SBK-L-20077, Core Operating Limits Report for Cycle 21

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Core Operating Limits Report for Cycle 21
ML20153A400
Person / Time
Site: Seabrook NextEra Energy icon.png
Issue date: 06/01/2020
From: Browne K
NextEra Energy Seabrook
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
SBK-L-20077
Download: ML20153A400 (17)
v • d • e


Text

NEXTera ENERGY.

SEABROOK June I, 2020 Docket No. 50-443 SBK-L-20077 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555 - 0001 Seabrook Station Core Operating Limits Report for Cycle 21 Pursuant to Technical Specification 6.8.1.6.c, NextEra Energy Seabrook, LLC has enclosed the latest revision of the Seabrook Station Core Operating Limits Rep01t (COLR) for Cycle 21.

If you have any questions regarding this information, please contact me at (603) 773-7932.  !- '

Sincerely, ite Director cc: D. Lew, NRC Region I Administrator J.Poole, NRC Project Manager P. Cataldo, NRC Senior Resident Inspector NextEra Energy Seabrook, LLC, P.O. Box 300, Lafayette Road, Seabrook, NH 03874

ENCLOSURE TO SBK-L-20077 1.0 Core Operating Limits Report (COLR)

This Core Operating Limits Report for Seabrook Station Unit 1, Cycle 21 has been prepared in accordance with the requirements of Technical Specification 6.8.1.6.

The Technical Specifications affected by this report are:

1) 2.2.1 Limiting Safety System Settings
2) 2.1 Safety Limits
3) 3.1.1.1 Shutdown Margin Limit for MODES 1, 2, 3, 4
4) 3.1.1.2 Shutdown Margin Limit for MODE 5
5) 3.1.1.3 Moderator Temperature Coefficient
6) 3.1.2.7 Minimum Boron Concentration for MODES 4, 5, 6
7) 3.1.3.5 Shutdown Bank Insertion Limit
8) 3.1.3.6 Control Rod Insertion Limits
9) 3.2.1 Axial Flux Difference
10) 3.2.2 Heat Flux Hot Channel Factor
11) 3.2.3 Nuclear Enthalpy Rise Hot Channel Factor
12) 3.2.5 DNB Parameters
13) 3.5.1.1 Boron Concentration Limits for MODES 1, 2, 3
14) 3.5.4 Boron Concentration Limits for MODES 1, 2, 3, 4
15) 3.9.1 Boron Concentration Limits for MODE 6 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 Technical Specification 6.8.1.6.

2.1 Limiting Safety System Settings: (Specification 2.2.1) 2.1.1 Cycle Dependent Overtemperature L1T Trip Setpoint Parameters and Function Modifier:

2.1.1.1 Kr = 1.210 2.1.1.2 K1 = 0.021 / °F 2.1.1.3 K3= 0.0011 / psig T Measured RCS T avg (°F ), and T' Indicated RCS Tavg at RATED THERMAL POWER (Calibration temperature for L1T instrumentation,~ 589.1°F).

p' Nominal RCS operating pressure, 2235 psig 6-1.1 SSTR Rev. 161

2.1.1.4 Channel Total Allowance (TA)= N.A.

2.1.1.5 Channel Z = N .A.

2.1.1.6 Channel Sensor Error (S) = N.A.

2.1.1.7 Allowable Value - The channel's maximum Trip Setpoint shall not exceed its computed Trip Setpoint by more than 0.5% of~ T span. Note that 0.5% of~T span is applicable to OT~T input channels ~T, Tavg and Pressurizer Pressure; 0.25% of~ T span is applicable to ~I.

2.1.1.8 f1(M) is a function of the indicated difference between top and bottom detectors of the power-range neutron ion chambers; with nominal gains to be selected based on measured instrument response during plant startup tests calibrations such that:

(1) For qt- qb between-20% and +8%, f1(M) 2 O; where qt and qb are percent RATED THERMAL POWER in the upper and lower halves of the core, respectively, and qt + qb is the total THERMAL POWER in percent RATED THERMAL POWER; (2) For each percent that the magnitude of qt - qb exceeds -20%, the ~T Trip Setpoint shall be automatically reduced by 2 2.87% of its value at RATED THERMAL POWER.

