L-2023-053, Core Operating Limits Report for Cycle 23

Core Operating Limits Report for Cycle 23

ML23095A202
Person / Time
Site:	Seabrook
Issue date:	04/05/2023
From:	Strand D NextEra Energy Seabrook
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
L-2023-053
Download: ML23095A202 (1)

Text

April 05, 2023 Docket No. 50-443 L-2023-053 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555 - 0001 Seabrook Station Core Operating Limits Report for Cycle 23 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 Report (COLR) for Cycle 23.

Should you have any questions regarding this submission, please contact Mr. Kenneth Mack, Fleet Licensing Manager, at 561-904-3635.

Sincerely, Dianne Strand General Manager Regulatory Affairs

Enclosure:

Seabrook Cycle 23 Core Operating Limits Report cc: NRC Region I Administrator NRC Project Manager NRC Senior Resident Inspector NextEra Energy Seabrook, LLC, P.O. Box 300, Lafayette Road, Seabrook, NH 03874

L-2023-053 NextEra Energy Seabrook Station Core Operating Limits Report for Cycle 23 ENCLOSURE Seabrook Cycle 23 Core Operating Limits Report (20 pages follow)

1.0 Core Operating Limits Report (COLR)

This Core Opera1ting Limits Report for Searook Station Unit 1, Cycle 23 has been prepared in accordance with the requirements of Techni1.:al SpeL:ification 6.8.1.6.

The Technical Specifications affected by this rep01t are:

1) 2.2.1 Limiting Safety System Settings

2) 2.1 Safety Limits

3) 3.1.l.i Shutdown lV!argin Limit for NOlJES 1, 2,3 1 4

4) 3.1.l.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 i.,imits

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.l 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 suhsections. 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 T Trip Setpoint Parameters and Function Modifier:

2.1.1.1 K1 = 1.210 2.1.1.2 Ki = 0.021 I )F 2.1.1.3 K -= O.Oull I psig T = Measured RCS Tavg (°F ), and T' = ndicated RCS Tavg at RATED THERMAL POWER Calibration temperature for T instrumentation, 589.1°F).

P = Nominal RCS operating pressure, 2235 psig 6-1.1

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 OTT input cham1els T, Tavg and Pressurizer Pressure; 0.25% of LT span is applicable to I.

2. l.1.8 f1(I) 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 instrnment response during plant startup tests ca1ibrations such that:

(1) For q: - q) between-20% and +8%, f1(Af) O; where qt and qb are percent RATED THERMAL POW'ER 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 2.87% of its value at RATED THERMAL POWER.

(3) For each percent that the magnitude of qt- qb exceeds +8%, the .LlT Trip Setpoint shall be automatically reduced by '2:: 1.71% of its value at RATED THERMAL POWER.

See Figure 5.

2.1.1.9 't1 = 0 seconds 2.1.1.10 't2 = 0 seconds 2.1.1.11 't3 :'.S 2 seconds 2.1.1.12 't4 28 seconds 2.1.1.13 'ts 4 seconds 2.1.1.14 't6 S 2 seconds 6-1.2

2.1.2 Cycle Dependent OverpowerT Trip Setpoint P arameters and Function Modifier:

2.1.2.1 K4 = 1.116 2.1.2.2 Ks = 0.020 / °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 T",

where:

T = Measured Tavg (°F ), and T" = Indicated Tavg at RATED THERMAL POWER (Calibration temperature forT instrumentation, 589 .1 °F).

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

2.1.2.5 Cl1annel Z = N.A.

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

2.1.2.7 Allowable Value - The channel's maximum T1ip Setpoint shall not exceed its computed Trip Setpoint by more than 0.5% of T span. Note that 0.5% ofT span is applicable to OPT input channelsT and Tavg.

2.1.2.8 fz(I) is disabled.

2.1.2.9 'C1 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 'C3 as defined in 2.1.1.11, above.

2.1.2.12 'C6 as defined in 2.1.1.14, above.

2.1.2.13 'C,- 10 seconds. It is recognized that exactly equal values cannot always be dialed into the numerator and denominator in the protection system hardware, even if the 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). TI1e lag time constant (denominator Tau value) may be less than 10 seconds or less than the value of the numerator Tau value (e.g., if the 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 feahire.

6-1.3

2.2 Safety Limits: (Specification 2.1.1) 2.2.l In Modes l and 2, the combination of Them1al Power, reactor coolant system highest loop average temperature and pressmizer 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% LiK/K, in MODES 1, 2 and 3.

2.3.2 The Shutdown Margin shall be greater than or equal to 2.3% LiK/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.l The Shutdown Margin shall be greater than or equal to 2.3% LiK/K.

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 Bo1ic Acid Storage System boron concentration shall be greater than or equal to 7000 ppm.

