Text

Cycle 24 Core Operating Limits Report Revisions 0, 1 and 2
	ML20121A009
Person / Time
Site:	Sequoyah
Issue date:	04/29/2020
From:	Rasmussen M; Tennessee Valley Authority
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	Download: ML20121A009 (39)
	v • d • e

Tennessee Valley Authority, Sequoyah Nuclear Plant, P.O. Box 2000, Soddy Daisy, Tennessee 37384 April 29, 2020 10 CFR 50.4 A TIN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Sequoyah Nuclear Plant, Unit 2 Renewed Facility Operating License No. DPR-79 NRC Docket No. 50-328

Subject:

SEQUOYAH UNIT 2 CYCLE 24 CORE OPERATING LIMITS REPORT REVISIONS 0, 1, AND 2

References:

1. TVA Letter to NRC, CNL-20-042, "Sequoyah Nuclear Plant Unit 2 - Exigent License Amendment Request to Revise Technical Specification 4.2.2, "Control Rod Assemblies" (SQN-TS-20-05)," dated April 17, 2020

2. NRC letter to TVA, "Sequoyah Nuclear Plant, Unit 2 - Issuance of Exigent Amendment No. 342 to Operate One Cycle with One Control Rod Removed (EPID L-2020-LLA-0078)," dated April 23, 2020 In accordance with Sequoyah Nuclear Plant (SQN) Unit 2 Technical Specification (TS) 5.6.3.d, enclosed is the Unit 2 Cycle 24 Core Operating Limits Report (COLR), Revisions 0, 1, and 2 that were issued on April 2, 21 and 25, 2020, respectively. Revision O was developed to support a core design and operation with 53 full-length control rod assemblies. Following core offload, fuel inspections identified one fuel assembly as damaged and would not be reinserted for Cycle 24 operation. Additionally, a determination was made to remove and not reinsert one of the full-length control rod assemblies following identification of wear to the H-08 control rod drive latch mechanism. A request to amendment SQN Unit 2 Technical Specifications for operation with one less control rod assembly was made by the reference 1. Based on these events Revision 1 was developed to permit Mode 6 core reload only. NRC approved TVA's amendment request by reference 2. COLR Revision 2 was issued for the core design and operation with one less full-length control rod assemblies and changes made for an alternate undamaged fuel assembly.

printed on recycled paper

U.S. Nuclear Regulatory Commission Page2 April 29, 2020 There are no new regulatory commitments in this letter. If you have any questions, please contact Jeffrey Sowa, SQN Site Licensing Manager at (423) 843-8129.

Respectfully,

~-

Matthew Rasmussen Site Vice President Sequoyah Nuclear Plant Enclosures

1. Sequoyah Unit 2 Cycle 24 Core Operating Limits Report, Revision 0

2. Sequoyah Unit 2 Cycle 24 Core Operating Limits Report, Revision 1

2. Sequoyah Unit 2 Cycle 24 Core Operating Limits Report, Revision 2 cc (Enclosure):

NRC Regional Administrator - Region II NRC Senior Resident Inspector - SQN

ENCLOSURE 1 SEQUOYAH UNIT 2 CYCLE 24 CORE OPERATING LIMITS REPORT REVISION 0

QA Record L36 200316 801 SEQUOYAH UNIT 2 CYCLE 24 CORE OPERATING LIMITS REPORT REVISION 0 March 2020 Prepared by:

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_________________________;/_________ 3/24/2020 Josh Elkins, PWR Fuel Engineering Date Verified by:

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ORC Chairman Date I 'i-2. -z (Y Plant Manager Date Date of PORC Affected Revision Aooroval Paaes Reason for Revision 0 See above All Initial issue SEQUOYAH UNIT 2 Page 1 of 16 Revision O

COLR FOR SEQUOYAH UNIT 2 CYCLE 24 1.0 Core Operating Limits Report This CORE OPERATING LIMITS REPORT (COLR) for Sequoyah Unit 2 Cycle 24 has been prepared in accordance with the requirements of Technical Specification (TS) 5.6.3.

The TSs affected by this Report are listed below.

COLR Section, TS Table and/or COLR Section Technical Specification COLR Parameter Figure Page (s) 3.1.1 SHUTDOWN MARGIN (SDM) SDM 2.1 3 BOL MTC Limit 2.2.1 4 Moderator Temperature Coefficient EOL MTC Limit 2.2.2 4 3.1.3 (MTC) 300 ppm Surveillance Limit 2.2.3 4 60 ppm Surveillance Limit 2.2.4 4 3.1.4 Rod Group Alignment Limits SDM 2.1.3 3 Shutdown Bank Insertion Limits 2.3 4 3.1.5 Shutdown Bank Insertion Limits SDM 2.1.4 3 Control Bank Insertion Limits 2.4, Figure 1 5, 14 3.1.6 Control Bank Insertion Limits SDM 2.1.5 3 PHYSICS TESTS Exceptions -

3.1.8 SDM 2.1.6 3 MODE 2 RTP FQ 2.5.1 6 K(Z) 2.5.2, Figure 2 6, 15 NSLOPEAFD 2.5.3 6 PSLOPEAFD 2.5.4 6 Heat Flux Hot Channel Factor 3.2.1 (FQ(X,Y,Z)) NSLOPEf2(I) 2.5.5 6 f2(I)

