ML051440813
| ML051440813 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 05/23/2005 |
| From: | Pace P Tennessee Valley Authority |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML051440813 (12) | |
Text
May 23, 2005 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 )
SEQUOYAH NUCLEAR PLANT (SQN) - UNIT 2 CYCLE 14 CORE OPERATING LIMITS REPORT (COLR)
In accordance with the SQN Unit 2 Technical Specifications 6.9.1.14.c, enclosed is the Unit 2 Cycle 14 COLR.
Please direct questions concerning this issue to me at (423) 843-7170 or J. D. Smith at (423) 843-6672.
Sincerely, Original signed by:
P. L. Pace Manager, Site Licensing and Industry Affairs Enclosure
SEQUOYAH UNIT 2 CYCLE 14 CORE OPERATING LIMITS REPORT REVISION 0 April 2005 Prepared by:
Originally Signed by T. D. Beu / 05/03/2005 Nuclear Fuel Design Date Verified by:
Originally Signed by John Strange / 05/03/2005 Nuclear Fuel Design Date Reviewed by:
Originally Signed by James F. Lemons / 05/03/2005 Nuclear Fuel Design Manager Date Originally Signed by R. S. Hawn / 05/04/2005 Reactor Engineering Supervisor Date Approved by:
Originally Signed by Heywood R. Rogers (# 6242) / 05/06/2005 PORC Chairman Date Originally Signed by D. A. Kulisek / 05/06/2005 Plant Manager Date Revision 0 Pages affected _____
Reason for Revision ___________________________________________________________________
SEQUOYAH - UNIT 2 Page 1 of 11 Revision 0
SEQUOYAH UNIT 2 CYCLE 14 1.0 CORE OPERATING LIMITS REPORT This Core Operating Limits Report (COLR) for Sequoyah Unit 2 Cycle 14 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 f1(I) trip reset function for OTT Trip (QTNL, QTPL) and rates of trip setpoint decrease per percent I (QTNS, QTPS)
TABLE 2.2-1 f2(I) trip reset function for OPT Trip (QPNL, QPPL) and rates of trip setpoint decrease per percent I (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 (FH(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 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 k/k/°F (BOL limit). With the
-5 measured BOL/ARO/HZP MTC more positive than -0.12 x 10 k/k/°F (as-measured MTC limit), establish control rod withdrawal limits to ensure the MTC remains less positive than 0 k/k/°F for all times in core life.
-4 The EOL/ARO/RTP MTC shall be less negative than or equal to -4.5 x 10 k/k/°F.
SEQUOYAH - UNIT 2 Page 2 of 11 Revision 0
SEQUOYAH UNIT 2 CYCLE 14 2.1.2 The 300 ppm surveillance limit is:
The measured 300 ppm/ARO/RTP MTC should be less negative than or equal to -3.75 x
-4 10 k/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:
Cycle 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 - AFD (Specification 3/4.2.1) 2.4.1 The axial flux difference (AFD) limits (AFDLimit) are provided in Figure 2.
2.5 Heat Flux Hot Channel Factor - FQ (X,Y,Z) (Specification 3/4.2.2)
FQ (X,Y,Z) shall be limited by the following relationships:
FQRTP FQ (X,Y,Z) ______
- K(Z) for P > 0.5 P
FQRTP FQ (X,Y,Z) ______
- K(Z) for P 0.5 0.5 where P = Thermal Power / Rated Thermal Power 2.5.1 FQRTP = 2.50 2.5.2 K(Z) is provided in Figure 3.
SEQUOYAH - UNIT 2 Page 3 of 11 Revision 0
SEQUOYAH UNIT 2 CYCLE 14 The following parameters are required for core monitoring per the Surveillance Requirements of Specification 3/4.2.2:
2.5.3 NSLOPEAFD = 1.11 where NSLOPEAFD = Negative AFD limit adjustment required to compensate for each 1% that FQ (X,Y,Z) exceeds BQDES.
2.5.4 PSLOPEAFD = 1.49 where PSLOPEAFD = Positive AFD limit adjustment required to compensate for each 1% that FQ (X,Y,Z) exceeds BQDES.
f (I) 2.5.5 NSLOPE 2 = 1.38 f (I) 2 where NSLOPE = Adjustment to negative OPT f2(I) limit required to compensate for each 1% that FQ (X,Y,Z) exceeds BCDES.
f (I) 2 2.5.6 PSLOPE = 1.64 f (I) 2 where PSLOPE = Adjustment to positive OPT f2(I) 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 < 3193 MWd/MTU 2.0%
For cycle burnups > 3193 MWd/MTU to < 5007 MWd/MTU 2.7%
For cycle burnups > 5007 MWd/MTU 2.0%
SEQUOYAH - UNIT 2 Page 4 of 11 Revision 0
SEQUOYAH UNIT 2 CYCLE 14 2.6 Nuclear Enthalpy Rise Hot Channel Factor - FH (X,Y) (Specification 3/4.2.3)
FH (X,Y) shall be limited by the following relationship:
FH (X,Y) < MAP(X,Y,Z) / AXIAL(X,Y) 2.6.1 MAP(X,Y,Z) is provided in Table 1.
