ML25128A220
| ML25128A220 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 05/06/2025 |
| From: | Brown G Northern States Power Company, Minnesota, Xcel Energy |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| L-MT-25-016 TD-XCL-NAD-MN-058, Rev 0 | |
| Download: ML25128A220 (1) | |
Text
ATTACHMENT MONTICELLO NUCLEAR GENERATING PLANT CYCLE 33 CORE OPERATING LIMITS REPORT TD-XCL-NAD-MN-058 Revision 0 (28 pages follow)
Monticello Cycle 33 Core Operating Limits Report (COLR)
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Page 1 of 28 TD-XCL-NAD-MN-058 Monticello Cycle 33 Core Operating Limits Report (COLR)
Revision 0 Prepared by: MOC LDR 600001263793 Michael Young Senior Engineer, Nuclear Analysis and Design Prepared by: MOC LDR 600001263792 Sam Jenko Senior Engineer, Nuclear Analysis and Design Verified by:
MOC LDR 600001263791 Steve Winston Senior Engineer, Nuclear Analysis and Design Reviewed by: MOC LDR 600001263790 Jared Birkmann Engineer II, Reactor Engineering Approved by: MOC LDR 600001263789 Melissa Limbeck Manager, Nuclear Analysis and Design
Monticello Cycle 33 Core Operating Limits Report (COLR)
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Page 2 of 28 REVISION HISTORY Revision Description 0
Initial Release.
Monticello Cycle 33 Core Operating Limits Report (COLR)
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Page 3 of 28 TABLE OF CONTENTS 1 CORE OPERATING LIMITS REPORT (COLR)...................................................................... 5 2 AVERAGE PLANAR LINEAR HEAT GENERATION RATE (APLHGR)................................ 6 2.1 MAPLHGR LIMITS........................................................................................................... 6 3 MINIMUM CRITICAL POWER RATIO (MCPR)....................................................................... 6 3.1 TECHNICAL SPECIFICATION SCRAM TIME DEPENDENCE.................................................. 7 3.2 TECHNICAL SPECIFICATION SCRAM SPEED (TSSS)........................................................ 8 3.3 NOMINAL SCRAM SPEED (NSS)...................................................................................... 8 3.4 SINGLE LOOP OPERATION (SLO)..................................................................................... 9 3.5 PRESSURE REGULATOR OUT-OF-SERVICE (PROOS)....................................................... 9 3.6 MAIN STEAM ISOLATION VALVE OUT-OF-SERVICE (MSIVOOS)........................................ 9 4 LINEAR HEAT GENERATION RATE (LHGR)...................................................................... 15 4.1 LHGR LIMITS................................................................................................................. 15 4.2 PRESSURE REGULATOR OUT-OF-SERVICE (PROOS)..................................................... 16 4.3 MAIN STEAM ISOLATION VALVE OUT-OF-SERVICE (MSIVOOS)...................................... 16 5 ROD BLOCK MONITOR (RBM)............................................................................................ 20 5.1 OPERABILITY REQUIREMENTS........................................................................................ 20 5.2 UPSCALE TRIP SETPOINT ALLOWABLE VALUES.............................................................. 20 6 AVERAGE POWER RANGE MONITOR (APRM) SIMULATED THERMAL POWER - HIGH, W ALLOWABLE VALUE.................................................................................................... 21 7 CORE STABILITY REQUIREMENTS.................................................................................... 22 7.1 BEO-III SOLUTION......................................................................................................... 22 7.2 BEO-III OPRM SETPOINTS............................................................................................ 22 7.3 BACKUP STABILITY PROTECTION (BSP) REGIONS.......................................................... 22 7.4 ACTIONS FOR ENTRY INTO SCRAM REGION.................................................................... 23 7.5 ACTIONS FOR ENTRY INTO CONTROLLED ENTRY REGION............................................... 23 8 TURBINE BYPASS SYSTEM RESPONSE TIME................................................................. 24 9 POWER-FLOW MAP............................................................................................................. 25 10 REFERENCES....................................................................................................................... 27 11 APPROVED ANALYTICAL METHODS................................................................................ 28
Monticello Cycle 33 Core Operating Limits Report (COLR)
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Page 4 of 28 LIST OF TABLES Table 1: ATRIUM 10XM MAPLHGR Limits................................................................................... 6 Table 2: ATRIUM 11 MAPLHGR Limits........................................................................................ 6 Table 3: SLMCPR......................................................................................................................... 7 Table 4: NSS SCRAM Insertion Time to CRD Notch Position...................................................... 8 Table 5:MCPRf Data*.................................................................................................................. 10 Table 6:MCPRp Data for TLO and TSSS*................................................................................... 11 Table 7:MCPRp Data for TLO and NSS*..................................................................................... 12 Table 8:MCPRp Data for SLO*.................................................................................................... 13 Table 9: ATRIUM 10XM Rated Condition LHGR Limits*............................................................ 15 Table 10: ATRIUM 11 Rated Condition LHGR Limits*................................................................ 