ML25051A176
| ML25051A176 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar  |
| Issue date: | 02/26/2025 |
| From: | Kimberly Green Plant Licensing Branch II |
| To: | Hulvey K Tennessee Valley Authority |
| Green K | |
| References | |
| EPID L-2024-LLA-0175 | |
| Download: ML25051A176 (1) | |
Text
February 26, 2025 Kimberly D. Hulvey General Manager, Nuclear Regulatory Affairs and Emergency Preparedness Tennessee Valley Authority 1101 Market Street, LP 4B-C Chattanooga, TN 37402-2801
SUBJECT:
WATTS BAR NUCLEAR PLANT, UNITS 1 AND 2 - REGULATORY AUDIT PLAN IN SUPPORT OF LICENSE AMENDMENT REQUEST TO ADOPT RISK-INFORMED COMPLETION TIMES (EPID L-2024-LLA-0175)
Dear Kimberly Hulvey:
By letter dated December 27, 2024, the Tennessee Valley Authority (TVA) requested to amend Facility Operating License Nos. NPF-90 and NPF-96 for Watts Bar Nuclear Plant, Units 1 and 2, respectively, to adopt Technical Specifications Task Force (TSTF) Traveler TSTF-505, Provide Risk-informed Extended Completion Times, RITSTF Initiative 4b, to permit the use of risk-informed technical specification completion times for certain actions required when limiting conditions for operation (LCO) are not met. Additionally, TVA requested to adopt Traveler TSTF-439-A, Revision 2, Eliminate Second Completion Times Limiting Time From Discovery of Failure To Meet an LCO.
The U.S. Nuclear Regulatory Commission (NRC) staff has identified the need for a regulatory audit to examine TVAs non-docketed information with the intent to gain understanding, to verify information, and to identify information that will require docketing to support the basis of the licensing or regulatory decision.
The NRC staff will conduct the audit virtually via Teams via an electronic portal established by TVA, from approximately March 17, through September 5, 2025, with formal audit calls to be scheduled during this period, as needed. A detailed audit plan is enclosed.
If you have any questions, please contact me at 301-415-1627 or by email at Kimberly.Green@nrc.gov.
Sincerely,
/RA/
Kimberly J. Green, Senior Project Manager Plant Licensing Branch II-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-390 and 50-391
Enclosure:
Audit Plan cc: Listserv
Enclosure REGULATORY AUDIT PLAN BY THE OFFICE OF NUCLEAR REACTOR REGULATION TO SUPPORT THE REVIEW OF LICENSE AMENDMENT REQUEST TO ADOPT RISK-INFORMED COMPLETION TIMES TENNESSEE VALLEY AUTHORITY WATTS BAR NUCLEAR PLANT, UNITS 1 AND 2 DOCKET NOS. 50-390 AND 50-391
1.0 BACKGROUND
By letter dated December 27, 2024 (Reference 1), Tennessee Valley Authority (TVA) submitted a license amendment request (LAR) to amend Facility Operating License Nos. NPF-90 and NPF-96 for Watts Bar Nuclear Plant (Watts Bar), Units 1 and 2, respectively. The proposed amendments would modify the Watts Bar units technical specification requirements to permit the use of risk-informed completion times (RICTs). TVA would implement RICTs according to a process developed by the Technical Specifications Task Force (TSTF) and described in Traveler TSTF-505, Provide Risk-Informed Extended Completion Times - RITSTF [Risk-Informed TSTF] Initiative 4b, Revision 2 (Reference 2). These RICTs would apply to certain actions required when particular limiting conditions for operation (LCOs) are not met. The proposed amendments would also incorporate TSTF-439, Eliminate Second Completion Times Limiting Time From Discovery of Failure to Meet an LCO, Revision 2 (Reference 3).
The staff from the U.S. Nuclear Regulatory Commissions (NRC) Office of Nuclear Reactor Regulation (NRR) has initiated its review of the LAR in accordance with office instruction LIC-101, License Amendment Review Procedures (Reference 4).