(3) For each percent that the magnitude of qt - qb exceeds +8%, the ~T Trip Setpoint shall be automatically reduced by 2 l. 71 % of its value at RATED THERMAL POWER.

See Figure 5.

2.1.1.9 1:1 = 0 seconds 2.1.1.10 1:2 = 0 seconds 2.1.1.11 1:3 :S 2 seconds 2.1.1.12 1:4 2 28 seconds 2.1.1.13 'ts ::::: 4 seconds 2.1.1.14 1:6 :S 2 seconds 6-1.2 SSTR Rev. 161

2.1.2 Cycle Dependent Overpower ~ T Trip Setpoint Parameters and Function Modifier:

2.1.2.l K4 = 1.116 2.1.2.2 Ks = 0.020 I °F for increasing average temperature and Ks= 0.0 for decreasing average temperature.

2.1.2.3 K6 = 0.00175 I °F for T > T" and K6 = 0.0 for T :s; T",

where:

T = Measured Tavg (°F ), and T" = Indicated Tavg at RATED THERMAL POWER (Calibration temperature for ~T instrumentation, :s; 589.l °F).

2.1.2.4 Channel Total Allowance (TA)= N.A.

2.1.2.5 Channel Z =N.A.

2.1.2.6 Channel Sensor Error (S) = N.A.

2.1.2. 7 Allowable Value - The channel's maximum Trip Setpoint shall not exceed its computed Trip Setpoint by more than 0.5% of ~T span. Note that 0.5% of ~T span is applicable to OP~ T input channels ~ T and Tavg.

2.1.2.8 fz(M) is disabled.

2.1.2.9 t1 as defined in 2.1.1.9, above.

2.1.2.10 t2 as defined in 2.1.1.10, above.

2.1.2.11 t3 as defined in 2.1.1.11, above.

2.1.2.12 1:6 as defined in 2.1.1.14, above.

2.1.2.13 t7 ~ 10 seconds. It is recognized that exactly equal values cannot always be dialed into the numerator and denominator in the protection system hardware, even ifthe nominal values are the same (10 seconds). Thus given the inequality sign in the COLR (greater than or equal to) the intent of the definition of this time constant applies primarily to the rate time constant (i.e. the Tau value in the numerator). The lag time constant (denominator Tau value) may be less than 10 seconds or less than the value of the numerator Tau value (e.g., ifthe numerator is set at 10.5, the denominator may be set to 10 or 9.5) and still satisfy the intent of the anticipatory protective feature.

6-1.3 SSTR Rev. 161

2.2 Safety Limits: (Specification 2.1.1) 2.2.1 In Modes 1 and 2, the combination of Thermal Power, reactor coolant system highest loop average temperature and pressurizer pressure shall not exceed the limits in Figure 6.

2.3 Shutdown Margin Limit for MODES 1, 2, 3, and 4: (Specification 3.1.1.1) 2.3 .1 The Shutdown Margin shall be greater than or equal to 1.3% Li:K/K, in MODES 1, 2 and 3.

2.3.2 The Shutdown Margin shall be greater than or equal to 2.3% 1'1K/K, in MODE 4.

2.3.3 The Boric Acid Storage System boron concentration shall be greater than or equal to 7000 ppm.

2.4 Shutdown Margin Limit for MODE 5: (Specification 3.1.1.2) 2.4.1 The Shutdown Margin shall be greater than or equal to 2.3% L1KIK.

2.4.2 The RCS boron concentration shall be greater than or equal to 2000 ppm when the reactor coolant loops are in a drained condition.

