ML21138A872

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Cycle 25 Core Operating Limits Report, Revision 0
ML21138A872
Person / Time
Site: Sequoyah Tennessee Valley Authority icon.png
Issue date: 05/18/2021
From: Marshall T
Tennessee Valley Authority
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML21138A872 (18)
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Sequoyah Nuclear Plant, Post Office Box 2000, Soddy Daisy, Tennessee 37384 May 18, 2021 10 CFR 50.4 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Sequoyah Nuclear Plant, Unit 1 Renewed Facility Operating License No. DPR-77 NRC Docket No. 50-327

Subject:

SEQUOYAH UNIT 1 CYCLE 25 CORE OPERATING LIMITS REPORT REVISION 0 In accordance with Sequoyah Nuclear Plant (SQN) Unit 1 Technical Specification (TS) 5.6.3.d, enclosed is the Unit 1 Cycle 25 Core Operating Limits Report (COLR), Revision 0 that was issued on April 22, 2021.

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, Thomas Marshall Site Vice President Sequoyah Nuclear Plant

Enclosure:

Sequoyah Unit 1 Cycle 25 Core Operating Limits Report, Revision 0 cc (Enclosure):

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

Marshall, Thomas B.

Digitally signed by Marshall, Thomas B.

Date: 2021.05.18 07:57:46 -04'00'

ENCLOSURE SEQUOYAH UNIT 1 CYCLE 25 CORE OPERATING LIMITS REPORT REVISION 0

QA RECORD L36 210325 800 SEQUOYAH UNIT 1 Page 1 of 16 Revision 0 SEQUOYAH UNIT 1 CYCLE 25 CORE OPERATING LIMITS REPORT REVISION 0 April 2021 Prepared by:

__________________________________________________________/_________________________

W. Kayla Verner-Dingle/Mark D. Porter, PWR Fuel Engineering and NSA Date Verified by:

__________________________________________________________/_________________________

Jamel C. Bell, PWR Fuel Engineering Date Reviewed by:

__________________________________________________________/_________________________

John A. Ritchie, PWR Fuel Engineering Manager Date

__________________________________________________________/_________________________

Eric L. Phillips, Reactor Engineering Manager Date Approved by:

_________________________________________________________/_________________________

PORC Chairman Date

__________________________________________________________/_________________________

Plant Manager Date Revision Date of PORC Approval Affected Pages Reason for Revision 0

See above All Initial issue.

Verner-Dingle, Whitney Kayla Digitally signed by Verner-Dingle, Whitney Kayla Date: 2021.03.26 17:29:46 -04'00' Porter, Mark Donald Digitally signed by Porter, Mark Donald DN: dc=gov, dc=tva, dc=main, ou=Main, ou=Corporate, ou=Users, cn=Porter, Mark Donald, email=mdporter@tva.gov Reason: I am the author of this document Date: 2021.03.26 17:37:19 -04'00' Digitally signed by Bell, Jamel C DN: dc=gov, dc=tva, dc=main, ou=Main, ou=Corporate, ou=Users, cn=Bell, Jamel C, email=jcbell3@tva.gov Reason: I have reviewed this document Location: TVA COC - WFH Date: 2021.03.26 18:05:04 -04'00' Ritchie, John A Digitally signed by Ritchie, John A DN: dc=gov, dc=tva, dc=main, ou=Main, ou=Corporate, ou=Users, cn=Ritchie, John A, email=jaritchie0@tva.gov Reason: I have reviewed this document Date: 2021.03.27 07:33:33 -04'00' Phillips, Eric Lewis Digitally signed by Phillips, Eric Lewis Date: 2021.03.28 11:32:55 -04'00' Hodge, James M.

Digitally signed by Hodge, James M.

Date: 2021.04.01 16:40:51 -04'00' Reneau, William Christopher Digitally signed by Reneau, William Christopher Date: 2021.04.05 12:34:23 -04'00'

COLR FOR SEQUOYAH UNIT 1 CYCLE 25 SEQUOYAH UNIT 1 Page 2 of 16 Revision 0 1.0 Core Operating Limits Report This CORE OPERATING LIMITS REPORT (COLR) for Sequoyah Unit 1 Cycle 25 has been prepared in accordance with the requirements of Technical Specification (TS) 5.6.3.

