7.6 5.2 Description The LHGR values are provided in the references listed in Tables 5-1 and 5-2. Linear interpolation should be used for the referenced values in Tables 5-1 and 5-2 as directed in Reference 15. The ARTS-based LHGR power-dependent multipliers (LHGRFAC(P)) are provided in Table 5-3.
Table 5-3 is valid for a maximum temperature reduction of 90°F for FFWTR operation (bounding for FWHOOS operation) (Reference 2). In certain configurations when the unit is operating with two FW pumps and two FW heater strings in service, there is the potential that there could be an asymmetric loss of feedwater heating (ALOFH) event of more than 100°F. Per Reference 8, operation in that configuration requires LHGRFAC(P) restriction provided in Table 5-4 for operation at or below 60% of rated power. The penalty provided in Table 5-4 is GNF3 specific per Reference 8.
The LHGR flow-dependent multipliers (LHGRFAC(F)) are provided in Table 5-5 as a function of the number of recirculation loops in operation. The SLO LHGR multiplier is provided and accounted for in these tables. The impact of AFTO on LHGR is addressed in Section 10.0.
PR/PLUOOS + TBSOOS values were obtained by taking the most limiting values of the two EOOS conditions (Reference 11). For the PR/PLUOOS + RPTOOS condition, the limits are listed in Section 10; these values are bounding for non-AFTO (i.e. SFTO) conditions. The power and flow dependent LHGR multipliers are sufficient to provide adequate protection for the off-rated conditions from an ECCS-LOCA analysis perspective.
Table 5-1 Linear Heat Generation Rate Limits - UO2 Rods (References 10 and 15)
Fuel Type LHGR Limit GNF3 See Table A-1 of Reference 15 Table 5-2 Linear Heat Generation Rate Limits - Gad Rods (References 10 and 15)
Fuel Type LHGR Limit GNF3 See Table A-2 of Reference 15
Constellation Energy Generation - Nuclear Fuels COLR PEACH BOTTOM 3 Rev. 21 P3C26 Core Operating Limits Report Page 15 of 29 Table 5-3 Power Dependent LHGR Multiplier LHGRFAC(P)
(Symmetric Feedwater Heating)
(References 2 and 11)
EOOS Combination Core Flow (%
of rated)
Core Thermal Power (% of rated) 22.6 26.3
> 26.3 40 55 65 85 100 Base
< 60 0.440 0.460 0.640 0.790 0.950 1.000 1.000 1.000
> 60 0.440 0.460 Base SLO
< 60 0.440 0.460 0.640 0.790 0.950 1.000 1.000 1.000
> 60 0.440 0.460 TBSOOS
< 60 0.410 0.460 0.640 0.790 0.950 1.000 1.000 1.000
> 60 0.410 0.430 TBSOOS SLO
< 60 0.410 0.460 0.640 0.790 0.950 1.000 1.000 1.000
> 60 0.410 0.430 RPTOOS
< 60 0.440 0.460 0.640 0.790 0.950 1.000 1.000 1.000
> 60 0.440 0.460 RPTOOS SLO
< 60 0.440 0.460 0.640 0.790 0.950 1.000 1.000 1.000
> 60 0.440 0.460 PR/PLUOOS
< 60 0.440 0.460 0.640 0.790 0.950 0.990 1.000 1.000
> 60 0.440 0.460 PR/PLUOOS SLO
< 60 0.440 0.460 0.640 0.790 0.950 0.990 1.000 1.000
> 60 0.440 0.460 PR/PLUOOS +
TBSOOS
< 60 0.410 0.460 0.640 0.790 0.950 0.990 1.000 1.000
> 60 0.410 0.430
Constellation Energy Generation - Nuclear Fuels COLR PEACH BOTTOM 3 Rev. 21 P3C26 Core Operating Limits Report Page 16 of 29 Table 5-4 Power Dependent LHGR Multiplier LHGRFAC(P)
(Asymmetric Loss of Feedwater Heating)
(Reference 8)
Reactor Power LHGR Restriction P < 60%
0.902 Table 5-5 Flow Dependent LHGR Multiplier LHGRFAC(F)
(Symmetric Feedwater Heating)
(Reference 2)
EOOS Combination Core Flow (% of rated) 30 65.5 80.3 110 LHGRFAC(F) Multiplier Dual Loop 0.660 0.900 1.000 1.000 Single Loop 0.660 0.900 0.900 0.900
Constellation Energy Generation - Nuclear Fuels COLR PEACH BOTTOM 3 Rev. 21 P3C26 Core Operating Limits Report Page 17 of 29 6.0 ROD BLOCK MONITOR SETPOINTS 6.1 Technical Specification Section 3.3.2.1 6.2 Description The RBM power-biased Allowable Values and MCPR Limits are provided in Table 6-1 with supporting documentation in References 2, 3, 8 and 9. GNF3 AFTO penalties will be applied to all fuel types in the core. The SFTO MCPR Limits apply when FWT difference is below 20°F.
