NL-22-0273, Core Operating Limits Report, Cycle 23, Version 1

Core Operating Limits Report, Cycle 23, Version 1

ML22103A238
Person / Time
Site:	Vogtle
Issue date:	04/12/2022
From:	Gayheart C Southern Nuclear Operating Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NL-22-0273
Download: ML22103A238 (15)

Text

Cheryl A. Gayheart 3535 Colonnade Parkway Regulatory Affairs Director Birmingham, AL 35243 205 992 5316 cagayhea@southernco.com April 12, 2022 Docket No.: 50-425 NL-22-0273 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001 Vogtle Electric Generating Plant - Unit 2 Core Operating Limits Report, Cycle 23, Version 1 Ladies and Gentlemen:

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 23, Version 1.

This letter contains no NRC commitments. If you have any questions, please contact 5\DQ

-R\FH at 205.992.6.

Respectfully submitted, Cheryl A. Gayheart Regulatory Affairs Director CAG/dsp/cbg

Enclosure:

VEGP Unit 2 COLR, Cycle 23, Version 1 cc: Regional Administrator NRR Project Manager - Vogtle 1 & 2 Senior Resident Inspector - Vogtle 1 & 2 RType: CVC7000

Vogtle Electric Generating Plant - Unit 2 Core Operating Limits Report, Cycle 23, Version 1 Enclosure VEGP Unit 2 COLR, Cycle 23, Version 1

CORE OPERATING LIMITS REPORT, VEGP UNIT 2 CYCLE 23 NOVEMBER 2021 1.0 CORE OPERATING LIMITS REPORT This Core Operating Limits Report (COLR) for VEGP Unit 2 Cycle 23 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 SHUTDOWN MARGIN - MODES 3, 4 and 5 3.1.3 Moderator Temperature Coefficient 3.1.5 Shutdown Bank Insertion Limits 3.1.6 Control Bank Insertion Limits 3.2.1 Heat Flux Hot Channel Factor - FQ(Z) 3.2.2 Nuclear Enthalpy Rise Hot Channnel Factor - FN¨H

3.2.3 Axial Flux Difference 3.9.1 Boron Concentration Page 1 of 13

CORE OPERATING LIMITS REPORT, VEGP UNIT 2 CYCLE 23 NOVEMBER 2021 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 NRC-approved methodologies as specified in Technical Specification 5.6.5.

2.1 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 'k/k.

2.2 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.

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CORE OPERATING LIMITS REPORT, VEGP UNIT 2 CYCLE 23 NOVEMBER 2021 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 'k/k/qF for power levels up to 70% RTP with a linear ramp to 0 'k/k/qF at 100% RTP.

The EOL/ARO/RTP-MTC shall be less negative than -5.35 x 10-4 'k/k/qF.1 2.3.2 The MTC Surveillance limits are:

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

-4.60 x 10-4 'k/k/qF.1 The revised predicted near-EOL 300 ppm MTC shall be calculated using Figure 6 and the following algorithm:

Revised Predicted MTC = Predicted MTC* + AFD Correction** + Predictive Correction***

where,

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

• • AFD Correction is the more negative value of:

{0 pcm/°F or (¨AFD

• AFD Sensitivity)}

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

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

The 60 ppm/ARO/RTP-MTC should be less negative than -5.20 x 10-4'k/k/qF.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 582.0 to 587.0 °F.

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CORE OPERATING LIMITS REPORT, VEGP UNIT 2 CYCLE 23 NOVEMBER 2021 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 - FQ(Z) (Specification 3.2.1)

FQRTP 2.6.1 FQ (Z ) d K (Z ) for P > 0.5 P

FQRTP FQ (Z ) d K (Z ) for P d 0.5 0.5 THERMALPOWER where: P RATEDTHERMALPOWER 2.6.2 FQRTP 2.50 2.6.3 K(Z) is provided in Figure 4.