PSLOPE 2.5.6 6 FQ(X,Y,Z) Appropriate Factor 2.5.7 6 TS LCO 3.2.1 Required Action A.3 2.5.8 6 MAP(X,Y,Z) 2.6.1, Table 2 6, 11 RRH 2.6.2 6 Nuclear Enthalpy Rise Hot Channel TRH 2.6.3 6 3.2.2 Factor (FH(X,Y)) FH(X,Y) Appropriate Factor 2.6.4 7 TS 3.2.2 Required Action A.4 2.6.5 7 TS 3.2.2 Required Action B.1 2.6.6 7 3.2.3 AXIAL FLUX DIFFERENCE (AFD) AFD Limits 2.7, Figure 3 7, 16 Reactor Trip System (RTS) QTNL, QTPL, QTNS, and QTPS 2.8.1 8 3.3.1 Instrumentation QPNL, QPPL, QPNS, and QPPS 2.8.2 9 3.9.1 Boron Concentration Refueling Boron Concentration 2.9 9 CORE OPERATING LIMITS 5.6.3 Analytical Methods Table 1 10 REPORT (COLR)

SEQUOYAH UNIT 2 Page 2 of 16 Revision 0

COLR FOR SEQUOYAH UNIT 2 CYCLE 24 2.0 Operating Limits The cycle-specific parameter limits for the TS listed in Section 1.0 are presented in the following subsections. These limits have been developed using the NRC approved methodologies specified in TS 5.6.3. The versions of the topical reports, which describe the methodologies used for this cycle, are listed in Table 1.

The following abbreviations are used in this section:

BOL stands for Beginning of Cycle Life EOL stands for End of Cycle Life RTP stands for RATED THERMAL POWER 2.1 SHUTDOWN MARGIN - SDM (TS 3.1.1, 3.1.4, 3.1.5, 3.1.6, 3.1.8) 2.1.1 For TS 3.1.1, SDM shall be 1.6 %k/k in MODE 2 with keff < 1.0, MODE 3 and MODE 4.

2.1.2 For TS 3.1.1, SDM shall be 1.0 %k/k in MODE 5.

2.1.3 For TS 3.1.4, SDM shall be 1.6 %k/k in MODE 1 and MODE 2.

2.1.4 For TS 3.1.5, SDM shall be 1.6 %k/k in MODE 1 and MODE 2.

2.1.5 For TS 3.1.6, SDM shall be 1.6 %k/k in MODE 1 and MODE 2 with keff 1.0.

2.1.6 For TS 3.1.8, SDM shall be 1.6 %k/k in MODE 2.

SEQUOYAH UNIT 2 Page 3 of 16 Revision 0

COLR FOR SEQUOYAH UNIT 2 CYCLE 24 2.2 Moderator Temperature Coefficient - MTC (TS 3.1.3) 2.2.1 The BOL MTC limit is:

less positive than -0.23 x 10-5 k/k/ºF.

2.2.2 The EOL MTC limit is:

less negative than or equal to -4.50 x 10-4 k/k/ºF.

2.2.3 The 300 ppm Surveillance limit is:

less negative than or equal to -3.80 x 10-4 k/k/ºF.

2.2.4 The 60 ppm Surveillance limit is:

less negative than or equal to -4.20 x 10-4 k/k/ºF.

2.3 Shutdown Bank Insertion Limits (TS 3.1.5) 2.3.1 Each shutdown bank shall be withdrawn to a position as defined below:

Cycle Burnup Steps (MWd/mtU) Withdrawn 0 225 to 231 SEQUOYAH UNIT 2 Page 4 of 16 Revision 0

COLR FOR SEQUOYAH UNIT 2 CYCLE 24 2.4 Control Bank Insertion Limits (TS 3.1.6) 2.4.1 The control banks shall be limited in physical insertion as shown in Figure 1.

2.4.2 Each control bank shall be considered fully withdrawn from the core at 225 steps.

2.4.3 The control banks shall be operated in sequence by withdrawal of Bank A, Bank B, Bank C, and Bank D. The control banks shall be sequenced in reverse order upon insertion.

2.4.4 Each control bank not fully withdrawn from the core shall be operated with the following overlap as a function of full out position.

Full Out Position (steps) Bank Overlap (steps) Bank Difference (steps) 225 97 128 226 98 128 227 99 128 228 100 128 229 101 128 230 102 128 231 103 128 SEQUOYAH UNIT 2 Page 5 of 16 Revision 0

COLR FOR SEQUOYAH UNIT 2 CYCLE 24 2.5 Heat Flux Hot Channel Factor - FQ(X,Y,Z) (TS 3.2.1)

RTP 2.5.1 FQ = 2.62 2.5.2 K(Z) is provided in Figure 2 2.5.3 NSLOPEAFD = 1.3 2.5.4 PSLOPEAFD = 1.6 2.5.5 NSLOPEf2(I) = 1.6 2.5.6 PSLOPEf2(I) = 2.3 M

2.5.7 The appropriate factor for increase in FQ (X,Y,Z) for compliance with SR 3.2.1.2 and SR 3.2.1.3 is specified as follows:

For all cycle burnups, use 2.0%.