15 Table 11:LHGRFACf Data*......................................................................................................... 17 Table 12:LHGRFACp Data for ATRIUM 10XM*.......................................................................... 18 Table 13:LHGRFACp Data for ATRIUM 11*................................................................................ 19 Table 14: RBM Operability Requirements.................................................................................. 20 Table 15: RBM Technical Specification Trip Setpoints and Allowable Values............................ 20 Table 16: APRM Simulated Thermal Power - High, W Allowable Value................................. 21 Table 17: Licensed OPRM Amplitude Setpoint........................................................................... 22 Table 18: BSP Endpoints for Normal Feedwater Temperature.................................................. 23 LIST OF FIGURES Figure 1: MCPRf Limits............................................................................................................... 10 Figure 2: MCPRp Limits for TLO and TSSS................................................................................ 11 Figure 3: MCPRp Limits for TLO and NSS.................................................................................. 12 Figure 4: MCPRp Limits for SLO................................................................................................. 13 Figure 5: Interim PROOS MFLCPR Limit for TLO and NSS....................................................... 14 Figure 6: LHGRFACf Multipliers.................................................................................................. 17 Figure 7: LHGRFACp Multipliers for ATRIUM 10XM................................................................... 18 Figure 8: LHGRFACp Multipliers for ATRIUM 11........................................................................ 19 Figure 9: Power-Flow Map.......................................................................................................... 26 LIST OF EQUATIONS Equation 1: MAPLHGR for SLO.................................................................................................... 6 Equation 2: Average SCRAM Time.............................................................................................. 7 Equation 3: Average SCRAM Time for Notch Position P Test...................................................... 8 Equation 4: MCPRf Calculation................................................................................................... 10 Equation 5: MCPRp Calculation for TLO and TSSS.................................................................... 11 Equation 6: MCPRp Calculation for TLO and NSS...................................................................... 12 Equation 7: MCPRp Calculation for SLO..................................................................................... 13 Equation 8: Interim PROOS MFLCPR Calculation for TLO and NSS......................................... 14 Equation 9: LHGRFACf Calculation............................................................................................ 17 Equation 10: LHGRFACp Calculation for ATRIUM 10XM........................................................... 18 Equation 11: LHGRFACp Calculation for ATRIUM 11................................................................. 19
Monticello Cycle 33 Core Operating Limits Report (COLR)
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CORE OPERATING LIMITS REPORT (COLR)
This Core Operating Limits Report (COLR) for Monticello Nuclear Generating Plant (MNGP) Cycle 33 is prepared in accordance with the requirements of Technical Specification 5.6.3. The core operating limits are developed using NRC-approved methodology as listed in Section 11 of this COLR and are established such that all applicable thermal limits of the plant safety analysis are met.
The base case limits support operation with the following Equipment Out-Of-Service (EOOS) conditions:
Up to three (3) Safety Relief Values Out-Of-Service (SRVOOS)
Up to one (1) Transversing Incore Probe Out-Of-Service (TIPOOS) or the equivalent number of TIP channels and a Local Power Range Monitor (LPRM) calibration interval of 1000 MWd/ST core average exposure Up to one (1) Main Steam Isolation Valve Out-Of-Service (MSIVOOS)
The following EOOS limits are also supported:
Single Loop Operation (SLO), which may be combined with other EOOS Pressure Regulator Out-Of-Service (PROOS)
A 0.03 penalty has been applied to the Safety Limit (SL) Minimum Critical Power Ratio (MCPR) when the ratio of core power to core flow is 42 MWth/Mlbm/hr in the Extended Flow Window (EFW) region. This penalty has been incorporated into the Operating Limit Minimum Critical Power Ratio (OLMCPR). The 0.03 penalty is not applied when MNGP is operating in the Maximum Extended Load Line Limit (MELLLA) region or operating in the Extended Flow Window (EFW) region where the ratio of core power to core flow is <42 MWth/Mlbm/hr. The OLMCPRs in Section 3 of this COLR were selected to ensure that the MCPR SLs of Technical Specification SL 2.1 are not violated. Note that SLO is not permitted in the EFW region.
This report includes the Best-estimate Enhanced Option III (BEO-III) long term stability solution, which is required to operate in the EFW (aka, MELLLA+) region of the Power-Flow map.
This report includes using S-RELAP5 Reference [1], XCOBRA Reference [2], RODEX4 Reference [3] and CASMO-4/MICROBURN-B2 Reference [4], as described in the Framatome THERMEX methodology report Reference [2] and neutronics methodology report Reference [5].
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AVERAGE PLANAR LINEAR HEAT GENERATION RATE (APLHGR)
The APLHGR limits as a function of average planar exposure bound all fuel lattice types in a given fuel bundle design to establish APLHGR limits for Technical Specification 3.2.1. APLHGR is monitored on a maximum (i.e. MAPLHGR) limit basis.