FQRTP K ( Z )

2.6.4 FQ ( Z ) d for P > 0.5 P W (Z )

FQRTP K ( Z )

FQ ( Z ) d for P d 0.5 0.5 W ( Z )

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

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

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CORE OPERATING LIMITS REPORT, VEGP UNIT 2 CYCLE 23 NOVEMBER 2021 2.7 Nuclear Enthalpy Rise Hot Channel Factor - FN¨H (Specification 3.2.2) 2.7.1 F'NH d F'RTP H 1  PF'H 1  P THERMALPOWER where: P RATEDTHERMALPOWER 2.7.2 F'RTP H 1.65 2.7.3 PF'H 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) 2.9.1 The boron concentration shall be greater than or equal to 2000 ppm.2 2

This concentration bounds the condition of keff d 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.

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CORE OPERATING LIMITS REPORT, VEGP UNIT 2 CYCLE 23 NOVEMBER 2021 Table 1 FQ(Z) PENALTY FACTOR Burnup Penalty (MWD/MTU) Factor 0 1.0659 150 1.0659 367 1.0635 584 1.0602 801 1.0546 1018 1.0473 1235 1.0395 1453 1.0313 1670 1.0236 1887 1.0200 8833 1.0200 9051 1.0240 9268 1.0224 9485 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.

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CORE OPERATING LIMITS REPORT, VEGP UNIT 2 CYCLE 23 NOVEMBER 2021 Table 2 RAOC W(Z)

Axial Elevation 150 3000 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 1.3208 1.3905 1.3305 1.2998 1.2263 1.2382 7 10.865 1.2951 1.3779 1.3249 1.2954 1.2225 1.2320 8 10.664 1.2800 1.3569 1.3138 1.2868 1.2108 1.2224 9 10.462 1.2661 1.3333 1.3005 1.2779 1.1996 1.2102 10 10.261 1.2426 1.3096 1.2863 1.2663 1.2031 1.2052 11 10.060 1.2217 1.2811 1.2698 1.2537 1.2091 1.2090 12 9.859 1.2105 1.2500 1.2509 1.2390 1.2157 1.2101 13 9.658 1.2105 1.2183 1.2364 1.2340 1.2135 1.2090 14 9.456 1.2078 1.1994 1.2231 1.2303 1.2142 1.2085 15 9.255 1.1975 1.1986 1.2246 1.2222 1.2099 1.2061 16 9.054 1.1917 1.2004 1.2286 1.2136 1.2047 1.2114 17 8.853 1.1992 1.1980 1.2283 1.2037 1.2020 1.2282 18 8.652 1.2022 1.1964 1.2264 1.1964 1.2090 1.2405 19 8.450 1.2059 1.1916 1.2213 1.1988 1.2197 1.2490 20 8.249 1.2077 1.1870 1.2177 1.2000 1.2314 1.2585 21 8.048 1.2106 1.1833 1.2142 1.2079 1.2412 1.2672 22 7.847 1.2142 1.1804 1.2111 1.2133 1.2488 1.2753 23 7.646 1.2138 1.1778 1.2122 1.2166 1.2540 1.2876 24 7.444 1.2117 1.1736 1.2104 1.2182 1.2578 1.2966 25 7.243 1.2066 1.1671 1.2050 1.2159 1.2572 1.3002 26 7.042 1.1998 1.1591 1.1972 1.2111 1.2537 1.2997 27 6.841 1.1915 1.1516 1.1881 1.2050 1.2487 1.2971 28 6.640 1.1813 1.1445 1.1772 1.1970 1.2425 1.2918 29 6.438 1.1707 1.1379 1.1649 1.1874 1.2366 1.2837 30 6.237 1.1620 1.1336 1.1514 1.1777 1.2295 1.2728 31 6.036 1.1558 1.1310 1.1371 1.1671 1.2213 1.2599 32 5.835 1.1488 1.1277 1.1262 1.1593 1.2116 1.2486 33 5.634 1.1432 1.1258 1.1237 1.1572 1.2025 1.2401 34 5.432 1.1396 1.1341 1.1255 1.1631 1.2003 1.2352 35 5.231 1.1397 1.1447 1.1357 1.1672 1.2024 1.2351 36 5.030 1.1473 1.1543 1.1445 1.1709 1.2032 1.2343 37 4.829 1.1543 1.1635 1.1530 1.1754 1.2045 1.2335 38 4.628 1.1609 1.1720 1.1609 1.1789 1.2045 1.2316 39 4.426 1.1668 1.1799 1.1681 1.1812 1.2030 1.2277 40 4.225 1.1716 1.1867 1.1744 1.1825 1.2000 1.2222 41 4.024 1.1757 1.1928 1.1800 1.1827 1.1968 1.2166 42 3.823 1.1786 1.1975 1.1846 1.1834 1.1940 1.2090 43 3.622 1.1833 1.2043 1.1878 1.1842 1.1900 1.1987 44 3.420 1.1894 1.2129 1.1918 1.1838 1.1853 1.1875 45 3.219 1.1935 1.2203 1.1959 1.1831 1.1800 1.1773 46 3.018 1.2016 1.2304 1.2029 1.1818 1.1762 1.1734 47 2.817 1.2120 1.2504 1.2109 1.1901 1.1815 1.1808 48 2.616 1.2235 1.2731 1.2224 1.2037 1.1924 1.1934 49 2.414 1.2401 1.2947 1.2402 1.2163 1.2029 1.2054 50 2.213 1.2579 1.3167 1.2594 1.2292 1.2136 1.2176 51 2.012 1.2753 1.3380 1.2776 1.2409 1.2228 1.2279 52 1.811 1.2924 1.3590 1.2955 1.2522 1.2316 1.2378 53 1.610 1.3086 1.3786 1.3125 1.2634 1.2408 1.2483 54 1.408 1.3238 1.3969 1.3287 1.2743 1.2503 1.2593 55 1.207 1.3382 1.4139 1.3438 1.2847 1.2597 1.2704 56 1.006 1.3515 1.4291 1.3576 1.2948 1.2692 1.2820

