ML20237F495

Safety Evaluation for Vogtle Electric Generating Plant Units 3 and 4 Amendment Nos. 184/182 (LAR 20-003)

ML20237F495
Person / Time
Site:	Vogtle
Issue date:	09/24/2020
From:	Alina Schiller NRC/NRR/VPOB
To:	City of Dalton, GA, Georgia Power Co, MEAG Power, Oglethorpe Power Corp, Southern Nuclear Operating Co
Alina Schiller Ex 8777
References
EPID: L-2020-LLA-0101, LAR 20-003
Download: ML20237F495 (13)

Text

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NOS. 184 AND 182 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 May 7, 2020 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML20128J334), as supplemented by letter dated June 22, 2020 (ADAMS Accession No. ML20174A451), 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. SNC License Amendment Request (LAR) 20-003R1 requested changes to COL Appendix A, Technical Specifications (TS) and the Updated Final Safety Analysis Report (UFSAR). Specifically, the requested amendment proposed the following changes:

TS 3.3.13, Engineered Safety Feature Actuation System (ESFAS) Main Control Room Isolation, Air Supply Initiation, and Electrical Load De-energization, Applicability is revised to exclude operability requirements of the Main Control Room (MCR) Air Supply Iodine or Particulate Radiation - High 2 function when the MCR envelope is isolated and the MCR emergency habitability system (VES) is operating.

TS 3.3.13 is revised to include Class 1E 24-Hour Battery Charger Input Undervoltage actuation signals for VES actuation and de-energization of the MCR air supply radiation monitoring sample pumps.

TS 3.8.1, DC Sources - Operating, and TS 3.8.2, DC Sources - Shutdown, are revised to include a Surveillance Requirement to verify each MCR air supply radiation monitoring sample pump de-energizes on an actual or simulated actuation signal.

UFSAR Figure 7.2-1 (Sheet 13 of 21), Functional Diagram Containment and Other Protection, the functional block is revised from DE-ENERGIZE MCR RADIATION MONITORS to DE-ENERGIZE MCR AIR SUPPLY RADIATION MONITOR SAMPLE PUMPS.

UFSAR subsection 7.3.1.2.17, Main Control Room Isolation, Air Supply Initiation, and Electrical Load De-energization, is revised to clarify the Class 1E 24-Hour Battery Charger Input Undervoltage actuation logic, change the load that is designed to be de-energized, and to further describe the protection provided by undervoltage actuation signal.

UFSAR Table 7.3-1, Engineered Safety Features Actuation Signals, (Sheets 6 and 9) revises the application of Note (8) and adds a new Note (13) stating De-energization of Main Control Room air supply radiation monitor sample pumps occurs on an extended undervoltage to Class 1E 24-hour battery chargers as shown in Figure 7.2-1, Sheet 13.

The supplement dated June 22, 2020, provided additional information that clarified the application, did not expand the scope of the application as originally noticed, and did not change the NRC staffs original proposed no significant hazards consideration determination as published in the Federal Register on June 16, 2020 (85 FR 36436).

2.0 REGULATORY EVALUATION

The requested amendment proposes to revise TS 3.3.13, TS 3.8.1, and TS 3.8.2 and UFSAR Tier 2 information that involve changes to these TS, as discussed in Section 1.0 of this safety evaluation. 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,1 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, Section 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 states that a license holder, including a holder of a combined license, must file an application for an amendment with the Commission that fully describes the changes desired.

The proposed LAR requires changes in the TS, and therefore a LAR is required to be submitted for NRC approval.

1 For VEGP Units 3 and 4, the licensee is partially exempt from the requirement in Section VIII.B.5.a regarding prior NRC approval of departures from Tier 2* information, as established by Section 2.D.(13) of the COL.

10 CFR 52.98(f) requires NRC approval for any modification to, addition to, or deletion from the terms and conditions of a COL. These activities involve changes to TS (COL Appendix A) and changes to the UFSAR that involve a change to TS. Therefore, NRC approval is required prior to making the plant specific proposed changes in this LAR.

10 CFR 50.36 specifies requirements for TS that 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. 10 CFR 50.36(c)(2) states, Limiting conditions for operation are the lowest functional capability or performance levels of equipment required for safe operation of the facility.

In accordance with 10 CFR 50.36(c)(2)(ii), a TS limiting condition for operation must be established for each item meeting one or more of the criteria in 10 CFR 50.36(c)(2)(ii).

