ML20247J464

Safety Evaluation Report for Vogtle Electric Generating Plant for Amendments 185/183 (LAR 20-004)

ML20247J464
Person / Time
Site:	Vogtle
Issue date:	10/14/2020
From:	Jennivine Rankin NRC/NRR/VPOB
To:	City of Dalton, GA, Georgia Power Co, MEAG Power, Oglethorpe Power Corp, Southern Nuclear Operating Co
Rankin J EX 1530
References
EPID L-2020-LLA-0095, LAR 20-004
Download: ML20247J464 (10)

Text

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NOS. 185 and 183 TO THE COMBINED LICENSE NOS. NPF-91 AND NPF-92, RESPECTIVELY SOUTHERN NUCLEAR OPERATING COMPANY, INC.

GEORGIA POWER COMPANY OGLETHORPE POWER CORPORATION MEAG POWER SPVM, LLC MEAG POWER SPVJ, LLC MEAG POWER SPVP, LLC CITY OF DALTON, GEORGIA VOGTLE ELECTRIC GENERATING PLANT UNITS 3 AND 4 DOCKET NOS.52-025 AND 52-026

1.0 INTRODUCTION

By letter dated April 30, 2020 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML20121A288), and supplemented by letter dated July 23, 2020, (ADAMS Accession No. ML20205L560), Southern Nuclear Operating Company (SNC) requested that the Nuclear Regulatory Commission (NRC) amend Vogtle Electric Generating Plant (VEGP) Units 3 and 4, Combined License (COL) Numbers NPF-91 and NPF-92, respectively. The License Amendment Request (LAR)20-004 requested changes to the upper limit of the Core Makeup Tank (CMT) boron concentration Technical Specification (TS)

Surveillance Requirement (SR), the mass of trisodium phosphate (TSP) required by TS Limiting Condition for Operation (LCO) and associated SR, and the frequency of performance of the CMT boron concentration TS SR. The requested amendment proposed changes to the licensing basis documents in the form of departures from the plant-specific Design Control Document (DCD) Tier 2 information (as incorporated into the UFSAR) and involves changes to the plant-specific TS (COL Appendix A).

The supplement dated July 23, 2020, provided additional information that clarified the application, did not expand the scope of the application as originally noticed, and did not change the Nuclear Regulatory Commission (NRC or the Commission) staffs original proposed no

significant hazards consideration determination as published in the Federal Register on June 2, 2020 (85 FR 33752).

2.0 REGULATORY EVALUATION

The Passive Core Cooling System (PXS) of the AP1000 reactor performs the primary function to provide emergency core cooling following postulated design basis events. The PXS is a safety-related system and consists of two Core Makeup Tanks (CMTs); two accumulators; the in-containment refueling water storage tank (IRWST); the passive residual heat removal heat exchanger; potential of Hydrogen (pH) adjustment baskets; associated piping, valves, instrumentation; and other related equipment.

The CMTs provide Reactor Coolant System (RCS) makeup and boration during events not involving loss of coolant when the normal makeup system is unavailable or insufficient. The two CMTs are located inside the containment at an elevation slightly above the reactor coolant loops. During normal operation, the CMTs are completely full of cold, borated water. The boration capability of these tanks provides adequate core shutdown margin following a steam line break. The CMTs are connected to the RCS through a discharge injection line and an inlet pressure balance line connected to a cold leg. The discharge line is blocked by two normally closed, parallel air-operated isolation valves that open on a loss of air pressure or electrical power, or on control signal actuation.

Because the CMTs are in open communication with the RCS via the balance line, whenever the CMT is sampled for surveillance purposes, the volume of removed water is replaced by RCS water via the balance line. The RCS water is typically at a lower boron concentration; therefore, each sample dilutes the CMT. Depending on the starting boron concentration in the CMT, there is the possibility that the sampling activity could cause the CMT boron concentration to fall to a point which would require borated makeup. Borated makeup at power is not desirable because it forces the displaced water back into the RCS via the balance line. This causes additional thermal transients on the balance line and also causes the potential for a reactivity excursion in the reactor if the boron concentration of the RCS is affected.

To mitigate these issues, SNCs proposed solution is to raise the upper boron concentration limit permitted for the CMT, extend the frequency of the CMT boron concentration surveillance, and to increase the mass of trisodium phosphate (TSP) required for the pH adjustment baskets.