2.4.3 The Boric Acid Storage System boron concentration shall be greater than or equal to 7000ppm.

2.5 Moderator Temperature Coefficient: (Specification 3.1.1.3) 2.5 .1 The Moderator Temperature Coefficient (MTC) shall be less positive than

+4.633 x 10-5Af(JK/°F for Beginning of Cycle Life (BOL), All Rods Out (ARO), Hot Zero Thermal Power conditions.

2.5.2 MTC shall be less negative than -5.5 x 10-4 Af(JK/°F for End of Cycle Life (EOL), ARO, Rated Thermal Power conditions.

2.5 .3 The 300 ppm ARO, Rated Thermal Power MTC shall be less negative than -4.6 x 10-4 Af(JK/°F (300 ppm Surveillance Limit).

2.5.4 The Revised Predicted near-EOL 300 ppm MTC shall be calculated using the algorithm contained in WCAP 13749-P-A:

Revised Predicted MTC =Predicted MTC + AFD Correction- 3 PCM/degree F If the Revised Predicted MTC is less negative than the SR 4.1.1.3.b 300 ppm surveillance limit and all the benchmark data contained in the surveillance procedure are met, then an MTC measurement in accordance with SR 4.1.1.3.b is not required to be performed.

6-1.4 SSTR Rev. 161

2.6 Minimum Boron Concentration for MODES 4, 5, 6 (Specification 3.1.2.7) 2.6.1 The Boric Acid Storage System boron concentration shall be greater than or equal to 7000 ppm.

2.7 Shutdown Bank Insertion Limit: (Specification 3.1.3.5)

2. 7.1 The shutdown banks shall be fully withdrawn. The fully withdrawn position is defined as the interval within 225 steps withdrawn to the mechanical fully withdrawn position inclusive.

2.8 Control Rod Insertion Limits: (Specification 3.1.3.6) 2.8.1 The control rod banks shall be limited in physical insertion as specified in Figure 1.

Control Bank A shall be at least 225 steps withdrawn.

2.9 Axial Flux Difference: (Specification 3.2.1) 2.9.l The indicated AFD must be within the Acceptable Operation Limits specified in Figure 2.

2.10 Heat Flux Hot Channel Factor: (Specification 3.2.2) 2.10.1 FRTPQ = 2.50 2.10.2 K(Z) is specified in Figure 3.

2.10.3 W(Z) is specified in Table 1.

The W(Z) data is applied over the cycle as follows:

BU< 150 MWD/MTU, linear extrapolation of 150 and 3000 MWD/MTU W(Z) data 150 ~BU< 6500 MWD/MTU, quadratic interpolation of 150, 3000, and 10000 MWD/MTU data 6500 ~BU <18000 MWD/MTU, quadratic interpolation of 3000, 10000, and 18000 MWD/MTU W(Z) data BU 2:_ 18000 MWD/MTU, linear extrapolation of 10000 and 18000 MWD/MTU W(Z) data Note: The FQ(Z) surveillance exclusion zone is specified by Technical Specification 4.2.2.2.g 2.10.4 The FMQ(Z) penalty factor is applied over the cycle as follows:

The FMQ(Z) penalty factor is 1.02.

6-1.5 SSTR Rev. 161

2.11 Nuclear Enthalpy Rise Hot Channel Factor: (Specification 3.2.3) 2.11.1 FN,rn ~ FNiiH(RTP) x ( 1 +PF x ( 1 -P ))

where P =THERMAL POWER I RATED THERMAL POWER.

2.11.2 For FNiiH measured by the fixed incore detectors:

FNiitt(RTP) = 1.586.

2.11.3 Power Factor Multiplier for FNiiH =PF= 0.3.

2.12 DNB Parameters (Specification 3.2.5) 2.12.l The Reactor Coolant System Tavg shall be less than or equal to 595.l degrees F.