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:
FHRM (X,Y) < BHNOM(X,Y) where FHRM (X,Y) = FH (X,Y) / [ MAPM / AXIAL(X,Y) ]
FH (X,Y) is the measured radial peak at location X,Y.
MAPM is the value of MAP(X,Y,Z) obtained from Table 1 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 FH (X,Y) limit will be preserved for operation within the LCO limits, including allowances for calculational 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 calculational 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 FH(X,Y) exceeds its limit.
P= Thermal Power / Rated Thermal Power SEQUOYAH - UNIT 2 Page 5 of 11 Revision 0
SEQUOYAH UNIT 2 CYCLE 14 2.6.6 TRH = 0.0334 when 0.8 < P < 1.0 TRH = 0.0167 when P < 0.8 where TRH = Reduction in OTT K1 setpoint required to compensate for each 1%
FH(X,Y) exceeds its limit.
P= Thermal Power / Rated Thermal Power 2.6.7 All cycle burnups shall use a 2% increase in FHM (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 [ f1(I) ] for Overtemperature Delta T-Trip (Specification 2.2.1)
The following parameters are required to specify the power level-dependent f1(I) trip reset term limits for the Overtemperature Delta-T trip function:
3.1.1 QTNL = -20%
where QTNL = Maximum negative I 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 I 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 I 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 I exceeds its positive limit at rated thermal power (QTPL).
SEQUOYAH - UNIT 2 Page 6 of 11 Revision 0
SEQUOYAH UNIT 2 CYCLE 14 3.2 Trip Reset Term [ f2(I) ] for Overpower Delta-T Trip (Specification 2.2.1)
The following parameters are required to specify the power level-dependent f2(I) trip reset term limits for the Overpower Delta-T trip function:
3.2.1 QPNL = -25%
where QPNL = Maximum negative I 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 I 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 I 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 I exceeds its positive limit at rated thermal power (QPPL).
SEQUOYAH - UNIT 2 Page 7 of 11 Revision 0
SEQUOYAH UNIT 2 CYCLE 14 Table 1 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) 1.1 2 1.9540 1.9 2 2.8169 4 1.9494 4 3.1537 6 1.9431 6 3.0026 8 1.9337 8 2.8465 10 1.9147 10 2.6987 1.2 2 2.1780 >1.9 2 2.5377 4 2.1682 4 2.8412 6 2.1543 6 2.7051 8 2.1317 8 2.5644 10 2.0855 10 2.4313 1.3 2 2.4025 2.2 2 2.6873 4 2.3875 4 3.3150 6 2.3672 6 3.1660 8 2.3029 8 3.0227 10 2.1902 10 2.7136 1.4 2 2.6264 2.6 2 2.6965 4 2.6047 4 3.5807 6 2.5629 6 3.5514 8 2.4204 8 3.3102 10 2.2893 10 2.9726 1.5 2 2.8525 3.0 2 2.9517 4 2.8119 4 3.8016 6 2.6771 6 4.1225 8 2.5251 8 3.6877 10 2.3839 10 3.3466 1.7 2 2.7765 3.5 2 3.1500 4 3.0191 4 4.1097 6 2.8610 6 4.1197 8 2.7036 8 3.7296 10 2.5528 10 3.4811 SEQUOYAH - UNIT 2 Page 8 of 11 Revision 0
SEQUOYAH UNIT 2 CYCLE 14 (0.605,231)
( Fully Wit hdraw n Re gion)
- 220 (0.575,225) 200
( 1.0,182) 180 Ro d B an k Step P ositio n 160 BANK C 140 120 (0,110) 100 BANK D 80 60 40 20 (0.09,0) 0 0 0.2 0.4 0.6 0.8 1 (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/mtU) 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 - UNIT 2 Page 9 of 11 Revision 0
SEQUOYAH UNIT 2 CYCLE 14 120 110
(-13,100) (7,100) 100 Unacceptable Unacceptable Operation Operation
% o f Rated Th erm al Po wer 90 80 Acceptable 70 Operation 60 50
(- 40,50) ( 28,50) 40 30 20 10 0
-50 -40 -30 -20 -10 0 10 20 30 40 50 Flux Difference (delta I) %
FIGURE 2 Axial Flux Difference Limits As A Function of Rated Thermal Power 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 10 of 11 Revision 0
SEQUOYAH UNIT 2 CYCLE 14 1.2 3.0 1.0 2.5 T o tal P eakin g, F Q 0.8 2.0 Core Height K(Z) FQ K(Z ) 0.6 0.000 1.000 2.500 1.5 6.285 1.000 2.500 7.995 0.966 2.415 9.705 0.920 2.300 0.4 1.0 12.000 0.858 2.145 0.2 0.5 0.0 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 11 of 11 Revision 0