MAPLHGR limits for the ATRIUM 10XM fuel and ATRIUM 11 fuel are determined based on the approved methodology referenced in Monticello Technical Specification 5.6.3.b and are loaded into the process computer for use in core monitoring calculations. Note MAPLHGR is fuel type dependent and is not affected by PROOS and MSIVOOS.
2.1 MAPLHGR Limits The MAPLHGR limits for ATRIUM 10XM and ATRIUM 11 shall be determined for TLO from Table 1 and Table 2, respectively, and the limits are reduced for SLO by the prescribed multiplier, as shown in Equation 1:
Equation 1: MAPLHGR for SLO Table 1: ATRIUM 10XM MAPLHGR Limits Average Planar Exposure
[GWD/MTU]
MAPLHGR Limit*
[kW/ft]
0 12.5 20 12.5 67 7.6
- SLO Multiplier = 0.70 Table 2: ATRIUM 11 MAPLHGR Limits Average Planar Exposure
[GWD/MTU]
MAPLHGR Limit*
[kW/ft]
0 10.0 20 10.0 60 9.0 69 7.2
- SLO Multiplier = 0.80 Interpolation between nearest data points is permitted.
Reference:
Technical Specification 3.2.1.
3 MINIMUM CRITICAL POWER RATIO (MCPR)
The cycle specific MCPR limits protect the MCPR95%/95% limit of 1.05 which is a generic value based on the ATRIUM 10XM and ATRIUM 11 fuel type and the ACE correlation.
Monticello Cycle 33 Core Operating Limits Report (COLR)
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Page 7 of 28 The cycle specific MCPR limits are based on MCPR99.9% values for the conditions in Table 3, which meet the requirement in Technical Specification 2.1.1.3; and combined with the limiting MCPR protect against Anticipated Operational Occurrences (AOOs) to establish OLMCPR limits for Technical Specification 3.2.2.
Table 3: SLMCPR Condition SLMCPR TLO outside of EFW or in EFW where ratio of core power to core flow <42 MWt /
Mlbm/hr 1.08 TLO in EFW where ratio of core power to core flow 42 MWt / Mlbm/hr 1.11 SLO 1.09 MCPR flow (MCPRf) and power-dependent (MCPRp) limits for the ATRIUM 10XM fuel and ATRIUM 11 fuel are determined based on the approved methodology referenced in Monticello Technical Specification 5.6.3.b and are loaded into the process computer for use in core monitoring calculations. Note MCPRf and MCPRp are fuel type independent.
3.1 Technical Specification SCRAM Time Dependence Technical Specification 3.1.4 and Table 3.1.4-1 provide the scram insertion time versus position requirements. Technical Specification Surveillance Requirements SR 3.1.4.1 - SR 3.1.4.4 provide the surveillance requirements for the Control Rod Drives (CRDs). Data from testing of the CRDs, or from an unplanned scram, is gathered in Surveillance Test 0081.
Using this cycle specific information, values of
can be calculated in accordance with the equation below for each notch position (P = 46, 36, 26, and 06).
Equation 2 is used to calculate the average of the current scram times for the cycle:
Equation 2: Average SCRAM Time N
N i
i P
ave P
1
Where:
=
The SCRAM time to notch position P for control rod i from its most recent surveillance test.
=
The number of operable control rods not declared slow (N 121).
=
The notch position (P = 46, 36, 26, and 06).
=
The sum of the most recent scram times for all operable control rods not declared slow (N) measured to notch position P to comply with the Technical Specification surveillance requirements SR 3.1.4.1, SR 3.1.4.2, SR 3.1.4.3, SR 3.1.4.4.
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Page 8 of 28 The average SCRAM time for notch position (P),
is tested against the Nominal SCRAM Speed (NSS) for that notch position () using Equation 3:
Equation 3: Average SCRAM Time for Notch Position P Test
Where:
=
The SCRAM time to notch position P for control rod i from its most recent surveillance test.
=
The NSS for the specified CRD Notch Position (P) from Table 4.
Table 4: NSS SCRAM Insertion Time to CRD Notch Position Notch Position (P) NSSP [s]
46 0.304 36 0.820 26 1.355 06 2.477 If the average SCRAM time satisfies the Equation 3 criteria for each notch position, continued plant operation under the NSS OLMCPR for pressurization events is permitted. If the average SCRAM time fails the Equation 3 criteria for any notch position, the Technical Specification SCRAM Speed (TSSS) OLMCPR must be used for pressurization events.
No interpolation between NSS and TSSS operating limits is allowed.
3.2 Technical Specification SCRAM Speed (TSSS)
The OLMCPR for TSSS does not account for SCRAM speeds that are faster than those required by Technical Specifications. TLO is discussed below, whereas SLO is discussed in Section 3.4.
The TSSS OLMCPR shall be determined for TLO from:
Maximum[{MCPRf from Figure 1}, {MCPRp from Figure 2}]
Reference:
Technical Specification 3.2.2.