2.5.8 TS LCO 3.2.1 Required Action A.3 reduces the Overpower Delta-T Trip setpoints (value of K4) at least 1% (in T span) for each 1% that FQC(X,Y,Z) exceeds its limit.

2.6 Nuclear Enthalpy Rise Hot Channel Factor - FH(X,Y) (TS 3.2.2) 2.6.1 MAP(X,Y,Z) is provided in Table 2.

2.6.2 RRH = 3.34 when 0.8 < P 1.0 RRH = 1.67 when P 0.8 Where RRH = Thermal power reduction required to compensate for each 1% that FH(X,Y) exceeds its limit.

P = THERMAL POWER / RATED THERMAL POWER 2.6.3 TRH = 0.0334 when 0.8 < P 1.0 TRH = 0.0167 when P 0.8 Where TRH = Reduction in Overtemperature Delta-T K1 setpoint required to compensate for each 1% that FH(X,Y) exceeds its limit.

P = THERMAL POWER / RATED THERMAL POWER SEQUOYAH UNIT 2 Page 6 of 16 Revision 0

COLR FOR SEQUOYAH UNIT 2 CYCLE 24 2.6.4 The appropriate factor for increase in FHM (X,Y) for compliance with SR 3.2.2.1 and SR 3.2.2.2 is specified as follows:

For all cycle burnups, use 2.0%.

2.6.5 TS LCO 3.2.2 Required Action A.4 reduces the Overtemperature Delta-T setpoint (K1 term in Table 3.3.1-1) by TRH multiplied by the FH minimum margin.

2.6.6 TS LCO 3.2.2 Required Action B.1 reduces the Overtemperature Delta-T setpoint (K1 term in Table 3.3.1-1) by TRH multiplied by the f1(I) minimum margin.

2.7 Axial Flux Difference - AFD (TS 3.2.3) 2.7.1 The AFD limits are specified in Figure 3.

SEQUOYAH UNIT 2 Page 7 of 16 Revision 0

COLR FOR SEQUOYAH UNIT 2 CYCLE 24 2.8 Reactor Trip System Instrumentation (TS 3.3.1) 2.8.1 Trip Reset Term [f1(I)] for Overtemperature Delta-T Trip The following parameters are required to specify the power level-dependent f1(I) trip reset term limits for Table 3.3.1-1 (function 6), Overtemperature Delta-T trip function:

2.8.1.1 QTNL = -20%

where QTNL = the maximum negative I setpoint at RATED THERMAL POWER at which the trip setpoint is not reduced by the axial power distribution.

2.8.1.2 QTPL = +5%

where QTPL = the maximum positive I setpoint at RATED THERMAL POWER at which the trip setpoint is not reduced by the axial power distribution.

2.8.1.3 QTNS = 2.50%

where QTNS = the percent reduction in Overtemperature Delta-T trip setpoint for each percent that the magnitude of I exceeds its negative limit at RATED THERMAL POWER (QTNL).

2.8.1.4 QTPS = 1.40%

where QTPS = the percent reduction in Overtemperature Delta-T trip setpoint for each percent that the magnitude of I exceeds its positive limit at RATED THERMAL POWER (QTPL).

SEQUOYAH UNIT 2 Page 8 of 16 Revision 0

COLR FOR SEQUOYAH UNIT 2 CYCLE 24 2.8.2 Trip Reset Term [f2(I)] for Overpower Delta-T Trip The following parameters are required to specify the power level-dependent f2(I) trip reset term limits for Table 3.3.1-1 (function 7), Overpower Delta-T trip function:

2.8.2.1 QPNL = -25%

where QPNL = the maximum negative I setpoint at RATED THERMAL POWER at which the trip setpoint is not reduced by the axial power distribution.

2.8.2.2 QPPL = +25%

where QPPL = the maximum positive I setpoint at RATED THERMAL POWER at which the trip setpoint is not reduced by the axial power distribution.

2.8.2.3 QPNS = 1.70%

where QPNS = the percent reduction in Overpower Delta-T trip setpoint for each percent that the magnitude of I exceeds its negative limit at RATED THERMAL POWER (QPNL).

2.8.2.4 QPPS = 1.70%

where QPPS = the percent reduction in Overpower Delta-T trip setpoint for each percent that the magnitude of I exceeds its positive limit at RATED THERMAL POWER (QPPL).

2.9 Boron Concentration (TS 3.9.1) 2.9.1 The refueling boron concentration shall be 2073 ppm.

SEQUOYAH UNIT 2 Page 9 of 16 Revision 0

COLR FOR SEQUOYAH UNIT 2 CYCLE 24 Table 1 COLR Methodology Topical Reports

1. BAW-10180-A, Revision 1, NEMO-Nodal Expansion Method Optimized, March 1993.

(Methodology for TS 3.1.1-SHUTDOWN MARGIN, 3.1.3-Moderator Temperature Coefficient, 3.9.1-Boron Concentration)

2. BAW-10169P-A, Revision 0, RSG Plant Safety Analysis - B&W Safety Analysis Methodology for Recirculating Steam Generator Plants, October 1989.