10CFR50.36(c)(2)(ii)(C) Criterion 3 refers to [a] structure, system, or component that is part of the primary success path and which functions or actuates to mitigate a design basis accident or transient that either assumes the failure of or presents a challenge to the integrity of a fission product barrier. 10 CFR 50.36(c)(3) states, Surveillance requirements are requirements relating to test, calibration, or inspection to assure that the necessary quality of systems and components is maintained, that facility operation will be within safety limits, and that the limiting conditions for operation will be met.

10 CFR 50.49 requires that licensees establish a program for qualifying specific electrical equipment.

The specific NRC technical requirements applicable to LAR 20-003 are the general design criterion/criteria (GDC) in Appendix A, General Design Criteria for Nuclear Power Plants, to 10CFRPart 50, Domestic Licensing of Production and Utilization Facilities. In particular, these technical requirements include the following GDC:

GDC 4, Environmental and dynamic effects design bases, states, Structures, systems, and components important to safety shall be designed to accommodate the effects of and to be compatible with the environmental conditions associated with normal operation, maintenance, testing, and postulated accidents, including loss-of-coolant accidents.

GDC 13, Instrumentation and control, states, in part, that [i]nstrumentation shall be provided to monitor variables and systems over their anticipated ranges for normal operation, for anticipated operational occurrences, and for accident conditions as appropriate to assure adequate safety, including those variables and systems that can affect the fission process, the integrity of the reactor core, the reactor coolant pressure boundary, and the containment and its associated systems.

GDC 17, Electric power systems, requires, in part, that [a]n onsite electric power system and an offsite electric power system shall be provided to permit functioning of structures, systems, and components important to safety. The safety function for each system (assuming the other system is not functioning) shall be to provide sufficient capacity and capability to assure that (1) specified acceptable fuel design limits and design conditions of the reactor coolant pressure boundary are not exceeded as a result of anticipated operational occurrences and (2) the core is cooled and containment integrity and other vital functions are maintained in the event of postulated accidents. The onsite electric power supplies, including the batteries, and the onsite electric distribution system, shall have sufficient independence, redundancy, and testability to perform their safety functions assuming a single failure.

GDC 18, Inspection and testing of electric power systems, requires that Electric power systems important to safety shall be designed to permit appropriate periodic inspection and testing of important areas and features, such as wiring, insulation, connections, and switchboards, to assess the continuity of the systems and the condition of their components.

The systems shall be designed with a capability to test periodically (1) the operability and functional performance of the components of the systems, such as onsite power sources, relays, switches, and buses, and (2) the operability of the systems as a whole and, under conditions as close to design as practical, the full operation sequence that brings the systems into operation, including operation of applicable portions of the protection system, and the transfer of power among the nuclear power unit, the offsite power system, and the onsite power system.

GDC 19, Control room, states that, A control room shall be provided from which actions can be taken to operate the nuclear power unit safely under normal conditions and to maintain it in a safe condition under accident conditions, including loss-of-coolant accidents. Adequate radiation protection shall be provided to permit access and occupancy of the control room under accident conditions without personnel receiving radiation exposures in excess of 0.05 Sv (5 rem) total effective dose equivalent (TEDE) as defined in § 50.2 for the duration of the accident.

GDC 21, Protection system reliability and testability, states, in part, that the protection system shall be designed to permit its periodic testing during reactor operation, including a capability to test channels independently to determine failures and losses of redundancy that may have occurred.

3.1 TECHNICAL EVALUATION

OF TS 3.3.13 APPLICABILITY CHANGE The LAR proposes to revise TS 3.3.13 Applicability to exclude operability of the MCR Air Supply Iodine or Particulate Radiation - High 2 function when the MCR envelope (MCRE) is isolated and the MCR VES is operating.

The nuclear island nonradioactive ventilation system (VBS) serves, in part, the MCR and the control support area (CSA). The VBS mixes outdoor air and air returned from the MCR and associated areas. The air is filtered, conditioned, and returned to the MCR and CSA. The supply to the MCR is monitored by two radiation monitor packages. Each MCR supply air duct radiation monitor package is comprised of a sample pump, a particulate detector, an iodine detector and a noble gas detector to continuously measure and record the concentration of radioactive materials in the air supplied to the MCR by the VBS air handling units. The sample pump is used to pull the MCR air past the radiation detectors. The air duct radiation monitors are used to maintain the MCR habitability by initiating ventilation systems following Design Basis Accidents (DBA) which could lead to exceeding the GDC 19 requirement that adequate radiation protection be provided to permit access and occupancy of the control room under accident conditions without personnel receiving radiation exposures exceeding 0.05 Sv (5 rem) total effective dose equivalent (TEDE) as defined in 10 CFR 50.2 for the duration of the accident.

