ML081580301

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Unit 2 Cycle 16 Core Operating Limits Report (COLR)
ML081580301
Person / Time
Site: Sequoyah Tennessee Valley Authority icon.png
Issue date: 06/03/2008
From: James Smith
Tennessee Valley Authority
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML081580301 (15)
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Text

Tennessee Valley Authority, Post Office Box 2000, Soddy-Daisy, Tennessee 37379-2000 June 3, 2008 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 Gentlemen:

In the Matter of ) Docket No. 50-328 Tennessee Valley Authority (TVA) )

SEQUOYAH NUCLEAR PLANT (SQN) - UNIT 2 CYCLE 16 CORE OPERATING LIMITS REPORT (COLR)

In accordance with SQN Unit 2 Technical Specification 6.9.1.14.c, enclosed is the Unit 2 Cycle 16 COLR.

Please direct questions concerning this issue to me at (423) 843-7170 or Russell R. Thompson at (423) 843-6672.

Sincerely, James D. Smith Manager, Site Licensing and Industry Affairs Enclosure cc (Enclosure):

Luis A. Reyes Regional Administrator, Region II U.S. Nuclear Regulatory Commission Sam Nunn Atlanta Federal Center 61 Forsyth Street, SW, Suite 23T85 Atlanta, Georgia 30323-8931 NRC Senior Resident Inspector Sequoyah Nuclear Plant 2600 Igou Ferry Road Soddy Daisy, Tennessee 37379-3624 Printed on recycled paper

QA RECORD L36 080527 804 SEQUOYAH UNIT 2 CYCLE 16 CORE OPERATING LIMITS REPORT REVISION 0 May 2008 Prepared by:

PWR Fuel Engineering Date PWR Fuel Engineering Date Reviewed by:

Date Reactor-Engineering Supervisor Date Approved by^

PORC^CRairmarjf Date Plant Manager Date Revision 0 Pages affected Reason for Revision:

SEQUOYAH-UNIT 2 Pagei of 14 Revision 0

COLR FOR SEQUOYAH UNIT 2 CYCLE 16 1.0 CORE OPERATING LIMITS REPORT This Core Operating Limits Report (COLR) for Sequoyah Unit 1 Cycle 16 has been prepared in accordance with the requirements of Technical Specification (TS) 6.9.1.14.

The TSs affected by this report are listed below:

TABLE 2.2-1 f^Al) trip reset function for OTAT Trip (QTNL, QTPL) and rates of trip setpoint decrease per percent Al (QTNS, QTPS)

TABLE 2.2-1 f2(AI) trip reset function for OPAT Trip (QPNL, QPPL) and rates of trip setpoint decrease per percent Al (QPNS, QPPS) 3/4.1.1.3 Moderator Temperature Coefficient (MTC) 3/4.1.3.5 Shutdown Rod Insertion Limit 3/4.1.3.6 Control Rod Insertion Limits 3/4.2.1 Axial Flux Difference (AFD) 3/4.2.2 Heat Flux Hot Channel Factor (FQ(X,Y,Z))

3/4.2.3 Nuclear Enthalpy Rise Hot Channel Factor (FAH(X,Y))

2.0 OPERATING LIMITS The cycle-specific parameter limits for the specifications listed in section 1.0 are presented in the following subsections. These limits have been developed using the NRC approved methodologies specified in TS 6.9.1.14. 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 ARO stands for All Rods Out HZP stands for Hot Zero THERMAL POWER EOL stands for End of Cycle Life RTP stands for RATED THERMAL POWER 2.1 Moderator Temperature Coefficient - MTC (Specification 3/4.1.1.3) 2.1.1 The MTC limits are:

The BOL/ARO/HZP MTC shall be less positive than 0 Ak/k/°F (BOL limit). With the measured BOL/ARO/HZP MTC more positive than -0.04 x 10"5 Ak/k/°F (as-measured MTC limit), establish control rod withdrawal limits to ensure the MTC remains less positive than 0 Ak/k/°F for all times in core life.

