ML18270A423
| ML18270A423 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 09/27/2018 |
| From: | Page M South Texas |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NOC-AE-18003600, STI: 34726880 | |
| Download: ML18270A423 (36) | |
Text
Nuclear Operating Company South Texas Pivfect Electric Generating Station P.O. Box 2 89 Wadsworth, Texas 77483 September 27, 2018 NOC-AE-18003600 10 CFR 50.36 Attention: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 South Texas Project Units 1 and 2 Docket No. STN 50-498 and STN 50-499 Revisions to the Unit 1 Cycle 21 and Unit 2 Cycle 20 Core Operating Limits Reports
Reference:
Letter from L.M. Regner, NRC, to G.T. Powelt, STPNOC, "South Texas Project, Units 1 and 2 - Issuance of Amendments to Revise Technical Specifications for Administrative Changes and to Relocate Fxy Exclusion Zones to the Core Operating Limits Report", June 7, 2018 (AE-NOC-18003111)
In accordance with Technical Specification 6.9.1.6.d, STP Nuclear Operating Company submits the attached revised Core Operating Limits Reports for Unit 1 Cycle 21 (Revision 2) and Unit 2 Cycle 20 (Revision 1). These revisions incorporate changes made in accordance with License Amendment Nos. 213 and 199 related to relocating the Fxy exclusion zones to the Core Operating Limits Reports.
There are no commitments in this letter.
If there are any questions regarding this matter, please contact Wendy Brost at (361) 972-8516 or me at (361) 972-4414.
c lichael C. Pa^e General Manager, Engineering web
Enclosures:
- 1. South Texas Project Unit 1 Cycle 21 Core Operating Limits Report, Revision 2
- 2. South Texas Project Unit 2 Cycle 20 Core Operating Limits Report, Revision 1 STI:34726880
NOC-AE-18003600 Page 2 of 2 ec:
Regional Administrator, Region IV D. S. Nuclear Regulatory Commission 1600 E.Lamar Blvd Arlington, Texas 76011-4511 Lisa M. Regner Senior Project Manager U.S. Nuclear Regulatory Commission One White Flint North (09E01) 11555 Rockville Pike Rockville, MD 20852 NRC Resident Inspector D. S. Nuclear Regulatory Commission P. 0. Box 289, Mail Code: MN116 Wadsworth,TX 77483
NOC-AE-18003600 South Texas Project Unit 1 Cycle 21 Core Operating Limits Report, Revision 2
Nuclear Operating Companyw SOUTH TEXAS PROJECT Unit 1 Cycle 21 CORE OPERATmG LIMITS REPORT Revision 2 Core Operating Limits Report Page 1 of 16
Unit I Cycle 21 SSP^ngS?y Core Operating Limits Report Rev. 2 Page 2 of 16 1.0 CORE OPERATING UMTTS REPORT This Core Operating Limits Report for STPEGS Unit 1 Cycle 21 has been prepared m accordance with the requirements of Technical Specification 6.9.1.6. The core operating limits have been developed using the NRC-approved methodologies specified in Technical Specification 6.9.1.6.
The Technical Specifications affected by this report are:
SAFETY LIMITS LIMITING SAFETY SYSTEM SETTINGS SHUTDOWN MARGIN MODERATOR TEMPERATURE COEFFICBBNT LIMITS SHUTDOWN ROD INSERTION LIMITS CONTROL ROD INSERTION LIMITS AFD LIMITS HEAT FLUX HOT CHANNEL FACTOR NUCLEAR ENTHALPY RISE HOT CHANNEL FACTOR DNB PARAMETERS 2.0 OPERATING UMTTS The cycle-specific parameter lunits for the specifications listed in Section 1.0 are presented below.
2.1 SAFETY LIMITS (Specification 2.1):
2.1.1 The combination of TBDERMAL POWER, pressurizer pressure, and the highest operating loop coolant temperature (Tavg) shall not exceed the limits shown in Figure 1.