When a MCR Air Supply Iodine or Particulate Radiation - High 2 signal occurs, the MCR air supply and exhaust pathways (safety-related) will be isolated and the MCR VES emergency air supply will be initiated. The VES provides MCR habitability in the event of a DBA. The VES consists of stored compressed air and its distribution system to the MCR. The VES can provide emergency ventilation and pressurization for the MCR. The VES also provides emergency passive heat sinks for the MCR, instrumentation and control (I&C) rooms, and direct current electrical equipment rooms. The VES can deliver the required air flow to the MCR and induce sufficient air flow through the passive filtration line to meet the ventilation and pressurization requirements for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

Whenever the MCRE is isolated and the VES is providing both pressurization of and breathing air to the MCRE, the safety function of the MCR air supply radiation monitoring packages and the High 2 MCR Air Supply Iodine or Particulate Radiation signal has already been achieved.

Therefore, it is not necessary to require operability of the MCR Air Supply Iodine or Particulate High 2 channel function when the MCRE is isolated and VES is in operation.

As currently written, TS 3.3.13 Actions for inoperable Iodine or Particulate Radiation monitors would require an immediate plant shutdown or suspension of irradiated fuel movement, even though in the case of no VBS flow the MCR is being protected by the differential pressure channels.

The licensee proposes to change TS 3.3.13 Applicability to exclude operability of the MCR Air Supply Iodine or Particulate Radiation - High 2 function when the MCRE is isolated and the VES is operating.

The NRC staff reviewed UFSAR Sections 6.4, Habitability Systems, and 9.4, Air-Conditioning, Heating, Cooling, and Ventilation System, along with the information provided in the LAR. The subject radiation monitoring systems form part of a system that is part of the primary success path and which functions to mitigate a DBA or transient that either assumes the failure of or presents a challenge to the integrity of a fission product barrier. In this case, isolating the MCR and initiating the VES. The staff confirmed that when the MCR has been isolated (i.e., VBS cannot supply air flow to the MCR) and when the VES is providing pressurization of and breathing air to the MCRE, the safety function of the MCR supply duct radiation monitoring packages and the MCR Air Supply Iodine or Particulate Radiation High - 2 signal is already accomplished, and therefore, the assumed safety function is maintained. The MCR environment will continue to be able to meet the habitability and equipment qualification requirements, as described in UFSAR Section 6.4 since the MCR will be isolated from the VBS air supply duct, the VES will provide the air supply, and load shedding of MCR non-safety-related loads will be performed. This proposed change is acceptable because the required TS function of the MCR intake monitors is to isolate the MCR intakes and initiate the MCR VES when high radiation is detected in the intake ducts (if radiation levels in the intake reach the High-2 setpoint). After the MCR air intake has been isolated and the VES is in operation, this function has already been achieved, so the TS need not require additional functionality, and with no air flowing through the intakes, there is no need for the monitors to continue to operate.

This change does not result in any change in the quantities of radioactive material released during any accident. In addition, the change would not be expected to result in any changes to the dose to MCR operators. The requirements and functions of the ventilation intake monitors are not changed when the MCR intakes are open (during normal or supplementary ventilation modes) and prior to emergency ventilation being initiated. As discussed above, when the VES is in operation and the outside air intake closed, there is no air entering the intakes, so it is not necessary for the MCR air intake monitors to be required to remain functional. As a result, the NRC staff finds that GDC 19 continues to be met. In addition, the NRC staff finds that the effects of radiation on equipment important to safety, as required by 10 CFR 50.49 and GDC 4, have not changed and continue to be met.

To incorporate this new provision into technical specifications, the licensee proposed adding the following note to TS 3.3.13:

Not applicable for the Main Control Room Air Supply Iodine or Particulate Radiation - High 2 function when the Main Control Room Envelope is isolated and the Main Control Room Emergency Habitability System is in operation.

Based on staff reviews of the LAR and guidance provided in the Writers Guide2, the staff finds that the licensee-proposed TS change is acceptable because it is in close alignment with the Writers Guide, consistent with the function of the MCR air supply radiation monitors as described in the UFSAR, there are no adverse impacts to safety as a result of the change and 10 CFR 50.36(c)(2), GDC 4, GDC 19, and 10 CFR 50.49 requirements will continue to be met.