2.0 REGULATORY AUDIT BASIS A regulatory audit is a planned license-or regulation-related activity that includes the examination and evaluation of primarily non-docketed information associated with the LAR. An audit is conducted to gain understanding, to verify information, and to identify information that will require docketing to support the basis of a licensing or regulatory decision. An audit will assist the NRC staff in efficiently conducting its review and gaining insights to TVAs processes and procedures. Information identified during the audit that the NRC staff relies upon to make the safety determination must be submitted on the docket. This audit will be conducted in accordance with NRR Office Instruction LIC-111, Regulatory Audits (Reference 5), with exceptions noted within this audit plan.
The NRC staff will perform the audit to support its evaluation of whether TVAs LAR can be approved per Title 10 of the Code of Federal Regulations (10 CFR), Section 50.90, Application for amendment of license, construction permit, or early site permit. The staffs review of the LAR will be informed by NUREG-0800, Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants, Section 19.2, Review of Risk Information Used to Support Permanent Plant-Specific Changes to the Licensing Basis (Reference 6). The audit will assist the staff with understanding TVAs proposed program for implementing RICTs for certain TSs.
3.0 REGULATORY AUDIT SCOPE AND METHODOLOGY The audit team will view the documentation and calculations that provide the technical support for the LAR. The scope of the NRC staffs audit will focus on the following subjects:
Understand how TVAs proposed program conforms to NRC-endorsed guidance in Nuclear Energy Institute (NEI) report NEI 06-09, Revision 0-A, Risk-Informed Technical Specifications Initiative 4b, Risk-Managed Technical Specifications (RMTS) Guidelines (Reference 7).
Gain a better understanding of the detailed calculations, analyses, and bases underlying the LAR and confirm the NRC staffs understanding of the LAR.
Gain a better understanding of the plants design features and its implications for the LAR.
Identify any information needed to enable the NRC staffs evaluation of the technical acceptability of the probabilistic risk assessment (PRA) used for this application.
Identify any information needed to enable the NRC staffs evaluation of whether the proposed changes challenge design-basis functions or adversely affect the capability or capacity of plant equipment to perform design-basis functions.
Identify questions and requests that may become formal requests for additional information (RAIs) per NRR Office Instruction LIC-115, Processing Requests for Additional Information (Reference 8).
The NRC staff will audit the PRA methods that TVA would use to determine the risk impact from which the revised completion times would be obtained, including TVAs assessments of internal events (including internal flooding) and fire as well as the treatment of uncertainties and evaluation of defense in depth. The NRC will also audit TVAs quantification of risk from significant external events, and whether TVA uses PRA or bounding methods. In addition, the audit team will discuss these topics with TVAs subject matter experts.
4.0 INFORMATION AND OTHER MATERIAL NECESSARY FOR THE AUDIT The NRC staff will request information and interviews throughout the audit period. The NRC staff will use an audit items list to identify the information to be audited (e.g., methodology, process information, and calculations) and the subjects of requested interviews and meetings.
The NRC staff will document the final audit items list as an enclosure to the audit report, which will be publicly available. The attachment to this audit plan includes the initial audit items list.
Throughout the audit period, the NRC staff will submit audit questions and audit-related requests to TVA so that TVA can better prepare for audit discussions with NRC staff. Any information accessed through TVAs portal will not be held or retained in any way by NRC staff.
The NRC staff requests that TVA have the information referenced in the attachment of this audit plan available and accessible for staffs viewing via a web-based electronic portal within 2 weeks of the date of this audit plan. The staff requests that any supplemental information requested be available and accessible for the staffs viewing within 1 week of the date of the NRCs notification to TVA of the new request. The NRC staff also requests that TVA notify the review team when an audit item is added to its electronic portal by sending an email to the NRC licensing project manager.