2.5 Moderator Temperature Coefficient: (Specification 3.1.1.J) 2.5.l The Moderator Temperature Coefficient (MTC) shall be less positive than

+4.573 x 10-5Af</K.J° 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 LiK/K/°F for End of Cycle Life (EOL), ARO, Rated Thermal Power conditions.

2.5.3 The 300 ppm ARO, Rated Thennal Power MTC shall be less negative than-4.6 x 10-4 LiK/K/° F (300 ppm Surveillance Limit).

2.5.4 The Revised Predicted near-EOL 300 ppm MTC shall be calculated using the alg01ithm contained in WCAP 1 3749-P-A:

Revised Predicted MTC = Predicted MTC + AFD Co1Tection- 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

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) 2.9.1 The indicated AFD must be within the Acceptable Operation Limits specified in Figures 2a or 2b.

2.10 Heat Flux Hot Channel Factor: (Specification 3.2.2) 2.10.1 Fow(z) :S (FoRTP/P)

• K(z) forP > 0.5 2.10.2 Fow(z) :S (FoRTP/ 0.5)

• K(z) forP :S 0.5 2.10.3 pRTP = 2.50 Q

2.10.4 FoW(z) = Fq11(z)

• W(z)/P]

• Rj forP > 0.5 forP :S 0.5 FoM(z) is the measured Fo(z) increased by the allowances for manufacturing tolerances (3%) and measurement uncertainty (5%).

For non-surveillance conditions, confinn forP > 0.5 forP :S 0.5 2.10.6 P = (ThennalPower)/ (Rated Them1alPower) 2.10.7 K(z) is specified in Figure 3.

6-1.5

2.10.8 W(z) is specified inTables la and lb, applicable to the RAOC Operating S paces (R OS) in Figures 2a and 2b, respectively.

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

BU< 150M WD/MTU, linear extrapolation of 150 and 3000 MWD/MTU W(z) data 150 BU< 6500MWD/MTU, quadratic interpolation of 150, 3000, and I 0000 MWD/MTU W(z) data 6500 BU< 18000 MWD/MTU, quadratic interpolation of 3000, 10000, and 18000 M\VD/MTUW(z) data BU218000MWD/MTU, linear extrapolation of 10000 and 18000 MWD/MTUW(z) data Note: The Fo(Z) surveillance exclusion zone is:

Lower core region from O to 10%, inclusive, and Upper core region from 90 to 100%, inclusive.

2.10.9 Rj is the penalty factor that accounts for the potential decreases in transient Fo margin between surveillances.This factor is specified inTable 2.

2.10.10 Table 3 provides the required limits onTHERMAL POWER and the requiredAFD reductions for the operating spaces defined in Figures 2a and 2b, in the event that additional margin is required.

2.11 Nuclear Enthalpy Rise Hot Channel Factor: (Specification 3.2.3) 2.11.1 F\lli $ FNm(RTP) x ( l + PF x ( 1-P ))

where P =THERMAL POWER I RATEDTHERMAL POWER .

2.11.2 For FNm measured by the fixed incore detectors:

pNm(RTP) = 1.586.

2.11.3 Power FactorM ultiplier for FNm=PF= 0.3.

6-1.6

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 Pressmizer Pressure shall be greater than 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 nom1al 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) 2.13.1 Each Accumulator shall have a boron concentration between 2400 and 2600 ppm.

2.14 Refueling Water Storage Tank Boron Concentration Limits for MODES 1, 2, 3, 4 (Specification 3.5.4) 2.14.1 The RWST shall have a boron concentration between 2500 and 2600 ppm.

2.15 Refueling Boron Concentration Limits for MODE 6 (Specification 3.9.1) 2.15.1 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.

6-1.7

Figure 1: Control Bank Insertion Limits Versus Thermal Power

- 200 C:

(0.0,188) 3:

175 "C

.r::.

(1.0,166)

§ 1 ti)

C.

125 U)

C:

.2

• - 100 ti) 0 75 (0.0,71)

C:

al 50 "C

0 0:::

25 (0.216,0.

0 0.0 0.2 0.4 0.6 0.8 1.0 Fractioo of Rated lhenml Po.\e-6-1.8

Figure 2a: Axial Flux Difference Operating Li.tnits Versus Thermal Power, ROSI RAOC Operating Space 1 (ROSl) 110

-14, 100 8,100 100 U nacce pta ble Unacceptable Operation Operation 90 80

a. 70 ni Acceptable 60 Operation

• 34, so 28,50 so 40 30 20 10 0

so .40 - 30 *20 -10 0 10 20 30 40 50 60 Axial Flux Difference (%Al) 6-1.9

Figure 2b: Axial Flux Difference Operating Limits Versus Therma. Pow.er-, ROS2 RAOC Operating Space 2 (ROS2) 110

-7, 100 5,100 100 U naccepta bl e Unacceptable Operation Operation 90 80

a. 70 e Acceptable ia 60 Operation

-22, 50 20, 50 50 40 30 20 10 0

so -40 - 30 -20 *10 0 10 20 30 40 50 60 Axial Flux Difference (%.61) 6-1.10

Figure 3: K(Z) Versus Core Height 1.2 1 (0.0, 1.