(Methodology for TS 3.1.3-Moderator Temperature Coefficient)

3. BAW-10163P-A, Revision 0, Core Operating Limit Methodology for Westinghouse-Designed PWRs, June 1989.

(Methodology for TS 3.3.1-Reactor Trip System Instrumentation [f1(I), f2(I) limits],

3.1.5-Shutdown Bank Insertion Limits, 3.1.6-Control Bank Insertion Limits, 3.2.1-Heat Flux Hot Channel Factor, 3.2.2-Nuclear Enthalpy Rise Hot Channel Factor, 3.2.3-AXIAL FLUX DIFFERENCE)

4. EMF-2328(P)(A), Revision 0 PWR Small Break LOCA Evaluation Model, March 2001.

(Methodology for TS 3.2.1-Heat Flux Hot Channel Factor)

5. BAW-10227P-A, Revision 1, Evaluation of Advanced Cladding and Structural Material (M5) in PWR Reactor Fuel, June 2003.

(Methodology for TS 3.2.1-Heat Flux Hot Channel Factor)

6. BAW-10186P-A, Revision 2, Extended Burnup Evaluation, June 2003.

(Methodology for TS 3.2.1-Heat Flux Hot Channel Factor)

7. EMF-2103P-A, Revision 0, Realistic Large Break LOCA Methodology for Pressurized Water Reactors, April 2003.

(Methodology for TS 3.2.1-Heat Flux Hot Channel Factor)

8. BAW-10241P-A, Revision 1, BHTP DNB Correlation Applied with LYNXT, July 2005.

(Methodology for TS 3.2.2-Nuclear Enthalpy Rise Hot Channel Factor, 3.3.1-Reactor Trip System Instrumentation [f1(I) limits])

9. BAW-10199P-A, Revision 0, The BWU Critical Heat Flux Correlations, August 1996.

(Methodology for TS 3.2.2-Nuclear Enthalpy Rise Hot Channel Factor, 3.3.1-Reactor Trip System Instrumentation [f1(I) limits])

10. BAW-10189P-A, CHF Testing and Analysis of the Mark-BW Fuel Assembly Design, January 1996.

(Methodology for TS 3.2.2-Nuclear Enthalpy Rise Hot Channel Factor, 3.3.1-Reactor Trip System Instrumentation [f1(I) limits])

11. BAW-10159P-A, BWCMV Correlation of Critical Heat Flux in Mixing Vane Grid Fuel Assemblies, August 1990.

(Methodology for TS 3.2.2-Nuclear Enthalpy Rise Hot Channel Factor, 3.3.1-Reactor Trip System Instrumentation [f1(I) limits])

12. BAW-10231P-A, Revision 1, COPERNIC Fuel Rod Design Computer Code, January 2004.

(Methodology for TS 3.3.1-Reactor Trip System Instrumentation [f2(I) limits])

SEQUOYAH UNIT 2 Page 10 of 16 Revision 0

COLR FOR SEQUOYAH UNIT 2 CYCLE 24 Table 2 Maximum Allowable Peaking Limits MAP(X,Y,Z) for Operation AXIAL(X,Y) ELEVATION MAP(X,Y,Z) AXIAL(X,Y) ELEVATION MAP(X,Y,Z)

(FT) (FT) 1 1.7084 1 2.4093 2 1.7084 2 2.4077 3 1.7083 3 2.4068 4 1.7082 4 2.4063 5 1.7081 5 2.4050 1.03 6 1.7079 1.3 6 2.4043 7 1.7078 7 2.4034 8 1.7073 8 2.3923 9 1.7072 9 2.3053 10 1.7072 10 2.1479 11 1.7066 11 2.0305 1 1.8764 1 2.7078 2 1.8761 2 2.6846 3 1.8758 3 2.6349 4 1.8755 4 2.5983 5 1.8750 5 2.5933 1.1 6 1.8746 1.4 6 2.6505 7 1.8732 7 2.6394 8 1.8731 8 2.5563 9 1.8729 9 2.4572 10 1.8733 10 2.2668 11 1.8320 11 2.1190 1 2.1327 1 2.8223 2 2.1321 2 2.7591 3 2.1315 3 2.6985 4 2.1306 4 2.6542 5 2.1295 5 2.6482 1.2 6 2.1290 1.5 6 2.7162 7 2.1286 7 2.7495 8 2.1274 8 2.6507 9 2.1254 9 2.5578 10 2.0247 10 2.3791 11 1.9355 11 2.2011 SEQUOYAH UNIT 2 Page 11 of 16 Revision 0

COLR FOR SEQUOYAH UNIT 2 CYCLE 24 Table 2 (continued)

AXIAL(X,Y) ELEVATION MAP(X,Y,Z) AXIAL(X,Y) ELEVATION MAP(X,Y,Z)