More specifically, SNCs proposed changes are as follows:

COL Appendix A, Technical Specifications Changes:

• SR 3.5.2.4 maximum boron concentration is revised from 3,700 parts per million (ppm) to 4500 ppm.

• SR 3.5.2.4 frequency is revised from 7 days to 31 days.

• LCO 3.6.8 and SR 3.6.8.1 required mass of TSP is revised from 25,920 pounds (lbs) to 26,460 lbs.

UFSAR Changes:

• Subsection 6.3.2.2.4, pH Adjustment Baskets, required mass of TSP is revised from at least 25,920 lbs to at least 26,460 lbs.

• Subsection 9.3.6.2.6, Borated Makeup, upper boron concentration of the Chemical and Volume Control System (CVS) ability for borated makeup is revised to reflect that 4,375 ppm is a nominal value.

• Subsection 6.3.2.2.1, Core Makeup Tanks, is revised to describe monitoring and trending of CMT temperatures to investigate potential CMT leakage.

The staff considered the following regulatory requirements in reviewing the LAR that included the proposed changes:

Title 10 of the Code of Federal Regulations (10 CFR) Part 52 Appendix D,Section VIII.B.5.a allows an applicant or licensee who references this appendix to depart from Tier 2 information, without prior NRC approval, unless the proposed departure involves a change to or departure from Tier 1 information, Tier 2* information, or the TS, or requires a license amendment under paragraphs B.5.b or B.5.c of the section.

10 CFR Part 52, Appendix D, VIII.C.6 states that after issuance of a license, Changes to the plant-specific TS will be treated as license amendments under 10 CFR 50.90. 10 CFR 50.90 addresses the application for amendment of license, construction permit, or early site permit. The proposed LAR requires changes to the TS, and therefore a LAR is required to be submitted for NRC approval.

10 CFR 50.36, TS impose limits, operating conditions, and other requirements upon reactor facility operation for the public health and safety. The TS are derived from the analyses and evaluations in the safety analysis report. In general, TS must contain: (1) safety limits and limiting safety system settings; (2) limiting conditions for operation; (3) surveillance requirements; (4) design features; and (5) administrative controls.

The specific NRC technical requirements applicable to LAR 20-004 are the general design criteria (GDC) in Appendix A, General Design Criteria for Nuclear Power Plants, to 10 CFR Part 50, Domestic Licensing of Production and Utilization Facilities. In particular, these technical requirements include the following GDC:

10 CFR Part 50, Appendix A GDC 14, Reactor coolant pressure boundary, requires that [t]he reactor coolant pressure boundary shall be designed, fabricated, erected, and tested so as to have an extremely low probability of abnormal leakage, of rapidly propagating failure, and of gross rupture.

10 CFR Part 50, Appendix A GDC 26, Reactivity control system redundancy and capability, requires that [t]wo independent reactivity control systems of different design principles shall be provided. One of the systems shall use control rods, preferably including a positive means for inserting the rods, and shall be capable of reliably controlling reactivity changes to assure that under conditions of normal operation, including anticipated operational occurrences, and with appropriate margin for malfunctions such as stuck rods, specified acceptable fuel design limits are not exceeded. The second reactivity control system shall be capable of reliably controlling the rate of reactivity changes resulting from planned, normal power changes (including xenon burnout) to assure acceptable fuel design limits are not exceeded. One of the systems shall be capable of holding the reactor core subcritical under cold conditions.

10 CFR Part 50, Appendix A GDC 27, Combined reactivity control systems capability, requires that [t]he reactivity control systems shall be designed to have a combined capability, in conjunction with poison addition by the emergency core cooling system, of reliably controlling reactivity changes to assure that under postulated accident

conditions and with appropriate margin for stuck rods the capability to cool the core is maintained.

10 CFR Part 50, Appendix A GDC 35, Emergency core cooling, requires that [a]

system to provide abundant emergency core cooling shall be provided. The system safety function shall be to transfer heat from the reactor core following any loss of reactor coolant at a rate such that (1) fuel and clad damage that could interfere with continued effective core cooling is prevented and (2) clad metal-water reaction is limited to negligible amounts.

10 CFR Part 50, Appendix A GDC 37, Testing of emergency core cooling system, requires, that [t]he emergency core cooling system shall be designed to permit appropriate periodic pressure and functional testing to assure (1) the structural and leaktight integrity of its components, (2) the operability and performance of the active components of the system, and (3) the operability of the system as a whole and, under conditions as close to design as practical, the performance of the full operational sequence that brings the system into operation, including operation of applicable portions of the protection system, the transfer between normal and emergency power sources, and the operation of the associated cooling water system.