The AFTO MCPR Limits apply with FWT difference between 20 and 55°F. AFTO conditions are discussed further in Section 10.
Table 6-1 Rod Block Monitor Setpoints (References 2, 3, 8 and 9)
Power Level Allowable Value(1,2)
Thermal Power (Application Conditions)
SFTO MCPR Limit(4)
AFTO MCPR Limit(5)
Low Trip Setpoint (LTSP) 124.0%
< 90% (All)
< 1.75
< 1.79 90% (3)
< 1.44
< 1.47 90% (TBSOOS)
< 1.51
< 1.54 Intermediate Trip Setpoint (ITSP) 119.2%
< 90% (All)
< 1.75
< 1.79 90% (3)
< 1.44
< 1.47 90% (TBSOOS)
< 1.51
< 1.54 High Trip Setpoint (HTSP) 114.2%
< 90% (All)
< 1.75
< 1.79 90% (3)
< 1.44
< 1.47 90% (TBSOOS)
< 1.51
< 1.54 Inoperable (INOP)
N/A
< 90% (All)
< 1.75
< 1.79 90% (3)
< 1.44
< 1.47 90% (TBSOOS)
< 1.51
< 1.54 (1) These setpoints (with RBM filter time constant between 0.1 seconds and 0.55 seconds) are based on cycle-specific rated RWE MCPR limits which are bounded by the OLMCPRs listed in Table 4-1.
(2) Corresponding Nominal Trip Setpoints (NTSP) can be found in calculation PE-0251 (Reference 9).
(3) These SFTO and AFTO MCPR Limits are applicable to Application Conditions Base, RPTOOS, PROOS and/or PLUOOS.
(4) This is the MCPR limit for SFTO below which the RBM is required to be OPERABLE (see COLR Reference 2 and TS Table 3.3.2.1-1).
(5) This is the MCPR limit for AFTO below which the RBM is required to be OPERABLE (see COLR Reference 2, COLR Reference 8, and TS Table 3.3.2.1-1).
Constellation Energy Generation - Nuclear Fuels COLR PEACH BOTTOM 3 Rev. 21 P3C26 Core Operating Limits Report Page 18 of 29 7.0 TURBINE BYPASS VALVE PARAMETERS 7.1 Technical Specification Section 3.7.6 7.2 Description The operability requirements for the steam bypass system are governed by Technical Specification 3.7.6. If the requirements cannot be met, the appropriate power and flow dependent limits for Turbine Bypass System Out-of-Service (TBSOOS) must be used. Table 7-1 includes the Turbine Bypass Valve response time parameters. The minimum number of bypass valves to maintain system operability is provided in Table 7-2 per Reference 12 and Technical Specification 3.7.6.
Table 7-1 Turbine Bypass System Response Time (Reference 12)
Maximum delay time before start of bypass valve opening following initial turbine inlet valve movement(1) 0.10 sec Maximum time after initial turbine inlet valve movement(1) for bypass valve position to reach 80% of full flow (includes the above delay time) 0.30 sec Table 7-2 Minimum Required Bypass Valves to Maintain System Operability (Reference 12)
Reactor Power No. of Valves in Service P 22.6% RTP 8
(1) First movement of any TSV or any TCV (whichever occurs first).
Constellation Energy Generation - Nuclear Fuels COLR PEACH BOTTOM 3 Rev. 21 P3C26 Core Operating Limits Report Page 19 of 29 8.0 EOC RECIRCULATION PUMP TRIP (EOC-RPT) OPERABILITY 8.1 Technical Specification Section 3.3.4.2 8.2 Description The operability requirements for the EOC-RPT are governed by Technical Specification 3.3.4.2.
