NL-24-0350, Core Operating Limits Report, Cycle 24, Version 2

Core Operating Limits Report, Cycle 24, Version 2

ML24269A173
Person / Time
Site:	Vogtle
Issue date:	09/25/2024
From:	Joyce R Southern Nuclear Operating Co
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
NL-24-0350
Download: ML24269A173 (1)

Text

A. Southern Nuclear September 25, 2024 Docket No.:

50-425 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001 Regulatory Affairs Vogtle Electric Generating Plant, Unit 2 Core Operating Limits Report, Cycle 24, Version 2 Ladies and Gentlemen:

3535 Colonnade Parkway Birmingham, AL 35243 205 992 5000 NL-24-0350 In accordance with Technical Specification (TS) 5.6.5.d for Vogtle Electric Generating Plant (VEGP), Southern Nuclear Operating Company (SNC) submits the VEGP Core Operating Limits Report (COLR) for Unit 2, Cycle 24, Version 2. Version 2 was generated to reflect a re-analyzed Vogtle Unit 2 Cycle 24 core design which includes a period of Extended Reduced Power Operation (ERPO) to provide operational flexibility, as needed, until cycle shutdown.

Consequently, updates were made to the factors for surveilling the Heat Flux Hot Channel Factor (F0 (z)) in accordance with Technical Specification 3.2.1, specifically those factors listed in Tables 1 and 2 of the COLR. No other changes to the COLR were required as a result of this reanalysis.

This letter contains no NRC commitments. If you have any questions, please contact Ryan Joyce at 205.992.6468.

Respectfully submitted, Ryan M. Joyce Licensing Manager RMJ/dsp/cbg

Enclosure:

Unit 2 Cycle 24 Core Operating Limits Report Version 2 cc:

Regional Administrator NRR Project Manager - Vogtle 1 & 2 Senior Resident Inspector - Vogtle 1 & 2 RType: CVC?000

Vogtle Electric Generating Plant, Unit 2 Core Operating Limits Report, Cycle 24, Version 2 Enclosure Unit 2 Cycle 24 Core Operating Limits Report Version 2

VOGTLE ELECTRIC GENERATING PLANT (VEGP) UNIT 2 CYCLE 24 CORE OPERATING LIMITS REPORT VERSION 2.0 August 2024

CORE OPERATING LIMITS REPORT, VEGP UNIT 2 CYCLE 24 AUGUST2024 1.0 CORE OPERATING LIMITS REPORT This Core Operating Limits Report (COLR) for VEGP Unit 2 Cycle 24 has been prepared in accordance with the requirements of Technical Specification 5.6.5.

The Technical Requirement affected by this report is listed below:

13.1.1 SHUTDOWN MARGIN - MODES 1 and 2 The Technical Specifications affected by this report are listed below:

3.1.1 3.1.3 3.1.5 3.1.6 3.2.1 3.2.2 3.2.3 3.9.1 SHUTDOWN MARGIN - MODES 3, 4 and 5 Moderator Temperature Coefficient Shutdown Bank Insertion Limits Control Bank Insertion Limits Heat Flux Hot Channel Factor - FQ(Z)

Nuclear Enthalpy Rise Hot Channnel Factor - FN AfI Axial Flux Difference Boron Concentration Page 1 of 13

CORE OPERATING LIMITS REPORT, VEGP UNIT 2 CYCLE 24 AUGUST2024 2.0 OPERA TING 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 NRC-approved methodologies as specified in Technical Specification 5.6.5.

2.1 2.2 SHUTDOWN MARGIN - MODES 1 and 2 (Technical Requirement 13.1.1) 2.1.1 The SHUTDOWN MARGIN shall be greater than or equal to 1.30 percent Wk.

SHUTDOWN MARGIN - MODES 3, 4 and 5 (Specification 3.1.1) 2.2.1 The SHUTDOWN MARGIN shall be greater than or equal to the limits shown in Figures 1 and 2.