3.2 TECHNICAL EVALUATION

OF OTHER TS 3.3.13 CHANGES In the LAR, the licensee proposed to make changes to COL Appendix A, TS 3.3.13 which governs operability of the MCR Air Supply Iodine or Particulate Radiation channels. The licensee reformatted the Limiting Condition for Operation (LCO) and Applicability of TS 3.3.13 into a new Table 3.3.13-1. As discussed above, in Table 3.3.13-1, the licensee excludes the Function of the MCR Air Supply Iodine or Particulate Radiation - High 2. The licensee proposes to include Class 1E 24-Hour Battery Charger Undervoltage as an additional Function to TS 3.3.13.

In the event of a Class 1E 24-Hour Battery Charger Undervoltage signal, the MCR is isolated, VES is initiated and the MCR air supply radiation monitor sample pumps are de-energized in order to conserve the battery capacity, maintain room temperature below the equipment qualification limitation, and maintain the assumed heat load for MCR habitability. In a loss of alternating current (ac) power event, the MCR air supply radiation monitor sample pumps are de-energized in order to conserve battery capacity. Verification that de-energization of the MCR air supply sample pump occurs on an actual or simulated signal from the Protection and Safety Monitoring System (PMS) will ensure that the qualified battery load profile remains bounded (i.e., de-energizing the MCR air supply sample pump, which is a non-essential load, will conserve battery capacity). The battery load profile analyses ensure the batteries can support the primary success path and safety functions for a loss of ac event. Class 1E 24-Hour Battery Charger Undervoltage Function would be added to TS 3.3.13 since this is a safety-related function that is an important assumption for a primary success path for mitigating a DBA.

Current TS 3.3.13 requires two channels of the MCR Air Supply Iodine or Particulate Radiation monitor High-2 channel and the MCR Differential Pressure Low channel to be OPERABLE 2 The Writers Guide was first published as a formal document in February of 1993 by the Nuclear Management and Resources Council, Inc. (NUMARC), as NUMARC 93-03, Writers Guide for the Restructured Technical Specifications. The current version of the Writers Guide was published in June of 2005 by the pressurized-water reactor (PWR) and boiling-water reactor (BWR) owners groups Technical Specifications Task Force (TSTF) as TSTF-GG-05-01, Writer's Guide for Plant-Specific Improved Technical Specifications, Revision 1 (Reference 9).

when in MODES 1, 2, 3, and 4, and during movement of irradiated fuel assemblies. If ac power is unavailable for more than 10 minutes, if MCR differential pressure is below the Low setpoint for more than 10 minutes, if High-2 particulate or iodine radioactivity is detected in the MCR supply air duct, or if there is a manual initiation of the MCR isolation, the PMS automatically isolates the MCR and operator habitability requirements are then met by the VES. VES operation in conjunction with automatic PMS actuation of load shedding provides the means for limiting the MCRE air temperature to a maximum average wet bulb globe temperature index for the MCR of less than 90°F during the first 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> following the loss of VBS operation. The PMS provides a phased load-shed (Stage 1 and Stage 2) of identified non-safety-related MCR heat loads to achieve the design basis safety-related MCR heat load profiles for events.

SNC proposes that the PMS logic be designed so that when the Class 1E 24-hour battery charger undervoltage signal is present for greater than 600 seconds, the PMS will send out an output to de-energize the sample pumps and at the same time to isolate the MCR, start the VES, and other actuations (i.e., load shed). De-energizing the MCR radiation monitor sample pumps is also credited for maintaining I&C room temperature below equipment qualification limits and maintaining the assumed heat load for the MCR during an extended loss of ac event.

When there is no air flow at the monitor sampling point (i.e., no VBS flow to the MCR), or when the monitor sample pumps are de-energized, the radiation monitors will no longer be able to perform their safety function to monitor the VBS supply air to the MCR. The radiation monitors will not be able to provide input to the PMS for the isolation of the MCR and initiation of the VES operation. However, as noted above, the signal for de-energizing the radiation monitor sample pumps is also an input for isolation of the MCR and activation of the VES.

Isolating the MCRE and activating the VES provides both pressurization of, and breathing air to, the MCRE, which is the safety-related configuration for the MCR. The safety function of the MCR air supply radiation monitoring packages and the High 2 MCR Air Supply Iodine or Particulate Radiation signal has already been achieved. Therefore, it is not necessary to require operability of the MCR Air Supply radiation monitor sample pumps when the MCRE is isolated and the VES is in operation.