10 CFR Part 50, Appendix A GDC 41, Containment atmosphere cleanup, requires that [s]ystems to control fission products, hydrogen, oxygen, and other substances which may be released into the reactor containment shall be provided as necessary to reduce, consistent with the functioning of other associated systems, the concentration and quality of fission products released to the environment following postulated accidents, and to control the concentration of hydrogen or oxygen and other substances in the containment atmosphere following postulated accidents to assure that containment integrity is maintained.

3.1 TECHNICAL EVALUATION

OF SR 3.5.2.4 AND UFSAR SUBSECTIONS 6.3.2.2.1 AND 9.3.6.2.6 CHANGES In LAR 20-004, SNC proposes changes to revise the SR 3.5.2.4 maximum boron concentration from 3700 ppm to 4500 ppm and SR 3.5.2.4 surveillance frequency from 7 days to 31 days. In the UFSAR, Subsection 9.3.6.2.6 upper boron concentration of the CVS ability for borated makeup is revised to reflect that the 4,375 ppm value is a nominal value. In the July 23, 2020 supplement, the licensee proposes changes to subsection 6.3.2.2.1 of the UFSAR to include a statement that the CMT temperature is monitored and trended to investigate potential leaks prior to alarm setpoints.

NRC Evaluation of SR 3.5.2.4 and UFSAR Subsections 6.3.2.2.1 and 9.3.6.2.6 Changes The staff evaluated the licensee submittal based on the requirements in the above GDCs. The CMTs are available to provide adequate boration to the Reactor Pressure Vessel (RPV) during certain events described in the Chapter 15 analysis. SR 3.5.2.4 is used to assure that the CMTs have the minimum boron concentration assumed in the accident analysis. The staff assessed the proposed change from a 7-day surveillance frequency to a 31-day surveillance frequency to determine whether the new surveillance would ensure the minimum boron

concentration would be available in the CMTs so that the accident analysis assumptions and GDCs would continue to be met.

To support its review of the LAR, the staff conducted an audit of a computational fluid dynamics (CFD) calculation. The results of the CFD calculation are described by the licensee in LAR-20-004. The CFD calculation predicted the temperature profile of the liquid in the CMT vs.

time based on different potential leakage rates of water from the CMT. When water leaves the CMT, it is replaced by hotter water from the RCS that is also at a lower boron concentration.

The leakage results in dilution that lowers the concentration of boron in the CMT. The CMT boron concentration could fall below that needed to ensure the analysis assumptions are met.

As hotter water enters the CMT from the balance line, the temperature of the CMT rises until it reaches an alarm setpoint. The licensee initially stated that the alarm temperature would be reached prior to dilution of the CMT boron concentration below the levels assumed in the analysis. During the audit, the staff requested information regarding the licensees ability to monitor and trend the temperature rise prior to reaching the alarm setpoint. On July 23, 2020, the licensee provided supplement, LAR-20-004S1, that demonstrated the ability to detect significant leakage prior to reaching the alarm setpoint by trending the CMT temperature.

The CFD analysis, as described by the licensee in LAR-20-004, determined the temperature changes that would occur over time in the CMT at various leakage rates. The licensee calculated how long it would take to reach the CMT temperature alarm setpoint, depending on the postulated leakage rates. These leakage rates were used to calculate the boron concentration in the tank at the time the alarm setpoint is reached. The licensee used the conservative assumption of 0 ppm boron concentration in the RCS for the analysis. A higher RCS boron concentration would slow the dilution of the CMT from RCS inleakage. A 3,400 ppm boron minimum concentration maintains the current accident analysis assumptions. The analysis showed that, for various leakage rates, the CMT temperature alarm setpoint would be reached well in advance of the concentration of boron in the CMT reaching the 3,400 ppm minimum limit. Smaller leak rates lead to slower changes in the CMT temperature. The CFD analysis demonstrated that a leakage rate of 0.1 gallons per minute (gpm) would result in the CMT reaching the alarm setpoint in 20 days. The same 0.1 gpm leakage rate was calculated to take 28 days to cause the minimum boron concentration in the CMT to be reached considering the initial conditions of the analysis. The analysis for different leak sizes showed that, for typical conditions, the temperature setpoint was reached well before the minimum boron concentration was reached. SR 3.5.2.1 verifies that the CMT temperature is below 120 degrees Fahrenheit (F). For the CFD analysis, the 120-degree F temperature is reached well before the minimum concentration is reached for all analyzed leak rates.