Page 2 of 13

CORE OPERATING LIMITS REPORT, VEGP UNIT 2 CYCLE 24 AUGUST2024 2.3 Moderator Temperature Coefficient (Specification 3.1.3) 2.3.1 The Moderator Temperature Coefficient (MTC) limits are:

The BOL/ARO/HZP-MTC shall be less positive than +0.7 x 10-4 Lik/k/°F for power levels up to 70% RTP with a linear ramp to O Llk/k/°F at 100% RTP.

The EOL/ARO/RTP-MTC shall be less negative than -4.75 x 10-4 Lik/k/°F. 1 2.3.2 The MTC Surveillance limits are:

The 300 pprn/ARO/RTP-MTC should be less negative than or equal to

-4.00 X 10-4 Llkfk/

0f.1 The revised predicted near-EOL 300 ppm MTC shall be calculated using Figure 6 and the following algorithm:

Revised Predicted MTC Correction***

Predicted MTC* + AFD Correction** + Predictive

where,

• Predicted MTC is calculated from Figure 6 at the bumup corresponding to the measurement of 300 ppm at RTP conditions,

• AFD Correction is the more negative value of:

{O pcrn/°F or (MFD

• AFD Sensitivity)}

where: LiAFD is the measured AFD minus the predicted AFD from an incore flux map taken at or near the bumup corresponding to 300 ppm, AFD Sensitivity= 0.08 pcrn/°F I LiAFD

• • • Predictive Correction is -3 pcrn/°F.

The 60 pprn/ARO/RTP-MTC should be less negative than -4.60 x 10-4 Lik/k/°F. 1 where: 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 1 Applicable for full-power T-average of 579.0 to 582.0 °F.

Page 3 of 13

CORE OPERATING LIMITS REPORT, VEGP UNIT 2 CYCLE 24 AUGUST2024 2.4 Shutdown Bank Insertion Limits (Specification 3.1.5) 2.4.1 The shutdown banks shall be withdrawn to a position greater than or equal to 225 steps.

2.5 Control Bank Insertion Limits (Specification 3.1.6) 2.5.1 The control rod banks shall be limited in physical insertion as shown in Figure 3.

2.6 Heat Flux Hot Channel Factor-Fo(Z) (Specification 3.2.1)

FRTP 2.6.1 FQ(Z) ~-Q-

• K(Z) for P > 0.5 p

2.6.2 2.6.3 2.6.4 FRTP FQ(Z)~-Q-*K(Z) forP::;0.5

0.5 where

THERMAL POWER P=-----------

RATED THERMAL POWER K(Z) is provided in Figure 4.

pRTP. K(Z)

F (Z) <

Q for P > 0.5 Q

P* W(Z) pRTP. K(Z)

F (Z) <

Q for P ::; 0.5 Q

0.5

• W(Z) 2.6.5 W(Z) values are provided in Table 2.

2.6.6 The Fo(Z) penalty factors are provided in Table 1.

Page 4 of13

CORE OPERATING LIMITS REPORT, VEGP UNIT 2 CYCLE 24 AUGUST2024 2.7 Nuclear Enthalpy Rise Hot Channel Factor-FN~H (Specification 3.2.2) where:

P=

THERMALPOWER RATED THERMAL POWER F/!P = 1.65 2.7.2 nn 2.7.3 PF Af{ = 0.3 2.8 Axial Flux Difference (Specification 3.2.3) 2.8.1 The Axial Flux Difference (AFD) Acceptable Operation Limits are provided in Figure 5.

2.9 Boron Concentration (Specification 3.9.1) 2 2.9.1 The boron concentration shall be greater than or equal to 2000 ppm.2 This concentration bounds the condition of k.,ff::;; 0.95 (all rods in less the most reactive rod) and subcriticality (all rods out) over the entire cycle. This concentration includes additional boron to address uncertainties and B10 depletion.