The new TS Table 3.3.13-1 proposed in this LAR includes a Function 3 for the Class 1E 24-Hour Battery Charger Undervoltage signal. This undervoltage signal is already used in the current UFSAR PMS logic Figure 7.2-1 (Sheet 15 of 21). There is no functional logic change proposed in this LAR for this undervoltage signal, and the only relevant proposed change is that the PMS output would result in the MCR air radiation monitoring sample pumps being de-energized, rather than the MCR air radiation monitors. De-energizing the MCR air radiation monitoring sample pumps is acceptable, as discussed above. In addition, the time response of this function is not modeled or included in the current safety analysis for VEGP Units 3 and 4.

Furthermore, the de-energization of the sample pumps is used to reduce the equipment room heat loads and save the battery capacity, which is a very slow process if compared to the response time of this function in the PMS. Hence, the response time testing for this function as a surveillance requirement is not necessary to ensure that the analyzed plant safety functions are achieved. Furthermore, for the above Function 3, normally channel check and channel operational test (COT) manual surveillances are required in TS. However, NRC approved SNC LAR 19-001 (Reference 7) and its associated Amendments 168 and 166 for VEGP Units 3 and 4 (Reference 8), which credited the PMS self-diagnostic functions together with added manual verification activities to adequately address the issue that would be addressed by manual surveillances for the channel check and COT. Therefore, the channel check and COT manual surveillances for the above Function 3 are not necessary. The NRC staff observes that the changes proposed in this LAR do not impact the PMS design; thus, the proposed changes have no effect on the PMS capability for periodic testing during reactor power operation. So, the NRC staff finds that the current compliance with GDC 21 is maintained.

The licensee identified that an existing function (Class 1E 24-Hour Battery Charger Undervoltage Function, which actuates VES and de-energizes MCR air supply radiation monitor sample pumps) described in the UFSAR meets 10CFR50.36 requirements but is not addressed in technical specifications. The licensee identified that the function meets 10CFR50.36(c)(2)(ii)(C) Criterion 3 and the licensee proposed a change to TS to ensure OPERABILITY of the signal path. Based on the discussion provided in Section 2 of the LAR, and the staffs evaluation provided above, the staff agrees with the licensee that this safety function meets 10CFR50.36(c)(2)(ii)(C) Criterion 3. Therefore, the staff finds that it is appropriate to establish a technical specification for this function.

To incorporate this function into TS, the licensee proposed changes to TS 3.3.13 that are described in the LAR and depicted in TS 3.3.13 markups. For example, the TS3.3.13 Limiting Condition for Operation and Applicability are reformatted into new Table3.3.13-1. The revised Table3.3.13-1 includes the new Function, Class 1E 24-Hour Battery Charger Undervoltage, along with Applicable MODES or Other Specified Conditions, Required Channels, Conditions, and Surveillance Requirements (SRs). In addition, to accommodate the new Function, three new Actions are added, four current Actions are revised, and a Note is added to SRs (refers to new Table 3.3.13-1). The specific changes are shown in Enclosure 5 of the June 22, 2020 supplement.

These changes do not result in any change in the quantities of radioactive material released during any accident. In addition, the changes would not be expected to result in any changes to the dose to MCR operators. As a result, the NRC staff finds that the radiological aspects of MCR habitability, as required by GDC 19, continue to be met. In addition, the NRC staff finds that the effects of radiation on equipment important to safety, as required by 10 CFR 50.49 and GDC 4, have not changed and continue to be met.

Based on staff reviews of the LAR and guidance provided with the Writers Guide, the staff finds that the licensee-proposed TS changes for this added Function are acceptable because they are in close alignment with the Writers Guide, they are consistent with VEGPs licensing basis, there are no adverse impacts to safety as a result of the change and 10CFR 50.36(c)(2),

10CFR 50.36(c)(3), 10 CFR 50.49, GDC 4, GDC 19, and GDC 21 requirements will continue to be met.

3.3 TECHNICAL EVALUATION

OF TS 3.8.1 AND TS 3.8.2 CHANGES With the addition of the Class 1E 24-Hour Battery Charger Undervoltage Function to TS 3.3.13, the licensee proposes changes to TS 3.8.1 and TS 3.8.2 to include a new SR. Specifically, the licensee is proposing to include SR 3.8.1.4 to TS 3.8.1 to verify the MCR air supply radiation monitor sample pump de-energizes on an actual or simulated actuation signal with a surveillance frequency of 24 months. In addition, the licensee proposes to modify SR 3.8.2.1, which would require the licensee to perform SR 3.8.1.4, to assure that the LCO of TS 3.8.2 will be met. The staff reviewed the LAR and the proposed changes to determine whether the requirements of GDC 17 and 18 are met.