The EOL/ARO/RTP MTC shall be less negative than or equal to -4.5 x 10"4 Ak/k/°F.

SEQUOYAH - UNIT 2 Page 2 of 14 Revision 0

COLR FOR SEQUOYAH UNIT 2 CYCLE 16 2.1.2 The 300 ppm surveillance limit is:

The measured 300 ppm/ARO/RTP MTC should be less negative than or equal to

-3.75x10"4Ak/k/°F.

2.2 Shutdown Rod Insertion Limit (Specification 3/4.1.3.5) 2.2.1 The shutdown rods shall be withdrawn to a position as defined below:

Cvcle Burnup (MWD/MTU) Steps Withdrawn

> 0 > 225 to < 231 2.3 Control Rod Insertion Limits (Specification 3/4.1.3.6) 2.3.1 The control rod banks shall be limited in physical insertion as shown in Figure 1.

2.4 Axial Flux Difference - AFP (Specification 3/4.2.1) 2.4.1 The axial flux difference (AFD) limits (AFDLimit) are provided in Figures 2A, 2B, and 2C.

2.5 Heat Flux Hot Channel Factor - Fn (X.Y.Z) (Specification 3/4.2.2)

FQ (X,Y,Z) shall be limited by the following relationships:

p RTP FQ (X,Y,Z) <

  • K(Z) for P > 0.5 P

p RTP FQ (X,Y,Z) <

  • K(Z) for P < 0.5 0.5 where P = Thermal Power / Rated Thermal Power 2.5.1 FQRTP =2.48

.2.5.2 K(Z) is provided in Figure 3.

SEQUOYAH - UNIT 2 Page 3 of 14 Revision 0

COLR FOR SEQUOYAH UNIT 2 CYCLE 16 The following parameters are required for core monitoring per the Surveillance Requirements of Specification 3/4.2.2:

2.5.3 NSLOPEAFD =

where NSLOPEAFD >EAFD = Negative AFD limit adjustment required to compensate for each 1% that FQ (X,Y,Z) exceeds BQDES.

2.5.4 PSLOPEAFD =2.20 where PSLOPEAFD = Positive AFD limit adjustment required to compensate for each 1% that FQ (X,Y,Z) exceeds BQDES.

2.5.5 NSLOPEf2(A°=1.27 where NSLOPE 2 = Adjustment to negative OPAT f2(AI) limit required to compensate for each 1% that FQ (X,Y,Z) exceeds BCDES.

2.5.6 f(Al) where PSLOPE 2 = Adjustment to positive OPAT f2(Al) limit required to compensate for each 1% that FQ (X,Y,Z) exceeds BCDES.

2.5.7 BQNOM(X,Y,Z) = Nominal design peaking factor, increased by an allowance for the expected deviation between the nominal design power distribution and the measurement.

2.5.8 BQDES(X,Y,Z) = Maximum allowable design peaking factor which ensures that the FQ (X,Y,Z) limit will be preserved for operation within the LCO limits, including allowances for calculational and measurement uncertainties.

2.5.9 BCDES(X,Y,Z) = Maximum allowable design peaking factor which ensures that the centerline fuel melt limit will be preserved for operation within the LCO limits, including allowances for calculational and measurement uncertainties.

BQNOM(X,Y,Z), BQDES(X,Y,Z), and BCDES(X,Y,Z) data bases are provided for input to the plant power distribution analysis codes on a cycle specific basis and are determined using the methodology for core limit generation described in the references in Specification 6.9.1.14.

2.5.10 The increase in FQM (X,Y,Z) for compliance with the 4.2.2.2.e Surveillance Requirements is defined as follows:

For cycle burnups 0 to 6686 MWd/mtU, use 2.0%

For cycle burnups 6686 to 7591 MWd/mtU, use 2.3%

For cycle burnups > 7591 MWd/mtU, use 2.0%

SEQUOYAH - UNIT 2 Page 4 of 14 Revision 0

COLR FOR SEQUOYAH UNIT 2 CYCLE 16 2.6 Nuclear Enthalpy Rise Hot Channel Factor - Fah fX.Y) (Specification 3/4.2.3)

Fah (X,Y) shall be limited by the following relationship:

FAH (X,Y) < MAP(X,Y,Z) / AXIAL(X,Y) 2.6.1 MAP(X,Y,Z) is provided in Table 2.

AXIAL(X,Y) is the axial peak from the normalized axial power shape.

The following parameters are required for core monitoring per the Surveillance Requirements of Specification 3/4.2.3:

FAHRM (X,Y) < BHNOM(X,Y) where FAHRM (X,Y) = FAHM (X,Y) / [ MAPM / AXIAL(X.Y) ]

FahM (X,Y) is the measured radial peak at location X,Y.

MAPM is the value of MAP(X,Y,Z) obtained from Table 2 for the measured peak.

2.6.2 BHNOM(X.Y) = Nominal design radial peaking factor, increased by an allowance for the expected deviation between the nominal design power distribution and the measurement.

2.6.3 BHDES(X,Y) = Maximum allowable design radial peaking factor which ensures that the Fah (X,Y) limit will be preserved for operation within the LCO limits, including allowances for calculations and measurement uncertainties.

2.6.4 BRDES(X,Y) = Maximum allowable design radial peaking factor which ensures that the steady state DNBR limit will be preserved for operation within the LCO limits, including allowances for calculations and measurement uncertainties.

BHNOM(X,Y), BHDES(X,Y) and BRDES(X,Y) data bases are provided for input to the plant power distribution analysis computer codes on a cycle specific basis and are determined using the methodology for core limit generation described in the references in Specification 6.9.1.14.

2.6.5 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 Fah(X,Y) exceeds its limit.

P = Thermal Power / Rated Thermal Power SEQUOYAH - UNIT 2 Page 5 of 14 Revision 0

COLR FOR SEQUOYAH UNIT 2 CYCLE 16 2.6.6 TRH = 0.0334 when 0.8 < P < 1.0 TRH = 0.0167 when P< 0.8 where TRH = Reduction in OTAT K-i setpoint required to compensate for each 1%

Fah(X,Y) exceeds its limit.

P = Thermal Power / Rated Thermal Power 2.6.7 All cycle burnups shall use a 2% increase in FAHM (X,Y) margin for compliance with the 4.2.3.2.d.1 Surveillance Requirement.

3.0 REACTOR CORE PROTECTIVE LIMITS 3.1 Trip Reset Term \ fi(AI) 1 for Overtemperature Delta T-Trip (Specification 2.2.1)

The following parameters are required to specify the power level-dependent f^Al) trip reset term limits for the Overtemperature Delta-T trip function:

3.1.1 QTNL = -20%

where QTNL = Maximum negative Al setpoint at rated thermal power at which the trip setpoint is not reduced by the axial power distribution.

3.1.2 QTPL = +5%

where QTPL = Maximum positive Al setpoint at rated thermal power at which the trip setpoint is not reduced by the axial power distribution.

3.1.3 QTNS = 2.50%

where QTNS = Percent reduction in Overtemperature Delta-T trip setpoint for each percent that the magnitude of Al exceeds its negative limit at rated thermal power (QTNL).

3.1.4 QTPS = 1.40%

where QTPS = Percent reduction in Overtemperature Delta-T trip setpoint for each percent that the magnitude of Al exceeds its positive limit at rated thermal power (QTPL).

SEQUOYAH - UNIT 2 Page 6 of 14 Revision 0

COLR FOR SEQUOYAH UNIT 2 CYCLE 16 3.2 Trip Reset Term \ UIA\) 1 for Overpower Delta-T Trip (Specification 2.2.1)

The following parameters are required to specify the power level-dependent f2(Al) trip reset term limits for the Overpower Delta-T trip function:

3.2.1 QPNL = -25%

where QPNL = Maximum negative Al setpoint at rated thermal power at which the trip setpoint is not reduced by the axial power distribution.

3.2.2 QPPL = +25%

where QPPL = Maximum positive Al setpoint at rated thermal power at which the trip setpoint is not reduced by the axial power distribution.

3.2.3 QPNS = 1.70%

where QPNS = Percent reduction in Overpower Delta-T trip setpoint for each percent that the magnitude of Al exceeds its negative limit at rated thermal power (QPNL).

3.2.4 QPPS = 1.70%

where QPPS = Percent reduction in Overpower Delta-T trip setpoint for each percent that the magnitude of Al exceeds its positive limit at rated thermal power (QPPL).

SEQUOYAH - UNIT 2 Page 7 of 14 Revision 0

COLR FOR SEQUOYAH UNIT 2 CYCLE 16 Table 1 COLR Methodology Topical Reports

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

(Methodology for Specification 3/4.1.1.3 - Moderator Temperature Coefficient)

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

(Methodology for Specification 3/4.1.1.3 - Moderator Temperature Coefficient)

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

June 1989.

(Methodology for Specifications 2.2.1 - Reactor Trip System Instrumentation Setpoints [fi(Al), f2(Al) limits], 3/4.1.3.5 - Shutdown Rod Insertion Limit, 3/4.1.3.6 - Control Rod Insertion Limits, 3/4.2.1 -

Axial Flux Difference, 3/4.2.2 - Heat Flux Hot Channel Factor, 3/4.2.3 - Nuclear Enthalpy Rise Hot Channel Factor)

4. BAW-10168P-A, Revision 3, "RSG LOCA - BWNT Loss of Coolant Accident Evaluation Model for Recirculating Steam Generator Plants," December 1996.

(Methodology for Specification 3/4.2.2 - 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 Specification 3/4.2.2 - Heat Flux Hot Channel Factor)

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

(Methodology for Specification 3/4.2.2 - Heat Flux Hot Channel Factor)

7. EMF-2103P-A, "Realistic Large Break LOCA Methodology for Pressurized Water Reactors",

April 2003.

(Methodology for Specification 3/4.2.2-Heat Flux Hot Channel Factor)

SEQUOYAH - UNIT 2 Page 8 of 14 Revision 0

COLR FOR SEQUOYAH UNIT 2 CYCLE 16 Table 2 Maximum Allowable Peaking Limits MAP(X,Y,Z)

AXIAL(X,Y) ELEVATION (ft) MAP(X,Y,Z) AXIAL(X,Y) ELEVATION (ft) MAP(X,Y,Z) 2 1.9540 2 2.8169 4 1.9494 4 3.1537 1.1 6 1.9431 1.9 6 3.0026 8 1.9337 8 2.8465 10 1.9147 10 2.6987 2 2.1780 2 2.5377 4 2.1682 4 2.8412 1.2 6 2.1543 >1.9 6 2.7051 8 2.1317 8 2.5644 10 2.0855 10 2.4313 2 2.4025 2 2.6873 4 2.3875 4 3.3150 1.3 6 2.3672 2.2 6 3.1660 8 2.3029 8 3.0227 10 2.1902 10 2.7136 2 2.6264 2 2.6965 4 2.6047 4 3.5807 1.4 6 2.5629 2.6 6 3.5514 8 2.4204 8 3.3102 10 2.2893 10 2.9726 2 2.8525 2 2.9517 4 2.8119 4 3.8016 1.5 6 2.6771 3.0 6 4.1225 8 2.5251 8 3.6877 10 2.3839 10 3.3466 2 2.7765 2 3.1500 4 3.0191 4 4.1097 1.7 6 2.8610 3.5 6 4.1197 8 2.7036 8 3.7296 10 2.5528 10 3.4811 SEQUOYAH - UNIT 2 Page 9 of 14 Revision 0

COLR FOR SEQUOYAH UNIT 2 CYCLE 16 (0.605,231)

(Fully Withdraw n RAninn\

  • s 220 ........ - j -/^ (0.575,225) --.~i

! i 200 /

i i i (1.0,182) 180 160 /

T" '  ;'

Q.

140 A BANKC 120 CO (0,110) 100 (0  !

^/--^BANKD CD 80 j  ;

60 * - *(- .4. .._. ._

I *;

40

.J 20 _

(0.09,0)/' i 0 0.2 0.4 0.6 0.8 (Fully Inserted)

Fraction of Rated Thermal Power FIGURE 1 Rod Bank Insertion Limits Versus Thermal Power, Four Loop Operation

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

Fully withdrawn shall be the position as defined below, Cycle Burnup (MWd/mtlh Steps Withdrawn

>0 >225 to <231 This figure is valid for operation at a rated thermal power of 3455 MWt 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-UNIT2 Page 10 of 14 Revision 0

COLR FOR SEQUOYAH UNIT 2 CYCLE 16 1ZU 110 i

(-13,100) (7,100) inn i  :

lUU Unacceptable/ Unacceptable 90 Operation

! /

/

f i\ j Operation l

I /

\  ! I l o 80 " V ' " ~"~ : " . l--- . ...

i i I Q_

Accept able >

70

/ Opera ion 60 i

i\ i... j... ...

/ I \\ ! i 50 (0 (-40,50) (28,50) '

DC .... . {.. . .

40 ... - j . _ ....

f" i

i

' ' I"""

i O

30 - - i-- ..].  ; -._. I...-

20 " - --- -- *

  • j I

10 - J-- - - 4 i I 0

-50 -40 -30 10 0 10 20 30 40 50 Flux Difference (delta I) %

FIGURE 2A Axial Flux Difference Limits As A Function of Thermal Power For Burnup Range of 0 EFPD to 356+10 EFPD This figure is valid for operation at a rated thermal power of 3455 MWt 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 11 of 14 Revision 0

COLR FOR SEQUOYAH UNIT 2 CYCLE 16 120 110

(-12,100) (5.5,100) 100 Unacceptable Unacceptable 90 Operation Operation 0) o 80 Q.

Acceptable 75 70 Opera ion 60 50

(-40,50) (28,50)

CC 40 30 20 10

-50 -40 -30 10 0 10 20 30 40 50 Flux Difference (delta I) %

FIGURE 2B Axial Flux Difference Limits As A Function of Thermal Power For Burnup Range of 356+10 EFPD to 483+10 EFPD This figure is valid for operation at a rated thermal power of 3455 MWt 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 12 of 14 Revision 0

COLR FOR SEQUOYAH UNIT 2 CYCLE 16 120 110

(-13,100) (7,100) 100 Unacceptable Unacceptable 90 Operation Operation o

5 o 80 Q.

Acceptable 75 70 Opera 60 1-50 (0 (-40,50) (28,50) 40 "o

30 .I-...

20 10 4-*

0

-50 -40 -30 10 0 10 20 30 40 50 Flux Difference (delta I) %

FIGURE 2C Axial Flux Difference Limits As A Function of Thermal Power For Burnup Range of 483+10 EFPD to EOL This figure is valid for operation at a rated thermal power of 3455 MWt 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 13 of 14 Revision 0

COLR FOR SEQUOYAH UNIT 2 CYCLE 16 1.2 1.0 0.8

£0.6 Core Height K(Z) 0.000 1.0000 6.285 1.0000 0.4 7.995 0.9348 9.705 0.8866 12.000 0.8303 0.2 0.0 0 2 4 6 8 10 12 Core Height (Feet)

FIGURE 3 K(Z) - Normalized FQ(X,Y,Z) as a Function of Core Height SEQUOYAH - UNIT 2 Page 14 of 14 Revision 0

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