The TSs affected by this Report are listed below.

TS Section Technical Specification COLR Parameter COLR

Section, Table and/or Figure COLR Page (s) 3.1.1 SHUTDOWN MARGIN (SDM)

SDM 2.1 3

3.1.3 Moderator Temperature Coefficient (MTC)

BOL MTC Limit EOL MTC Limit 300 ppm Surveillance Limit 60 ppm Surveillance Limit 2.2.1 2.2.2 2.2.3 2.2.4 4

4 4

4 3.1.4 Rod Group Alignment Limits SDM 2.1.3 3

3.1.5 Shutdown Bank Insertion Limits Shutdown Bank Insertion Limits SDM 2.3 4

2.1.4 3

3.1.6 Control Bank Insertion Limits Control Bank Insertion Limits 2.4, Figure 1 5, 14 SDM 2.1.5 3

3.1.8 PHYSICS TESTS Exceptions -

MODE 2 SDM 2.1.6 3

3.2.1 Heat Flux Hot Channel Factor (FQ(X,Y,Z))

FQ RTP 2.5.1 6

K(Z) 2.5.2, Figure 2 6, 15 NSLOPEAFD 2.5.3 6

PSLOPEAFD 2.5.4 6

NSLOPEf2(I) 2.5.5 6

PSLOPEf2(I) 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

3.2.2 Nuclear Enthalpy Rise Hot Channel Factor (FH(X,Y))

MAP(X,Y,Z) 2.6.1, Table 2 6, 11 RRH 2.6.2 6

TRH 2.6.3 6

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 3.3.1 Reactor Trip System (RTS)

QTNL, QTPL, QTNS, and QTPS QPNL, QPPL, QPNS, and QPPS 2.8.1 8

Instrumentation 2.8.2 9

3.9.1 Boron Concentration Refueling Boron Concentration 2.9 9

5.6.3 CORE OPERATING LIMITS REPORT (COLR)

Analytical Methods Table 1 10

COLR FOR SEQUOYAH UNIT 1 CYCLE 25 SEQUOYAH UNIT 1 Page 3 of 16 Revision 0 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.

COLR FOR SEQUOYAH UNIT 1 CYCLE 25 SEQUOYAH UNIT 1 Page 4 of 16 Revision 0 2.2 Moderator Temperature Coefficient - MTC (TS 3.1.3) 2.2.1 The BOL MTC limit is:

less positive than

-0.22 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 (MWd/mtU)

Steps Withdrawn 0

225 to 231

COLR FOR SEQUOYAH UNIT 1 CYCLE 25 SEQUOYAH UNIT 1 Page 5 of 16 Revision 0 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

COLR FOR SEQUOYAH UNIT 1 CYCLE 25 SEQUOYAH UNIT 1 Page 6 of 16 Revision 0 2.5 Heat Flux Hot Channel Factor - FQ(X,Y,Z) (TS 3.2.1) 2.5.1 FQ RTP

=

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 2.5.7 The appropriate factor for increase in FQ M(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 FQ C(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

COLR FOR SEQUOYAH UNIT 1 CYCLE 25 SEQUOYAH UNIT 1 Page 7 of 16 Revision 0 2.6.4 The appropriate factor for increase in FH M (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.

COLR FOR SEQUOYAH UNIT 1 CYCLE 25 SEQUOYAH UNIT 1 Page 8 of 16 Revision 0 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).

COLR FOR SEQUOYAH UNIT 1 CYCLE 25 SEQUOYAH UNIT 1 Page 9 of 16 Revision 0 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 2052 ppm.

COLR FOR SEQUOYAH UNIT 1 CYCLE 25 SEQUOYAH UNIT 1 Page 10 of 16 Revision 0 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])

COLR FOR SEQUOYAH UNIT 1 CYCLE 25 SEQUOYAH UNIT 1 Page 11 of 16 Revision 0 Table 2 Maximum Allowable Peaking Limits MAP(X,Y,Z) for Operation AXIAL(X,Y)

ELEVATION (FT)

MAP(X,Y,Z)

AXIAL(X,Y)

ELEVATION (FT)

MAP(X,Y,Z) 1.03 1

2 3

4 5

6 7

8 9

10 11 1.7084 1.7084 1.7083 1.7082 1.7081 1.7079 1.7078 1.7073 1.7072 1.7072 1.7066 1.3 1