The licensee proposes changes to COL Appendix A, to revise TS 3.8.1 to include a new SR 3.8.1.4. Specifically, the licensee added a surveillance to verify the MCR air supply radiation monitor sample pump de-energizes on an actual or simulated actuation signal from the PMS with a surveillance frequency of 24 months. This surveillance is only required to be met when the MCR supply radiation monitor sample pump is energized. The licensee states that the current required surveillances on the Class 1E 24-hour batteries are unchanged. The proposed change to add periodic testing of the de-energization of the MCR air supply radiation monitor sample pumps on an actual or simulated actuation signal, supports testing of the operability and functional performance of the assumed battery load profile.

The staff evaluated the SR and surveillance frequency in TS 3.8.1 SR 3.8.1.4 and determined the new SR 3.8.1.4 does not impact the battery capacity and capability and does not adversely affect the ability to test the battery chargers and batteries. The addition of SR 3.8.1.4 provides verification that the MCR air supply radiation monitor sample pump de-energizes on an actual or simulated signal from the PMS and assures that the non-essential Class 1E 24-hour battery loads are shed to maintain the assumed battery load profile. Therefore, the staff finds the proposed changes to TS 3.8.1 acceptable.

The licensee proposes changes to COL Appendix A, TS 3.8.2 to revise SR 3.8.2.1. Specifically, the licensee proposes to modify a statement in SR 3.8.2.1 from For DC sources required to be OPERABLE, the following SRs are applicable to The following SRs are applicable and add SR 3.8.1.4 to the list of SRs that are applicable when performing SR 3.8.2.1. The staff evaluated the SR in TS 3.8.2 SR 3.8.2.1 and determined that SR 3.8.2.1 would require the licensee to perform SR 3.8.1.4, to assure that the LCO of TS 3.8.2 will be met. Therefore, the staff finds the proposed changes to TS 3.8.2 acceptable.

The staff evaluated the proposed changes to TS 3.8.1 and TS 3.8.2 and determined that they do not affect the design of the Class 1E batteries and battery chargers. The battery load profile analyses will remain bounding to ensure the batteries can support the primary success path and safety functions for a loss of ac event. The staff finds the functions of the battery chargers and batteries are not changed and the safety equipment continues to perform its intended safety function, thus continues to meet the requirements of GDC 17. Additionally, the staff evaluated the SR for the TS and determined that the proposed changes do not adversely affect the ability to test the battery chargers and batteries; thus the requirements of GDC 18 continue to be met.

Based on the proposed information, the staff concludes that the proposed TS changes do not impact the licensees compliance with the requirements in 10 CFR Part 50, Appendix A, GDC 17 and 18. Therefore, the staff finds the proposed changes to be acceptable.

Based on staff reviews of the LAR and guidance provided with the Writers Guide, the staff finds that the licensee-proposed changes to TS 3.8.1 and 3.8.2 are acceptable because they are in close alignment with the Writers Guide, they are consistent with VEGPs licensing basis, there are no adverse impacts to safety as a result of the change and 10CFR50.36(c)(3) requirements will be met.

3.4 TECHNICAL EVALUATION

OF UFSAR CHAPTER 7 CHANGES In LAR 20-003, SNC proposed the following changes to UFSAR Chapter 7, Instrumentation and Controls, which are also associated with the TS changes described above:

i.

Change the description of the functional block from DE-ENERGIZE MCR RADIATION MONITORS to DE-ENERGIZE MCR AIR SUPPLY RADIATION MONITOR SAMPLE PUMPS in UFSAR Figure 7.2-1 (Sheet 13 of 21) ii.

Change UFSAR Subsection 7.3.1.2.17 to clarify the Class 1E 24-hour battery charger input undervoltage actuation logic, to de-energize the MCR air radiation monitoring sample pumps rather than the radiation monitors, and further describe the protection provided by the undervoltage actuation signal iii.

Change UFSAR Table 7.3-1 (Sheets 6 and 9) and its notes to revise the application of Note (8) and add a new Note (13) stating De-energization of Main Control Room air supply radiation monitor sample pumps occurs on an extended undervoltage to Class 1E 24-hour battery chargers as shown in Figure 7.2-1, Sheet 13 For VEGP Units 3 and 4, when the ac power is available, the VBS provides normal and abnormal heating, ventilation, and air conditioning (HVAC) service to the MCR, I&C rooms, and a few other areas. In addition, the VBS is also designed to control the radiological habitability in the MCR when a source of ac power is available. But, if the loss of the ac power is more than 10 minutes, if the MCR differential pressure is below the Low setpoint for more than 10 minutes, if High-2 particulate or iodine radioactivity is detected in the MCR supply air duct, or if there is a manual initiation of the MCR isolation, the PMS automatically isolates the MCR and at the same time actuates the MCR VES to meet the MCR operator habitability requirements.

