NL-20-1130, Core Operating Limits Report, Cycle 22, Version 2

Core Operating Limits Report, Cycle 22, Version 2

ML20274A159
Person / Time
Site:	Vogtle
Issue date:	09/29/2020
From:	Gayheart C Southern Nuclear Operating Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NL-20-1130
Download: ML20274A159 (16)

Text

Cheryl A. Gayheart 3535 Colonnade Parkway Regulatory Affairs Director Birmingham, AL 35243 205 992 5316 cagayhea@southernco.com September 29, 2020 Docket No.: 50-425 NL-20-1130 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 22, Version 2 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 22, Version 2.

This letter contains no NRC commitments. If you have any questions, please contact Jamie Coleman at 205.992.6611.

Respectfully submitted, Cheryl A. Gayheart Regulatory Affairs Director CAG/kgl/sm

Enclosure:

VEGP Unit 2 COLR, Cycle 22, Version 2 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 22, Version 2 Enclosure VEGP Unit 2 COLR, Cycle 22, Version 2

VOGTLE ELECTRIC GENERATING PLANT (VEGP) UNIT 2 CYCLE 22 CORE OPERATING LIMITS REPORT Version 2 August 2020

CORE OPERATING LIMITS REPORT, VEGP UNIT 2 CYCLE 22 AUGUST 2020 1.0 CORE OPERATING LIMITS REPORT This Core Operating Limits Report (COLR) for VEGP Unit 2 Cycle 22 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 - FNH 3.2.3 Axial Flux Difference 3.9.1 Boron Concentration Page 1 of 13

CORE OPERATING LIMITS REPORT, VEGP UNIT 2 CYCLE 22 AUGUST 2020 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 including those 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 22 AUGUST 2020 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/°F for power levels up to 70% RTP with a linear ramp to 0 k/k/°F at 100% RTP.

The EOL/ARO/RTP-MTC shall be less negative than -5.35 x 10-4 k/k/°F. 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/°F. 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/°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 582.0 to 587.0 °F.

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CORE OPERATING LIMITS REPORT, VEGP UNIT 2 CYCLE 22 AUGUST 2020 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 ) K ( Z ) for P > 0.5 P

FQRTP FQ ( Z ) K ( Z ) for P 0.5 0.5 THERMAL POWER where: P=

RATED THERMAL POWER 2.6.2 FQRTP = 2.50 2.6.3 K(Z) is provided in Figure 4.

FQRTP K ( Z )

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

FQRTP K ( Z )

FQ ( Z ) for P 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 22 AUGUST 2020 2.7 Nuclear Enthalpy Rise Hot Channel Factor - FNH (Specification 3.2.2) 2.7.1 H ( 1 + PFH (1 P ))