The OLMCPR for NSS does take into account the measured SCRAM speeds that are faster than the Technical Specification requirements, thus reducing the potential consequences of a limiting transient. TLO is discussed below, whereas SLO is discussed in Section 3.4. The NSS OLMCPR shall be determined for TLO from:
Maximum[{MCPRf from Figure 1}, {MCPRp from Figure 3}]
Reference:
Technical Specification 3.2.2.
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Page 9 of 28 3.4 Single Loop Operation (SLO)
For SLO, the SCRAM speed and PROOS conditions are bounded by a single set of limits and shall be determined from:
Maximum[{MCPRf from Figure 1}, {MCPRp from Figure 4}]
Reference:
Technical Specification 3.2.2.
3.5 Pressure Regulator Out-Of-Service (PROOS)
This section provides MCPRp limits when a backup pressure regulator is not operational (also called PROOS).
The Pressure Regulator Failure Down-Scale (PRFDS) event without backup pressure regulator was evaluated in Reference [6]. For TLO, PROOS MCPRp is bounded by the TSSS MCPRp, and therefore Section 3.2 applies. For SLO, Section 3.4 should be used.
An interim MFLCPR limit is provided in Figure 5 for TLO and NSS. This limit should only be used if the GARDEL thermal limit input has NOT been modified as described in Section 3.2.
That is, only Section 3.2 or Figure 5, individually, should be used to calculate the appropriate PROOS limits.
3.6 Main Steam Isolation Valve Out-Of-Service (MSIVOOS)
The one (1) MSIVOOS condition was evaluated in Reference [6]. The results show for both ATRIUM 10XM and ATRIUM 11 the OLMCPR limits are bounded by Section 3.2 and Section 3.3.
Operation with one MSIVOOS is limited to power levels 75% of rated.
Monticello Cycle 33 Core Operating Limits Report (COLR)
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Page 10 of 28 Figure 1: MCPRf Limits Equation 4: MCPRf Calculation Where:
=
Core Flow [%Rated].
=
Power [%Rated].
=
Intercept for linear interpolation, given in Table 5.
=
Slope for linear interpolation, given in Table 5.
Table 5:MCPRf Data*
Validity Intercept Slope Flow [%]
Power [%] Fuel Type A
B 20 F 30 25 P 100 All 1.9800
-0.0080 30 < F 80 25 P 100 All 1.9920
-0.0084 80 < F 107 25 P 100 All 1.3200 0.0000
- Interpolation results are accurate to three (3) decimals.
Monticello Cycle 33 Core Operating Limits Report (COLR)
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Page 11 of 28 Figure 2: MCPRp Limits for TLO and TSSS Equation 5: MCPRp Calculation for TLO and TSSS Where:
=
Core Flow [%Rated].
=
Power [%Rated].
=
Intercept for linear interpolation, given in Table 6.
=
Slope for linear interpolation, given in Table 6.
Table 6:MCPRp Data for TLO and TSSS*
Validity Intercept Slope Flow [%]
Power [%]
Fuel Type A
B All 25 P 40 All 2.5200 0.0000 All 40 < P 50 All 2.1200 0.0000 All 50 < P 60 All 2.7700
-0.0130 All 60 < P 70 All 1.9900 0.0000 All 70 < P 80 All 2.4100
-0.0060 F 82.9 80 < P 90 All 2.6500
-0.0090 F 82.9 90 < P 100 All 2.3800
-0.0060 F > 82.9 80 < P 90 All 3.2100
-0.0160 F > 82.9 90 < P 100 All 2.0400
-0.0030
- Interpolation results are accurate to three (3) decimals.
Monticello Cycle 33 Core Operating Limits Report (COLR)
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Page 12 of 28 Figure 3: MCPRp Limits for TLO and NSS Equation 6: MCPRp Calculation for TLO and NSS Where:
=
Core Flow [%Rated].
=
Power [%Rated].
=
Intercept for linear interpolation, given in Table 7.
=
Slope for linear interpolation, given in Table 7.
Table 7:MCPRp Data for TLO and NSS*
Validity Intercept Slope Flow [%]
Power [%]
Fuel Type A
B All 25 P 40 All 2.5200 0.0000 All 40 < P 50 All 2.7400
-0.0190 All 50 < P 60 All 1.9900
-0.0040 All 60 < P 70 All 2.2900
-0.0090 All 70 < P 80 All 1.7300
-0.0010 F 82.9 80 < P 90 All 1.8900
-0.0030 F 82.9 90 < P 100 All 2.3400
-0.0080 F > 82.9 80 < P 90 All 2.2100
-0.0070 F > 82.9 90 < P 100 All 2.2100
-0.0070
- Interpolation results are accurate to three (3) decimals.
Monticello Cycle 33 Core Operating Limits Report (COLR)
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Page 13 of 28 Figure 4: MCPRp Limits for SLO Equation 7: MCPRp Calculation for SLO Where:
=
Core Flow [%Rated].
=
Power [%Rated].
=
Intercept for linear interpolation, given in Table 8.
=
Slope for linear interpolation, given in Table 8.