5.0 TEAM ASSIGNMENTS The following table identifies the NRC audit team members, including contractors, and their respective focus areas:
Name Email Review Area (Organization)
Kimberly Green (1)
Kimberly.Green@nrc.gov Plant Licensing Branch LPL II-2 (LPL2-2)
Jigar Patel (2) (3)
Jigar.Patel@nrc.gov PRA Licensing Branch A (APLA)
Ching Ng Ching.Ng@nrc.gov Charles Moulton Charles.Moulton@nrc.gov PRA Licensing Branch B (APLB)
Jay Robinson Jay.Robinson@nrc.gov Anne-Marie Grady Anne-Marie.Grady@nrc.gov PRA Licensing Branch C (APLC)
Sunwoo Park Sunwoo.Park@nrc.gov Vijay Goel Vijay.Goel@nrc.gov Electrical Engineering Branch (EEEB)
Liliana Ramadan Liliana.Ramadan@nrc.gov Norbert Carte Norbert.Carte@nrc.gov Instrumentation and Controls Branch (EICB)
Raul Hernandez Raul.Hernandez@nrc.gov Containment and Plant Systems Branch (SCPB)
Brian Lee Brian.Lee@nrc.gov Containment and Plant Systems Branch (SCPB)
Robert Beaton Robert.Beaton@nrc.gov Nuclear Systems Performance Branch (SNSB)
Fred Forsaty Fred.Forsaty@nrc.gov Nuclear Systems Performance Branch (SNSB)
Andrea Russell Andrea.Russell@nrc.gov Technical Specifications Branch (STSB)
TBD (4)
Pacific Northwest National Laboratory (PNNL)
TBD (4)
Notes:
(1) NRR Division of Operating Reactor Licensing Project Manager (2) Technical Lead (3) Contracting Officer Representative (4) NRC Contractor 6.0 LOGISTICS The audit will be conducted using a secure, online electronic portal, established by the licensee to present supporting documentation and calculations and by interviews with the licensees subject matter experts, virtually. The audit will begin within 2 weeks of the date of this audit plan and last through September 5, 2025.
A desktop audit will take place between approximately June 1 and August 1, 2025. The NRCs licensing project manager will inform the licensee of the entrance and exit meeting dates when they are established. The NRC project manager will coordinate with the licensee to set dates and times to discuss information needs and questions arising from the NRCs audit of the information. The NRC staff may change and/or add audit dates and times when deemed necessary. Audit meeting agenda and questions will be sent in advance of the audit meeting.
7.0 SPECIAL REQUESTS The NRC requests access to requested documents and information through an online web-based portal that allows the NRC staff and contractors to access documents. The following conditions associated with the portal should be maintained while the NRC staff and contractors have access to the portal:
The portal will be password-protected. A separate password will be assigned to each member of the NRC staff and NRC contractors participating in the audit.
The portal should prevent the NRC participants from printing, saving, downloading, or collecting any information directly from the online portal.
Conditions of use of the portal will be displayed on the login screen and will require acknowledgment by each user.
TVA should provide the username, password, and other portal access information directly to members of the NRC audit team. The names and contact information of the NRC staff and contractors participating in the audit are provided in the table in section 5 above. All other communications should be coordinated through the NRC project manager. The NRC project manager will inform TVA via routine communications when the NRC staff no longer needs access to the electronic portal.
8.0 DELIVERABLES The NRC staff will issue an audit summary report within approximately 90 days after the end of the audit and prior to completing its safety evaluation of the LAR. The staff may ask RAIs needed to complete the review of the LAR but will issue any such RAIs separately from audit-related correspondence in accordance with NRR Office Instruction LIC-115, Processing Requests for Additional Information (Reference 8).
9.0 REFERENCES
- 1. Letter from Kimberly Hulvey, Tennessee Valley Authority, to the U.S. Nuclear Regulatory Commission, License Amendment Request to Revise Technical Specifications to Adopt Risk-Informed Completion Times TSTF-505-A, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4b (WBN-TS-19-29), December 27, 2024 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML24362A110).
- 2. Attachment 3 (TSTF-505, Revision 2) to the letter from the Technical Specification Task Force, TSTF Comments on Draft Safety Evaluation for Traveler TSTF-505, Provide Risk-Informed Extended Completion Times, and Submittal of TSTF-505, Revision 2, July 2, 2018 (ML18183A493).
- 3. Technical Specification Task Force, TSTF-439, Revision 2, Eliminate Second Completion Times Limiting Time From Discovery of Failure to Meet an LCO, June 20, 2005 (ML051860296).
- 4. U.S. Nuclear Regulatory Commission, NRR Office Instruction LIC-101, Revision 6, License Amendment Review Procedures, July 31, 2020 (ML19248C539).