In the supplement dated July 23, 2020, the licensee provided a discussion of site monitoring and trending of the CMT temperatures. The temperature is recorded daily for SR 3.5.2.1. By plant procedures, monitoring and trending of the CMT temperature would be implemented and an abnormal rise in temperature would be identified before the CMT temperature reached the alarm setpoint. The licensee stated that such a temperature rise would result in an investigation of potential leakage from the CMT.

Based on the results of the CFD calculation in LAR 20-004, as confirmed in the staff audit, and the description of site procedures in LAR-20-004S1, the staff concluded that the licensee provided reasonable assurance that the CMT boron concentration will remain above the minimum needed for the Chapter 15 analysis. The changes to SR 3.5.2.4 and associated changes to UFSAR, Subsections 6.3.2.2.1 and 9.3.6.2.6, do not affect the function of the CMT as it maintains the minimum boron concentration and allows the CMT to be sampled on a

frequency that assures the operability of the CMT. Therefore, GDC 26, 27, 35, and 37 are still met as discussed below.

10 CFR Part 50, Appendix A GDC 26 requires, in part, that [t]wo independent reactivity control systems of different design principles shall be provided. The second reactivity control system is chemical shim (boric acid). The proposed change to the CMT upper boron concentration limit does not impact the ability of this system to provide this function since the analyses use the lower limit boron concentration of 3,400 ppm and the proposed change to the CMT boron concentration surveillance frequency to 31 days does not impact the ability to detect boron dilution of the CMT.

10 CFR Part 50, Appendix A GDC 27 requires that [t]he reactivity control systems be designed to have a combined capability, in conjunction with poison addition by the emergency core cooling system, of reliably controlling reactivity changes to assure that under postulated accident conditions and with appropriate margin for stuck rods the capability to cool the core is maintained. The proposed changes do not affect the means of making and holding the core subcritical under these conditions because the analysis is based on the lower boron concentration limit which did not change.

10 CFR Part 50, Appendix A GDC 35 requires a system to provide abundant emergency core cooling whose safety function is to transfer heat from the reactor core following any loss of reactor coolant at a rate such that fuel and clad damage that could interfere with continued effective core cooling is prevented and clad metal-water reaction is limited to negligible amounts. The proposed changes do not change the design of the system to perform these functions with abundant emergency core cooling.

10 CFR Part 50, Appendix A GDC 37 requires, in part, that the emergency core cooling system be designed to permit appropriate periodic functional testing to assure the operability of the system. The testing of the CMT boron concentration at the proposed frequency is sufficient to assure the operability of the system.

Based on the technical review conducted by the staff, the licensee provided reasonable assurance that it can maintain CMT boron concentration within the TS limits when implementing the less frequent sampling interval specified in SR 3.5.2.4. The licensee has the ability to detect leakage from the CMT that could result in a reduction of CMT boron concentration to less than the LCO minimum value between sample intervals. Maintaining the boron concentration within the required band is ensured by 3 actions:

• (1) Sampling the CMT to determine the boron concentration.

• (2) Verifying CMT temperature is less than 120 degrees F.

• (3) Trending CMT temperature to determine if potential leakage exists.

Actions (1) and (2) are addressed by the SRs which require the following:

• SR 3.5.2.4 - Sampling to determine CMT boron concentration every 31 Days, as proposed in the LAR.

• SR 3.5.2.1. - Monitoring to ensure CMT temperature is less than 120 degrees F every 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> (unchanged by the LAR).

To address condition (3), in the July 23, 2020, supplement the licensee stated that it would add language to the UFSAR, Subsection 6.3.2.2.1, as follows: Core makeup tank temperature is monitored and trended to investigate potential leaks prior to alarm setpoints. The licensee also stated that the CMT temperature would be trended by site procedures. The licensees

procedures to trend CMT temperature as documented in the UFSAR are sufficient to meet the intent that SRs are established to ensure that the LCOs are met.

The actions that are credited by the licensee provide reasonable assurance that the lowest level of functional capability of the CMT is met to support safe plant operation. These actions also provide assurance that the plant is operated such that the assumptions in the analyses are valid, even with the reduced CMT sampling frequency. Therefore, the requirements of 10 CFR 50.36 are met.