Table 8:MCPRp Data for SLO*
Validity Intercept Slope Flow [%]
Power [%]
Fuel Type A
B F 52.5 25 P 40 All 2.5300 0.0000 F 52.5 40 < P 50 All 2.1300 0.0000 F 52.5 50 < P 60 All 2.7300
-0.0120 F 52.5 60 < P 66 All 2.0100 0.0000
- Interpolation results are accurate to three (3) decimals.
Monticello Cycle 33 Core Operating Limits Report (COLR)
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Page 14 of 28 Figure 5: Interim PROOS MFLCPR Limit for TLO and NSS Equation 8: Interim PROOS MFLCPR Calculation for TLO and NSS
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Page 15 of 28 4
LINEAR HEAT GENERATION RATE (LHGR)
The LHGR limits as a function of peak pellet exposure bound every node of the fuel rod including the natural uranium lattices to establish LHGR limits for Technical Specification 3.2.3.
LHGR limits for the ATRIUM 10XM fuel and ATRIUM 11 fuel at rated conditions are presented in Table 9 and Table 10, respectively. For off-rated conditions, the LHGR limits are modified by flow (LHGRFACf) and power-dependent (LHGRFACp) multipliers for off-rated conditions. The limits are based on the approved methodology referenced in Monticello Technical Specification 5.6.3.b and are loaded into the process computer for use in core monitoring calculations. Note that LHGR, LHGRFACf, and LHGRFACp are fuel type dependent; and LHGRFACp is also SCRAM speed and fuel batch dependent.
Table 9: ATRIUM 10XM Rated Condition LHGR Limits*
Peak Pellet Exposure
[GWD/MTU]
LHGR Limit
[kW/ft]
0.0 14.1 18.9 14.1 74.4 7.4
- Linear extrapolation beyond the final point in the table is allowed.
Table 10: ATRIUM 11 Rated Condition LHGR Limits*
Peak Pellet Exposure
[GWD/MTU]
LHGR Limit
[kW/ft]
0.0 13.6 21.0 13.6 53.0 10.2 80.0 3.5
- Linear extrapolation beyond the final point in the table is allowed.
4.1 LHGR Limits The LHGR limits for ATRIUM 10XM rated and adjusted for off-rated conditions and SCRAM speed shall be determined for TLO or SLO from:
{LHGR from Table 9}*Minimum[{LHGRFACf from Figure 6}, {LHGRFACp from Figure 7}]
The LHGR limits for ATRIUM 11 rated and adjusted for off-rated conditions and SCRAM speed shall be determined for TLO or SLO from:
{LHGR from Table 10}*Minimum[{LHGRFACf from Figure 6}, {LHGRFACp from Figure 8}]
Reference:
Technical Specification 3.2.3.
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Page 16 of 28 4.2 Pressure Regulator Out-Of-Service (PROOS)
The PRFDS event without backup pressure regulator was evaluated in Reference [6]. The results show for both ATRIUM 10XM and ATRIUM 11 the LHGR limits are bounded by Section 4.1.
4.3 Main Steam Isolation Valve Out-Of-Service (MSIVOOS)
The one (1) MSIVOOS condition was evaluated in Reference [6]. The results show for both ATRIUM 10XM and ATRIUM 11 the LHGR limits are bounded by Section 4.1. Operation with one MSIVOOS is limited to power levels 75% of rated.
Monticello Cycle 33 Core Operating Limits Report (COLR)
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Page 17 of 28 Figure 6: LHGRFACf Multipliers Equation 9: LHGRFACf Calculation Where:
=
Core Flow [%Rated].
=
Power [%Rated].
=
Intercept for linear interpolation, given in Table 11.
=
Slope for linear interpolation, given in Table 11.
Table 11:LHGRFACf Data*
Validity Intercept Slope Flow [%]
Power [%]
Fuel Type A
B 0 F 30 25 P 100 ATRIUM 10XM 0.5200 0.0000 30 < F 84.8 25 P 100 ATRIUM 10XM 0.2572 0.0088 84.8 < F 107 25 P 100 ATRIUM 10XM 1.0000 0.0000 0 F 30 25 P 100 ATRIUM 11 0.5500 0.0000 30 < F 83.1 25 P 100 ATRIUM 11 0.2958 0.0085 83.1 < F 107 25 P 100 ATRIUM 11 1.0000 0.0000
- Interpolation results are accurate to three (3) decimals.
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Page 18 of 28 Figure 7: LHGRFACp Multipliers for ATRIUM 10XM Equation 10: LHGRFACp Calculation for ATRIUM 10XM Where:
=
Core Flow [%Rated].
=
Power [%Rated].
=
Intercept for linear interpolation, given in Table 12.
=
Slope for linear interpolation, given in Table 12.