2.2 LIMITING SAFETY SYSTEM SETTINGS (Specification 2.2):
2.2.1 The Loop design flow for Reactor Coolant Flow-Low is 98,000 gpm.
D 2) 3)
4) 5)
6) 7)
8) 9)
10) 2.1 2.2 3/4.1.1.1 3/4.1.1.3 3/4.1.3.5 3/4.1.3.6 3/4.2.1 3/4.2.2 3/4.2.3 3/4.2.5
Unit 1 Cycle 21 Core Operating Limits Report Rev. 2 Page 3 of 16 2.2.2 The Over-temperature AT and Over-power AT setpoint parameter values are listed below:
Over-temperature AT Setpoint Parameter Values TI measured reactor vessel AT lead/lag time constant, TI = 8 sec T2 measured reactor vessel AT lead/lag time constant, T2 = 3 sec T3 measured reactor vessel AT lag time constant, 1:3 = 2 sec t4 measured reactor vessel average temperature lead/lag time constant, T4 = 28 sec TS measured reactor vessel average temperature lead/lag time constant, ts = 4 sec t6 measured reactor vessel average temperature lag time constant, 15 = 2 sec Ki Overtemperature AT reactor tip setpomt, K.r = 1.14 K2 Overtemperature AT reactor trip setpoint Tavg coefEicient, K2 = 0.028/°F Ks Overtemperature AT reactor tap setpoint pressure coefficient, Ks = 0.00143/psi T Nominal full power Tavg, T$ 592.0 °F P' Nominal RCS pressure, P' = 2235 psig fi(AT) is a function of the indicated difference between top and bottom detectors of the power-range neutron ion chambers; with gains to be selected based on measured instmment response during plant startup tests such that:
(1) For qi - qb between -70% and +8%, fi(AT) = 0, where qi and qb are percent RATED THERMAL POWER in the top and bottom halves of the core respectively, and qi + qb is total THERMAL POWER in percent of RATED THERMAL POWER; (2) For each percent that qi - qb is more negative than -70%, the AT Trip Setpoint shall be automatically reduced by 0.0% of its value at RATED THERMAL POWER, and (3) For each percent that qi - qb is more positive than +8%, the AT Trip Setpoint shall be automatically reduced by 2.65% of its value at RATED THERMAL POWER.
(Reference 3.6 and Section 4.4.1.2 of Reference 3.7)
Over-power AT Setpoint Parameter Values TI measured reactor vessel AT lead/lag tune constant, TI = 8 sec T2 measured reactor vessel AT lead/lag time constant, T2 = 3 sec T3 measured reactor vessel AT lag time constant, 13 = 2 sec t6 measured reactor vessel average temperature lag time constant, T6 = 2 sec T? Time constant utilized in the rate-lag compensator for Tavg, T? = 10 sec K.4 Overpower AT reactor trip setpoint, K4 = 1.08 K5 Overpower AT reactor trip setpoint Tavg rate/lag coefBcient, K.5 = 0.02/°F for increasing average temperature, and Ks = 0 for decreasing average temperafcire Kfi Overpower AT reactor trip setpoint Tavg heatup coefBcient K6 = 0.002/°F for T > T', and K6 = OforT^ T" T" Indicated full power Tavg, T"$ 592.0 °F 6(AT) = 0 for all (AI)
Unit 1 Cycle 21
^y^ng^y Core Operating Limits Report Rev. 2 Page 4 of 16 2.3 SHUTDOWN MARGIN1 (Specification 3.1.1.1):
The SHUTDOWN MARGIN shall be:
2.3.1 Greater than 1.3% Ap for MODES 1 -and 2*
- See Special Test Exception 3.10.1 2.3.2 Greater fhan the limits in Figure 2 for MODES 3 and 4.
2.3.3 Greater than the limits m Figure 3 for MODE 5.
2.4 MODERATOR TEMPERATURE COEFNCIENT (Specification 3.1.1.3):
2.4.1 The BOL, ARO, MTC shall be less positive than the limits shown in Figure 4.
2.4.2 The EOL, ARO, HFP, MTC shall be less negative than -62.6 pcm/°F.
2.4.3 The 300 ppm, ARO, HFP, MTC shall be less negative than -53.6 pcm/°F (300 ppm Surveillance Limit).
Where: BOL stands for Begiiming-of-Cycle Life, EOL stands for End-of-Cycle Life, ARO stands for All Rods Out, HFP stands for Hot Full Power (100% RATED THERMAL POWER),
HFP vessel average temperature is 592 °F.
2.4.4 The Revised Predicted near-EOL 300 ppm MTC shall be calculated using the algorithm from the document referenced by Technical Specification 6.9.1.6.b. 10:
Revised Predicted MTC = Predicted MTC + AFD Correction - 3 pcm/°F If the Revised Predicted MTC is less negative than the COLR Section 2.4.3 limit and all of the benchmark data contained in the surveillance procedure are met, then an MTC measurement in accordance with S.R. 4.1.1.3b is not required.
2.5 ROD mSERTION UMtTS1 (Specification 3.1.3.5 and 3.1.3.6):
2.5.1 All banks shall have the same Full Out Position (POP) of either 256 or 259 steps withdrawn.
2.5.2 The Control Banks shall be limited in physical insertion as specified in Figure 5.
2.5.3 Individual Shutdown bank rods are fully withdrawn when the Bank Demand Indication is at the POP and the Rod Group Height Limiting Condition for Operation is satisfied (T.S. 3.1.3.1).
The Shutdown Margin and Rod Insertion limits account for the removal ofRCCA D6 in Shutdown Bank A.
Unit 1 Cycle 21
^e^p^ng^y ^orc Operating Limits Report Rev. 2 Page 5 of 16 2.6 AXIALFLUXDCTFERENCE (Specification 3.2.1):
2.6.1 AFD limits as required by Technical Specification 3.2.1 are determined by Constant Axial Offset Control (CAOC) Operations with an AFD target band of+5, -10%.
