ML070440147

Sequoyah, Unit 1, Cycle 15 Core Operating Limits Report (Colr) Revision 1

ML070440147
Person / Time
Site:	Sequoyah
Issue date:	01/31/2007
From:	Morris G W Tennessee Valley Authority
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML070440147 (14)

Text

Tennessee Valley Authority, Post Office Box 2000, Soddy-Daisy, Tennessee 37384-2000 January 31, 2007 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 Gentlemen:

In the Matter of ) Docket No. 50-327 Tennessee Valley Authority SEQUOYAH NUCLEAR PLANT (SQN) -UNIT 1 CYCLE 15 CORE OPERATING LIMITS REPORT (COLR) REVISION 1 In accordance with the SQN Unit 1 Technical Specifications 6.9.1.14.c, enclosed is the revised Unit 1 Cycle 15 COLR.The COLR was revised to incorporate changes in the heat flux hot channel factor, elevation dependant adjustment factor, and the axial flux difference limits. These revised factors were necessary to improve operating margins for SQN Unit 1.Please direct questions concerning this issue to me at (423)843-7170.Sincerely, Glenn W. Morris Manager, Site Licensing and Industry Affairs Enclosure A4o/Printed on recycled paper U.S. Nuclear Regulatory Commission Page 2 January 31, 2007 cc (Enclosure):

Mr. Brendan T. Moroney, Senior Project Manager U.S. Nuclear.Regulatory Commission Mail Stop 08G-9a One White Flint North 11555 Rockville Pike Rockville, Maryland 20852-2739 SEQUOYAH UNIT I CYCLE 15 CORE OPERATING LIMITS REPORT'REVISION 1 January 2007 Prepared by: Original Signed byT. D. Beu / January 18, 2007 PWR Fuel Engineering Date Verified by: Original Signed by B. S. Catalanotto

/ January 18, 2007 PWR Fuel Engineering Date Reviewed by: Original Signed by C. S. Faulkner / January 18, 2007 PWR Fuel Engineering Manager Date Original Signed by C. A. Griffin / January 19, 2007 Reactor Engineering Supervisor Date Approved by: Original Signed by M. H. Palmer / January 23, 2007 PORC Chairman Date Original Signed by D. A. Kulisek / January 24, 2007 Plant Manager Date Revision 1 Pages affected 1. 3.4, 12-14 Reason for Revision To incorporate changes in the FQ limit, K(Z) curve, and AFD limits due to a revised Large Break LOCA analysis to improve operatinq margins SEQUOYAH -UNIT I Revision I Page 1 of 14 SEQUOYAH UNIT I CYCLE 15 1.0 CORE OPERATING LIMITS REPORT This Core Operating Limits Report (COLR) for Sequoyah Unit 1 Cycle 15 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 1 (AI) trip reset function for OTAT Trip (QTNL, QTPL) and rates of trip setpoint decrease per percent Al (QTNS, QTPS)TABLE 2.2-1 f 2 (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 -0.16 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/0 F.SEQUOYAH -UNIT 1 Page 2 of 14 Revision 1 SEQUOYAH UNIT 1 CYCLE 15 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 10 -4 Ak/k/°F.2.2 Shutdown Rod Insertion Limit (Specification 314.1.3.5) 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 (AFDLrmnt) are provided in Figures 2A, 2B, and 2C.2.5 Heat Flux Hot Channel Factor -Fa (XY,Z) (Specification 314.2.2)FQ (X,Y,Z) shall be limited by the following relationships:

FQRTP FQ (X,Y,Z) < -* K(Z) for P > 0.5 P FQ RTP FQ (X,Y,Z) < --K(Z) for P< 0.5 0.5 where P = Thermal Power I Rated Thermal Power I RTP 2.5.1 FT = 2.48 2.5.2 K(Z) is provided in Figure 3.SEQUOYAH -UNIT 1 Page 3 of 14 Revision 1 SEQUOYAH UNIT 1 CYCLE 15 The following parameters are required for core monitoring per the Surveillance Requirements of Specification 3/4.2.2: 2.5.3 NSLOPEAFD

= 1.18 where NSLOPEAFD

=2.5.4 PSLOPEAFD

= 1.73 Negative AFD limit adjustment required to compensate for each 1% that FQ (X,Y,Z) exceeds BQDES.Positive AFD limit adjustment required to compensate for each 1% that F 0 (X,Y,Z) exceeds BQDES.where PSLOPEAFD

=2.5.5 NSLOPE2(A)

= 1.38 where NSLOPE f 2 (AI) =Adjustment to negative OPAT f 2 (AI) limit required to compensate for each 1% that FQ (X,Y,Z) exceeds BCDES.2.5.6 PSLOPE f2(Al = 2.02 where PSLOPE f2(A) =2.5.7 BQNOM(X,Y,Z)

=2.5.8 BQDES(X,Y,Z)

=2.5.9 BCDES(X,Y,Z)

=Adjustment to positive OPAT f 2 (AI) limit required to compensate for each 1% that FQ (X,Y,Z) exceeds BCDES.Nominal design peaking factor, increased by an allowance for the expected deviation between the nominal design power distribution and the measurement.