Table 12:LHGRFACp Data for ATRIUM 10XM*
Validity Intercept Slope Flow [%] Power [%] SCRAM Speed Fuel Type A
B F 60 25 P 40 Both ATRIUM 10XM 0.1700 0.0080 F > 60 25 P 40 Both ATRIUM 10XM 0.1867 0.0073 All 40 < P 50 Both ATRIUM 10XM 0.4600 0.0040 All 50 < P 80 Both ATRIUM 10XM 0.3933 0.0053 All 80 < P 90 Both ATRIUM 10XM 0.6600 0.0020 All 90 < P 100 NSS ATRIUM 10XM -0.0600 0.0100 All 90 < P 100 TSSS ATRIUM 10XM 0.3000 0.0060
- Interpolation results are accurate to three (3) decimals.
Monticello Cycle 33 Core Operating Limits Report (COLR)
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Page 19 of 28 Figure 8: LHGRFACp Multipliers for ATRIUM 11 Equation 11: LHGRFACp Calculation for ATRIUM 11 Where:
=
Core Flow [%Rated].
=
Power [%Rated].
=
Intercept for linear interpolation, given in Table 13.
=
Slope for linear interpolation, given in Table 13.
Table 13:LHGRFACp Data for ATRIUM 11*
Validity Intercept Slope Flow [%] Power [%] SCRAM Speed Fuel Type A
B F 60 25 P 40 Both ATRIUM 11 0.1400 0.0080 F > 60 25 P 40 Both ATRIUM 11 0.1733 0.0067 All 40 < P 50 Both ATRIUM 11 0.4900 0.0030 All 50 < P 80 Both ATRIUM 11 0.3400 0.0060 All 80 < P 90 Both ATRIUM 11 0.5000 0.0040 All 90 < P 100 NSS ATRIUM 11 Once Burn 0.0500 0.0090 All 90 < P 100 NSS ATRIUM 11 Fresh
-0.1300 0.0110 All 90 < P 100 TSSS ATRIUM 11 0.4100 0.0050
- Interpolation results are accurate to three (3) decimals.
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Page 20 of 28 5
ROD BLOCK MONITOR (RBM) 5.1 Operability Requirements The Rod Withdrawal Error (RWE) analysis performed in Reference [6] validated that the following MCPR values in Table 14 provide the required margin for full withdrawal of any control rod:
Table 14: RBM Operability Requirements Power [%Rated]* Operation MCPR [-]
30 P < 90 TLO 1.99 SLO 2.00 90 P TLO 1.44
- Note that the RBM is not credited below 30%
power as identified in Section 5.2.
When MCPR is below the limit for the conditions of Table 14, then a limiting control rod pattern exists and the RBM is required to be operable.
Reference:
Technical Specification Table 3.3.2.1-1 Function 1.
5.2 Upscale Trip Setpoint Allowable Values The RBM upscale Trip Setpoints and Allowable Values are calculated in Reference [7] and summarized in Table 15:
Table 15: RBM Technical Specification Trip Setpoints and Allowable Values Function Power*
[%Rated]
Trip Setpoint
[of full scale]
Allowable Values
[of full scale]
Low Power Range - Upscale 30 P < 65 121.2/125 121.6/125 Intermediate Power Range - Upscale 65 P < 85 116.2/125 116.6/125 High Power Range - Upscale 85 P 111.2/125 111.6/125
- MCPR is below limit specified in Section 5.1.
Reference:
Technical Specification Table 3.3.2.1-1 Functions 1.a, 1.b, and 1.c.
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Page 21 of 28 6
AVERAGE POWER RANGE MONITOR (APRM) SIMULATED THERMAL POWER - HIGH, W ALLOWABLE VALUE The Average Power Range Monitor (APRM) Simulated Thermal Power - High, W Allowable Value for TLO and SLO shall be determined from Table 16:
Table 16: APRM Simulated Thermal Power - High, W Allowable Value Operation SSTP [%Rated]
TLO 0.6167.2% 116%
SLO 0.5561.5%
Where:
=
SCRAM setting in percent of rated thermal power (2004 MWth).
=
Loop recirculation flow rate in percent of rated.
=
Difference between two-loop and single-loop effective recirculation flow at the same core flow (W = 5.4% for single loop operation, W = 0.0 for two-loop operation).
Reference:
Technical Specification Table 3.3.1.1-1, Function 2.b, footnote (b), and Reference [8]
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CORE STABILITY REQUIREMENTS 7.1 BEO-III Solution Monticello has implemented the Framatome BEO-III long term stability solution using the OPRM as described in Reference [9]. Exposure points are analyzed to provide margin to MCPR and Independent Channel Oscillation at a 95/95 confidence level. The BEO-III evaluation is documented in Reference [6]. A Backup Stability Protection (BSP) evaluation is also documented in Reference [6].