2 3

4 5

6 7

8 9

10 11 2.4093 2.4077 2.4068 2.4063 2.4050 2.4043 2.4034 2.3923 2.3053 2.1479 2.0305 1.1 1

2 3

4 5

6 7

8 9

10 11 1.8764 1.8761 1.8758 1.8755 1.8750 1.8746 1.8732 1.8731 1.8729 1.8733 1.8320 1.4 1

2 3

4 5

6 7

8 9

10 11 2.7078 2.6846 2.6349 2.5983 2.5933 2.6505 2.6394 2.5563 2.4572 2.2668 2.1190 1.2 1

2 3

4 5

6 7

8 9

10 11 2.1327 2.1321 2.1315 2.1306 2.1295 2.1290 2.1286 2.1274 2.1254 2.0247 1.9355 1.5 1

2 3

4 5

6 7

8 9

10 11 2.8223 2.7591 2.6985 2.6542 2.6482 2.7162 2.7495 2.6507 2.5578 2.3791 2.2011

COLR FOR SEQUOYAH UNIT 1 CYCLE 25 SEQUOYAH UNIT 1 Page 12 of 16 Revision 0 Table 2 (continued)

AXIAL(X,Y)

ELEVATION (FT)

MAP(X,Y,Z)

AXIAL(X,Y)

ELEVATION (FT)

MAP(X,Y,Z) 1.6 1

2 3

4 5

6 7

8 9

10 11 2.8935 2.8252 2.7571 2.7055 2.6985 2.7776 2.8428 2.7401 2.6471 2.4862 2.2766 1.9 1

2 3

4 5

6 7

8 9

10 11 3.0267 2.9676 2.8960 2.8345 2.8256 2.9291 3.0655 2.9714 2.8741 2.7780 2.4797 1.7 1

2 3

4 5

6 7

8 9

10 11 2.9545 2.8786 2.8103 2.7522 2.7457 2.8308 2.9230 2.8209 2.7287 2.5873 2.3478

>1.9 1

2 3

4 5

6 7

8 9

10 11 2.6005 2.5794 2.5536 2.5118 2.4500 2.4520 2.6494 2.5446 2.4371 2.2595 2.0819 1.8 1

2 3

4 5

6 7

8 9

10 11 2.9942 2.9271 2.8570 2.7942 2.7875 2.8823 2.9967 2.8980 2.8027 2.6853 2.4156 2.1 1

2 3

4 5

6 7

8 9

10 11 2.7049 2.6623 2.6375 2.5288 2.5460 2.5252 2.7990 2.6963 2.5830 2.4527 2.1796

COLR FOR SEQUOYAH UNIT 1 CYCLE 25 SEQUOYAH UNIT 1 Page 13 of 16 Revision 0 Table 2 (continued)

AXIAL(X,Y)

ELEVATION (FT)

MAP(X,Y,Z)

AXIAL(X,Y) ELEVATION (FT)

MAP(X,Y,Z) 2.3 1

2 3

4 5

6 7

8 9

10 11 2.7475 2.7275 2.6457 2.6125 2.5774 2.5707 2.9015 2.7773 2.6757 2.4740 2.2722 2.5 1

2 3

4 5

6 7

8 9

10 11 2.8372 2.7099 2.7081 2.6340 2.6483 2.6284 3.0303 2.8965 2.8111 2.7019 2.3542

COLR FOR SEQUOYAH UNIT 1 CYCLE 25 SEQUOYAH UNIT 1 Page 14 of 16 Revision 0 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.

COLR FOR SEQUOYAH UNIT 1 CYCLE 25 SEQUOYAH UNIT 1 Page 15 of 16 Revision 0 FIGURE 2 K(Z) - Normalized FQ(X,Y,Z) as a Function of Core Height (TS 3.2.1) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 0

2 4

6 8

10 12 Core Height (Feet)

K(Z)

Elevation K(z)

(ft) 0.000 1.0000 6.285 1.0000 7.995 1.0000 9.705 1.0000 12.000 1.0000

COLR FOR SEQUOYAH UNIT 1 CYCLE 25 SEQUOYAH UNIT 1 Page 16 of 16 Revision 0 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.

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