Page 5 of 13

CORE OPERATING LIMITS REPORT, VEGP UNIT 2 CYCLE 24 AUGUST2024 Table 1 FQ(Z) PENALTY FACTOR Burnup Penalty Burnup Penalty (MWD/MTU)

Factor (MWD/MTU)

Factor 0

1.0200 7981 1.0271 150 1.0200 8199 1.0276 368 1.0330 8417 1.0311 585 1.0476 8634 1.0297 803 1.0586 8852 1.0277 1020 1.0629 9069 1.0227 1238 1.0582 9287 1.0200 1455 1.0503 12332 1.0310 1673 1.0410 12550 1.0294 1890 1.0397 12767 1.0278 2108 1.0367 12985 1.0263 2325 1.0322 13202 1.0243 2543 1.0265 13420 1.0224 2760 1.0210 13638 1.0210 2978 1.0200 13855 1.0213 7329 1.0221 14073 1.0200 7546 1.0237 20381 1.0203 7764 1.0258 20599 1.0200 Notes:

1. The Penalty Factor, to be applied to FQ(Z) in accordance with SR 3.2.1.2, is the maximum factor by which FQ(Z) is expected to increase over a 39 EFPD interval (surveillance interval of 31 EFPD plus the maximum allowable extension not to exceed 25% of the surveillance interval per SR 3.0.2) starting from the burnup at which the FQ(Z) was determined.

2. Linear interpolation is adequate for intermediate cycle burnups.

3. For all cycle burnups outside the range of the table, a penalty factor of 1.0200 shall be used.

Page 6 of 13

CORE OPERATING LIMITS REPORT, VEGP UNIT 2 CYCLE 24 AUGUST2024 Table 2 RAOCW(Z)

Axial Elevation 150 4000 8000 12000 16000 20000 Point (feet)

MWD/MTU MWD/MTU MWD/MTU MWD/MTU MWD/MTU MWD/MTU 1-5 12.072 - 11.267 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 6

11.066 1.3467 1.3668 1.2976 1.2548 1.2465 1.2403 7

10.865 1.3346 1.3557 1.2891 1.2568 1.2386 1.2417 8

10.664 1.3133 1.3296 1.2727 1.2574 1.2196 1.2274 9

10.462 1.2887 1.3106 1.2540 1.2582 1.2113 1.2083 10 10.261 1.2643 1.2927 1.2416 1.2557 1.2112 1.2016 11 10.060 1.2440 1.2728 1.2368 1.2580 1.2172 1.2013 12 9.859 1.2328 1.2449 1.2334 1.2550 1.2209 1.2038 13 9.658 1.2262 1.2133 1.2226 1.2510 1.2174 1.2071 14 9.456 1.2201 1.1810 1.2129 1.2415 1.2170 1.2093 15 9.255 1.2131 1.1616 1.1991 1.2400 1.2217 1.2123 16 9.054 1.2056 1.1474 1.1861 1.2344 1.2230 1.2151 17 8.853 1.1963 1.1377 1.1833 1.2227 1.2162 1.2137 18 8.652 1.1984 1.1352 1.1840 1.2174 1.2091 1.2160 19 8.450 1.2034 1.1405 1.1893 1.2193 1.2119 1.2233 20 8.249 1.2037 1.1437 1.1917 1.2223 1.2216 1.2381 21 8.048 1.2097 1.1454 1.1922 1.2297 1.2354 1.2526 22 7.847 1.2131 1.1458 1.1910 1.2347 1.2464 1.2646 23 7.646 1.2134 1.1443 1.1877 1.2373 1.2548 1.2740 24 7.444 1.2117 1.1419 1.1833 1.2383 1.2615 1.2818 25 7.243 1.2071 1.1374 1.1760 1.2351 1.2636 1.2846 26 7.042 1.2006 1.1316 1.1671 1.2292 1.2623 1.2839 27 6.841 1.1927 1.1263 1.1575 1.2218 1.2592 1.2816 28 6.640 1.1827 1.1238 1.1493 1.2125 1.2539 1.2777 29 6.438 1.1727 1.1226 1.1408 1.2015 1.2460 1.2736 30 6.237 1.1625 1.1211 1.1326 1.1901 1.2371 1.2678 31 6.036 1.1561 1.1187 1.1234 1.1774 1.2269 1.2608 32 5.835 1.1494 1.1160 1.1162 1.1695 1.2153 1.2522 33 5.634 1.1451 1.1236 1.1153 1.1641 1.2095 1.2438 34 5.432 1.1428 1.1388 1.1261 1.1685 1.2094 1.2390 35 5.231 1.1450 1.1536 1.1361 1.1715 1.2136 1.2410 36 5.030 1.1543 1.1676 1.1458 1.1766 1.2169 1.2435 37 4.829 1.1625 1.1810 1.1549 1.1817 1.2201 1.2441 38 4.628 1.1704 1.1939 1.1634 1.1855 1.2216 1.2441 39 4.426 1.1775 1.2060 1.1711 1.1881 1.2214 1.2423 40 4.225 1.1834 1.2169 1.1779 1.1895 1.2196 1.2387 41 4.024 1.1885 1.2268 1.1840 1.1898 1.2165 1.2335 42 3.823 1.1925 1.2359 1.1886 1.1885 1.2110 1.2252 43 3.622 1.1975 1.2437 1.1935 1.1855 1.2034 1.2141 44 3.420 1.2032 1.2511 1.2002 1.1823 1.1953 1.2023 45 3.219 1.2067 1.2597 1.2058 1.1816 1.1869 1.1925 46 3.018 1.2171 1.2695 1.2107 1.1891 1.1943 1.1947 47 2.817 1.2305 1.2937 1.2239 1.2016 1.2082 1.2074 48 2.616 1.2429 1.3228 1.2429 1.2132 1.2204 1.2212 49 2.414 1.2548 1.3506 1.2622 1.2248 1.2329 1.2348 so 2.213 1.2664 1.3790 1.2817 1.2364 1.2452 1.2484 51 2.012 1.2806 1.4068 1.3003 1.2468 1.2560 1.2601 52 1.811 1.2975 1.4343 1.3185 1.2568 1.2663 1.2712 53 1.610 1.3136 1.4600 1.3359 1.2668 1.2768 1.2829 54 1.408 1.3290 1.4840 1.3523 1.2766 1.2875 1.2950 55 1.207 1.3435 1.5062 1.3676 1.2861 1.2981 1.3073 56 1.006 1.3569 1.5260 1.3816 1.2953 1.3087 1.3199 57-61 0.805 - 0.000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 Top and Bottom 5 Points Excluded per Technical Specification B3.2.1.