Reference:
Technical Specification 3.3.1.1 7.2 BEO-III OPRM Setpoints A reload BEO-III evaluation has been performed in accordance with the licensing methodology described in Reference [9]. The OPRM setpoints for TLO are conservative relative to SLO and are, therefore, bounding. The OPRM Period Based Detection Algorithm (PBDA) instrumentation setpoints for use in Technical Specification LCO 3.3.1.1 Table 3.3.1.1-1 Function 2.f shall not exceed Table 17:
Table 17: Licensed OPRM Amplitude Setpoint Confirmation Count Setpoint OPRM Amplitude Setpoint 20 1.24
Reference:
Technical Specification 3.3.1.1 7.3 Backup Stability Protection (BSP) Regions The BSP regions are shown in Figure 9. The BSP regions are an integral part of the Technical Specification required alternative method to detect and suppress thermal hydraulic instability oscillations in that they identify areas of the Power-Flow map where there is an increased probability that the reactor core could experience a thermal hydraulic instability.
Regions are identified that are either excluded from planned entry and continued operation (SCRAM Region), or where planned entry is not permitted unless specific operating restrictions are met and specific actions are required to be taken to immediately leave the region following inadvertent or forced entry (Controlled Entry Region). The boundaries of these regions are established on a cycle-specific basis based upon core decay ratio calculations from Reference
[6] performed using NRC-approved methodology.
The BSP regions are only applicable when the Upscale Trip function of the OPRM is inoperable.
However, immediate action is required to leave Region I even if the OPRMs are operable. The BSP region boundaries were calculated for nominal feedwater temperature conditions. The endpoints of the regions are defined in Table 18. The region boundaries shown in Figure 9 are defined using the Generic Shape Function (GSF), which is described in Reference [9].
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Page 23 of 28 Table 18: BSP Endpoints for Normal Feedwater Temperature Endpoint Power
[%]
Flow
[%]
Definition A1 56.5 40.0 Scram Region boundary, high flow control line (HFCL)
B1 42.5 33.7 Scram Region boundary, intersection of the 100% OLTP load line and Natural Circulation Line (NCL)
A2 64.4 50.0 Controlled entry region boundary, HFCL B2 28.5 31.2 Controlled entry region boundary, intersection of the 70% OLTP load line and NCL
Reference:
Technical Specification 3.3.1.1 7.4 Actions For Entry Into Scram Region If the Upscale Trip function of the OPRM is inoperable, initiate immediate manual scram upon determination that Region I has been entered. If entry is unavoidable, early scram initiation is appropriate.
7.5 Actions For Entry Into Controlled Entry Region If the Upscale Trip function of the OPRM is inoperable, and entry into Region II is inadvertent or forced, immediate exit from region is required. The region can be exited by control rod insertion.
Increasing the core flow by restarting an idle recirculation pump is not an acceptable method of exiting the region.
Deliberate entry into the Controlled Entry Region requires compliance with at least one of the stability controls outlined below:
- 1) Maintain core average boiling boundary (BB) 4.0 feet.
- 2) Maintain core decay ratio (DR) < 0.6 as calculated by an on-line stability monitor.
- 3) Continuous dedicated monitoring of real time control room neutron monitoring instrumentation with manual scram required upon indication of a reactor instability induced power oscillation.
Caution is required whenever operating near the Controlled Entry Region boundary (i.e., within approximately 10% of core power or core flow), and it is recommended that the amount of time spent operating near this region be minimized.
Reference:
Technical Specification 3.3.1.1
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TURBINE BYPASS SYSTEM RESPONSE TIME The Turbine Bypass System Response Time shall be that time interval from when the main turbine trip solenoid is activated until 80% of the turbine bypass capacity is established. The Turbine Bypass System Response Time shall be 1.1 seconds.
Reference:
Technical Specification 1.1, Surveillance Requirement 3.7.7.3.
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POWER-FLOW MAP The Power-Flow Map is shown in Figure 9. The Power-Flow Map is consistent with a rated power of 2004 MWth as described in Reference [10]. The Backup Stability Protection (BSP) lines are described in Section 7.
Region I in Figure 9 is the SCRAM Region and Region II is the Controlled Entry Region. These two regions are applicable when the Oscillation Power Range Monitor (OPRM) Upscale Trip is inoperable.
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Page 26 of 28 Figure 9: Power-Flow Map
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Page 27 of 28 10 REFERENCES
[1] ANP-10300P-A, Revision 1, AURORA-B: An Evaluation Model for Boiling Water Reactors; Application to Transient and Accident Scenarios, January 2018.
[2] XN-NF-80-19(P)(A) Volume 3 Revision 2, Exxon Nuclear Methodology for Boiling Water Reactors, THERMEX: Thermal Limits Methodology Summary Description, Exxon Nuclear Company, January 1987.
[3] BAW-10247PA Revision 0, Realistic Thermal-Mechanical Fuel Rod Methodology for Boiling Water Reactors, February 2008.
[4] EMF-2158(P)(A) Revision 0, Siemens Power Corporation Methodology for Boiling Water Reactors: Evaluation and Validation of CASMO-4/MICROBURN-B2, Siemens Power Corporation, October 1999.
[5] XN-NF-80-19(P)(A) Volume 1 and Supplements 1 and 2, Exxon Nuclear Methodology for Boiling Water Reactors - Neutronic Methods for Design and Analysis, Exxon Nuclear Company, March 1983.