2.6.2 The AFD shall be maintained within fhe ACCEPTABLE OPERATION portion of Figure 6, as required by Technical Specifications.
2.7 HEAT VLVK HOT CHANNEL FACTOR (Specification 3.2.2):
2.7.1 F^TP=2.55.
2.7.2 K(Z) is provided in Figure 7.
2.7.3 The Fxy limits for RATED THERMAL POWER (F^IT) within specific core planes shall be:
2.7.3.1 Less than or equal to 2.1 02 for all cycle bumups for all core planes containing Bank "D" control rods, and 2.7.3.2 Less than or equal to the appropriate core height-dependent value from Table 1 for all unrodded core planes.
2.7.3.3 PFxy=0.2.
These Fxy limits were used to confirm that the heat flux hot channel factor FQ(Z) will be limited by Technical Specification 3.2.2 assuming the most-limitmg axial power distributions expected to result for the insertion and removal of Control Banks C and D during operation, including the accompanying variations in the axial xenon and power distributions, as described in WCAP-8385. Therefore, these Fxy limits provide assurance that the initial conditions assumed m the LOCA analysis are met, along with the ECCS acceptance criteria of 10 CFR 50.46.
2.7.4 The Fxy limits from Section 2.7.3 above are not applicable m the following core plane regions as measured in percent of core height from the bottom of the fuel:
2.7.4.1 Lower core region from 0 to 15%, inclusive, 2.7.4.2 Upper core region from 85 to 100%, inclusive, 2.7.4.3 Grid plane regions at 22.4%, 34.2%, 46.0%, 57.8%, 69.5%, and 81.3%,
(grid plane regions +/- 2%, inclusive), and 2.7.4.4 Core plane regions within +/- 2% of core height (+/- 3.36 inches) about the bank demand position of the bank "D" control rods.
2.7.5 Core Power Distribution Measurement Uncertainty for the Heat Flux Hot Channel.
Factor 2.7.5.1 If the Power Distribution Monitoring System (PDMS) is operable, as defmed in the Technical Requirements Manual Section 3.3.3.12, the core power distribution measurement uncertainty (UFQ) to be applied to the FQ(Z) and Fxy(Z) usmg the PDMS shall be calculated by:
UFQ = (1.0 + (UQ/IOO))*UE
Unit 1 Cycle 21
^BSL?p2£ng^S£2ny Core Operating Limits Report Rev. 2 Page 6 of 16 Where:
UQ = Uncertainty for power peaking factor as defmed in Equation 5-19 from the document referenced by Technical Specification 6.9.1.6.b.ll UE = Engineering uncertainty factor of 1.03.
This uncertainty is calculated and applied automatically by the Power Distribution Monitoring System (PDMS).
2.7.5.2 If the moveable detector system is used, the core power distribution measurement uncertainty (UFQ) to be applied to the FQ(Z) and Fxy(Z) shall be calculated by:
UPQ=UQU*UE Where:
UQU = Base FQ measurement uncertainty of 1.05.
UE = Engineering uncertainty factor of 1.03.
2.8 ENTHALPY MSE HOT CHANNEL FACTOR (Specification 3.2.3):
2.8.1 FSP = 1.62 2.8.2 PFAH = 0.3 2.8.3 Core Power Distribution Measurement Uncertainty for the Enthalpy Rise Hot Channel Factor 2.8.3.1 If the Power Distribution Monitoring System (PDMS) is operable, as defmed m the Technical Requu-ements Manual Section 3.3.3.12, the core power distribution measurement uncertainty (UFAH) to be applied to the F&
using the PDMS shall be the greater of:
UpAH=1.04 OR UFAH=I.O+(UAH/IOO)
Where:
UAH = Uncertainty for power peaking factor as defmed in Equation 5-19 from the document referenced in Technical Specification 6.9.1.6.b.ll.
This uncertainty is calculated and applied automatically by the Power Distribution Monitoring System.
2.8.3.2 If the moveable detector system is used, the core power distoibution measurement uncertainty (UFAH) shall be:
UFAH=1.04
Unit 1 Cycle 21 S£a2-?p^g^22E^y Core Operating Limits Report Rev. 2 Page 7 of 16 2.9 DNB PARAMETERS (Specification 3.2.5):
2.9.1 The foUowmg DNB-related parameters shall be maintained within the following limits: 1 2.9.1.1 Reactor Coolant System Tavg ^ 595 °F 2, 2.9.1.2 Pressurizer Pressure > 2200 psig3, 2.9.1.3 Minimum Measured Reactor Coolant System Flow > 403,000 gpm4.
3.0 REFERENCES
3.1 Letter from J. M. Ralston QVestmghouse) to R. P. Dunn (STPNOC), "South Texas Project Electric Generatmg Station Unit 1 Cycle 21 Redesign Fmal Reload Evaluation" NF-TG-17-7, Rev. 1 (ST-UB-NOC-17003573, Rev. 1) dated April 12,2017.