These W(Z) values are consistent with Figure 5, and are valid over the HFP Tavg temperature range from 579.0 to 582.0°F.

Page 7 of 13

CORE OPERATING LIMITS REPORT, VEGP UNIT 2 CYCLE 24 AUGUST2024 FIGURE 1 REQUIRED SHUTDOWN MARGIN FOR MODES 3 AND 4 (FOUR LOOPS FILLED AND VENTED AND AT LEAST ONE REACTOR COOLANT PUMP RUNNING)

.lo:

.lo:

<l dP z

H C!)

~

~

~

0 A E-<

iii Cll 5. 0 4. 0 3. 0 2. 0 1.0 0. 0 0

50 0 ACCEPTABLE OPERATING REGION (2' 00,.. 1 D)

./

V

/

V REQUI RED SHUTDOWN MARGIN I V V J

(11

, )

V 00,.. 2 V

/

/

/ /

V

/ V

!UNACCEPTABLE OPERATING REGION I

( 95 C, L. 3 0) 1 000 1500 200 0 25 00 RCS BORON CONCENTRATION (ppm)

Page 8 of13

CORE OPERATING LIMITS REPORT, VEGP UNIT 2 CYCLE 24 AUGUST2024 FIGURE 2 REQUIRED SHUTDOWN MARGIN FOR MODES 4 AND 5 (MODE 4 WHEN FIGURE 1 NOT APPLICABLE)

~

~

-<]

dP z

1-4 C!)

p::

~

~

0 A E-i

i::

ti) 5.0 4. 0 3. 0 2. 0 1.0 0.0 0

(2' 00 I

'

• 9 ~ /

/

/

/ /

/

//

!ACCEPTABLE OPERATI NG REGION I /

/

/

V

/

/

I REQUIRED SHUTDOWN MARGINV //

(1 50, ** 8 5)

V V V

V V

V UNACCEPTABLE OPERATING REGI ON

/

( ll6C, l.O 0) 50 0 100 0 15 00 2 000 250 0 RCS BORON CONCENTRATION (ppm)