(FT) (FT) 1 2.8935 1 3.0267 2 2.8252 2 2.9676 3 2.7571 3 2.8960 4 2.7055 4 2.8345 5 2.6985 5 2.8256 1.6 6 2.7776 1.9 6 2.9291 7 2.8428 7 3.0655 8 2.7401 8 2.9714 9 2.6471 9 2.8741 10 2.4862 10 2.7780 11 2.2766 11 2.4797 1 2.9545 1 2.6005 2 2.8786 2 2.5794 3 2.8103 3 2.5536 4 2.7522 4 2.5118 5 2.7457 5 2.4500 1.7 6 2.8308 >1.9 6 2.4520 7 2.9230 7 2.6494 8 2.8209 8 2.5446 9 2.7287 9 2.4371 10 2.5873 10 2.2595 11 2.3478 11 2.0819 1 2.9942 1 2.7049 2 2.9271 2 2.6623 3 2.8570 3 2.6375 4 2.7942 4 2.5288 5 2.7875 5 2.5460 1.8 6 2.8823 2.1 6 2.5252 7 2.9967 7 2.7990 8 2.8980 8 2.6963 9 2.8027 9 2.5830 10 2.6853 10 2.4527 11 2.4156 11 2.1796 SEQUOYAH UNIT 2 Page 12 of 16 Revision 0

COLR FOR SEQUOYAH UNIT 2 CYCLE 24 Table 2 (continued)

AXIAL(X,Y) ELEVATION MAP(X,Y,Z) AXIAL(X,Y) ELEVATION MAP(X,Y,Z)

(FT) (FT) 1 2.7475 1 2.8372 2 2.7275 2 2.7099 3 2.6457 3 2.7081 4 2.6125 4 2.6340 5 2.5774 5 2.6483 2.3 6 2.5707 2.5 6 2.6284 7 2.9015 7 3.0303 8 2.7773 8 2.8965 9 2.6757 9 2.8111 10 2.4740 10 2.7019 11 2.2722 11 2.3542 SEQUOYAH UNIT 2 Page 13 of 16 Revision 0

COLR FOR SEQUOYAH UNIT 2 CYCLE 24 Fraction of RATED THERMAL POWER FIGURE 1 Rod Bank Insertion Limits Versus THERMAL POWER, Four Loop Operation (TS 3.1.6)

Fully withdrawn region shall be the condition where shutdown and control banks are at a position within the interval of 225 and 231steps withdrawn.

Fully withdrawn shall be the position as defined below, Cycle Burnup (MWd/mtU) Steps Withdrawn 0 225 to 231 This figure is valid for operation at a RATED THERMAL POWER of 3455 MWth when the LEFM is in operation.

If the LEFM becomes inoperable, then prior to the next NIS calibration, the maximum allowable power level must be reduced by 1.3% in power, and the rod insertion limit lines must be increased by 3 steps withdrawn until the LEFM is returned to operation.

SEQUOYAH UNIT 2 Page 14 of 16 Revision 0

COLR FOR SEQUOYAH UNIT 2 CYCLE 24 1.2 1.0 0.8 K(Z) 0.6 Elevation K(z)

(ft) 0.000 1.0000 0.4 6.285 1.0000 7.995 1.0000 9.705 1.0000 12.000 1.0000 0.2 0.0 0 2 4 6 8 10 12 Core Height (Feet)

FIGURE 2 K(Z) - Normalized FQ(X,Y,Z) as a Function of Core Height (TS 3.2.1)

SEQUOYAH UNIT 2 Page 15 of 16 Revision 0

COLR FOR SEQUOYAH UNIT 2 CYCLE 24 FIGURE 3 AXIAL FLUX DIFFERENCE Limits As A Function of RATED THERMAL POWER For Burnup Range 0 EFPD to EOL (TS 3.2.3)

This figure is valid for operation at a RATED THERMAL POWER of 3455 MWth when the LEFM is in operation.

If the LEFM becomes inoperable, then prior to the next NIS calibration, the maximum allowable power level must be reduced by 1.3% in power, and the AFD limit lines must be made more restrictive by 1% in AFD until the LEFM is returned to operation.

SEQUOYAH UNIT 2 Page 16 of 16 Revision 0

ENCLOSURE 2 SEQUOYAH UNIT 2 CYCLE 24 CORE OPERATING LIMITS REPORT REVISION 1

QA Record L36 200418 801 SEQUOYAH UNIT 2 CYCLE 24 MODE 6 CORE OPERATING LIMITS REPORT REVISION 1 April 2020 Prepared by:

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4/20/2020 Josh Elkins, PWR Fuel Engineering Date Verified by:

0<91..i~ *'9n<d by 8'4l , _ C ON:dc-gov, dc* M. dc-nwlt\ N-~lr\ ou-Co,po,, te Olr"U~1,, cn*,Bdl, ~ C. ctNll* Jcbtlllftv*-90" Re.uon: I twve ,~ ti\!, documtn, O.te:: 2020..()4..20 14'.l(k()S-04'00' /

Jamel Bell, PWR Fuel Engineering Date Reviewed by:

- - - - - - - - - - - - - - -- - - - - - - - - I- - - - -Date John Ritchie, PWR Fuel Engineering Manager Catalanotto, Brandon s Digitally signed by Catalanotto, Brandon Date: 2020.04.29 16:19:32 -04'00' s

Brandon S. Catalanotto, Reactor Engineering Manager Date Approved by:

Date of PORC Affected Revision Aooroval Paoes Reason for Revision 0 4/2/2020 All Initial issue.

Loading an assembly without an RCCA in core location H-08, 1 See above All and discharae of assemblv ML04. Aoolicable to Mode 6 onlv.