3.2 NUREG-1346, Technical Specifications, South Texas Project Unit Nos. 1 and 2.
3.3 STPNOC Calculation ZC-7035, Rev. 2, "Loop Uncertainty Calculation for RCS Tavg Instrumentation," Section 10.1.
3.4 STPNOC Calculation ZC-7032, Rev. 6, "Loop Uncertainty Calculatiott for Narrow Range Pressurizer Pressure Monitoring Instmmentation," Section 2.3, Page 9.
3.5 Letter jfrom J. S Wyble (Westinghouse) to T. J. Jordan (STPNOC), "STP Nuclear Operating Company Units 1 & 2 Power Uprate PCWG Parameters," ST-WN-NOC-00-000072 dated December 15,2000, STI 31218644.
3.6 Letter from J. M. Ralston CWestinghouse) to D. F. Hoppes (STPNOC), "South Texas Project Electric Generating Station Units 1 and 2 Documentation of the fi(AT) Function in OTAT Setpoint Calculation," NF-TG-11-93 (ST-UB-NOC-11003215) dated November 10,2011.
3.7 Document RSE-U1, Rev. 8, "Unit 1 Cycle 21 Reload Safety Evaluation and Core Operating Limits Report." (CR Action 15-23765-6)
A discussion of the processes to be used to take these readings is provided in the basis for Technical Specification 3.2.5.
Includes a 1.9 °F measurement uncertainty per Reference 3.3, Page 37.
3 Limit not applicable during either a Thermal Power ramp in excess of 5% ofRTP per minute or a Thermal Power step in excess of 10% RTP. Per Technical Specification 3.2.5 Bases, this includes a 10.7 psi measurement uncertainty as read on the QDPS display, which is bounded by the 9.6 psi averaged measurement calculated in Reference 3.4.
Includes the flow measurement uncertainty of 2.8% from Reference 3.5.
sss Nuclear Operating Company Unit 1 Cycle 21 Core Operating Limits Report Rev. 2 Page 8 of 16 Figure 1 Reactor Core Safety Limits - Four Loops in Operation 660 640 Q62Q
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Nuclear Operating Company Unit 1 Cycle 21 Core Operating Limits Report Rev. 2 Page 9 of 16 Figure 2 Required Shutdown Margin for Modes 3 & 4 7.0 6.0 5.0
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Nuclear Operating Company Unit 1 Cycle 21 Core Operating Limits Report Rev. 2 Page 10 of 16 Figure3 Required Shutdown Margin for Mode 5 7.0 6.0 5.0
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Nuclear Operating Company Unit 1 Cycle 21 Core Operating Limits Report Rev. 2 Page 11 of 16 Figure 4 MTC versus PowerLevel i
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Nuclear Operating Company Unit 1 Cycle 21 Core Operating Limits Report Rev. 2 Page 12 of 16 Hgupe'5 Control Rod Insertion Limits* versus ?ower Level
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Nuclear Operating Company Unit 1 Cycle 21 Core Operating Limits Report Rev. 2 Page 13 of 16 Figure 6 AFD Limits versus Power Level 110 100 90 80 gi70' 0ft I 60 41^
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Unit 1 Cycle 21 Core Operating Limits Report Rev. 2 Page 15 of 16 Table 1 (Part 1 of 2)
Unrodded Fxy for Each Core Height for Cycle Burnups Less Than 10,090 MWD/MTU Core Height (Ft.)
14.0 13.8 13.6 13.4 13.2 13.0 12.8 12.6 12.4 12.2 12.0 11.8 11.6 11.4 11.2 11.0 10.8 10.6 10.4 10.2 10.0 9.8 9.6 9.4 9.2 9.0 8.8 8.6 8.4 8.2 8.0 7.8 7.6 7.4 7.2 7.0 Axial Point 1
2 3
4 5
6 7
8 9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 Unrodded Fxy 7.401 5.801 4.200 2.815 2.534 2.276 2.204 2.186 2.120 2.066 2.039 2.048 2.075 2.061 2.017 1.984 1.972 1.964 1.934 1.950 1.994 2.004 1.934 1.913 1.908 1.903 1.909 1.929 1.987 2.038 1.999 1.937 1.934 1.955 1.950 1.940 Core Height (Ft.)
6.8 6.6 6.4 6.2 6.0 5.8 5.6 5.4 5.2 5.0 4.8 4.6 4.4 4.2 4.0 3.8 3.6 3.4 3.2 3.0 2.8 2.6 2.4 2.2 2.0 1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0 Axial Point 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 Unrodded Fxy 1.982 2.031 2.008 1.953 1.924 1.956 1.967 1.973.
2.019 2.083 2.096 2.042 1.975 1.985 1.984 1.973 1.981 2.024 2.050 1.992 1.939 1.943 1.947 1.955 1.988 2.048 2.049 1.957 1.895 1.937 2.254 3.025 4.318 6.145 '
9.182
Unit 1 Cycle 21 Core Operating Limits Report Rev. 2 Page 16 of 16 Table 1 (Part 2 of 2)
Unrodded Fxy for Each Core Height for Cycle Burnups Greater Than or Equal to 10,000 MWD/MTU Core Height (Ft.)