If the requirements cannot be met, the appropriate power and flow dependent limits for EOC Recirculation Pump Trip Out of Service (RPTOOS) must be used. Table 8-1 includes the total RPT response time parameter.
Table 8-1 Recirculation Pump Trip Response Time (Reference 12)
Total Recirculation Pump Trip Response Time The time from when the turbine valves (turbine control valve or turbine stop valve) start to close until complete arc suppression of the EOC-RPT circuit breakers as described in Reference 7.
0.175 sec
Constellation Energy Generation - Nuclear Fuels COLR PEACH BOTTOM 3 Rev. 21 P3C26 Core Operating Limits Report Page 20 of 29 9.0 STABILITY PROTECTION 9.1 Technical Specification Section 3.3.1.1, Table 3.3.1.1-1 Function 2.f 9.2 Description Per Reference 2, the cycle-specific DSS-CD SAD Setpoint was confirmed to be 1.10 for DLO and SLO. The Automated Backup Stability Protection (BSP) Setpoints are provided in Table 9-1. The Manual BSP Endpoints for Normal FWT and Reduced FWT are provided in Table 9-2 and Table 9-3, respectively. Table 9-3 is intended for feedwater temperatures 10-90°F below nominal (Reference 2).
Table 9-1 Automated BSP Setpoints for the Scram Region (Reference 2)
Parameter Symbol Value Slope of ABSP APRM flow-biased trip linear segment.
mTrip 1.37 ABSP APRM flow-biased trip setpoint power intercept.
Constant Power Line for Trip from zero Drive Flow to Flow Breakpoint value.
PBSP-Trip 37.9% RTP ABSP APRM flow-biased trip setpoint drive flow intercept.
Constant Flow Line for Trip.
WBSP-Trip 55.4% RDF Flow Breakpoint value WBSP-Break 26.0% RDF
Constellation Energy Generation - Nuclear Fuels COLR PEACH BOTTOM 3 Rev. 21 P3C26 Core Operating Limits Report Page 21 of 29 Table 9-2 (1,2)
Manual BSP Endpoints for Normal Feedwater Temperature (Reference 2)
Endpoint Power (%) Flow (%)
Definition A1 80.9 59.5 Scram Region Boundary, HFCL B1 39.1 31.0 Scram Region Boundary, NCL A2 80.9 59.6 Controlled Entry Region Boundary, HFCL B2 27.6 30.1 Controlled Entry Region Boundary, NCL Table 9-3 (1,2)
Manual BSP Endpoints for Reduced Feedwater Temperature (Reference 2)
Endpoint Power (%) Flow (%)
Definition A1 65.3 52.4 Scram Region Boundary, HFCL B1 34.9 30.7 Scram Region Boundary, NCL A2 68.3 56.3 Controlled Entry Region Boundary, HFCL B2 27.6 30.1 Controlled Entry Region Boundary, NCL (1) Station may elect to place additional administrative margin on the endpoints provided in Table 9-2 and Table 9-3, per Reference 14.
(2) The BSP Boundary for Normal and Reduced Feedwater Temperature is defined by the MELLLA boundary line, per Reference 14.
Constellation Energy Generation - Nuclear Fuels COLR PEACH BOTTOM 3 Rev. 21 P3C26 Core Operating Limits Report Page 22 of 29 10.0 ASYMMETRIC FEEDWATER TEMPERATURE OPERATION (AFTO)
AFTO is the result of the specific configuration of the feedwater lines at Peach Bottom. A reduction in heating in either the A or the C heater strings will result in a temperature mismatch between the feedwater flows entering the opposite sides of the reactor vessel. This temperature mismatch may result in errors in the thermal limit values calculated by the core monitoring system. Thermal limit values for all conditions and events are impacted by these errors, excluding SLO conditions.
AFTO is defined as operation in a feedwater heater/string configuration that results in a specified threshold difference as described in Reference 8. There is no AFTO penalty for a FWT difference less than or equal to 20°F. For a difference between 20 and 55°F there is a 4% LHGR penalty, a 3% MAPLHGR penalty, and a 2% MCPR penalty. Thermal limits are unanalyzed for a difference above 55°F. GNF3 AFTO penalties will be applied to all fuel types in the core. The MCPR penalty for AFTO also applies to RBM Operability MCPR Limits, which are addressed in Section 6.0.
10.1 MAPLHGR LIMITS An appropriate penalty must be applied to MAPLHGR limits under AFTO for varying temperature differentials per Reference 8. The reduction factor listed in Table 10-1 is the maximum penalty for the full range of analyzed FWT mismatches, bounding all smaller temperature deltas.
Table 10-1 AFTO MAPLHGR Reduction Factor (Asymmetric Feedwater Heating)
(Reference 8)
AFTO Reduction Factor 20°F < FWT DELTA 55°F 0.970
Constellation Energy Generation - Nuclear Fuels COLR PEACH BOTTOM 3 Rev. 21 P3C26 Core Operating Limits Report Page 23 of 29 10.2 MCPR LIMITS The OLMCPRs during AFTO with a FWT difference greater than 20°F are provided in Table 10-2.
The ARTS-based MCPR(P) limits and multipliers (Kp) for use during AFTO conditions are provided in Table 10-3. The MCPR(F) limits for AFTO are provided in Table 10-4. The power-and flow-dependent OLMCPR curves were obtained from Reference 2 and were adjusted with a penalty for feedwater temperature difference greater than 20°F as per Reference 8. PR/PLUOOS + TBSOOS and PR/PLUOOS + RPTOOS values were obtained by taking the most limiting values of the two EOOS conditions (Reference 11).
Table 10-2 AFTO Operating Limit Minimum Critical Power Ratio 20°F < FWT DELTA 55°F (Asymmetric Feedwater Heating)
(References 2, 8, and 11)
EOOS Combination SCRAM Time Option(1)
Cycle Exposure 8124 MWd/ST
> 8124 MWd/ST BASE B
1.43 1.42 A
1.45 1.45 TBSOOS B
1.51 1.51 A
1.51 1.51 RPTOOS B
1.43 1.42 A
1.45 1.45 PR/PLUOOS B
1.43 1.42 A
1.45 1.45 PR/PLUOOS +
TBSOOS B
1.51 1.51 A
N/A N/A PR/PLUOOS +
RPTOOS B
1.43 1.42 A
N/A N/A (1) When Tau does not equal 0 or 1, use linear interpolation.
Constellation Energy Generation - Nuclear Fuels COLR PEACH BOTTOM 3 Rev. 21 P3C26 Core Operating Limits Report Page 24 of 29 Table 10-3 AFTO Power Dependent MCPR Limit Adjustments and Multipliers MCPR(P) 20°F < FWT DELTA 55°F (Asymmetric Feedwater Heating)
(References 2, 8, and 11)
EOOS Combination Core Flow
(% of rated)
Core Thermal Power (% of rated) 22.6 26.3
> 26.3 40 55 65
< 85
> 85 100 MCPR(P)
OLMCPR Multiplier, Kp Base
< 60 2.52 2.36 1.405 1.285 1.210 1.130 1.056 1.056 1.000
> 60 2.52 2.42 TBSOOS
< 60 2.96 2.68 1.405 1.285 1.210 1.130 1.061 1.061 1.000
> 60 2.96 2.91 RPTOOS
< 60 2.52 2.36 1.405 1.285 1.210 1.130 1.056 1.056 1.000
> 60 2.52 2.42 PR/PLUOOS
< 60 2.52 2.36 1.405 1.285 1.210 1.170 1.119 1.066 1.000
> 60 2.52 2.42 PR/PLUOOS + TBSOOS
< 60 2.96 2.68 1.405 1.285 1.210 1.170 1.119 1.066 1.000
> 60 2.96 2.91 PR/PLUOOS + RPTOOS
< 60 2.52 2.36 1.405 1.285 1.210 1.170 1.119 1.066 1.000
> 60 2.52 2.42 Table 10-4 AFTO Flow Dependent MCPR Limits MCPR(F) 20°F < FWT DELTA 55°F (Asymmetric Feedwater Heating)
(References 2 and 8)
Flow
(% rated)
MCPR(F)
Limit 30.0 1.59 90.4 1.22 110.0 1.22
Constellation Energy Generation - Nuclear Fuels COLR PEACH BOTTOM 3 Rev. 21 P3C26 Core Operating Limits Report Page 25 of 29 10.3 LHGR LIMITS The ARTS-based LHGRFAC(P) values for AFTO operation are provided in Table 10-5. The LHGRFAC(F) values for AFTO in DLO are provided in Table 10-6. The power-and flow-dependent LHGR multipliers were obtained from Reference 2 and were adjusted with the GNF3 penalties as per Reference 8. PR/PLUOOS + TBSOOS and PR/PLUOOS + RPTOOS values were obtained by taking the most limiting values of the two EOOS conditions (Reference 11).
Table 10-5 AFTO Power Dependent LHGR Multiplier LHGRFAC(P) 20°F < FWT DELTA 55°F (Asymmetric Feedwater Heating)
(References 2, 8 and 11)
EOOS Combination Core Flow
(% of rated)
Core Thermal Power (% of rated) 22.6 26.3
> 26.3 40 55 65 85 100 Base
< 60 0.422 0.442 0.614 0.758 0.912 0.960 0.960 0.960
> 60 0.422 0.442 TBSOOS
< 60 0.394 0.442 0.614 0.758 0.912 0.960 0.960 0.960
> 60 0.394 0.413 RPTOOS
< 60 0.422 0.442 0.614 0.758 0.912 0.960 0.960 0.960
> 60 0.422 0.442 PR/PLUOOS
< 60 0.422 0.442 0.614 0.758 0.912 0.950 0.960 0.960
> 60 0.422 0.442 PR/PLUOOS +
TBSOOS
< 60 0.394 0.442 0.614 0.758 0.912 0.950 0.960 0.960
> 60 0.394 0.413 PR/PLUOOS +
RPTOOS
< 60 0.422 0.442 0.614 0.758 0.912 0.950 0.960 0.960
> 60 0.422 0.442 Table 10-6 AFTO Flow Dependent LHGR Multiplier LHGRFAC(F) 20°F < FWT DELTA 55°F (Asymmetric Feedwater Heating)
(References 2 and 8)
EOOS Combination Core Flow (% of rated) 30 65.5 80.3 110 LHGRFAC(F) Multiplier Dual Loop 0.634 0.864 0.960 0.960
Constellation Energy Generation - Nuclear Fuels COLR PEACH BOTTOM 3 Rev. 21 P3C26 Core Operating Limits Report Page 26 of 29 11.0 MODES OF OPERATION The following conditions are supported by the Peach Bottom 3 Cycle 26 licensing analysis; operation in a condition (or conditions) is controlled by station procedures. If a combination of options is not listed, it is not supported. Table 11-1 provides allowed modes of operation with thermal limit sets in the COLR. Table 11-2 provides all EOOS included in the Base condition. Table 11-3 provides power level restrictions that support specific operating conditions.
Table 11-1 Modes of Operation (References 2 and 11)
EOOS Options Supported Scram Speed Option Supported Recirculation Loop Operation Supported SFTO/AFTO Base(1,2)
A or B DLO or SLO(3)
SFTO or AFTO TBSOOS A or B DLO or SLO(3)
SFTO or AFTO RPTOOS A or B DLO or SLO(3)
SFTO or AFTO PR/PLUOOS A or B DLO or SLO(3)
SFTO or AFTO PR/PLUOOS + TBSOOS(6)
B DLO SFTO or AFTO PR/PLUOOS + RPTOOS B
DLO SFTO or AFTO(4)
Table 11-2 EOOS Options Included in 'Base' Conditions (Reference 2)
Condition 1 TBVOOS 2 SRVOOS 1 MSIVOOS(5) 1 TCV/TSVOOS(5)
Table 11-3 Power Level Restrictions (Reference 2)
Condition Power Level Restriction (% rated) 1 TCVOOS and/or 1 TSVOOS 90 1 TCVOOS and/or 1 TSVOOS + TBSOOS 85 1 MSIVOOS 75 (1) The 'Base' condition includes the options listed in Table 11-2.
(2) The 'Base' condition includes operation with FWHOOS/FFWTR. Operation not permitted in the MELLLA+
Region for reduced FWT conditions as controlled by station procedures.
(3) Operation in SLO not permitted in the MELLLA+ Region as controlled by station procedures.
(4) AFTO limits bound SFTO limits.
(5) Permitted at power levels provided in Table 11-3 and in the applicable station procedure.
(6) TCVSC event is bounded by the PR/PLUOOS + TBSOOS condition per Reference 4.
Constellation Energy Generation - Nuclear Fuels COLR PEACH BOTTOM 3 Rev. 21 P3C26 Core Operating Limits Report Page 27 of 29 12.0 METHODOLOGY The analytical methods used in determining the core operating limits have been previously reviewed and approved by the NRC, specifically those described in the following document:
- 1. General Electric Standard Application for Reactor Fuel, Global Nuclear Fuel Document No. NEDE-24011-P-A-32, August 2024 and U.S. Supplement, NEDE-24011-P-A-32-US, August 2024.
13.0 REFERENCES
- 1. "Subsequent Renewed Facility Operating License", Constellation Document, Docket No. 50-278, Subsequent Renewed License No. DPR-56.
- 2. "Supplemental Reload Licensing Report for Peach Bottom Unit 3 Reload 25 Cycle 26, Global Nuclear Fuel Document No. 008N4922, Revision 0, May 2025.
- 3. GNF3 Fuel Design Cycle-Independent Analyses for Peach Bottom Atomic Power Station Units 2 and 3, Global Nuclear Fuel Document No. 006N4378, Revision 1, October 2022.
- 4. Thermal Limits Evaluation for the TCV Slow Closure Event for Peach Bottom, Constellation Technical Evaluation EC 632705, Revision 1, November 2021.
- 5. Clarify Rated Feedwater Temp for Feedwater Temp Reduction Curves, Constellation Technical Evaluation EC 628049, Revision 0, August 2019.
- 6. Safety Analysis Report for Peach Bottom Atomic Power Station, Units 2 and 3, Thermal Power Optimization, General Electric Hitachi Document NEDO-33873, Revision 0, February 2017 (ADAMS Accession #ML17048A444).
- 7. Determination of Time Required to Initiate Trip Signal to the RPT CKT, Constellation Calculation No.
PE-0173, Revision 1A, January 2019.
- 8. Evaluation of Peach Bottom Atomic Power Station Units 2 and 3 Asymmetric Feedwater Temperature Operation with GNF3 Fuel, Global Nuclear Fuel Document No. 006N0624, Revision 0, December 2020.
- 9. Provide Allowable Values (AV) and Nominal Trip Setpoints (NTSP) for Various Setpoint Functions of the NUMAC PRNM System, Constellation Calculation No. PE-0251, Revision 4A, October 2024.
- 10. "Fuel Bundle Information Report for Peach Bottom Unit 3 Reload 25 Cycle 26, Global Nuclear Fuel Document No. 008N4923, Revision 0, April 2025.
- 11. Peach Bottom Atomic Power Station Units 2 and 3 GNF3 PROOS and/or PLUOOS and EOOS Combination Limits Report, Global Nuclear Fuel Document No. 006N7704, Revision 1, September 2021.
- 12. Peach Bottom Unit 3 Cycle 26 OPL-3, Constellation TODI NF240766, Revision 0, December 2024.
- 13. TRITON11TM LUAs in Peach Bottom Unit 3 Cycle 26, Global Nuclear Fuel Document No. 009N9116, Revision 0, May 2025.
Constellation Energy Generation - Nuclear Fuels COLR PEACH BOTTOM 3 Rev. 21 P3C26 Core Operating Limits Report Page 28 of 29
- 14. GE Hitachi Boiling Water Reactor Detect and Suppress Solution - Confirmation Density, General Electric Hitachi Document NEDC-33075P-A, Revision 8, November 2013.
- 15. GNF3 Generic Compliance with NEDE-24011-P-A (GESTAR II), Global Nuclear Fuel Document NEDC-33879P, Revision 5, August 2024.
- 16. TRITON11 Lead Use Assemblies Licensing Report for Peach Bottom Atomic Power Station Unit 3, Westinghouse Report NF-BCEG-25-010, Revision 0, September 2025.
Constellation Energy Generation - Nuclear Fuels COLR PEACH BOTTOM 3 Rev. 21 P3C26 Core Operating Limits Report Page 29 of 29 APPENDIX A POWER/FLOW OPERATING MAP FOR MELLLA+ WITH TPO (Reference 6)
BSP Boundary