To ensure that the minimum boron concentration required in the CMT is maintained over a longer sampling interval, the CMT maximum boron concentration specified in SR 3.5.2.4 was increased from 3,700 to 4,500 ppm in case dilution over time occurs. This change is acceptable because the amount of buffering agent was increased in TS 3.6.8 to ensure adequate pH control. The change in the amount of buffering agent is discussed in Section 3.2 of this safety evaluation (SE).

The licensee did not address the effect of the change on TS 3.5.3 which relies on the SRs from TS 3.5.2. Under some lower power mode conditions monitoring and trending CMT temperature would not be effective in identifying leakage from the CMT. This is an error or non-conservatism in application of this TS SR to identify leakage. However, since in lower power modes with lower reactivity, the importance of boron concentration in the CMT for reactivity control is very low. Therefore, NRC staff determined that the safety significance of this issue is very low, and has no impact on the conclusions in this SE.

3.2 TECHNICAL EVALUATION

OF LCO 3.6.8, SR 3.6.8.1 AND UFSAR SUBSECTION 6.3.2.2.4 CHANGES In LAR 20-004, SNC proposes changes to revise LCO 3.6.8 and SR 3.6.8.1 required TSP from 25,920 lbs to 26,460 lbs. In the UFSAR, Subsection 6.3.2.2.4 the required mass of TSP is revised from at least 25,920 lbs to at least 26,460 lbs.

NRC Evaluation of LCO 3.6.8, SR 3.6.8.1 and UFSAR, Subsection 6.3.2.2.4 Changes The NRC staff reviewed LAR 20-004 and the associated TS and TS Bases. The NRC staff notes that a previous change in the required mass of the TSP was submitted by letter dated September 13, 2017 (ADAMS Accession No. ML17256A626). This request, LAR 17-032, was reviewed by the NRC staff and subsequently approved by letter dated February 27, 2018 (ADAMS Accession No. ML18030A614). LAR 17-032 proposed to change the mass of TSP required inside containment from 26,460 lbs to 25,920 lbs, which was a result of finalizing the design. Additionally, the maximum volume of post-accident containment water volume was changed from 908,000 gallons to 867,308 gallons. LAR 20-004 proposes to change back the required mass of TSP to the original amount of 26,460 lbs, which was previously approved in the original design.

The NRC staff reviewed the changes to the UFSAR, Subsection 6.3.2.2.4, pH Adjustment Baskets, presented in LAR 20-004 with respect to PXS. The PXS primary function is to provide emergency core cooling following postulated design basis events. PXS is a safety-related system which includes the pH adjustment baskets located in the containment sump that contains granulated TSP to control the pH of the RCS water. In the event of a design basis accident, acids and bases, such as nitric acid (HNO), hydrochloric acid (HCl), and cesium hydroxide (CsOH), can potentially be introduced into the RCS water which may impact the pH.

Additionally, iodine may be released from the fuel to containment. To limit potential iodine release outside of containment the pH of the water is adjusted by the addition of TSP for iodine retention and for long-term loss of material on metallic components in the RCS. Furthermore, maintaining pH of the RCS water helps reduce the potential for stress corrosion cracking of stainless steel components in a post-flood up condition where chlorides can potentially affect these components during a long-term flood up event. TSP is capable of maintaining containment sump water pH within a range of 7.0 to 9.5.

The staff also reviewed proposed changes to TS 3.6.8 and SR 3.6.8.1. The amendment changes the required amount of TSP in the baskets from 25,920 lbs to 26,460 lbs. There were also changes in the TS Bases that changed the maximum volume of post-accident containment water from 867,308 gallons to 867,830 gallons. Additionally, the TS Bases also changed the containment water maximum boron concentration from 3,014 ppm to 3,050 ppm.

The staff evaluated the proposed changes to UFSAR, Subsection 6.3.2.2.4 and TS 3.6.8 by auditing the calculations documented in Westinghouse Document No. APP-PXS-M3C-021, AP1000 Post LOCA pH Adjustment, rev 3 (ADAMS Accession No. ML20226A103). The APP-PXS-M3C-021, rev. 3 document contains the calculations, methodology, and inputs for calculating the containment post-accident pH in a borated solution. The document also provides a detailed analysis of the different variables of boron concentration from different systems and includes margins to account for other sources of acids and bases that build up over time. The staff confirmed the assumptions and methodology were consistent with information provided in LAR-20-004 by performing independent verification of various aspects of the analysis. The staff also confirmed the margins were consistent with the approved AP1000 design. As part of this audit, the staff gained a better understanding of the calculations and analyses supporting LAR 20-004 and was able to confirm the information provided by the licensee in the LAR. Therefore, based on information provided in LAR 20-004, the NRC staff concludes there is reasonable assurance that the pH will be maintained between 7 and 9.5 during the post-LOCA period. Thus, the staff finds both changes to the UFSAR, Subsection 6.3.2.2.4, and the TS LCO 3.6.8 acceptable.