SEQUOYAH UNIT 2 Page 1 of 2 Revision 1

MODE 6 COLR FOR SEQUOYAH UNIT 2 CYCLE 24 1.0 CORE OPERATING LIMITS REPORT This CORE OPERATING LIMITS REPORT (COLR) for Sequoyah Unit 2 Cycle 24 has been prepared in accordance with the requirements of the Technical Specification (TS) 5.6.3.

The TSs affected by this report are listed below:

3.1.1 SHUTDOWN MARGIN (SDM) 3.1.3 Moderator Temperature Coefficient (MTC) 3.1.4 Rod Group Alignment Limits 3.1.5 Shutdown Bank Insertion Limits 3.1.6 Control Bank Insertion Limits 3.1.8 PHYSICS TESTS Exceptions - MODE 2 3.2.1 Heat Flux Hot Channel Factor (FQ(X,Y,Z))

3.2.2 Nuclear Enthalpy Rise Hot Channel Factor F¨H(X,Y) 3.2.3 AXIAL FLUX DIFFERENCE (AFD) 3.3.1 Reactor Trip System (RTS) Instrumentation 3.9.1 Boron Concentration 5.6.3 CORE OPERATING LIMITS REPORT (COLR) 2.0 OPERATING LIMITS This COLR is only valid for MODE 6. The cycle-specific parameter limits for specifications 3.1.1, 3.1.3, 3.1.4, 3.1.5, 3.1.6, 3.1.8, 3.2.1, 3.2.2, 3.2.3 and 3.3.1 are not applicable in MODE 6 and are not provided. The parameter limit for 3.9.1 is provided in the following subsection. This limit has been developed using the NRC approved NEMO methodology specified in TS 5.6.3. The version of the topical report for the NEMO methodology is BAW-10180-A, Rev. 1.

2.1 BORON CONCENTRATION (TS 3.9.1) 2.1.1 The rHIXHOLQJERURQFRQFHQWUDWLRQVKDOOEH2077 ppm.

SEQUOYAH UNIT 2 Page of 2 Revision 1

ENCLOSURE 3 SEQUOYAH UNIT 2 CYCLE 24 CORE OPERATING LIMITS REPORT REVISION 2

QA Record L36 200423 803 SEQUOYAH UNIT 2 CYCLE 24 CORE OPERATING LIMITS REPORT REVISION 2 April 2020 Prepared by:

Digitally *gnl!d by Bel( Jamel C OM: dc=gov, dc=tva., dc* maln. ou=Maln, ou=Corpon1te, OU=lkers, cnsBell, Jamel C. emall*Jcbell30tva.gov fleason: 1am the author of this document

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Date: 2020.04.23 20-.29:11 -04'00' Jamel C. Bell, PW R Fuel Engineering Date Verified by:

Elk.Ins, Joshua Thomas flate: Digitally signed by Elkins.Joshua Thomas 2020.04.23 20:39:52 -04'00'

- - - - - - - - - - - - - - - - - - - - - - - - -I- - - - - - - - - - -

Josh T. Elkins, PW R Fuel Engineering Date Reviewed by:

R*t h* J h A I C Ie O n i Digitally signed by Ritchie, John A DN:dc=gov,dc=tva,dc=maln,ou=Maln,ou:::Corporate, ou=Users,cn::Rltchle,JohnA.emaU=jarltchleO@tva.gov I ffd"cr>n: I have reviewed this document

- - - - - - - - - - - - - - - - - - - - - - - - -I- - - - - - - - - - -

Datt: 2020.04.23 20:43:01 *<l4'00' John A . Ritchie, PW R Fuel Engineering Manager Date signed by Catalanotto, Brandon S Cata Ian Otto, Brand On S Digitally 1 Sate: 2020.04.23 21 :16: 12 -04'00'

- - - - - - - - - - - - - - - - - - - - - - - - - -- I - - - - -- - - -

Brandon S. Catalanotto, Reactor Engineering Manager Date Date of PORC Affected Revision Aooroval Paoes Reason for Revision 0 04/02/2020 All Initial issue.

Loading an assembly without an RCCA in core location H-08, 1 04/21/2020 All and discharoe of assembly ML04. Aoolicable to Mode 6 onlv.

Support implementation of amended Technical Specification (TS) 4.2.2, "Control Rod Assemblies," which would perm it the SQN2 2 See above All Cycle 24 (S2C24) core to contain 52 full length control rods with no full length control rod assembly in core location H-08.

SEQUOYAH UNIT 2 Page 1 of 16 Revision 2

COLR FOR SEQUOYAH UNIT 2 CYCLE 24 1.0 Core Operating Limits Report This CORE OPERATING LIMITS REPORT (COLR) for Sequoyah Unit 2 Cycle 24 has been prepared in accordance with the requirements of Technical Specification (TS) 5.6.3.

The TSs affected by this Report are listed below.