- 5. U.S. Nuclear Regulatory Commission, NRR Office Instruction LIC-111, Revision 1, Regulatory Audits, October 31, 2019 (ML19226A274).
- 6. U.S. Nuclear Regulatory Commission, NUREG-0800, Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants: LWR Edition, Section 19.2, Review of Risk Information Used to Support Permanent Plant-Specific Changes to the Licensing Basis:
General Guidance, June 2007 (ML071700658).
- 7. Nuclear Energy Institute (NEI), NEI 06-09, Revision 0-A, Risk-Informed Technical Specifications Initiative 4b, Risk-Managed Technical Specifications (RMTS) Guidelines -
Industry Guidance Document, October 2012 (ADAMS Package Accession No. ML122860402).
- 8. U.S. Nuclear Regulatory Commission, NRR Office Instruction LIC-115, Revision 1, Processing Requests for Additional Information, August 9, 2021 (ML21141A238).
Attachment:
TSTF-505 Audit Items List
Attachment TSTF-505 AUDIT ITEMS LIST Item #
Audit Item 1
Reports cited in Enclosure 2 of the LAR of full-scope and focused-scope peer reviews, self-and gap assessments (including findings, observations, and dispositions), and closure reviews of facts and observations (F&Os).
2 For the PRAs identified under Item #1 above, plant-specific documentation (e.g.,
uncertainty notebooks) related to:
- a. The review of the PRA model assumptions and sources of uncertainty (generic and plant-specific assumptions/uncertainties) for the TSTF-505 LAR.
3 PRA notebooks for the modeling of FLEX equipment and FLEX human error probabilities credited in the PRAs.
4 PRA notebooks for the modeling of digital control systems, including basis for the representative failure probabilities.
5 If modeled, PRA notebooks associated with the modeling of open phase condition in electrical switchyards and the open phase isolation system.
6 Documentation of how shared or cross-tied systems are modeled in the PRA.
7 Fire PRA notebooks containing the results of the fire PRA, including risk importance measures.
8 If not included in #7 above:
Fire PRA F&O closure reports Ordered list of top fire scenarios for each unit (i.e., those contributing 1% or more of the calculated fire risk)
Risk summary (i.e., core damage frequency and large early release frequency) for each fire area for each unit Fire area to physical analysis unit crosswalk 9
- b. Documentation that supports the screening of external hazards.
10 Documentation supporting the example risk-informed completion times (RICT) calculations presented in LAR Enclosure 1, Table E1-2.
11 Documentation supporting the development of the real-time risk tool and benchmarking it against the PRA.
12 PRA configuration control and update procedures, including when the PRA is updated (i.e., unscheduled and scheduled PRA updates).
13 If available, final RICT program procedures (e.g., for risk management actions, PRA functionality determination, and recording limiting conditions for operation).
[TVA may choose (optional) to provide draft RICT program procedures if final procedures are not available.]
Item #
Audit Item 14 Alternating current and direct current main single line (preferably simplified) electrical power distribution drawings relating to the TS LCOs 3.8.1, 3.8.4, 3.8.7, and 3.8.9.
15 Other documentation that the licensee determines to be responsive to the U.S.
Nuclear Regulatory Commission staffs information requests.
ML25051A176 OFFICE NRR/DORL/LPLII-2/PM NRR/DORL/LPLII-2/LA NRR/DRA/APLA/BC NAME KGreen ABaxter RPascarelli DATE 02/19/2025 02/21/2025 02/19/2025 OFFICE NRR/DRA/APLB/BC NRR/DRA/APLC/BC NRR/DEX/EICB/BC NAME EDavidson ANeuhausen FSacko DATE 02/25/2025 02/21/2025 02/25/2025 OFFICE NRR/DEX/EEEB/BC NRR/DSS/SCPB/BC NRR/DSS/SNSB/BC NAME WMorton (SRay for)
MValentin (BLee for)
DMurdock DATE 02/20/2025 02/25/2025 02/20/2025 OFFICE NRR/DSS/STSB/BC NRR/DORL/LPLII-2/BC NRR/DORL/LPLII-2/PM NAME SMehta DWrona KGreen DATE 02/25/2025 02/26/2025 02/26/2025