14.0 13.8 13.6 13.4 13.2 13.0 12.8 12.6 12.4 12.2.
12.0 11.8 11.6 11.4 11.2 11.0 10.8 10.6 10.4 10.2 10.0 9.8 9.6 9.4 9.2 9.0 8.8 8.6 8.4 8.2 8.0 7.8 7.6 7.4 7.2 7.0 Axial Point 1
2 3
4 5
6 7
8 9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 Unrodded Fxy 6.408 5.134 3.860 2.756 2.530 2.280 2.139 2.070 2.002 1.991 2.001 2.029 2.061 2.055 2.029 2.015 2.026 2.033 2.043 2.073 2.119 2.137 2.104 2.076 2.088 2.099 2.110 2.127 2.166 2.201 2.166 2.133 2.134 2.146 2.157 2.169 Core Height CFt.)
6.8 6.6 6.4 6.2 6.0 5.8 5.6 5.4 5.2 5.0 4.8 4.6 4.4 4.2 4.0 3.8 3.6 3.4 3.2 3.0 2.8 2.6 2.4 2.2 2.0 1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0 Axial Point 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 Unrodded Fxy 2.210 2.246 2.213 2.155 2.121 2.113 2.101 2.088 2.105 2.139 2.133 2.075 2.027 2.022 2.009 1.993 1.994 2.028 2.050 1.992 1.939 1.925 1.907 1.879 1.889 1.936 1.965 1.943 1.956 2.067 2.434 3.163 4.275 5.814 8.515
NOC-AE-18003600 South Texas Project Unit 2 Cycle 20 Core Operating Limits Report, Revision 1
Nuclear Operating Company SOUTH TEXAS PROJECT Unit 2 Cycle 20 CORE OPERATING LBiITS REPORT Revision 1 Core Operating Limits Report Page 1 of 16
Unit 2 Cycle 20 aSW^"' Core Operating Limits Report Rev. 1 Page 2 of 16 1.0 CORE OPERATING LIMITS REPORT This Core Operating Limits Report for STPEGS Unit 2 Cycle 20 has been prepared in accordance with the requirements of Technical Specification 6.9.1.6. The core operating limits have been developed using the NRC-approved methodologies specified in Technical Specification 6.9.1.6.
The Technical Specifications affected by this report are:
SAFETY LIMITS LIMITING SAFETY SYSTEM SETTINGS SHUTDOWN MARGIN MODERATOR TEMPERATURE COEFFICffiNT LIMITS SHUTDOWN ROD INSERTION LIMITS CONTROL ROD INSERTION LIMITS AFD LIMITS HEAT FLUX HOT CHANNEL FACTOR NUCLEAR ENTHALPY RISE HOT CHANNEL FACTOR DNB PARAMETERS 2.0 OPERATmG LIMITS The cycle-specific parameter limits for the specifications listed in Section 1.0 are presented below.
2.1 SAFETY UMTTS (Specification 2.1):
2.1.1 The combination of THERMAL POWER, pressurizer pressure, and the highest operating loop coolant temperature (Tavg) shall not exceed fhe limits shown in Figure 1.
2.2 UMmNG SAFETY SYSTEM SETTmGS (Specification 2.2):
2.2.1 The Loop design flow for Reactor Coolant Flow-Low is 98,000 gpm.
1) 2)
3) 4)
5) 6)
7) 8)
9) 10) 2.1 2.2 3/4.1.1.1 3/4.1.1.3 3/4.1.3.5 3/4.1.3.6 3/4.2.1 3/4.2.2 3/4.2.3 3/4.2.5
Unit 2 Cycle 20 Core Operating Limits Report Rev. 1 Page 3 of 16 2.2.2 The Over-temperature AT and Over-power AT setpoint parameter values are listed below:
Over-temperature AT Setpoint Parameter Values TI measured reactor vessel AT lead/lag tune constant, n = 8 sec xi measured reactor vessel AT lead/lag time constant, T2 = 3 sec T3 measured reactor vessel AT lag tune constant, TS = 2 sec T4 measured reactor vessel average temperature lead/lag time constant, 14 = 28 sec T5 measured reactor vessel average temperature lead/lag time constant, T5 = 4 sec t6 measured reactor vessel average temperature lag tune constant, ie = 1 sec Ki Overtemperature AT reactor trip setpoint, Ki = 1.14 Kz Overtemperature AT reactor trip setpoint Tavg coefficient, Ks = 0.028/°F Ks Overtemperature AT reactor trip setpoint pressure coefficient, Ks = 0.00143/psi T Nominal full power Tavg, T'$ 592.0 °F P' Nominal RCS pressure, P' = 2235 psig fi(AI) is a function of the indicated difference between top and bottom detectors of the power-range neutron ion chambers; with gains to be selected based on measured instrument response during plant startup tests such that:
(1) For qi - qb between -70% and +8%, fi(AT) = 0, where qi and qb are percent RATED THERMAL POWER in the top and bottom halves of the core respectively, and qt + qb is total THERMAL POWER in percent of RATED THERMAL POWER; (2) For each percent that qi - qb is more negative than -70%, the AT Trip Setpoiat shall be automatically reduced by 0.0% of its value at RATED THERMAL POWER; and (3) For each percent that qi - qb is more positive than +8%, the AT Trip Setpoint shall be automatically reduced by 2.65% of its value at RATED THERMAL POWER.