COLR Section, TS Table and/or COLR Section Technical Specification COLR Parameter Figure Page (s) 3.1.1 SHUTDOWN MARGIN (SDM) SDM 2.1 3 BOL MTC Limit 2.2.1 4 Moderator Temperature Coefficient EOL MTC Limit 2.2.2 4 3.1.3 (MTC) 300 ppm Surveillance Limit 2.2.3 4 60 ppm Surveillance Limit 2.2.4 4 3.1.4 Rod Group Alignment Limits SDM 2.1.3 3 Shutdown Bank Insertion Limits 2.3 4 3.1.5 Shutdown Bank Insertion Limits SDM 2.1.4 3 Control Bank Insertion Limits 2.4, Figure 1 5, 14 3.1.6 Control Bank Insertion Limits SDM 2.1.5 3 PHYSICS TESTS Exceptions -

3.1.8 SDM 2.1.6 3 MODE 2 RTP FQ 2.5.1 6 K(Z) 2.5.2, Figure 2 6, 15 AFD NSLOPE 2.5.3 6 AFD PSLOPE 2.5.4 6 Heat Flux Hot Channel Factor 3.2.1 f (I) 2.5.5 6 (FQ(X,Y,Z)) NSLOPE 2 f2(I)

PSLOPE 2.5.6 6 FQ(X,Y,Z) Appropriate Factor 2.5.7 6 TS LCO 3.2.1 Required Action A.3 2.5.8 6 MAP(X,Y,Z) 2.6.1, Table 2 6, 11 RRH 2.6.2 6 Nuclear Enthalpy Rise Hot Channel TRH 2.6.3 6 3.2.2 Factor (FH(X,Y)) FH(X,Y) Appropriate Factor 2.6.4 7 TS 3.2.2 Required Action A.4 2.6.5 7 TS 3.2.2 Required Action B.1 2.6.6 7 3.2.3 AXIAL FLUX DIFFERENCE (AFD) AFD Limits 2.7, Figure 3 7, 16 Reactor Trip System (RTS) QTNL, QTPL, QTNS, and QTPS 2.8.1 8 3.3.1 Instrumentation QPNL, QPPL, QPNS, and QPPS 2.8.2 9 3.9.1 Boron Concentration Refueling Boron Concentration 2.9 9 CORE OPERATING LIMITS 5.6.3 Analytical Methods Table 1 10 REPORT (COLR)

SEQUOYAH UNIT 2 Page 2 of 16 Revision 2

COLR FOR SEQUOYAH UNIT 2 CYCLE 24 2.0 Operating Limits The cycle-specific parameter limits for the TS listed in Section 1.0 are presented in the following subsections. These limits have been developed using the NRC approved methodologies specified in TS 5.6.3. The versions of the topical reports, which describe the methodologies used for this cycle, are listed in Table 1.

The following abbreviations are used in this section:

BOL stands for Beginning of Cycle Life EOL stands for End of Cycle Life RTP stands for RATED THERMAL POWER 2.1 SHUTDOWN MARGIN - SDM (TS 3.1.1, 3.1.4, 3.1.5, 3.1.6, 3.1.8) 2.1.1 For TS 3.1.1, SDM shall be 1.6 %k/k in MODE 2 with keff < 1.0, MODE 3 and MODE 4.

2.1.2 For TS 3.1.1, SDM shall be 1.0 %k/k in MODE 5.

2.1.3 For TS 3.1.4, SDM shall be 1.6 %k/k in MODE 1 and MODE 2.

2.1.4 For TS 3.1.5, SDM shall be 1.6 %k/k in MODE 1 and MODE 2.

2.1.5 For TS 3.1.6, SDM shall be 1.6 %k/k in MODE 1 and MODE 2 with keff 1.0.

2.1.6 For TS 3.1.8, SDM shall be 1.6 %k/k in MODE 2.

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COLR FOR SEQUOYAH UNIT 2 CYCLE 24 2.2 Moderator Temperature Coefficient - MTC (TS 3.1.3) 2.2.1 The BOL MTC limit is:

less positive than -0.23 x 10-5 k/k/ºF.

2.2.2 The EOL MTC limit is:

less negative than or equal to -4.50 x 10-4 k/k/ºF.

2.2.3 The 300 ppm Surveillance limit is:

less negative than or equal to -3.80 x 10-4 k/k/ºF.

2.2.4 The 60 ppm Surveillance limit is:

less negative than or equal to -4.20 x 10-4 k/k/ºF.

2.3 Shutdown Bank Insertion Limits (TS 3.1.5) 2.3.1 Each shutdown bank shall be withdrawn to a position as defined below:

Cycle Burnup Steps (MWd/mtU) Withdrawn 0 225 to 231 SEQUOYAH UNIT 2 Page 4 of 16 Revision 2

COLR FOR SEQUOYAH UNIT 2 CYCLE 24 2.4 Control Bank Insertion Limits (TS 3.1.6) 2.4.1 The control banks shall be limited in physical insertion as shown in Figure 1.

2.4.2 Each control bank shall be considered fully withdrawn from the core at 225 steps.

2.4.3 The control banks shall be operated in sequence by withdrawal of Bank A, Bank B, Bank C, and Bank D. The control banks shall be sequenced in reverse order upon insertion.

2.4.4 Each control bank not fully withdrawn from the core shall be operated with the following overlap as a function of full out position.