For the VBS, there are two MCR supply air duct radiation monitor packages, APP-VBS-JS-01A and APP-VBS-JS-01B, each of which is comprised of a sample pump and monitors to continuously measure and record the concentration of radioactive materials in the air supplied to the MCR by the VBS air handling units. The sample pump is used to pull the MCR air past the radiation monitors.

The VES includes a compressed air supply contained in a set of storage tanks to supply the required air flow to the MCR, equipment to provide electrical load de-energization, and passive heat sinks to maintain the temperature in the MCR within limits for human performance. The VES is separate from the VBS.

With the above three changes (i), (ii), and (iii), SNC proposed in this LAR to send the PMS actuation output to de-energize (or load shed) the VBS MCR air radiation monitor sample pumps, instead of the VBS MCR air radiation monitors, when the ac power is unavailable for more than 10 minutes. As described above for the VBS, when there is a loss of the ac power for more than 10 minutes, the MCR is isolated and the VES is initiated automatically by the PMS to meet the MCR operator habitability requirements. For such a condition, it is not necessary to require operability of the MCR air supply duct radiation monitor system when the MCR is isolated and VES is in operation. In addition, the VES operation does not depend on the MCR air supply duct radiation monitoring systems of the VBS.

Therefore, for the proposed change to de-energize the VBS MCR air radiation monitor sample pumps, instead of its radiation monitors, when the ac power is unavailable for more than 10 minutes, the NRC staff finds that there is no adverse impact and no change either to the relevant PMS logic design or its safety function. Additionally, this proposed change to de-energize (or load shed) the VBS MCR air radiation monitor sample pumps, instead of the radiation monitors, also conserves the Class 1E battery capacity in the plant Class 1E DC and uninterruptible power supply system (IDS). Furthermore, the de-energization of the VBS MCR air radiation monitor sample pumps, instead of the radiation monitors, reduces heat loads produced in the I&C room, which then helps to maintain I&C room temperature below equipment qualification limits and to preserve the assumed total heat load for the MCR during an extended loss of ac power (i.e., an extended undervoltage to Class 1E 24-hour battery chargers). Hence, the NRC staff finds that the proposed change does not impact the current compliance with 10 CFR 50.49 and GDC 4.

However, the initial submittal (Reference 1) of this LAR stated that the de-energization of MCR air supply radiation monitor sample pumps occurs on an extended undervoltage to Class 1E 24-hour battery chargers coincident with the MCR isolation, air supply initiation, and electrical load de-energization actuation signal. The NRC staff concluded that this statement was not consistent with the PMS logic, as indicated in the revised UFSAR Functional Diagram 7.2-1 (Sheet 13 of 21). This modified diagram shows that, whenever there is an extended undervoltage to Class 1E 24-hour battery chargers, the de-energization of the VBS MCR air supply radiation monitor sample pumps occurs and does not need to be coincident with other actuations, although those other actuations are designed to happen at the same time with the de-energization of the radiation monitor sample pumps. In the supplemental information (Reference 2) submitted, the NRC staff finds that SNC revised the statement to correctly reflect the PMS logic as shown in UFSAR Functional Diagram 7.2-1 (Sheet 13 of 21).

For VEGP Units 3 and 4, the plant Class 1E IDS provides electrical power for safety related and vital control instrumentation loads, including monitoring equipment and MCR emergency lighting. It also provides power for safe shutdown when all the onsite and offsite ac power sources are lost and cannot be recovered for up to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. The IDS includes four independent safety related Class 1E DC electrical power subsystems (Divisions A, B, C, and D).

Divisions A and D each consist of one battery bank, one battery charger, and the associated control equipment and interconnecting cable. Divisions B and C each consist of two battery banks, two battery chargers, and the associated control equipment and interconnecting cabling.