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.

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 all cycle burnups 2.0%SEQUOYAH -UNIT I Page 4 of 14 Revision I SEQUOYAH UNIT I CYCLE 15 2.6 Nuclear Enthalpy Rise Hot Channel Factor -FAH MXY) (Specification 3/4.2.3)FAH (X,Y) shall be limited by the following relationship:

FAN (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: FAHR M (X,Y) < BHNOM(X,Y) where FAHRM (XY) = FARM (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)

=2.6.4 BRDES(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 calculational and measurement uncertainties.

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 RRH = 1.67 where RRH =when 0.8 < P < 1.0 when P < 0.8 Thermal power reduction required to compensate for each 1% that FAH(X,Y)exceeds its limit.P = Thermal Power / Rated Thermal Power SEQUOYAH -UNIT 1 Page 5 of 14 Revision I SEQUOYAH UNIT I CYCLE 15 3.2 Trip Reset Term f f 2 (AI) 1 for Overpower Delta-T Trip (Specification 2.2.1)The following parameters are required to specify the power level-dependent f 2 (AI) 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 =3.2.3 QPNS = 1.70%where QPNS =Maximum positive Al setpoint at rated thermal power at which the trip setpoint is not reduced by the axial power distribution.

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).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).3.2.4 QPPS = 1.70%where QPPS =SEQUOYAH -UNIT I Page 7 of 14 Revision I SEQUOYAH UNIT I CYCLE 15 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-1 01 69P-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

[f 1 (AI), f 2 (AI) 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)SEQUOYAH -UNIT I Page 8 of 14 Revision I I -. ~SEQUOYAH UNIT I CYCLE 15 Table 2 Maximum Allowable Peaking Limits MAP(X,Y,Z)

AXIAL(X,Y)

ELEVATION (ft) MAP(X,Y,Z) 1.1 2 1.9540 4 1.9494 6 1.9431 8 1.9337 10 1.9147 1.2 2 2.1780 4 2.1682 6 2.1543 8 2.1317 10 2.0855.1.3 2 2.4025 4 2.3875 6 2.3672 8 2.3029 10 2.1902 1.4 2 2.6264 4 2.6047 6 2.5629 8 2.4204 10 2.2893 1.5 2 2.8525 4 2.8119 6 2.6771 8 2.5251 10 2.3839 1.7 2 2.7765 4 3.0191 6 2.8610 8 2.7036 10 2.5528 AXIAL(X,Y)

ELEVATION (ft) MAP(X,Y,Z) 1.9 2 2.8169 4 3.1537 6 3.0026 8 2.8465 10 2.6987>1.9 2 2.5377 4 2.8412 6 2.7051 8 2.5644 10 2.4313 2.2 2 2.6873 4 3.3150 6 3.1660 8 3.0227 10 2.7136 2.6 2 2.6965 4 3.5807 6 3.5514 8 3.3102 10 2.9726 3.0 2 2.9517 4 3.8016 6 4.1225 8 3.6877 10 3.3466 3.5 2 3.1500 4 4.1097 6 4.1197 8 3.7296 10 3.4811 SEQUOYAH -UNIT I Page 9 of 14 Revision 1 SEQUOYAH UNIT 1 CYCLE 15 220 ---- 44552s- 4 200 ... -o 140____ __ ____0,11~120 _180 (0,110).2 1600 _ _ _ _ _80 BANTIAN D _014 I1 60o_ _(0.09,0I 0 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/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 1 Page 10 of 14 Revision I SEQUOYAH UNIT 1 CYCLE 15 120 1 110 -+ -- + i (-11,100)

(7,100)100 __ ___ --ý --Ulacceptabl Jnac eptarle 90 -- L7 Operatio--- -Orail--S -Ac able 70E -Op ion-M= 60 --_I--S50 -(-40,50) (28,50)40____ __0 d-30 _20 -_ _ _ _ _ _10 _ _ _0 I I I ! I I-50 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 254+10 EFPD to 431+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 I Page 12 of 14 Revision 1 SEQUOYAH UNIT I CYCLE 15 120 110 +_ _ _(-13,100)

(5,100)100 Uaptab~ naccepta le 90g-oOeraior

_ _ --Ope ratiol o 80 -__ --I. aeptble E 70 -Vd -on.60 L_ I_ L_60-a) 50 __ __(-40,50) F- F ('28,50)T.~40 -_ +__0~30___20__ ____ __ __ __ __ __o0 I I I t I I-50 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 431+10 EFPD to EOC 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 maxdmum 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 I Page 13 of 14 Revision 1 SEQUOYAH UNIT 1 CYCLE 15 1.2 1.0 0.8-. 0.6 0.4 0.2 0.0 0 2 4 6 8 10 12 Core Height (Feet)FIGURE 3 K(Z) -Normalized FQ(XYZ) as a Function of Core Height SEQUOYAH -UNIT I Page 14 of 14 Revision I