Full Out Position (steps) Bank Overlap (steps) Bank Difference (steps) 225 97 128 226 98 128 227 99 128 228 100 128 229 101 128 230 102 128 231 103 128 SEQUOYAH UNIT 2 Page 5 of 16 Revision 2

COLR FOR SEQUOYAH UNIT 2 CYCLE 24 2.5 Heat Flux Hot Channel Factor - FQ(X,Y,Z) (TS 3.2.1)

RTP 2.5.1 FQ = 2.62 2.5.2 K(Z) is provided in Figure 2 2.5.3 NSLOPEAFD = 1.3 2.5.4 PSLOPEAFD = 1.6 2.5.5 NSLOPEf2(I) = 1.6 2.5.6 PSLOPEf2(I) = 2.3 M

2.5.7 The appropriate factor for increase in FQ (X,Y,Z) for compliance with SR 3.2.1.2 and SR 3.2.1.3 is specified as follows:

For all cycle burnups, use 2.0%.

2.5.8 TS LCO 3.2.1 Required Action A.3 reduces the Overpower Delta-T Trip setpoints (value of K4) at least 1% (in T span) for each 1% that FQC(X,Y,Z) exceeds its limit.

2.6 Nuclear Enthalpy Rise Hot Channel Factor - FH(X,Y) (TS 3.2.2) 2.6.1 MAP(X,Y,Z) is provided in Table 2.

2.6.2 RRH = 3.34 when 0.8 < P d 1.0 RRH = 1.67 when P d 0.8 Where RRH = Thermal power reduction required to compensate for each 1% that FH(X,Y) exceeds its limit.

P = THERMAL POWER / RATED THERMAL POWER 2.6.3 TRH = 0.0334 when 0.8 < P d 1.0 TRH = 0.0167 when P d 0.8 Where TRH = Reduction in Overtemperature Delta-T K1 setpoint required to compensate for each 1% that FH(X,Y) exceeds its limit.

P = THERMAL POWER / RATED THERMAL POWER SEQUOYAH UNIT 2 Page 6 of 16 Revision 2

COLR FOR SEQUOYAH UNIT 2 CYCLE 24 2.6.4 The appropriate factor for increase in FHM (X,Y) for compliance with SR 3.2.2.1 and SR 3.2.2.2 is specified as follows:

For all cycle burnups, use 2.0%.

2.6.5 TS LCO 3.2.2 Required Action A.4 reduces the Overtemperature Delta-T setpoint (K1 term in Table 3.3.1-1) by TRH multiplied by the FH minimum margin.

2.6.6 TS LCO 3.2.2 Required Action B.1 reduces the Overtemperature Delta-T setpoint (K1 term in Table 3.3.1-1) by TRH multiplied by the f1(I) minimum margin.

2.7 Axial Flux Difference - AFD (TS 3.2.3) 2.7.1 The AFD limits are specified in Figure 3.

SEQUOYAH UNIT 2 Page 7 of 16 Revision 2

COLR FOR SEQUOYAH UNIT 2 CYCLE 24 2.8 Reactor Trip System Instrumentation (TS 3.3.1) 2.8.1 Trip Reset Term [f1(I)] for Overtemperature Delta-T Trip The following parameters are required to specify the power level-dependent f1(I) trip reset term limits for Table 3.3.1-1 (function 6), Overtemperature Delta-T trip function:

2.8.1.1 QTNL = -20%

where QTNL = the maximum negative I setpoint at RATED THERMAL POWER at which the trip setpoint is not reduced by the axial power distribution.

2.8.1.2 QTPL = +5%

where QTPL = the maximum positive I setpoint at RATED THERMAL POWER at which the trip setpoint is not reduced by the axial power distribution.

2.8.1.3 QTNS = 2.50%

where QTNS = the percent reduction in Overtemperature Delta-T trip setpoint for each percent that the magnitude of I exceeds its negative limit at RATED THERMAL POWER (QTNL).

2.8.1.4 QTPS = 1.40%

where QTPS = the percent reduction in Overtemperature Delta-T trip setpoint for each percent that the magnitude of I exceeds its positive limit at RATED THERMAL POWER (QTPL).

SEQUOYAH UNIT 2 Page 8 of 16 Revision 2

COLR FOR SEQUOYAH UNIT 2 CYCLE 24 2.8.2 Trip Reset Term [f2(I)] for Overpower Delta-T Trip The following parameters are required to specify the power level-dependent f2(I) trip reset term limits for Table 3.3.1-1 (function 7), Overpower Delta-T trip function:

2.8.2.1 QPNL = -25%

where QPNL = the maximum negative I setpoint at RATED THERMAL POWER at which the trip setpoint is not reduced by the axial power distribution.

2.8.2.2 QPPL = +25%

where QPPL = the maximum positive I setpoint at RATED THERMAL POWER at which the trip setpoint is not reduced by the axial power distribution.

2.8.2.3 QPNS = 1.70%

where QPNS = the percent reduction in Overpower Delta-T trip setpoint for each percent that the magnitude of I exceeds its negative limit at RATED THERMAL POWER (QPNL).

2.8.2.4 QPPS = 1.70%

where QPPS = the percent reduction in Overpower Delta-T trip setpoint for each percent that the magnitude of I exceeds its positive limit at RATED THERMAL POWER (QPPL).

2.9 Boron Concentration (TS 3.9.1) 2.9.1 The refueling boron concentration shall be 2077 ppm.

SEQUOYAH UNIT 2 Page 9 of 16 Revision 2