(Reference 3.6 and Section 4.4.1.2 of Reference 3.7)
Over-power AT Setpoint Parameter Values TI measured reactor vessel AT lead/lag time constant, TI = 8 sec 1:2 measured reactor vessel AT lead/lag tune constant, 12 +/-= 3 sec T3 measured reactor vessel AT lag time constant, T3 = 2 sec T6 measured reactor vessel average temperature lag tkne constant, T6 = 2 sec T? Time constant utilized in the rate-lag compensator for Tavg, T7 = 10 sec K4 Overpower AT reactor trip setpoint, K4 = 1.08 K5 Overpower AT reactor trip setpoint Tavg rate/lag coefficient, K5 = 0.02/°F for increasing average temperafcire, and K5 = 0 for decreasing average temperature Kfi Overpower AT reactor trip setpoint Tavg heatup coefficient K6 = 0.002/°F for T > T\\ and K6 = OforT$ T" T' Indicated fall power Tavg, T'^ 592.0 °F
£(AI) = 0 for all (AT)
Unit 2 Cycle 20 S<2-?PSng.£S£E2ny Core Operating Limits Report Rev. 1 Page 4 of 16 2.3 SHUTDOWN MARGIN (Specification 3.1.1.1):
The SHUTDOWN MARGIN shall be:
2.3.1 Greater than 1.3% Ap for MODES 1 and 2*
- See Special Test Exception 3.10.1 2.3.2 Greater than the limits in Figure 2 for MODES 3 and 4.
2.3.3 Greater than the limits in Figure 3 for MODE 5.
2.4 MODERATOR TEMPERATURE COEEFICIENT (Specification 3.1.1.3):
2.4.1 The BOL, ARO, MTC shall be less positive than the limits shown in Figure 4.
2.4.2 The EOL, ARC, HFP, MTC shall be less negative than -62.6 pcm/°F.
.2.4.3 The 300 ppm, ARO, HFP, MTC shall be less negative fhan -53.6 pcm/°F (300 ppm Surveillance Limit).
Where: BOL stands for Beginning-of-Cycle Life, EOL stands for End-of-Cycle Life, ARO stands for All Rods Out, HFP stands for Hot Full Power (100% RATED THERMAL POWER),
HFP vessel average temperahire is 592 °F.
2.4.4 The Revised Predicted near-EOL 300 ppm MTC shall be calculated using the algorithm from Technical Specification 6.9.1.6.b.l0:
Revised Predicted MTC = Predicted MTC + AFD Correction - 3 pcm/°F If the Revised Predicted MTC is less negative than the COLR Section 2.4.3 limit and all of the benchmark data contained in the surveillance procedure are met, then an MTC measurement in accordance with S.R. 4.1.1.3b is not required.
2.5 RODmSERTIONLBflTS (Specification 3.1.3.5 and 3.1.3.6):
2.5.1 All banks shall have the same Full Out Position (POP) of either 256 or 259 steps withdrawn.
2.5.2 The Control Banks shall be limited in physical insertion as specified in Figure 5.
2.5.3 Individual Shutdown bank rods are fully withdrawn when the Bank Demand Indication is at the POP and the Rod Group Height Limiting Condition for Operation is satisfied (T.S. 3.1.3,1).
Unit 2 Cycle 20
£e£>p^nB^>>' Core Operating Limits Report Rev. 1 Page 5 of 16 2.6 AXIAL FLUX DIFFERENCE (Specification 3.2.1):
2.6.1 AFD limits as required by Technical Specification 3.2. 1 are determined by Constant Axial Offset Control (CAOC) Operations with an AFD target band of+5, -10%.
2.6.2 The AFD shall be maintained within the ACCEPTABLE OPERATION portion of Figure 6, as required by Technical Specifications.
2.7 HEAT FLUX HOT CHANNEL FACTOR (Specification 3.2.2):
2.7.1 F^= 2.55.
2.7.2 K(Z) is provided m Figure 7.
2.7.3 The Fxy limits for RATED THERMAL POWER (F^TP) within specific core planes shall be:
2.7.3.1. Less than or equal to 2.102 for all cycle bumups for all core planes containing Bank "D" control rods, and 2.7.3.2 Less than or equal to the appropriate core height-dependent value from Table 1 for all unrodded core planes.