FNH FRTP THERMAL POWER where: P=

RATED THERMAL POWER 2.7.2 H = 1.65 FRTP 2.7.3 PFH = 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 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 22 AUGUST 2020 Table 1 FQ(Z) PENALTY FACTOR Burnup Penalty (MWD/MTU) Factor 0 1.0274 150 1.0274 367 1.0294 584 1.0300 801 1.0294 1018 1.0289 1235 1.0286 1452 1.0279 1670 1.0269 1887 1.0230 2104 1.0200 9050 1.0200 9267 1.0208 9484 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 22 AUGUST 2020 Table 2 RAOC W(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 1.2977 1.3367 1.3177 1.2524 1.2312 1.1960 7 10.865 1.2805 1.3235 1.3077 1.2487 1.2306 1.1951 8 10.664 1.2637 1.2929 1.2928 1.2395 1.2212 1.1919 9 10.462 1.2455 1.2643 1.2763 1.2297 1.2094 1.1880 10 10.261 1.2259 1.2442 1.2579 1.2147 1.2007 1.1848 11 10.060 1.2030 1.2193 1.2354 1.2095 1.2018 1.1823 12 9.859 1.1975 1.1954 1.2133 1.2051 1.2040 1.1836 13 9.658 1.1966 1.1771 1.1944 1.2000 1.2074 1.1869 14 9.456 1.1952 1.1732 1.1907 1.1975 1.2088 1.1903 15 9.255 1.1918 1.1733 1.1934 1.1983 1.2095 1.2003 16 9.054 1.1905 1.1792 1.1931 1.2008 1.2111 1.2113 17 8.853 1.1908 1.1781 1.1902 1.2011 1.2095 1.2193 18 8.652 1.1929 1.1795 1.1909 1.2022 1.2078 1.2283 19 8.450 1.1975 1.1744 1.1933 1.2089 1.2112 1.2333 20 8.249 1.1995 1.1690 1.1950 1.2150 1.2226 1.2444 21 8.048 1.2057 1.1695 1.1961 1.2184 1.2321 1.2561 22 7.847 1.2094 1.1719 1.1963 1.2200 1.2394 1.2665 23 7.646 1.2098 1.1715 1.1987 1.2193 1.2444 1.2789 24 7.444 1.2084 1.1700 1.1985 1.2174 1.2480 1.2883 25 7.243 1.2041 1.1661 1.1949 1.2120 1.2475 1.2924 26 7.042 1.1980 1.1606 1.1890 1.2044 1.2442 1.2926 27 6.841 1.1904 1.1552 1.1817 1.1959 1.2395 1.2907 28 6.640 1.1807 1.1503 1.1726 1.1872 1.2334 1.2862 29 6.438 1.1704 1.1458 1.1620 1.1791 1.2281 1.2789 30 6.237 1.1608 1.1411 1.1504 1.1711 1.2216 1.2687 31 6.036 1.1498 1.1351 1.1379 1.1623 1.2143 1.2568 32 5.835 1.1430 1.1283 1.1303 1.1555 1.2055 1.2433 33 5.634 1.1378 1.1258 1.1259 1.1539 1.1984 1.2327 34 5.432 1.1378 1.1367 1.1259 1.1568 1.1945 1.2282 35 5.231 1.1414 1.1491 1.1332 1.1629 1.1986 1.2280 36 5.030 1.1501 1.1606 1.1424 1.1676 1.2021 1.2278 37 4.829 1.1579 1.1716 1.1509 1.1715 1.2042 1.2274 38 4.628 1.1652 1.1820 1.1589 1.1743 1.2048 1.2263 39 4.426 1.1719 1.1917 1.1662 1.1760 1.2039 1.2233 40 4.225 1.1775 1.2003 1.1728 1.1766 1.2016 1.2185 41 4.024 1.1822 1.2081 1.1782 1.1765 1.1981 1.2133 42 3.823 1.1863 1.2150 1.1853 1.1742 1.1924 1.2066 43 3.622 1.1895 1.2210 1.1934 1.1737 1.1849 1.1975 44 3.420 1.1931 1.2258 1.2003 1.1759 1.1767 1.1879 45 3.219 1.1963 1.2320 1.2056 1.1767 1.1703 1.1772 46 3.018 1.2055 1.2477 1.2135 1.1831 1.1708 1.1722 47 2.817 1.2183 1.2670 1.2228 1.1963 1.1801 1.1784 48 2.616 1.2306 1.2852 1.2340 1.2095 1.1911 1.1903 49 2.414 1.2423 1.3045 1.2520 1.2227 1.2018 1.2018 50 2.213 1.2541 1.3256 1.2719 1.2359 1.2126 1.2135 51 2.012 1.2658 1.3466 1.2909 1.2480 1.2220 1.2235 52 1.811 1.2773 1.3672 1.3095 1.2596 1.2310 1.2330 53 1.610 1.2901 1.3865 1.3271 1.2711 1.2403 1.2431 54 1.408 1.3040 1.4046 1.3438 1.2821 1.2498 1.2536 55 1.207 1.3173 1.4213 1.3592 1.2927 1.2592 1.2643 56 1.006 1.3295 1.4364 1.3732 1.3028 1.2686 1.2753

• 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 22 AUGUST 2020 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 22 AUGUST 2020 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 22 AUGUST 2020 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 225 and 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 22 AUGUST 2020 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 22 AUGUST 2020 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 22 AUGUST 2020 FIGURE 6 PREDICTED HFP 300 PPM MTC VS CYCLE BURNUP

-28.0 Moderator Temperature Coefficient

-28.5

-29.0 (pcm/°F)

-29.5

-30.0 17000 18000 19000 20000 21000 22000 Cycle Burnup (MWD/MTU)

Cycle Burnup Moderator Temperature Coefficient (MWD/MTU) (pcm/°F) 17000 -28.45 18000 -28.73 19000 -29.03 20000 -29.31 21000 -29.57 22000 -29.88 Page 13 of 13