• 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 582.0 to 587.0°F.

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CORE OPERATING LIMITS REPORT, VEGP UNIT 2 CYCLE 23 NOVEMBER 2021 FIGURE 1 REQUIRED SHUTDOWN MARGIN FOR MODES 3 AND 4 (FOUR LOOPS FILLED AND VENTED AND AT LEAST ONE REACTOR COOLANT PUMP RUNNING)

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CORE OPERATING LIMITS REPORT, VEGP UNIT 2 CYCLE 23 NOVEMBER 2021 FIGURE 2 REQUIRED SHUTDOWN MARGIN FOR MODES 4 AND 5 (MODE 4 WHEN FIGURE 1 NOT APPLICABLE)

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CORE OPERATING LIMITS REPORT, VEGP UNIT 2 CYCLE 23 NOVEMBER 2021 FIGURE 3 ROD BANK INSERTION LIMITS VERSUS % OF RATED THERMAL POWER (Fully Withdrawn*)

Fully withdrawn shall be the condition where control rods are at a position within the interval t 225 and d 231 steps withdrawn.

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.

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CORE OPERATING LIMITS REPORT, VEGP UNIT 2 CYCLE 23 NOVEMBER 2021 FIGURE 4 K(Z) - NORMALIZED FQ(Z) AS A FUNCTION OF CORE HEIGHT Page 11 of 13

CORE OPERATING LIMITS REPORT, VEGP UNIT 2 CYCLE 23 NOVEMBER 2021 FIGURE 5 AXIAL FLUX DIFFERENCE LIMITS AS A FUNCTION OF % RATED THERMAL POWER FOR RAOC Page 12 of 13

CORE OPERATING LIMITS REPORT, VEGP UNIT 2 CYCLE 23 NOVEMBER 2021 FIGURE 6 PREDICTED HFP 300 PPM MTC VS CYCLE BURNUP

-28.0 Moderator Temperature Coefficient (pcm/°F)

-28.5

-29.0

-29.5

-30.0

-30.5 16000 17000 18000 19000 20000 21000 Cycle Burnup (MWD/MTU)

Cycle Burnup Moderator Temperature Coefficient (MWD/MTU) (pcm/°F) 16000 -28.56 17000 -28.88 18000 -29.16 19000 -29.46 20000 -29.73 21000 -30.04 Page 13 of 13