2.12.2 The Pressurizer Pressure shall be greaterthan or equal to 2185 PSIG.

Note: Technical Specification Bases 3/4.2.5, "DNB Parameters" indicates that the limits on DNB-related parameters assure consistency with the normal steady-state envelope of operation assumed in the transient and accident analyses. Operating procedures include allowances for measurement and indication uncertainty so that the limits in the COLR for Tavg and pressurizer pressure are not exceeded. Consistent with the Bases, the values of these DNB parameters are the limiting Tavg and pressurizer pressure assumed in the transient and accident analyses.

2.13 Accumulator Boron Concentration Limits for MODES 1,2,3 (Specification 3.5.1.1) 2.13.l Each Accumulator shall have a boron concentration between 2300 and 2600 ppm.

2.14 Refueling Water Storage Tank Boron Concentration Limits for MODES 1, 2, 3, 4 (Specification 3.5.4) 2.14.l The RWST shall have a boron concentration between 2400 and 2600 ppm.

2.15 Refueling Boron Concentration Limits for MODE 6 (Specification 3.9.1) 2.15.l The Refueling Boron Concentration shall be greater than or equal to 2240 ppm.

2.15.2 The Boric Acid Storage System boron concentration shall be greater than or equal to 7000 ppm.

6-1.6 SSTR Rev. 161

Figure 1: Control Bank Insertion Limits Versus Thermal Power

-c:

~

200 ,________,

'-----~~~

(0.0,188)

~ 175 l-------+-------+-~~--+--------+--------1 "C (1.0, 166)

.c:

~ 150 I--~~-+-~~~

"'a.

.$ 125 l-------+-------+-----+-----------lol~------1 ti) c:

0 100 1--~-------t~~~---+-~~~--+-~---~--+-~~----1 E

~

"'0 75 .___~~~1-~~--+~~~-#-+~~~-+~~~--1

~

c:

nl III 50 1 - - - - - - - - + - - - - - - f - - - - . , _ __ _--+-_ _ _- - + - - - - 1 "C

0 a::

(0.216,0.0 0 1--..l--"--l---J....;~---"-----1.--"~.__...._..I..-....__.__.____.___..__.~.__........._.

0.0 0.2 0.4 0.6 0.8 1.0 Fraction of Rated Thermal Power 6-1.7 SSTR Rev. 161

Figure 2: Axial Flux Difference Operating Limits Versus Thermal Power 110

(-14,100) 1<8,100)1 II I 100 UNACCEPTABLE OPERATION II '\ UNACCEPTABLE OPERATION 90 (I)

J 3:: 80 0

CL.

-ns 70 I \

E (I)

.c 60 I

' I ACCEPTABLE

\ I f-

...ns 50

'a (I) I OPERATION I

\

...ct:c 40 I(-34.501 I (2a,so11 I

(I)

I!

...u (I)

I I CL. 30 20 l

I I I!

10 0 ' '

50 30 -20 -10 0 10 20 30 40 50 60 Axial Flux Difference (%01)

Note: %DI= %111 6-1.8 SSTR Rev. 161

Figure 3: K(Z) Versus Core Height 1.2 I(o.o,tooo) I I(6.0,1.000) I 1

I(12.00,0.925) 0.8 N

~ 0.6 0.4 0.2 0 I I I I 0 1 2 3 4 5 6 7 8 9 10 11 12 Core Height (Feet) 6-1.9 SSTR Rev. 161

Figure 4: Deleted 6-1.10 SSTR Rev. 161

Figure 5: f1(AI) Function 1-40.91, 60 60 0

-60 -40 -20 0 20 40 60 l-20, ol Al Band (percen~

~

6-1.11 SSTR Rev . 161

Figure 6: Safety Limits 660 2425 psia 2400 psia e:

-I-'

c Q)

E- 620 Q) 1--- 2000 psia Q) 01 0

g2 600

<C

(_/)

(_)

0::::

580 560-+-_.._-'--'--+---'---'--'--+--'--'--'--+----'"----'-----'----il--'"--,__,__+-~~-'--l 0 .2 .4 .6 .8 1.2 Fraction of Rated Thermal Power 6-1.12 SSTR Rev. 161

