ML24262A003
| ML24262A003 | |
| Person / Time | |
|---|---|
| Issue date: | 09/26/2024 |
| From: | O'Donnell E NRC/RES/DE/RGDB |
| To: | |
| References | |
| DG-1290, Rev 1, DG-1417 | |
| Download: ML24262A003 (5) | |
Text
U.S. Nuclear Regulatory Commission Public Meeting Summary
Title:
Public Meeting to discuss Draft Regulatory Guides (DG)-1290 Revision 1, Design Basis Floods for Nuclear Power Plants and DG-1417 Guidance for Assessment of Flooding Hazards due to Water Control Structure Failures and Incidents
Date of Meeting: Monday September 9, 2024
Location: One White Flint North, Room 1F-23
Type of Meeting: Hybrid Meeting - Information meeting with an opportunity for Q&A
Purpose of the Meeting:
This was an information meeting with the Nuclear Energy Institute (NEI) to discuss DG-1290 Revision 1 and the related guide DG-1417 before closure of the public comment period on September 13th, 2024.
General Details:
DG-1290 Revision 1 and DG-1417 are related guides. DG-1290 Revision 1 is proposed Revision 3 of RG 1.59. It was released previously for public comment on February 23, 2022 (87 FR 10260). The comment period closed on April 11, 2022. The Response to Comments can be found in ADAMS under ML23320A026.
DG-1417 is a proposed new guide (RG 1.256). It incorporates the interim staff guidance from JLD-ISG-2013-01, Guidance for Assessment of Flooding Hazards Due to Dam Failure, (ML13151A153) into the NRCs regulatory guidance framework. ISGs are meant to be withdrawn after their immediate purpose has been fulfilled or else integrated formally into the NRCs regulatory guidance framework and that action is planned for completion with the issuance of RG 1.256 when it is finished.
Because they are related guides DG-1290 Revision 1 and DG-1417 were jointly released for a 30 day comment period (89 FR573372) on July 15, 2024. The comment period was subsequently extended to September 13, 2024 (89 FR 60580).
Summary of Presentations
Much of the discussion followed the slides provided by NEI (ML24249A201) prior to the meeting. The slides on DG-1290 Revision 1 focused on the following six areas:
NEI Comments on DG-1290
Level of conservatism In several places the documents state that all inputs and assumptions must be conservative. Recommend revising to state that the overall analysis must be shown to be demonstrably conservative as opposed to every individual input and assumption.
1x10-06 as a metric The technical basis and use of 1x10-06 is unclear and as is NRCs intended use of this value as a metric. Given the limited information
available to inform a flooding hazard, implementation will be challenging.
Reference to DG-1290 Revision 1 refers to withdrawn standards including withdrawn/unused ANSI/ANS-2.12-1978, Guidelines for Combining Natural and standards External Man-Made Hazards at Power Reactor Sites, and ANSI/ANS-58.21-2007, External Events in PRA Methodology. It is not recommended to reference withdrawn standards that were largely not used and are not reviewed or maintained. It is also noted that parts of these standards are not consistent with other guidance in this document.
Important to safety To avoid future confusion for advance reactors (ARs), Small especially in the Modular Reactors (SMRs) (as has existed in the current fleet re: GL context of ARs/SMRs 84-01) the term important to safety should be removed from (Appendix K) Appendix K. Recommend use of the terms safety-related, non-safety-related with special treatment, and/or non-safety-related with no special treatment as endorsed in NEI 18-04.
Climate change Although perhaps the simplest to project, sea level rise is not the only variable potentially impacted by climate change. Recommend acknowledgement of NRC and industry processes which can assure that new climate data and better projections in the future are considered for impact to plant safety.
Old data sets In several locations, the document presents that many data sets available for use in developing the flood hazard are several decades old and have not been updated. In order to prevent the unfamiliar reader from having the impression that only old and out of date data is being used, consider updating this text to acknowledge NRC (e.g., POAHNI) and industry processes continuously monitor for new information (data, methods, science) to assess and respond to impacts to plant safety.
NEIs comments on DG-1417 are summarized as Practical Implementation Challenges
DG-1417 states that either methods or data needed to perform some of the analysis identified in the DG-1417 are not available
DG-1417 provides a wealth of relevant information, however
o Technical basis for expecting assessment of dam failure probabilities with anticipated events and processes s of 1x10 -06 to 1x10-07 is not clear
o Unclear how the information can be used to achieve the stated level of precision
Therefore, the only viable pathways for implementation are:
o Successfully screen out the dams; or
o NRC communicates that dams are acceptable (i.e., can be assumed not to fail); or
o assume total dam failure with concurrent assumptions and deterministically compare with DB flood for NPP, which goes well beyond what is needed for reasonable assurance of adequate protection
==
Conclusion:==
Following the NEI presentation there was opportunity for members of the public to comment. Participants were informed that for comments to be considered in the revision of the guides they need to be submitted form ally in writing by September 13th, 2024.
Action Items/Next Steps:
- At the close of the public comment period on September 13 th, 2024, the NRC staff will address the formal comments submitted by the public.
Attachments:
- Meeting agenda
- Attendee list
- Meeting slides
Attachments
Agenda
10.00 am - 10.05 am Meeting opening, housekeeping and Edward ODonnell introductions
10.05 am - 10.10 am Meeting objectives Meraj Rahimi/Barbara Hayes
10.10 am - 10.30 am NEI presentation TBA
10.30 am - 11.50 pm Discussion
11.50 am - 12.00 pm Closing remarks
Attendees
Ahn, Hosung, NRC Annett, James H, Contractor - Constellation Nuclear.
Annon. Mike, PMP Basiq, Mohammad Bellini, Joe, Aterrra Solutions Bergman, Jana, Curtiss Wright, Idaho Falls Brown, Melanie H Choromokos, Rob, EPRI Curran, Bridget, NRC.
Facemire, Jon, Nuclear Energy Institute Farahmandfar, Zeinab, NRC Ferrante, Fernando, EPRI Gunter. Paul, Director of the Reactor Oversight Project at Beyond Nuclear.
Hayes, Barbara, NRC Henry, Stu Jiang, Joy Justice, Quentin, Westinghouse Kanney, Joseph, NRC Kappel, Bill, Applied Weather Services Lee, Michael, NRC Luchsinger, Deb, Preferred Licensing Services Lyman, Edwin, Union of Concern Scientists Miller, Andrew Mittman, Jeffrey, Consultant Mohammad, Jan.
Ng, Kit, Bechtel.
ODonnell, Edward, NRC
Pimentel, Frances, Nuclear Energy Institute Pope. Steven, Information Systems Laboratories Rady, Jeff, NRC Rahimi, Meraj, NRC Richards, John Schlamp, Janelle. Barge Design Solutions Schneider, Raymond E, Westinghouse See, Kenneth, NRC Sheehan, Neil, NRC Tiruneh, Nebiyuh, NRC Toohill, Spencer, The Breakthrough Institute Voelsing, