Text

Core Operating Limits Report (COLR) - Cycle 23, Revision 1
	ML23310A307
Person / Time
Site:	River Bend
Issue date:	11/06/2023
From:	Crawford R; Entergy Operations
To:	; Office of Nuclear Reactor Regulation, Document Control Desk
References
	RBG-48264
	Download: ML23310A307 (1)
	v • d • e

entergy Randy Crawford Manger Regulatory Assurance 225-381-4177 RBG-48264 November 6, 2023 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001

Subject:

River Bend Station Core Operating Limits Report (COLR) - Cycle 23, Revision 1 River Bend Station, Unit 1 NRG Docket No. 50-458 Renewed Facility Operating License No. NPF-47

Reference:

River Bend Station Core Operating Limits Report (COLR) - Cycle 23, Revision 0 (ML23151A413)

The Enclosure to this letter contains Revision 1 of the River Bend Station Core Operating Limits Report for Cycle 23. Changes are annotated with change bars. This report is submitted in accordance with Technical Specification 5.6.5.d of Appendix A of the Facility Operating License.

General Electric Hitachi (GEH) Safety Communication 21-04 (SC21-04) Rev. 0 identifies a metastable flow condition that may exist in a BWR/6 in core locations fed by a side entry orifice adjacent to two core support cross beams. The vendor has been unable to determine the frequency of occurrence of this flow condition, if any. To be conservative, it is assumed this condition always exists, so a minimum critical power ratio (MCPR) penalty is always applied.

Subsequent to the issuance of RBS COLR Cycle 23, Rev. O (ML23151A413), it was identified that the equations for operating limit minimum critical power ratio (OLMCPR) and rated MCPR multipliers (K(P)) in Figures 7.0.a and 7.0.b in the COLR were not updated for the MCPR penalties from SC21-04 Rev. 1. The RBS core monitoring system databanks contain the appropriate MCPR limits updated for SC21-04 Rev. 1, and the equations in two of the figures in the COLR are being revised to match the other specifically calculated power-dependent minimum critical power ratio (MCPRp) figures and tables which contain the SC21-04 Rev. 1 penalties.

This letter does not contain any new commitments.

If you require additional information, please contact Randy Crawford at (225) 381-4177 or rcrawfo@entergy.com.

River Bend Station, 5485 U.S. Highway 61N, St. Francisville, LA 70775

RBG-48264 Page 2 of 2 Respectfully, Randy Crawford RC/bj

Enclosure:

River Bend Station Core Operating Limits Report - Cycle 23, Revision 1 cc: NRC Regional Administrator - Region IV NRC Project Manager - River Bend Station NRC Senior Resident Inspector - River Bend Station

Enclosure RBG-48264 River Bend Station Core Operating Limits Report - Cycle 23, Revision 1

River Bend Station Core Operating Limits Report Cycle 23 Revision 1 Page 1 of 37 COLR Rev. 23-1

River Bend Station Core Operating Limits Report Cycle 23 Revision 1 REVISION HISTORY Revision Revision Description 0 Initial Issue 1 Revised to update the equations on Figures 7.0.a and 7.0.b to incorporate the SC21-04 Rev. 1 MCPR penalties, and updated SRLR revision from 0 to 1.

Page 2 of 37 COLR Rev. 23-1

River Bend Station Core Operating Limits Report Cycle 23 Revision 1 TABLE OF CONTENTS 1.0 PURPOSE ...................................................................................................................... 5 2.0 SCOPE ........................................................................................................................... 5

3.0 REFERENCES

............................................................................................................... 5 3.1 CURRENT CYCLE REFERENCES ....................................................................................................................... 5 3.2 METHODOLOGY REFERENCES ......................................................................................................................... 6 4.0 DEFINITIONS ................................................................................................................. 6 5.0 CORE DESIGN ............................................................................................................... 8 5.1 REFERENCE CORE LOADING PATTERN ............................................................................................................. 8 5.2 CONTROL RODS.............................................................................................................................................. 8 6.0 AVERAGE PLANAR LINEAR HEAT GENERATION RATE (APLHGR) ....................... 8 7.0 MINIMUM CRITICAL POWER RATIO (MCPR).............................................................. 8 7.1 FLOW-DEPENDENT MINIMUM CRITICAL POWER RATIO (MCPRF) VALUES: ......................................................... 9 7.2 POWER-DEPENDENT MINIMUM CRITICAL POWER RATIO (MCPRP) VALUES: ...................................................... 9 8.0 LINEAR HEAT GENERATION RATE (LHGR) ............................................................... 9 8.1 EXPOSURE-DEPENDENT LINEAR HEAT GENERATION RATE (LHGR) VALUES: .................................................. 10 8.2 FLOW-DEPENDENT LINEAR HEAT GENERATION RATE FACTORS (LHGRFACF) VALUES: .................................. 10 8.3 POWER-DEPENDENT LINEAR HEAT GENERATION RATE FACTORS (LHGRFACP) VALUES:................................ 10 9.0 STABILITY ................................................................................................................... 10 9.1 STABILITY REGION BOUNDARIES AND SETPOINTS ........................................................................................... 11 9.2 APRM FLOW BIASED SIMULATED THERMAL POWERHIGH TIME CONSTANT (SR 3.3.1.1.14) .......................... 12 Page 3 of 37 COLR Rev. 23-1

River Bend Station Core Operating Limits Report Cycle 23 Revision 1 LIST OF TABLES:

Table 7.0: OLMCPR Summary Table ....................................................................................................................... 14 LIST OF FIGURES:

Figure 6.1-1: GNF3 MAPLHGR ................................................................................................................................ 13 Figure 7.0.a: C23 MCPRp limit and K(P) multiplier for Application Conditions 1, 2, 4, and 5 .................................. 15 Figure 7.0.b: C23 MCPRp limit and K(P) multiplier for Application Conditions 3, 6, and 7 ...................................... 16 Figure 7.1-1: BOC-EOC MCPRF limit, TLO and SLO for Application Condition 1-7 ................................................ 17 Figure 7.2-1a: BOC-MOC MCPRP limit, TLO and SLO for Application Condition 1, 4 ............................................ 18 Figure 7.2-1b: MOC-EOC MCPRP limit, TLO and SLO for Application Condition 1, 4 ............................................ 19 Figure 7.2-2a: BOC-MOC MCPRP limit, TLO and SLO for Application Condition 2, 5 ............................................ 20 Figure 7.2-2b: MOC-EOC MCPRP limit, TLO and SLO for Application Condition 2, 5 ............................................ 21 Figure 7.2-3a: BOC-MOC MCPRP limit, TLO and SLO for Application Condition 3, 6, 7 ........................................ 22 Figure 7.2-3b: MOC-EOC MCPRP limit, TLO and SLO for Application Condition 3, 6, 7 ........................................ 23 Figure 8.2-1a: BOC-EOC TLO LHGRFACF Multiplier for Application Conditions 1-7 .............................................. 24 Figure 8.2-1b: BOC-EOC SLO LHGRFACF Multiplier for Application Conditions 1-7 .............................................. 25 Figure 8.3-1: GNF3 LHGRFACP Multiplier for Application Condition 1, 2, 4, and 5 ................................................. 26 Figure 8.3-2: GNF3 LHGRFACP Multiplier for Application Condition 3, 6, and 7 ..................................................... 27 Figure 9.1-1: Monitored Region Boundary (Case 1) ................................................................................................ 28 Figure 9.1-2: Monitored Region Boundary (Case 2) ................................................................................................ 29 Figure 9.1-3: APRM for High Scram and Restricted Region Boundary (TLO Case 1) ............................................ 30 Figure 9.1-4: APRM for High Scram and Restricted Region Boundary (TLO Case 2) ............................................ 31 Figure 9.1-5: APRM for High Scram and Restricted Region Boundary (SLO Case 1) ............................................ 32 Figure 9.1-6: APRM for High Scram and Restricted Region Boundary (SLO Case 2) ............................................ 33 Figure 9.1-7: APRM for High Rod-Block Setpoints (TLO Case 1) ........................................................................... 34 Figure 9.1-8: APRM for High Rod-Block Setpoints (TLO Case 2) ........................................................................... 35 Figure 9.1-9: APRM for High Rod-Block Setpoints (SLO Case 1) ........................................................................... 36 Figure 9.1-10: APRM for High Rod-Block Setpoints (SLO Case 2) ......................................................................... 37 Page 4 of 37 COLR Rev. 23-1

River Bend Station Core Operating Limits Report Cycle 23 Revision 1 1.0 PURPOSE The COLR is controlled as a License Basis Document and is revised accordingly for each fuel cycle or remaining portion of a fuel cycle. Any revisions to the COLR must be submitted to the NRC for information as required by Tech Spec 5.6.5 and tracked by RBS License Commitment L11358.

2.0 SCOPE As defined in Technical Specification 1.1, the COLR is the document that provides the core operating limits for the current fuel cycle. This document is prepared in accordance with Technical Specification 5.6.5 for each reload cycle using NRC-approved analytical methods.

The limits included in this report are:

1) LCO 3.2.1, Average Planar Linear Heat Generation Rate (APLHGR)

2) LCO 3.2.2, Minimum Critical Power Ratio (MCPR), including power and flow dependent limits

3) LCO 3.2.3, Linear Heat Generation Rate (LHGR), including power and flow dependent limits

4) LCO 3.2.4, Fraction of Core Boiling Boundary (FCBB)

5) LCO 3.3.1.1, RPS Instrumentation (RPS), Function 2.b

6) LCO 3.3.1.3, Periodic Based Detection System (PBDS)

3.0 REFERENCES

This section contains the background, cycle-specific, and methodology references used in the current cycle reload analysis.

3.1 Current Cycle References 3.1.1 ECH-NE-22-00027, Rev. 1, Supplemental Reload Licensing Report for River Bend Station - Unit 1, Reload 22, Cycle 23, GNF, 006N6220, Rev. 1, October 2023.

3.1.2 ECH-NE-22-00026, Rev. 0, Fuel Bundle Information Report for River Bend Station - Unit 1 Reload 22 Cycle 23, GNF, 006N6221, Rev. 0, November 2020.

3.1.3 Letter, R. E. Kingston to G. W. Scronce, Time Constant Values for Simulated Thermal Power Monitor, RBC-46410, November 30, 1995.

3.1.4 RBS Updated Safety Analysis Report 3.1.5 GNF006N6222, Rev. 0, Nuclear Design Report for River Bend Cycle 23, GNF, KGO-ENO-LD1-22-89, September 2022.

3.1.6 TDP-0065 Rev. 8 OPL-7 Design Data.

3.1.7 ECH-NE-18-00033 Rev. 0, Entergy Operations, Inc. River Bend Station TRACG Implementation for Reload Licensing Transient Analysis (T1309); GEH 003N9955-R0, July 2018.

3.1.8 SC 21-04, Rev. 1, Fuel Support Side Entry Orifice Meta-Stable Flow for 2 Beam Locations in the BWR/6 Reactors, GEH, June 17, 2021.

Page 5 of 37 COLR Rev. 23-1

River Bend Station Core Operating Limits Report Cycle 23 Revision 1 3.2 Methodology References The following are applicable to GNF supplied fuel.

3.2.1 NEDE-24011-P-A-31-US, General Electric Standard Application for Reactor Fuel (GESTAR-II),

November 2020.

3.2.2 NEDC-33879P, Revision 4, GNF3 Generic Compliance with NEDE-24011-P-A (GESTAR II),

August 2020.

4.0 DEFINITIONS 4.1 Average Planar Linear Heat Generation Rate (APLHGR) - the APLHGR shall be applicable to a specific planar height and is equal to the sum of the linear heat generation rates for all the fuel rods in the specified bundle at the specified height divided by the number of fuel rods in the fuel bundle.

4.2 Average Planar Exposure - the Average Planar Exposure shall be applicable to a specific planar height and is equal to the sum of the exposure of all the fuel rods in the specified bundle at the specified height divided by the number of fuel rods in the fuel bundle.

4.3 Critical Power Ratio (CPR) - the ratio of that power in the assembly, which is calculated by application of the fuel vendors appropriate boiling correlation, to cause some point in the assembly to experience boiling transition, divided by the actual assembly operating power.

4.4 Core Operating Limits Report (COLR) - The River Bend Station specific document that provides core operating limits for the current reload cycle in accordance with Technical Specification 5.6.5.

4.5 Linear Heat Generation Rate (LHGR) - the LHGR shall be the heat generation per unit length of fuel rod. It is the integral of the heat flux over the heat transfer area associated with the unit length.

4.6 Minimum Critical Power Ratio (MCPR) - the MCPR shall be the smallest CPR which exists in the core.

4.7 MCPR Safety Limit (SLMCPR, MCPR 99.9%) - the cycle specific minimum value of the CPR that ensures that 99.9% of the fuel rods avoid boiling transition during any moderate frequency transient.

4.8 SLMCPR95/95 - the cycle independent, fuel design dependent MCPR safety limit found in the technical specifications that ensures there is a 95% probability at a 95% confidence level that no rods will be susceptible to transition boiling.

4.9 Aligned Drive Flow - Adjusted FCTR card input drive flow signal that accounts for actual variations in the core flow to drive flow relationship.

4.10 Monitored Region - The area of the core power and flow operating domain where the reactor may be susceptible to reactor instabilities under conditions exceeding the licensing basis of the current reactor system.

4.11 Restricted Region - The area of the core power and flow operating domain where the reactor is susceptible to reactor instabilities in the absence of restrictions on core void distributions.

4.12 Setpoint Setup - A FCTR card feature that sets the normal non-setup E1A APRM flow-biased scram and control rod block trip reference setpoints associated with the Exclusion and Restricted Regions higher to permit required reactor maneuvering in the Restricted Region when stability controls are in effect.

4.13 End of Rated (EOR) - the cycle exposure corresponding to all rods out, 100% power/100% flow, and normal feedwater temperature. (Corresponding to Core Average Exposure 35,799 MWd/MT, or 32,477 MWd/ST) [Reference 3.1.1. Section 3].

Page 6 of 37 COLR Rev. 23-1

River Bend Station Core Operating Limits Report Cycle 23 Revision 1 4.14 MOC - Middle of Cycle (EOR - 4,409 MWd/MT, 4,000 MWd/ST) [Reference 3.1.1, Table 1].

4.15 EOC - End of Cycle 4.16 FFWTR - Final Feedwater Temperature Reduction.

4.17 FHOOS - Feedwater Heater Out of Service.

4.18 PROOS - Pressure Regulator Out of Service.

4.19 SLO - Single Loop Operation.

4.20 TBOOS -Turbine Bypass Out of Service 4.21 GNF - Global Nuclear Fuel 4.22 EOC-RPT - End of Cycle Recirculation Pump Trip 4.23 Reference Core Loading Pattern - The Core Loading Pattern Used for Reload Licensing Analysis.

4.24 Application Condition - The combination of equipment out of service conditions for which LHGRFAC and MCPR limits are determined [Reference 3.1.1, Section 11]. The Application Conditions are as follows:

Application FWHOOS / EOC-RPT PROOS TBOOS Condition FFWTR OOS 1 X 2 X X 3 X X 4 X X 5 X X X 6 X X X 7 X X X X All application conditions address the licensed core flow.

4.25 Pbypass - Reactor Thermal Power (RTP) level below which the Turbine Stop Valve position and the Turbine Control Valve fast closure scrams are bypassed. Per TS Table 3.3.1.1-1, Pbypass RTP =

40% RTP.

4.26 Operating Limit MCPR (OLMCPR) - Limiting transients are analyzed either with TRACG or other NRC-approved methodologies. The types of transients evaluated are loss of flow, increase in pressure and power, positive reactivity insertion, and coolant temperature increase. The TRACG methodology calculates an operating limit MCPR (OLMCPR) for the transient initial condition that will result in no more than 0.1% of the fuel rods susceptible to boiling transition. The other methodologies calculate a reduction in CPR for each transient, with the largest change in CPR (delta-CPR) resulting from the limiting transient. When the largest delta-CPR is added to the MCPR SL, an OLMCPR is obtained. The OLMCPR, calculated by either the TRACG or other methodology, sets the core operating limits.

Page 7 of 37 COLR Rev. 23-1

River Bend Station Core Operating Limits Report Cycle 23 Revision 1 5.0 CORE DESIGN 5.1 Reference Core Loading Pattern The original Reference Core Loading pattern is presented in Reference 3.1.1. The Reference Loading Pattern (RLP) pattern can be found in Reference 3.1.5.

5.2 Control Rods The River Bend core utilizes the GE design control rods, non GE design CR-82M and CR-82M-1 bottom entry cruciform control rods. These control rod designs are discussed in more detail in Reference 3.1.4, Sections 4.1 and 4.2.

6.0 AVERAGE PLANAR LINEAR HEAT GENERATION RATE (APLHGR)

Per Technical Specification 3.2.1, all APLHGR values shall not exceed the exposure-dependent limits reported as follows:

Fuel Type Figure GNF3 6.1-1 For single loop operation (SLO), an ECCS/LOCA multiplier of 0.83 [Reference 3.1.1, Table 9] is applied to the APLHGR limits for the GNF3 fuel type.

7.0 MINIMUM CRITICAL POWER RATIO (MCPR)

For Cycle 23, the cycle specific SLMCPR (MCPR99.9%) for Two Loop Operation (TLO) is 1.09. The cycle specific SLMCPR (MCPR99.9%) for Single Loop operation is 1.11. [Reference 3.1.1, Section 11]

Per Technical Specification 3.2.2, the MCPR values shall be equal to or greater than the operating limit for operation at 23.8% of rated thermal power. The operating limit is the maximum of the flow-dependent minimum critical power ratio (MCPRF) and the power-dependent minimum critical power ratio (MCPRP).

For power level less than Pbypass, the MCPRp can be directly read from Figure 7.0.a for AOO application conditions when Pressure Regulator is operable or from Figure 7.0.b, when Pressure Regulator is out of service.

Above Pbypass, the MCPRp is the product of the rated power and flow MCPR application condition operating limit presented in Table 7.0 [Ref. 3.1.1, Section 11, Limiting Pressurization Events OLMCPR Summary Table], and the K(P) factor presented in Figure 7.0.a for AOO application conditions when Pressure Regulator is operable, or from Figure 7.0.b, when Pressure Regulator is out of service.

MCPRF and MCPRP, including the calculated MCPRP limits for thermal powers above Pbypass, are provided in Sections 7.1 and 7.2 below. These limits address the Cycle 23 cycle exposure ranges, two loop (TLO) and single loop operation (SLO), and seven application conditions.

During SLO, the Operating Limit MCPR shall be increased to account for the Pump Seizure limit and the higher SLMCPR in SLO. The GNF3 Rated Power Equivalent SLO Pump Seizure event OLMCPR is limiting at 1.47 for BOC-EOC operation. For SLO, the MCPR F and MCPRP below Pbypass operating limits are 0.02 greater than the two loop value [Reference 3.1.1, Section 11]. For calculated MCPR P limits for thermal powers above Pbypass, use SLO figures provided for Section 7.2 below.

GEH Safety Communication 21-04 (Reference 3.1.8) identifies a metastable flow condition that may exist in a BWR/6 in core locations fed by a side entry orifice adjacent to two core support cross beams. The vendor has been unable to determine the frequency of occurrence of this flow condition, if any. This flow Page 8 of 37 COLR Rev. 23-1

River Bend Station Core Operating Limits Report Cycle 23 Revision 1 condition results in a higher loss coefficient and lower CPR (applied as higher MCPR limits). To be conservative, it is assumed this condition always exists, so a MCPR penalty is always applied. The MCPR limits from the SRLR (Reference [3.1.1]) are updated to apply the penalty recommended by SC 21-04 as directed by Reference [3.1.6].

7.1 Flow-Dependent Minimum Critical Power Ratio (MCPR F) Values:

The MCPRF curves from Reference 3.1.1, Appendix D, applicable to all Cycle 23 exposures for TLO and SLO limits are found in the following figure:

Figure Application Condition TLO and SLO GNF3 1-7 7.1-1 7.2 Power-Dependent Minimum Critical Power Ratio (MCPR P) Values:

The TLO and SLO MCPRP curves include the Reference 3.1.1, Appendix D reported MCPRP for thermal powers no larger than Pbypass, and the calculated MCPRP limits for thermal powers above Pbypass. They are found in the following figures:

Figure Application Condition BOC - MOC MOC - EOC GNF3 GNF3 1, 4 7.2-1a 7.2-1b 2, 5 7.2-2a 7.2-2b 3, 6, 7 7.2-3a 7.2-3b More limiting values of the power dependent limits may be used in lieu of those indicated by a particular operating mode. For example, EOC values may be used instead of the MOC values.

8.0 LINEAR HEAT GENERATION RATE (LHGR)

Per Technical Specification 3.2.3, the LHGR values for any rod at any axial location shall not exceed the exposure-dependent limits multiplied by the smaller of either the power-dependent or flow-dependent LHGR factors.

For single loop operation (SLO), ECCS/LOCA multiplier of 0.83 [Reference 3.1.1, Table 9] is applied to the LHGRF limits for all fuel types.

For two recirculation loop and single recirculation loop operation the LHGR multiplier is as follows:

For two recirculation loop operation:

LHGRFAC = MIN (LHGRFACP, LHGRFACF)

For single loop operation:

LHGRFAC = MIN (LHGRFACP, LHGRFACF(SLO))

Page 9 of 37 COLR Rev. 23-1

River Bend Station Core Operating Limits Report Cycle 23 Revision 1 8.1 Exposure-Dependent Linear Heat Generation Rate (LHGR) Values:

GNF3 exposure-dependent LHGR values are considered GNF proprietary and will not be contained in the COLR. As described in Reference 3.1.2, Section 1, the GNF3 LHGR values may be found in Reference 3.2.2.

8.2 Flow-Dependent Linear Heat Generation Rate Factors (LHGRFAC F) Values:

The LHGRFACF curves are from Reference 3.1.1, Appendix D and are found on Figure 8.2-1a for TLO, and on Figure 8.2-1b for SLO. Figures 8.2-1a and Figure 8.2-1b are valid for all Cycle 23 fuel in BOC to EOC exposure range.

8.3 Power-Dependent Linear Heat Generation Rate Factors (LHGRFAC P) Values:

The LHGRFACP curves are from Reference 3.1.1, Appendix D and are found in the following figures:

Figure Application Conditions GNF3 TLO and SLO, BOC-EOC 1, 2, 4, and 5 8.3-1 3, 6, and 7 8.3-2 More limiting values of the power dependent multipliers may be used in lieu of those indicated by a particular operating mode.

9.0 STABILITY The following Technical Specifications / Technical Requirements contain stability related requirements:

TS 3.2.4, Fraction of Core Boiling Boundary (FCBB)

TS 3.3.1.1, RPS Instrumentation (RPS)

TS 3.3.1.3, Periodic Based Detection System (PBDS)

TR 3.3.1.1, RPS Instrumentation (RPS)

TR 3.3.2.1, Control Rod Block Instrumentation Page 10 of 37 COLR Rev. 23-1

River Bend Station Core Operating Limits Report Cycle 23 Revision 1 9.1 Stability Region Boundaries and Setpoints This section contains region boundaries, setpoints and other stability related requirements. The stability region boundaries and setpoints are as follows Description Figure Monitored Region Boundary (Case 1) 9.1-1 Monitored Region Boundary (Case 2) 9.1-2 APRM Flow Biased Simulated Thermal Power - High Scram Setpoints and Restricted 9.1-3 Region Boundary (Two Recirculation Loop Operation - Case 1)

APRM Flow Biased Simulated Thermal Power - High Scram Setpoints and Restricted 9.1-4 Region Boundary (Two Recirculation Loop Operation - Case 2)

APRM Flow Biased Simulated Thermal Power - High Scram Setpoints and Restricted 9.1-5 Region Boundary (Single Recirculation Loop Operation - Case 1)

APRM Flow Biased Simulated Thermal Power - High Scram Setpoints and Restricted 9.1-6 Region Boundary (Single Recirculation Loop Operation - Case 2)

APRM Flow Biased Neutron Flux - High Rod-Block Setpoints (Two Recirculation Loop 9.1-7 Operation - Case 1)

APRM Flow Biased Neutron Flux - High Rod-Block Setpoints (Two Recirculation Loop 9.1-8 Operation - Case 2)

APRM Flow Biased Neutron Flux - High Rod-Block Setpoints (Single Recirculation Loop 9.1-9 Operation - Case 1)

APRM Flow Biased Neutron Flux - High Rod-Block Setpoints (Single Recirculation Loop 9.1-10 Operation - Case 2)

Note: For Figures 9.1-3 to 9.1-10, the Nominal Setpoints should be used for indicating the entry into a particular stability region as allowed and appropriate actions be taken prior to the entry In the table above, two distinct operating states (Case 1 and Case 2) are considered. These are described as follows:

Case 1 - Normal Feedwater Heating Operation or Low Reactor Power :

TFW at rated TFW DESIGN at rated 50 F , and rated equivalent at off-rated reactor conditions OR P 30% RTP Case 2 - Reduced Feedwater Heating Operation:

TFW at rated TFW DESIGN at rated 50 F AND P 30% RTP The APRM Flow Biased Simulated Thermal Power - High scram setpoint and Restricted Region Boundary, and APRM Flow Biased Neutron Flux - High Rod-Block Setpoints are given in terms of aligned drive flow.

The aligned drive flow is calculated from the input drive flow using the following relationship:

Page 11 of 37 COLR Rev. 23-1

River Bend Station Core Operating Limits Report Cycle 23 Revision 1 101.209 40 31.028 100 70.181 WD~

WD 70.181 100 40 Where: W D~ = FCTR card input drive flow in percent rated, WD = Aligned drive flow in percent rated, 40 = Low flow drive flow alignment setting, and 100 = High flow drive flow alignment setting.

9.2 APRM Flow Biased Simulated Thermal PowerHigh Time Constant (SR 3.3.1.1.14)

The simulated thermal power time constant is 6 +/- 0.6 seconds (Reference 3.1.3). Thus the maximum simulated thermal power time constant for use in meeting the surveillance requirement is 6.6 seconds.

Page 12 of 37 COLR Rev. 23-1

River Bend Station Core Operating Limits Report Cycle 23 Revision 1 Average Planar MAPLHGR Limit Exposure (GWd/MT) (kW/ft) 0.00 14.36 23.40 13.01 45.00 10.75 63.50 8.00 70.00 6.00 Page 13 of 37 COLR Rev. 23-1

River Bend Station Core Operating Limits Report Cycle 23 Revision 1 Table 7.0: OLMCPR Summary Table Operating Limit MCPR (OLMCPR)

Application 100% RTP, GNF3, TLO Condition BOC - MOC MOC - EOC 1 1.32 1.38 2 1.34 1.38 3 1.38 1.43 4 1.32 1.38 5 1.34 1.38 6 1.38 1.43 7 1.38 1.43 Page 14 of 37 COLR Rev. 23-1

River Bend Station Core Operating Limits Report Cycle 23 Revision 1 Figure 7.0.a - MCPRp limit and K(P) multiplier for Application Conditions 1, 2, 4, and 5 2.2 Operating Limit MCPR (P) = K(P)

Operating Limit MCPR(100) 2.1 For P<23.8%: No Thermal Limits Monitoring Required, No limits specified.

Rated MCPR Multiplier - K(P) for P>40%, OLMCPR (P) for P<Pbypass 2.0 For 23.8%PP(Bypass), P(Bypass)=40%

OLMCPR(P)=1.79 +0.0086*(40%-P), Flow<50%

1.9 OLMCPR(P)=1.92 +0.0154*(40%-P), Flow50%

For P>P(Bypass) 1.8 K(P)=1.220+0.00330*(50%-P), 40%< P 50%

K(P)=1.150+0.00350*(70%-P), 50%< P 70%

K(P)=1.045+0.00260*(85%-P), 70%< P 85%

1.7 K(P)=1.000+0.00300*(100%-P), 85%< P 100%

1.6 1.5 1.4 1.3 1.2 1.1 1.0 20 30 40 50 60 70 80 90 100 110 Power (% rated)

Page 15 of 37 COLR Rev. 23-1

River Bend Station Core Operating Limits Report Cycle 23 Revision 1 Figure 7.0.b - MCPRp limit and K(P) multiplier for Application Conditions 3, 6, and 7 2.2 Operating Limit MCPR (P) = K(P)

Operating Limit MCPR(100) 2.1 For P<23.8%: No Thermal Limits Monitoring Required, No limits specified.

Rated MCPR Multiplier - K(P) for P>40%, OLMCPR (P) for P<Pbypass 2.0 For 23.8%PP(Bypass), P(Bypass)=40%

OLMCPR(P)=1.79 +0.0086*(40%-P), Flow<50%

1.9 OLMCPR(P)=1.92 +0.0154*(40%-P), Flow50%

1.8 For P>P(Bypass)

K(P)=1.351+0.00750*(50%-P), 40%< P 50%

K(P)=1.272+0.00395*(70%-P), 50%< P 70%

1.7 K(P)=1.226+0.00307*(85%-P), 70%< P 85%

K(P)=1.000+0.00327*(100%-P), 85%< P 100%

1.6 1.5 1.4 1.3 1.2 1.1 1.0 20 30 40 50 60 70 80 90 100 110 Power (% rated)

Page 16 of 37 COLR Rev. 23-1

River Bend Station Core Operating Limits Report Cycle 23 Revision 1 Flow Loop Manual Loop Loop Manual Loop Auto

(% Rated) TLO Auto TLO SLO SLO 30.0 1.73 1.73 1.75 1.75 40.0 1.66 1.66 1.68 1.68 50.0 1.58 1.58 1.60 1.60 60.0 1.50 1.50 1.52 1.52 70.0 1.41 1.41 1.43 1.43 80.0 1.33 1.33 1.36 1.36 90.0 1.26 1.28 1.28 1.30 91.3 1.24 1.28 1.27 1.30 100.0 1.24 1.27 1.27 1.29 109.5 1.24 1.27 1.27 1.29 Page 17 of 37 COLR Rev. 23-1

River Bend Station Core Operating Limits Report Cycle 23 Revision 1 Power < 50.0% 50% Power < 50.0% 50%

(% Rated) Flow, SLO Flow, SLO (% Rated) Flow, TLO Flow, TLO 23.8 1.95 2.19 23.8 1.93 2.17 40.0 1.81 1.94 40.0 1.79 1.92 40.0 1.93 40.0 1.66 50.0 1.88 50.0 1.61 70.0 1.78 70.0 1.52 70.0 1.68 70.0 1.43 85.0 1.61 85.0 1.38 85.0 1.61 85.0 1.38 100.0 1.54 100.00 1.32 Page 18 of 37 COLR Rev. 23-1