The first battery bank in each of the four divisions, designated as the "24-hour" battery bank, provides power to the loads required for the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> following an event. The second battery bank in Divisions B and C, designated as the "72-hour" battery bank, is used for those loads requiring power for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> following an event. The loads on the battery banks (including those on the associated inverters) are grouped according to their role in response to a DBA. Loads which are a one time or limited duration load (engineered safety features (ESF) actuation cabinets and reactor trip function) required within the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> following an accident are connected to the 24-hour battery bank. Loads which are continuous or required beyond the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> following an accident (emergency lighting, post-accident monitoring, and qualified data processing system) are connected to the 72-hour battery bank. Therefore, the low battery charger undervoltage signals used for the ESF functions involved in the proposed changes in this LAR are from the 24-hour battery banks. Therefore, in the above proposed changes (ii) and (iii), the NRC staff finds that 24-hour added to the description of the low battery charger undervoltage signals is made to just distinguish them from those from 72-hour battery banks and, hence is acceptable.

In the IDS, there are two undervoltage relays provided on the input to each of the four 24-hour battery charger inputs to detect the loss of ac power. As depicted in the unchanged UFSAR Functional Diagram Figure 7.2-1 (Sheet 15 of 21), the PMS logic, which is designed to produce the Class 1E 24-hour battery charger undervoltage signal used to de-energize the VBS MCR air radiation monitor sample pumps and other actuations, is based on a two-out-of-two undervoltage relays with a time delay to the battery charger for Divisions A or C coincident with an undervoltage to the battery chargers for Divisions B or D. It is a one-out-of-two taken twice logic, not a two-out-of-four logic. But, the two-out-of-four logic is used in the current UFSAR Subsection 7.3.1.2.17 and notes for Table 7.3-1 to describe the relevant logic in Figure 7.2-1 (Sheet 15 of 21). Hence, in the above changes (ii) and (iii), SNC proposed to remove two-out-of-four in the description for the four 24-hour battery charger undervoltage signal inputs. The NRC staff finds that removing two-out-of-four correctly represents the logic as depicted in UFSAR Figure 7.2-1 (Sheet 15 of 21). The NRC staff notes that there is no change to the PMS logic itself for the Class 1E 24-hour battery charger undervoltage signal.

Overall, the NRC staff finds that the above changes (i), (ii), and (iii) in this subsection do not impact the physical configuration of the PMS hardware and do not impact safety-related PMS software implementation either. Those proposed changes do not have adverse impacts to the PMS safety functions to meet the criterion in GDC 13. Therefore, the NRC staff finds that the criteria in GDC 13 remain satisfied and the proposed changes are acceptable.

4.0 STATE CONSULTATION

In accordance with the Commission's regulations in 10 CFR 50.91(b)(2), the Georgia State official was notified of the proposed issuance of notified of the proposed issuance of the amendment on July 14, 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 Part20, Standards for Protection Against Radiation, 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 as published in the Federal Register on June 16, 2020 (85 FR 36436). Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10CFR51.22(c)(9).

Pursuant to 10CFR51.22(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. Southern Nuclear Operating Company, Vogtle Electric Generating Plant Units 3 and 4, Request for License Amendment: Technical Specification 3.3.13 for Main Control Room Emergency Habitability System (VES) Instrumentation Applicability Change and Include Undervoltage Actuation (LAR 20-003), May 7, 2020 (ADAMS Accession No. ML20128J334).

2. Southern Nuclear Operating Company, Vogtle Electric Generating Plant Units 3 and 4, Revision to License Amendment Request: Technical Specification 3.3.13 for Main Control Room Emergency Habitability System (VES) Instrumentation Applicability Change and Include Undervoltage Actuation (LAR 20-003R1), June 22, 2020 (ADAMS Accession No. ML20174A451).

3. 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).

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

5. Vogtle Electric Generating Plant Unit 3, Current Facility Combined License NPF-91, Revised June 23, 2020 (ADAMS Accession No. ML14100A106).

6. Vogtle Electric Generating Plant Unit 4, Current Facility Combined License NPF-92, Revised June 23, 2020 (ADAMS Accession No. ML14100A135).

7. Southern Nuclear Operating Company, Vogtle Electric Generating Plant Units 3 and 4, Request for License Amendment Regarding Protection and Safety Monitoring System Surveillance Requirement Reduction Technical Specification Revision (LAR 19-001),

March 25, 2019 (ADAMS Accession No. ML19084A309).

8. Amendment Nos. 168 and 166 to VEGP Units 3 and 4 COLs, November 21, 2019 (ADAMS Accession No. ML19297C791).

9. TSTF-GG-05-01, Writer's Guide for Plant-Specific Improved Technical Specifications, Revision 1, June 2005 (ADAMS Accession No. ML060720511).