ML23146A154

Summary of May 25, 2023, Meeting with Southern Nuclear Operating Company

ML23146A154
Person / Time
Site:	Vogtle
Issue date:	06/05/2023
From:	Gleaves W Office of Nuclear Reactor Regulation
To:
Gleaves W
References
Download: ML23146A154 (4)

Text

LICENSEE: Southern Nuclear Operating Company FACILITY: Vogtle Electric Generating Plant, Units 3 and 4

SUMMARY

OF MAY 25, 2023, MEETING WITH SOUTHERN NUCLEAR OPERATING COMPANY On May 25, 2023, at 10:00 a.m. Eastern Daylight Time (EDT), the U.S. Nuclear Regulatory Commission (NRC) held a virtual public meeting with representatives of Southern Nuclear Operating Company (SNC or the licensee). The purpose of the meeting was to discuss the SNC-proposed changes to the licenses including technical specifications (TS) for Vogtle Electric Generating Plant (VEGP) Units 3 & 4. This discussion centered on Vogtle Units 3 & 4 License Amendment Request (LAR)23-003, titled, Technical Specification 3.7.9, Spent Fuel Pool Makeup Water Sources, dated March 24, 2023, found in the Agencywide Documents Access and Management (ADAMS) (ML23083B967).

The staff stated that this LAR is in the acceptance review process and has not been formally accepted for review by NRC as staff information insufficiencies have been identified. The staff described two information insufficiencies items (ML23135A789). Following the description of the insufficiencies, SNC was invited to clarify its submittal by directing NRC to where on the docket the information it is requesting exists or to state its position on these items.

The first NRC-identified information insufficiency discussed was the evaluation of the spent fuel pool (SFP) safety related makeup water sources against limiting conditions for operation (LCO) selection Criteria 2 and 3 of Title 10 of the Code of Federal Regulations (10 CFR) 50.36(c)(2)(ii),

which provided that in the event of an extended loss of normal SFP cooling, the SFP makeup sources listed in TS 3.7.9 may be required for adequate cooling for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. An extended loss of normal SFP cooling because of a loss of non-safety related alternating current (AC) electrical power to the pumps when the decay heat load in the SFP exceeds 4.0 megawatts thermal (MWt) is a transient evaluated in VEGP Units 3 and 4 Updated Final Safety Analysis Report (UFSAR) Section 9.1.3.4.3, Abnormal Conditions.

SNC stated that the criteria in 10 CFR 50.36 did not apply to this transient because it is not a design basis accident or transient, which are addressed in Chapter 6, Engineered Safety Features, and Chapter 15, Accident Analyses. SNC stated that the Final Policy Statement on Technical Specifications Improvements for Nuclear Power Reactors Commission (in the Federal Register at 58 FR 39132, dated July 22, 1993) specifically mentioned, design basis accident or transient, in regard to TS. The staff agreed to review the policy statement. SNC stated that none of the standard technical specifications (STS) reflect TS for the SFP cooling system.June 5, 2023

The second NRC-identified information insufficiency item relates to a reference to NUREG-1793, Final Safety Evaluation Report for AP1000, Section 16.2.10, which states that the makeup water function does not satisfy any of the criteria for 50.36(c)(2)(ii) and are included in an LCO for defense in depth. The staff stated that the Final Safety Evaluation Report statement is based on the AP600, and it did not consider the increased heat load from the additional fuel assemblies in the SFP for the AP1000. The staff stated that a loss of normal SFP cooling is still considered to be a UFSAR Chapter 9, Auxiliary Systems, event. However, with the increased capacity of the AP1000 SFP fuel assembly storage capacity and the potentially greater decay heat load, the loss of normal SFP cooling analysis determined that the pool alone did not have enough water volume to maintain pool water level above the stored fuel for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. Therefore, the additional makeup water sources are needed to protect the stored fuel during high decay heat load conditions as discussed in UFSAR Section 9.1.3.4.3.

SNC stated that the design, since AP600, has considered makeup water from the cask washdown pit to provide adequate makeup water volume to keep water level above the stored fuel for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. NRC stated that for AP600 the additional makeup water sources were considered a defense-in-depth feature but must be credited for AP1000 because of the increased heat load in the SFP during refueling. The staff stated it would further review the basis for including the SFP makeup water sources in the AP600 generic TS. SNC stated that the increased SFP postulated decay heat load for the AP1000 did not change the category (as defined in ANSI N 18.2-1973, Nuclear Safety Criteria for the Design of Stationary Pressurized Water Reactor Plants) of the loss of normal pool cooling event, which is outside the scope of event categories intended for evaluation by LCO selection Criteria 2 and 3. This event is not a design basis accident or transient but is an abnormal occurrence. SNC clarified that the SFP decay heat load analysis during core offload does not allow a pool heat load greater than the boil-off heat removal capacity of the available passive makeup water sources while maintaining a pool water level above the irradiated fuel assemblies seated in the fuel storage racks to provide adequate cooling to protect fuel integrity.

The staff stated that the process outlined in NRCs LIC-109 (Rev. 3) for acceptance review will be followed. The staff stated that it would not decide the outcome of that process at this meeting but only after consideration of any information provided by SNC. No regulatory decisions were made at this meeting.

The meeting notice and agenda are available in ADAMS (ML23139A239). A list of attendees is enclosed.

There were approximately 21 participants on the call, including NRC staff, SNC staff, and public. No questions or comments for the staff from the public were proffered. The meeting ended at 10:51 a.m. EDT. The staff did not receive any Public Meeting Feedback forms.

Please direct any inquiries to me at 301415-5848 or Bill.Gleaves@nrc.gov.

Sincerely, William (Billy) Gleaves, Senior Project Manager Vogtle Project Office Office of Nuclear Reactor Regulation Docket Nos.52-025, 52026

Enclosure:

List of Attendees cc: Listserv Signed by Gleaves, William on 06/05/23

LIST OF ATTENDEES

May 25, 2023

NRC Meeting with Southern Nuclear Operating Company

Name Organization

Billy Gleaves Brian Wittick Tanny Santos Garry Armstrong James Gaslevic Lauren Nist NRC Craig Harbuck Raul Hernandez Hanry Wagage Michael Spencer MJ Ross-Lee

Amy Chamberlain Ryan Henderson Southern Nuclear Operating Company and Eddie Grant Contractors Nathan Chapman Dan McGraw

Jana Bergman Members of the Public

Enclosure

ML23146A154 OFFICE NRR/VPO/VPOB NRR/VPO/VPOB NRR/VPO/VPOB NRR/DRO/IOLB NAME WGleaves WG RButler RB CSantos CS LNist LN DATE Jun 2, 2023 Jun 5, 2023 Jun 5, 2023 Jun 5, 2023 OFFICE NRR/VPO/VPOB NAME WGleaves WG DATE Jun 5, 2023