ML24221A158
| ML24221A158 | |
| Person / Time | |
|---|---|
| Issue date: | 08/19/2024 |
| From: | John Hanna NRC/NRR/DRA/APOB |
| To: | Reinaldo Rodriguez NRC/NRR/DRA/APOB |
| Hanna J | |
| References | |
| Download: ML24221A158 (1) | |
Text
August 19, 2024 MEMORANDUM TO:
Reinaldo Rodriguez, Acting Chief PRA Oversight Branch Division of Risk Assessment Office of Nuclear Reactor Regulation FROM:
John Hanna, Senior Reactor Analyst PRA Oversight Branch Division of Risk Assessment Office of Nuclear Reactor Regulation
SUBJECT:
SUMMARY
OF JULY 17, 2024, STATUS OF RISK EVALUATION GUIDANCE UPDATES DEVELOPED BY GREATR (GROUP FOR RISK EVALUATION AND ASSESSMENT TOOLS REVIEW)
On July 17, 2024, the U.S. Nuclear Regulatory Commission (NRC) staff held an observation public meeting with the Nuclear Energy Institute (NEI) and industry to continue the discussions between the NRC staff, industry stakeholders, and the public regarding ongoing work on the GREATR initiative. This meeting offered an opportunity for the industry and public to gain familiarity and to provide feedback on the staffs modifications to the Diverse and Flexible Coping Strategies (FLEX) factor modelling for onsite and offsite power recoveries, as well as solutions for more detailed initiating event assessment simulations and changes to the Risk Assessment Standardization Project of Operational Events volume 1 handbook.
The presentation materials for the public meeting are available in the Agencywide Documents Access and Management System (ADAMS) under the following Accession Numbers: NRC Presentation (ML24197A057) and NEI presentation (ML24197A065). The public meeting announcement is available in ADAMS (ML24185A244). A list of attendees is included in. The details of the meeting and discussion points are contained in Enclosure 2.
As of the date of this summary, the Public Meeting Feedback System has not received any feedback.
No regulatory decisions or commitments were made at the meeting.
Please direct any inquiries to Mr. John Hanna at 404-387-3910 or by email at John.Hanna@nrc.gov.
Enclosures:
- 1. List of Attendees
- 2. Meeting Details Garmoe, Alexander signing of Hanna, John on 08/19/24
ML24221A158 *by e-mail NRR-106 OFFICE NRR/DRA/APOB NRR/DRA/APOB/BC*
NAME JHanna RRodriguez DATE 8/19/2024 8/19/2024 LIST OF ATTENDEES JULY 17, 2024, PUBLIC MEETING WITH NUCLEAR ENERGY INSTITUTE AND OTHER INDUSTRY STAKEHOLDERS ON THE STATUS OF RISK EVALUATION GUIDANCE UPDATES DEVELOPED BY GREATR (GROUP FOR RISK EVALUATION AND ASSESSMENT TOOLS REVIEW)
Alex Garmoe NRC John Hanna NRC Antonios Zoulis NRC Dolan, Bradley Wicker Tennessee Valley Authority (TVA)
Ballard, John David Tennessee Valley Authority (TVA)
Loyd, Suzanne CONSTELLATION Carr, Michelle APS Daniel Geary NRC Linthicum, Roy R CONSTELLATION Galvan, Bryan PGE Lundy Pressley NRC Carroll, Bryan C DUKE-ENERGY McDonald, Jeffrey A TVA Ratchford, Andy JENSEN-HUGHES Gore, Jonathan David TVA Latonia Enos-Sylla NRC Kasi Rhodes DTEENERGY Erick Ball NRC Mehdi Reisi Fard NRC Hudson Molly STPEGS Gilbreath, Jeremiah A.
SOUTHERN Shepard, Matthew PGE Cymbor, Michael APS Rapp, Douglas VISTRA Rishel, Robert I DUKE-ENERGY Haro, Xavier CONSTELLATION Vincent, Keith FPL John Lane NRC Hiller, Justin W AMEREN David Gennardo NRC Degonish, Matthew M AMEREN Kindred, Gerry Wane TVA Karten, Luke FPL Michelle Kichline NRC Stringfellow, Joseph FPL Sietze Rotton NRC Ferrante, Fernando EPRI Palenzuela, Jadie FPL Sisco, Carlos WINSTON Joel Jenkins NRC Meena Khanna (She/Her/Hers)
NRC Christopher Hunter NRC Nicholson, Mark Andrew TVA MEETING DETAILS JULY 17, 2024, PUBLIC MEETING WITH NUCLEAR ENERGY INSTITUTE AND OTHER INDUSTRY STAKEHOLDERS ON THE STATUS OF RISK EVALUATION GUIDANCE UPDATES DEVELOPED BY GREATR (GROUP FOR RISK EVALUATION AND ASSESSMENT TOOLS REVIEW)
PURPOSE The purpose of this meeting is to provide an update of ongoing work by the GREATR staff and offer an opportunity for questions and comments.
Meeting Details Opening remarks begin with a statement by the U.S. Nuclear Regulatory Commission (NRC) that three draft resolutions are to be presented, and the NRC presentation (ML24197A057) is shown. The Nuclear Energy Institute (NEI) representative opens with statement expressing strong interest in the topics, emphasizing efficiency, realism, clarity, predictability, and uniformity of significance determination (SDP) and oversight processes.
An overview of the project's charter's purpose is shown and stakeholders are listed, as well as the recently completed tasks, such as FLEX phase two. The first of the three issues, regarding Emergency Power System/offsite electrical power (OEP) modelling is introduced, with early events being treated different than later ones. New guidance is to be introduced regarding modelling the events, with there being "hard" and "easy" methods, and issues and approaches for a more dynamic PRA modelling method is brought up. Breakpoints for an offsite/onsite power scenario is shown, and FLEX application as well as plant specific and industry data organization/availability are discussed. A basic description of the hard and easy modelling methods are explained and discussed. The NRC consensus that current recovery models are overly optimistic is brought up, and this is discussed with NEI representatives.
The second issue brought up is regarding initiating event assessment and the lack of granularity for doing so. A proposed solution is shown with changes to the Risk Assessment Standardization Project (RASP) of Operational Events guidance manual and modifications to the assessment process matrix. Downsides to the solution are brought up and discussed. The NRC expresses intent to remove the requirement to hold a planning Significance and Enforcement Review Panel (SERP) for initiating event evaluations to improve SDP efficiency, given improved guidance for initiating event evaluations, and this plan is discussed.
An overview of the changes to the RASP volume 1 handbook is shown, with a focus and discussion on common cause failure modelling, as well as a mention of Human Error Probability floor values. Southern Nuclear Company introduces the desire for additional flexibility for PRA result threshold boundaries. NEI then begins their presentation (ML24197A065) on recommendations for the SDP process. Additional discussion on common cause failures and their failure models, as well as the desire for increased flexibility in differentiating green and white risk classifications.
Meeting concludes with the key takeaways that emphasizes the reduction of excess conservatisms, transparent and frequent communication between the NRC and licensees, and the further alignment of NRC and industry SPAR models. The industry requested additional engagement on common cause failure and the NRC plans to hold a public meeting in the future.
Additionally, the NRC plans to share the draft RASP manual in a future ROP bimonthly meeting.