2.7.3.3 PFxy = 0.2.
These Fxy limits were used to confu-m that the heat flux hot channel factor FQ(Z) will be limited by Technical Specification 3.2.2 assuming the most-limiting axial power distributions expected to result for the insertion and removal of Corrtrol Banks C and D during operation, mcludmg the accompanying variations in the axial xenon and power distributions, as described in WCAP-8385. Therefore, these Fxy limits provide assurance that the mitial conditions assumed in fhe LOCA analysis are met, along with the ECCS acceptance criteria of 10 CFR 50.46.
2.7.4 The Fxy limits from Section 2.7.3 above are not applicable in the following core plane regions as measured m percent of core height from the bottom of the fuel:
2.7.4.1 Lower core region from 0 to 15%, inclusive, 2.7.4.2 Upper core region from 85 to 100%, inclusive, 2.7.4.3 Grid plane regions at 22.4%, 34.2%, 46.0%, 57.8%, 69.5%, and 81.3%,
(grid plane regions +/- 2%, inclusive), and 2.7.4.4 Core plane regions within +/- 2% of core height (+/- 3.36 inches) about the bank demand position of the bank "D" control rods.
2.7.5 Core Power Distribution Measurement Uncertainty for the Heat Flux Hot Channel Factor 2.7.5.1 If the Power Distribution Monitoring System (PDMS) is operable, as defmed m the Technical Requirements Manual Section 3.3.3.12, the core power distribution measurement uncertainty (UFQ) to be applied to the FQ(Z) and Fxy(Z) usmg the PDMS shall be calculated by:
UFQ = (1.0 + (UQ/IOO))*UE
Unit 2 Cycle 20
^e^)P^ns^B,y Core Operating Limits Report Rev. 1 Page 6 of 16 Where:
UQ = Uncertainty for power peaking factor as defmed in Equation 5-19 from the document referenced by Technical Specification 6.9.1.6.b.ll UE = Engineering uncertamty factor of 1.03.
This uncertainty is calculated and applied automatically by the Power Distribution Monitoring System (PDMS).
2.7.5.2 If the moveable detector system is used, the core power distribution measurement uncertainty (UFQ) to be applied to the FQ(Z) and Fxy(Z) shall be calculated by:
UFQ=UQU*UE "Where:
UQU = Base FQ measurement uncertainty of 1.05.
UE = Engineering uncertainty factor of 1.03.
2.8 ENTHALPY MSE HOT CHANNEL FACTOR (Specification 3.2.3):
2.8.1 F§SP = 1.62 2.8.2 PFAH = 0.3 2.8.3 Core Power Distribution Measurement Uncertainty for the Enthalpy Rise Hot Channel Factor 2.8.3.1 If the Power Distribution Monitoring System (PDMS) is operable, as defined in the Technical Requirements Manual Section 3.3.3.12, the core power distribution measurement uncertainty (UFAH) to be applied to the F&
using the PDMS shall be the greater of:
UpAH=1.04 OR UFAH=I.O+(UAH/IOO)
Where:
UAH = Uncertainty for power peaking factor as defined in Equation 5-19 from the document referenced in Technical Specification 6.9.1.6-b.ll.
This uncertainty is calculated and applied automatically by the Power Distribution Monitoring System.
2.8.3.2 If the moveable detector system is used, the core power distribution measurement uncertainty (UFAH) shall be:
UFAH=1.04
Unit 2 Cycle 20
^e^p^ng^y Core Operating Limits Report Rev. 1 Page 7 of 16 2.9 DNB PARAMETERS (Specification 3.2.5):
2.9.1 The following DNB-related parameters shall be maintained within the following limits (nominal values from Reference 3.1, as annotated below):1 2.9.1.1 Reactor Coolant System Tavg ^ 595 °F 2, 2.9.1.2 Pressurizer Pressure > 2200 psig3, 2.9.1.3 Minimum Measured Reactor Coolant System Flow > 403,000 gpm4.
3.0 REFERENCES
3.1 Letter firom A. S. Ganey CWestinghouse) to R. F. Duim (STPNOC), "South Texas Project Electric Generating Station Unit 2 Cycle 20 Final Reload Evaluation" NF-TG-18-12 (ST-UB-NOC-18003632) dated February 6,2018.
3.2 NUREG-1346, Technical Specifications, South Texas Project Unit Nos. 1 and 2.
3.3 STPNOC Calculation ZC-7035, Rev. 2, "Loop Uncertainty Calculation for RCS Tavg Instrumentation," Section 10.1.
3.4 STPNOC Calculation ZC-7032, Rev. 6, "Loop Uncertainty Calculation for Narrow Range Pressurizer Pressure Monitoring Instrumentation," Section 2.3, Page 9.
3.5 Letter from J. S Wyble (Westinghouse) to T. J. Jordan (STPNOC), "STP Nuclear Operating Company Units 1 & 2 Power Uprate PCWG Parameters," ST-WN-NOC-00-000072 dated December 15,2000, STI 31218644.
3.6 Letter from J. M. Ralston (Westinghouse) to D. P. Hoppes (STPNOC), "South Texas Project Electric Generating Station Units 1 and 2 Documentation of the fi(AI) Function in OTAT Setpoint Calculation," NF-TG-11-93 (ST-UB-NOC-11003215) dated November 10,2011.