)I I 1 (6.0, 1 .<XX>)I 1

11(12.00,0

.925)1 0.8 -

I 0.6

. J_

0.4 0.2 -

I I I I I ' I I 0 1 2 3 4 5 6 7 8 9 10 11 12 Qre 1-feig,t (Feet) 6-1.11

Figure 4: Deleted 6-1.12

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

-60 -40 -20 0 20 40 60 1.2o,oj IBand(percenV-:-::---::,

6-1.13

Figure 6: Safety Limits 66{)

2425 psia LL I 2400 psia O>

64{)

e:::

s

'C E 62{)

Q) 2000 psia Q)

O>

0 Q) 60{) 1935psia

(/")

(_)

et::

58{)

0 .2 .4 .6 .8 1.2 Fraction of Rated Thermal Power 6-1.14

Table la: W(Z,BU) versus Axial Height for ROS1 (Sheet i. of2)

HEIGHT (Z) W{Z,BU) W(Z,BU) W(Z,BU) \\'(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 1.3993 1.3771 1.2785 1.2797 1.4 l.3845 1.3607 1.2683 1.2687 1.6 1.3674 1.3421 1.2563 1.2559 1.8 1.3485 1.3219 1.2429 1.2417 2.0 1.3282 1.2995 1.2285 1.2264 2.2 1.3070 1.2794 l.2B6 1.2107 2.4 1.2849 1.2641 1.1991 1.1961 2.6 1.2631 l.2491 1.1856 1.1829 2.8 1.2467 1.2334 1.1741 1.1692 3.0 1.2352 1.2203 1.1666 1.1590 3.2 1.2241 1.2094 1.1609 1.1533 3.4 1.2131 l.1980 1.1542 1.1511 3.6 1.2069 l.1872 1.1470 1.1518 3.8 1.2007 1.1814 1.1392 1.1532 4.0 1.1938 1.1764 1.1322 1.1543 4.2 1.1864 1.1701 1.1275 1.1548 4.4 1.1783 l.1635 1.1243 1.1547 4.6 1.1696 l.1562 1.1205 1.1538 4.8 1.1602 1.1483 l.1]63 1.1519 5.0 1.1502 1.1397 1.1]16 1.1493 5.2 1.1397 1.1306 1.1066 1.1453 5.4 1.1283 l.1208 1.1006 1.1409 5.6 1.1164 l.1103 1.0943 1.1405 5.8 1.1085 1.1008 1.0970 1.1466 6.0 1.1073 1.0993 1.1076 1.1562 6.2 1.1100 1.1021 1.1207 1.1646 6.4 1.1136 1.1025 1.1328 1.1722 6.6 1.1179 1.1023 1.1440 1.1818 6.8 1.1214 1.1027 1.1540 1.1903 7.0 1.1233 1.1068 1.1626 1.1970 7.2 1.1253 1.1125 1.1697 1.2019 7.4 1.1282 1.1165 1.1753 1.2048 7.6 1.1299 1.1195 1.1792 1.2056 7.8 1.1305 1.1223 1.1816 1.2045 8.0 1.1300 1.1253 1.1816 1.2002 8.2 1.1284 1.1280 1.1824 1.1980 8.4 1.1257 1.1303 l.1861 1.1986 8.6 1.1219 1.1336 1.1878 1.1976 8.8 1.1195 1.1387 1.1895 1.1973 6-1. l 5

Table la: W(Z,BU) versus Axial Height for ROS1 (Sheet 2 of2)

HEIGHT (Z) W{Z,BU) W(Z,BU) W(Z,BU) \\'(Z,BU)

(Feet) 150 3000 10000 18000 MWD/MTU MWD/MTU MWD/MTU MWD/MTU 9.0 1.1194 1.1475 1.1951 1.1938 9.2 1.1224 1.1569 1.2046 1.1967 9.4 1.1302 1.1681 l.2 li5 l 1.2150 9.6 1.1472 1.1887 1.2269 1.2352 9.8 1.1724 1.2111 1.2479 1.2542 10.0 1.1993 1.2320 1.2696 1.2695 10.2 1.2232 1.2548 1.2892 1.2878 10.4 1.2468 1.2799 1.3092 1.3110 10.6 1.2686 1.3021 1.3281 1.3291 10.8 1.2681 1.3248 1.3434 1.3421

>11.0 1.0000 1.0000 1.0000 1.0000 ote: The FQ(Z) surveillance exclusion zone is 10%.