Table 1: W(Z,BU) versus Axial Height (Sheet 1 of2)

HEIGHT (Z) W(Z,BU) W(Z,BU) W(Z,BU) W(Z,BU)

(Feet) 150 3000 10000 18000 MWD/MTU MWD/MTU MWD/MTU MWD/MTU

Sl.0 1.0000 1.0000 1.0000 1.0000 1.2 1.3751 1.3667 1.2792 1.2805 1.4 1.3610 1.3508 1.2680 1.2704 1.6 1.3445 1.3326 1.2550 1.2587 1.8 1.3262 1.3129 1.2413 1.2455 2.0 1.3067 1.2947 1.2274 1.2313 2.2 1.2858 1.2779 1.2129 1.2163 2.4 1.2651 1.2600 1.1980 1.2008 2.6 1.2498 1.2417 1.1841 1.1852 2.8 1.2358 1.2290 1.1715 1.1689 3.0 1.2204 1.2191 1.1597 1.1587 3.2 1.2081 1.2085 1.1507 1.1546 3.4 1.2027 1.1976 1.1454 1.1520 3.6 1.1979 1.1869 1.1392 1.1535 3.8 1.1926 1.1812 1.1352 1.1551 4.0 1.1868 1.1771 1.1327 1.1563 4.2 1.1805 1.1715 1.1298 1.1570 4.4 1.1736 1.1657 1.1267 1.1570 4.6 1.1662 1.1591 1.1232 1.1563 4.8 1.1581 1.1520 1.1193 1.1548 5.0 1.1494 1.1441 1.1150 1.1522 5.2 1.1402 1.1357 1.1102 1.1489 5.4 1.1303 1.1265 1.1047 1.1443 5.6 1.1189 1.1166 1.0989 1.1400 5.8 1.1152 1.1072 1.0984 1.1446 6.0 1.1148 1.1042 1.1071 1.1562 6.2 1.1176 1.1071 1.1211 1.1644 6.4 1.1229 1.1078 1.1329 1.1719 6.6 1.1274 1.1078 1.1441 1.1790 6.8 1.1310 1.1078 1.1542 1.1862 7.0 1.1335 1.1094 1.1630 1.1927 7.2 1.1347 1.1149 1.1703 1.1973 7.4 1.1345 1.1192 1.1760 1.2002 7.6 1.1331 1.1223 1.1801 1.2014 7.8 1.1297 1.1246 1.1827 1.2008 8.0 1.1260 1.1251 1.1827 1.1984 8.2 1.1231 1.1254 1.1824 1.1946 8.4 1.1198 1.1302 1.1868 1.1895 8.6 1.1173 1.1348 1.1904 1.1816 8.8 1.1125 1.1400 1.1940 1.1821 6-1.13 SSTR Rev. 161

Table 1: W(Z,BU) versus Axial Height (Sheet 2 of2)

HEIGHT (Z) W(Z,BU) W(Z,BU) W(Z,BU) W(Z,BU)

(Feet) 150 3000 10000 18000 MWD/MTU MWD/MTU MWD/MTU MWD/MTU 9.0 1.1111 1.1492 1.2013 1.1877 9.2 1.1179 1.1627 1.2134 1.1917 9.4 1.1250 1.1761 1.2269 1.2018 9.6 1.1301 1.1933 1.2408 1.2121 9.8 1.1445 1.2126 1.2611 1.2320 10.0 1.1716 1.2302 1.2849 1.2611 10.2 1.1980 1.2473 1.3047 1.2898 10.4 1.2218 1.2700 1.3212 1.3144 10.6 1.2455 1.2949 1.3339 1.3348 10.8 1.2683 1.3185 1.3451 1.3504 2:11.0 1.0000 1.0000 1.0000 1.0000 Note: The FQ(Z) surveillance exclusion zone is 10%.

The W(z) values in this table were generated assuming a base case surveillance at full power.

6-1.14 SSTR Rev. 161

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