Page 9 of 13

CORE OPERATING LIMITS REPORT, VEGP UNIT 2 CYCLE 24 AUGUST2024 FIGURE3 ROD BANK INSERTION LIMITS VERSUS% OF RATED THERMAL POWER Ill Pl 220 200 2l 140 tll

~ 120 H

E-t H

tll

~ 100

~

Ill 80 A

0

~

60 40 20 0

(Fully Withdrawn*)

V

( 2'

• o;i; 22,

/

/

/

V

/

V

/

V

/

V

/

/

/

BANK B:

/

/

/

I/

/

/

V V

/

/

a%

]61

/

/

/

/

,I

/

/

BANK c 1

/

V V

V

/

/

/

V

/

/

V V

V

,I

/

/

/

/

I/

I/

1BANK 0 1 I/

/

/

V V

/

/

/

( %, ' 6}

/

/

V

/

/

/

( 31.12 ;i;

( } /

'/

0 10 20 30 40 50 60 70 POWER{% of Rated Thermal Power)

78. %.

( ll C%,

/

/

/

/

V I/

80 90

• Fully withdrawn shall be the condition where control rods are at a position within the interval ~ 225 and ::; 231 steps withdrawn.

2 I )

61 V

V V

V l 1D NOTE: The Rod Bank Insertion Limits are based on the control bank withdrawal sequence A, B, C, D and a control bank tip-to-tip distance of 115 steps.

0 Page 10 of13

CORE OPERATING LIMITS REPORT, VEGP UNIT 2 CYCLE 24 AUGUST2024 FIGURE4 K(Z) - NORMALIZED FQ(Z) AS A FUNCTION OF CORE HEIGHT i:t:

0 f-f u

1. 4

1. 2 r!: 1. 0 C> z H

~

~

Pi O. 8 A

~

N H

M

~

p,:

O 0. 6 z

0. 2 0. 0 0

2 FQ =

CORE HT.

0. 00 6. 00 12.0 4

2. 50 K ( Z )

1. 00

1. 00

.92 5 6

8 1 0 12 CORE HEIGHT (fe et)

Page 11 of 13

CORE OPERATING LIMITS REPORT, VEGP UNIT 2 CYCLE 24 AUGUST2024 FIGURES AXIAL FLUX DIFFERENCE LIMITS AS A FUNCTION OF% RATED THERMAL POWER FORRAOC M

Q)

~

0 p..

,-I Ill

~

Q)

..c:

E-4 "Cl Q)

.j.)

Ill r:r:

11-1 0

dP r:r:

~

0 p..

120 llO 100 9 0 8 0 70 60 5 0 40 3 0 20 10 0

- 50 u

I

(- 15, 10 0 )

I I (+10, 1 00)

I J

\\

-JAO i,EP' 'ABI E I

\\

UN,,CC} PTJJ BLE I

\\

\\

I

\\

I A::.'.CE ~TAI LE

\\

I

\\

I

\\

I

\\

I

\\

I (- 3 o, 50)

I (+ 2 6, 50)

- 40

- 30

- 20

- 1 0 0

10 20 30 40 50 AXIAL FLUX DIFFERENCE (percent ~I)

Page 12 of 13

CORE OPERATING LIMITS REPORT, VEGP UNIT 2 CYCLE 24 FIGURE6 PREDICTED HFP 300 PPM MTC VS CYCLE BURNUP

.j.l C:

Cl)

- 26. 0

• n - 26. s

• r-1 1M 1M Cl) 0 CJ Cl)

M

.B 111 M

Cl) ~-2 7. 0 Cl)

E-t M

0

.j.l 111 M

~

~

""'" ~ ' ' ' 1, ' "' ' ',..

~

r",. ' "" '

- 27.5 1 6000 17000 18000 19000 20000 Cycle Burnup (MWD/MTU) 16000 17000 18000 19000 20000 21000 Cycle Burnup (MWD/MTU)

Moderator Temperature Coefficient (pcm/°F)

-26.12

-26.35

-26.59

-26.82

-27.04

-27.27

.... ~

AUGUST2024 21000 Page 13 of 13