The pH adjustment prevents corrosion of metal objects in the reactor coolant pressure boundary and therefore supports the requirements of GDC 14. The staff finds that the changes submitted by the licensee are acceptable because the pH will be maintained between 7 and 9.5 to reduce the probability of stress corrosion cracking of austenitic stainless-steel components in post-accident conditions. Therefore, the proposed changes continue to comply with GDC 14.

As stated in 10 CFR Part 50, Appendix A, GDC 41, the function of the containment atmosphere cleanup system is to control fission product releases to the reactor containment following a postulated accident. The staff finds that the changes submitted by the licensee are acceptable based on the staffs evaluation of the licensees analysis indicating that the pH will be maintained above 7 in order to support the retention of iodine in the containment. The addition of the TSP to maintain a pH of 7 or higher will mitigate an adverse pH change, if other acids and bases are introduced into the RCS water.

Based on the review of the information submitted in LAR 20-004, the staff concludes that the proposed UFSAR changes continue to comply with the requirements in 10 CFR Part 50, Appendix A, GDC 41. Therefore, the staff finds the proposed changes to be acceptable.

Specifying the correct minimum amount of TSP in the TS provides reasonable assurance that the analysis assumptions regarding the absorption of iodine in the post-LOCA fluid are valid,

even with greater CMT boron concentrations. The SR requires the same amount of TSP as the LCO so it is adequate to ensure the LCO is met. Therefore, the requirements of 10 CFR 50.36 are met.

4.0 STATE CONSULTATION

In accordance with the Commission's regulations, the Georgia State official was notified of the proposed issuance of the amendment on August 28, 2020. The State official had no comments.

5.0 ENVIRONMENTAL CONSIDERATION

The amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and changes surveillance requirements. The staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration, and there has been no public comment on such finding (85 FR 33752) dated June 2, 2020. Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.

6.0 CONCLUSION

The staff has concluded, based on the considerations discussed in Section 3.0 that there is reasonable assurance that: (1) the health and safety of the public will not be endangered by operation in the proposed manner, (2) there is reasonable assurance that such activities will be conducted in compliance with the Commissions regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public. Therefore, the staff finds the changes proposed in this license amendment acceptable.

7.0 REFERENCES

1. Westinghouse Electric Company, Westinghouse Proprietary Class 2, AP1000 Post LOCA pH Adjustment, dated July 25, 2018 (Document No. APP-PXS-M3C-021, Revision 3).

2. Combined License NPF-91 for Vogtle Electric Generating Plant Unit 3, Southern Nuclear Operating Company (ADAMS Accession No. ML14100A106).

3. Combined License NPF-92 for Vogtle Electric Generating Plant Unit 4, Southern Nuclear Operating Company (ADAMS Accession No. ML14100A135).

4. Southern Nuclear Operating Company, Vogtle Electric Generating Plant Units 3 and 4, Request for License Amendment: Core Makeup Tank Boron Concentration Requirements (LAR-20-004), April 30, 2020 (ADAMS Accession No. ML20121A288).

5. Southern Nuclear Operating Company, Vogtle Electric Generating Plant Units 3 and 4, Supplement to Request for License Amendment: Core Makeup Tank Boron Concentration Requirements (LAR-20-004), July 23, 2020 (ADAMS Accession No. ML20205L560).

6. Vogtle Electric Generating Plant Units 3 and 4, Updated Final Safety Analysis Report, Revision 9, and Tier 1, Revision 8, June 15, 2020 (ADAMS Accession No. ML20181A311).

7. Westinghouse Electric Companys AP1000 Design Control Document, Revision 19, June 13, 2011 (ADAMS Accession No. ML11171A500).

8. Audit Report for Vogtle Electric Generating Plant Units 3 and 4, Request for License Amendment: Core Makeup Tank Boron Concentration Requirement (LAR 20-004), U.S.

Nuclear Regulatory Commission, August 19, 2020 (ADAMS Accession No. ML20226A103).

Principal Contributors: T.Gardner S.Smith J.Miller Date: October 14, 2020