[6] ANP-4137P, Revision 0, Monticello Cycle 33 Reload Safety Analysis, February 2025.
[7] Calculation CA-08-051, Rev 0, Instrument Setpoint Calculation - Rod Block Monitor (RBM)
PRNM Setpoints for CLTP and EPU Operation.
[8] Letter from D. Musolf (NSP) to Director, Office of Nuclear Reactor Regulation, NRC Revision 1 to License Amendment Request Dated September 7, 1976, Single Loop Operation dated July 2, 1982.
[9] ANP-10344P-A, Revision 0, Framatome Best-estimate Enhanced Option III Methodology March 2021.
[10] ANP-3295P, Revision 3, Monticello Licensing Analysis For EFW (EPU/MELLLA+),
February 2016.
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Page 28 of 28 11 APPROVED ANALYTICAL METHODS XN-NF-81-58(P)(A)
Rev. 2 and Supplements 1 and 2, RODEX2 Fuel Rod Thermal-Mechanical Response Evaluation Model, March 1984 EMF-85-74(P)
Rev. 0 Supplement 1(P)(A) and Supplement 2(P)(A), RODEX2A (BWR) Fuel Rod Thermal-Mechanical Evaluation Model, February 1998 ANF-89-98(P)(A)
Rev. 1 and Supplement 1, Generic Mechanical Design Criteria for BWR Fuel Designs, May 1995 XN-NF-80-19(P)(A)
Volume 1 and Supplements 1 and 2, Exxon Nuclear Methodology for Boiling Water Reactors - Neutronic Methods for Design and Analysis, March 1983 XN-NF-80-19(P)(A)
Volume 4 Rev. 1, Exxon Nuclear Methodology for Boiling Water Reactors:
Application of the ENC Methodology to BWR Reloads, June 1986 EMF-2158(P)(A)
Rev. 0 Siemens Power Corporation Methodology for Boiling Water Reactors:
Evaluation and Validation of CASMO-4/MICROBURN-B2, October 1999.
XN-NF-80-19(P)(A)
Volume 3 Rev. 2, Exxon Nuclear Methodology for Boiling Water Reactors, THERMEX: Thermal Limits Methodology Summary Description, January 1987 EMF-2209(P)(A)
Rev. 3 SPCB Critical Power Correlation, September 2009 EMF-2245(P)(A)
Rev. 0 Application of Siemens Power Corporation's Critical Power Correlations to Co-Resident Fuel, August 2000 EMF-2361(P)(A)
Rev. 0 EXEM BWR-2000 ECCS Evaluation Model, May 2001 EMF-2292(P)(A)
Rev. 0 ATRIUM'-10: Appendix K Spray Heat Transfer Coefficients, September 2000 EMF-CC-074(P)(A)
Volume 4 Rev. 0, BWR Stability Analysis: Assessment of STAIF with Input from MICROBURN-B2, August 2000 BAW-10247PA Rev. 0 Realistic Thermal-Mechanical Fuel Rod Methodology for Boiling Water Reactors, February 2008 ANP-10298PA Rev. 1 ACE/ATRIUM 10XM Critical Power Correlation, March 2014 ANP-10307PA Rev. 0 AREVA MCPR Safety Limit Methodology for Boiling Water Reactors, June 2011 BAW-10255(P)(A)
Rev. 2 Cycle-Specific DIVOM Methodology Using the RAMONA5-FA Code, May 2008 BAW-10247P-A Rev. 0 Supplement 2P-A, Realistic Thermal-Mechanical Fuel Rod Methodology for Boiling Water Reactors Supplement 2 Mechanical Methods August 2018 ANP-10340P-A Rev. 0 Incorporation of Chromia Doped Fuel Properties in AREVA Approved Methods May 2018 ANP-10335P-A Rev. 0 ACE/ATRIUM 11 Critical Power Correlation May 2018 ANP-10333P-A Rev. 0 AURORA-B: An Evaluation Model for Boiling Water Reactors; Application to Control Rod Drop Accident (CRDA) March 2018 ANP-10300P-A Rev. 1 AURORA-B: An Evaluation Model for Boiling Water Reactors; Application to Transient and Accident Scenarios January 2018 ANP-10332P-A Rev. 0 AURORA-B: An Evaluation Model for Boiling Water Reactors; Application to Loss of Coolant Accident Scenarios June 2019 ANP-10344P-A Rev. 0 Framatome Best-estimate Enhanced Option III Methodology March 2021 NEDE-24011-P-A Rev. 20 General Electric Standard Application for Reactor Fuel (GESTAR)
NEDE-24011-P-A-US Rev. 20 General Electric Standard Application for Reactor Fuel (GESTAR) -
Supplement for the United States NEDO-31960-A BWR Owners Group - Long Term Stability Solutions Licensing Methodology with Supplement 1 November 1995 NEDO-32465-A Reactor Stability Detect and Suppress Solutions Licensing Basis Methodology and Reload Applications August 1996