Tn .. W(z) V.Jlues in this tabl.. wel'e gnratecl as:;amir..g a base case su1r;,eillance at full power.

6-1.16

Table lb: W(Z,BU) versus Axial Height for R02 Sheet 1 of2)

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

(Feet) 150 3000 10000 18000 M\¥D/MTU MWD/MTU :MWD/MTU MWD/MTU

Sl.0 1.0000 1.0000 1.0000 1.0000 1.2 1.2660 1.2612 1.1694 1.1575 1.4 1.2543 1.2478 1.1602 1.1497 1.6 1.2406 1.2324 1.1494 1.1406 1.8 1.2256 1.2155 1.1375 1.1305 2.0 1.2096 1.1974 1.1248 1.1197 2.2 1.1930 1.1792 l.1H8 1.1086 2.4 1.1761 1.1624 1.0988 1.0974 2.6 1.1 -93 1.1480 1.0861 1.0863 2.8 1.1425 1.1358 1.0729 1.0762 3.0 1.1283 1.1275 1.0673 1.0729 3.2 1.1208 1.1231 1.0670 1.0731 3.4 1.1191 1.1204 1.0660 1.0774 3.6 1.1161 1.1170 1.0651 1.0838 3.8 1.1123 1.1131 1.0642 1.0902 4.0 1.1112 1.1097 1.0656 1.0963 4.2 1.1108 1.1075 1.0695 1.1023 4.4 1.1101 1.1064 1.0728 1.1078 4.6 1.1091 1.1048 1.0761 1.1127 4.8 1.1078 1.1030 1.0793 1.1170 5.0 1.1064 1.1007 1.0822 1.1206

-.2 1.1060 1.0983 1.0847 1.1235 5.4 1.1063 1.0965 1.0869 1.1253 5.6 1.1058 1.0965 1.0885 1.1275 5.8 1.1062 1.0980 1.0890 1.1356 6.0 1.1064 1.1001 1.0926 1.1443 6.2 1.1075 1.1017 1.0995 1.1509 6.4 1.1106 1.1024 1.1065 1.1566 6.6 1.1140 1.1023 1.1]27 1.1609 6.8 1.1164 1.1023 1.U78 1.1637 7.0 1.1178 1.1027 1.1218 1.1649 7.2 1.1181 1.1032 1.1246 1.1644 7.4 1.1172 1.1025 1.1262 1.1623 7.6 1.1150 1.1010 1.1266 1.1583 7.8 1.1115 1.0986 1.1257 1.1527 8.0 1.1063 1.0953 1.1229 1.1444 8.2 1.1013 1.0912 1.1217 1.1375 8.4 1.0980 1.0863 1.1231 1.1334 8.6 1.0930 1.0832 1.1265 1.1279 8.8 1.0874 1.0829 1.1301 1.1275 6-1.17

Table lb: W(Z,BU) versus Axial Height for ROS2 Sheet_ of2)

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

(Feet) 150 3000 10000 18000 M\¥D/MTU MWD/MTU :MWD/MTU MWD/MTU 9.0 1.0858 1.0860 1.1330 1.1303 9.2 1.0870 1.0930 1.1355 1.1352 9.4 1.0908 1.1006 1.1372 1.1399 9.6 1.0918 1.1164 1.1404 1.1422 9.8 1.0928 1.1359 1.1581 1.1551 10.0 1.1000 1.1 -46 1.1781 1.1695 10.2 1.1167 1.1750 1.1957 1.1806 10.4 l.1374 1.1977 1.2141 1.1905 10.6 l. l 560 1.2179 1.2316 1.1980 10.8 1.1547 1.2386 1.2460 1.2021 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 po'¥ er.

6-1.18

Table 2: Rj Margin Decrease Factors for ROSI (Figure 2a) and ROS2 (Figure 2b)

Cycle Burnup Range Rj (MWD/MTU)

ROSI ROS2 BOL to 150 1.000 1.000 151 to 3000 1.018 1.040 3001 to 10000 1.012 1.008 10001 to EOL 1.008 1.007 6-1.19

Table 3: Required THERMAL POWER Limits and AFD Reductions Required Required FQ w(z) Required AFD RAOC THERMAL Margin Reduction O?erating Space POWER Limit Improvement (o/oAFD)

(o/oRTPi 1 )

ROS1 (Figure 2a) > 0 °/o s 50% NIA ROS2 (Figure 2b) > QO/o S 50 °/o N/A Note l: Should ROS l not provide sufficient margin to the F ::J.w z) limit, ROS2 may be used. Should none of the RAOC Operating Spaces provided sufficient margin to the F qw(z) limit the THERMAL POWER is limited to less than 50%.

6-1.20