3.7 Document RSE-U2, Rev. 8, "Unit 2 Cycle 20 Reload Safety Evaluation and Core Operating Limits Report." (CR Action 15-23765-7)
' A discussion of the processes to be used to take these readings is provided in fhe basis for Technical Specification 3.2.5.
2 Includes a 1.9 °F measurement uncertainty per Reference 3.3, Page 37.
3 Lunit not applicable during either a Thermal Power ramp in excess of 5% ofRTP per minute or a Thermal Power step in excess of 10% RTP. Per Technical Specification 3.2.5 Bases, this includes a 10.7 psi measurement uncertainty as read on the QDPS display, which is bounded by the 9.6 psi averaged measurement calculated in Reference 3.4.
Includes the flow measurement uncertainty of 2.8% from Reference 3.5.
Nuclear Operating Company Unit 2 Cycle 20 Core Operating Limits Report Rev. 1 Page 8 of 16 Figure 1 Reactor Core Safety Limits - Four Loops in Operation 1(2,664.52)1 660 652.
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Nuclear Operating Company
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Nuclear Operating Company Unit 2 Cycle 20 Core Operating Limits Report Rev. 1 Page 12 of 16 KgureS ControlRttd InsertioiBlitnufa* versus Power Iievel:
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Unit 2 Cycle 20 Core Operating Limits Report Rev. 1 Page 15 of 16 Table 1 (Part 1 of 2)
Unrodded Fxy for Each Core Height for Cycle Burnups Less Than 10000 MWD/MTU Core Height CFt.)
14.0 13.8 13.6 13.4 13.2 13.0 12.8 12.6 12.4 12.2 12.0 11.8 11.6 11.4 11.2 11.0 10.8 10.6 10.4 10.2 10.0 9.8 9.6 9.4 9.2 9.0 8.8 8.6 8.4 8.2 8.0 7.8 7.6 7.4 7.2 7.0 Axial Point 1
2 3
4 5
6 7
8 9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 Unrodded Fxy 7.129 5.560 3.993 2.657 2.474 2.191 2.096 2.097 2.049 1.987 1.948 1.960 2.005 1.992 1.944 1.913 1.905 1.894 1.869 1.881 1.931 1.944 1.881 1.859 1.863 1.865 1.872 1.893 1.959 2.023 1.987 1.936 1.931 1.941 1.936 1.925 Core Height (Ft.)
6.8 6.6 6.4 6.2 6.0 5.8 5.6 5.4 5.2 5.0 4.8 4.6 4.4 4.2 4.0 3.8 3.6 3.4 3.2 3.0 2.8 2.6 2.4 2.2 2.0 1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0 Axial Point 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 Unrodded Fxy 1.979 2.046 2.017 1.943 1.906 1.939 1.948 1.948 1.993 2.065 2.084 2.027 1.959 1.975 1.977 1.963 1.969 2.017 2.051 1.995 1.944 1.947 1.951 1.922 1.897 1.915 1.916 1.824 1.750 1.780 2.068 2.763 3.936 5.599 8.325
Unit 2 Cycle 20 Core Operating Limits Report Rev. 1 Page 16 of 16 Table 1 (Part 2 of 2)
Unrodded Fxy for Each Core Height for Cycle Burnups Greater Than or Equal to 10000 MWD/MTU Core Height (Ft.)
14.00 13.80 13.60 13.40 13.20 13.00 12.80 12.60 12.40 12.20 12.00 11.80 11.60 11.40 11.20 11.00 10.80 10.60 10.40 10.20 10.00 9.80 9.60 9.40 9.20 9.00 8.80 8.60 8.40 8.20 8.00 7.80 7.60 7.40 7.20 7.00 Axial Point 1
2 3
4 5
6 7
8 9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 Unrodded Fxy 6.389 5.096 3.803 2.698 2.550 2.273 2.120 2.061 1.999 1.977 1.976 2.016 2.073 2.069 2.023 2.004 2.015 2.019 2.021 2.056 2.116 2.144 2.104 2.068 2.084 2.096 2.103 2.120 2.174 2.222 2.180 2.138 2.138 2.149 2.158 2.164 Core Height (Ft.)
6.80 6.60 6.40 6.20 6.00 5.80 5.60 5.40 5.20 5.00 4.80 4.60 4.40 4.20 4.00 3.80 3.60 3.40 3.20 3.00 2.80 2.60 2.40 2.20 2.00 1.80 1.60 1.40 1.20 1.00 0.80 0.60 0.40 0.20 0.00 Axial Point 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 Unrodded Fxy 2.208 2.253 2.219 2.152 2.114 2.105 2.093 2.077 2.097 2.137 2.135 2.073 2.023 2.018 2.005 1.988 1.989 2.029 2.056 1.998 1.943 1.927 1.899 1.872 1.894 1.941 1.971 1.950 1.963 2.074 2.444 3.182 4.307 5.855 8.547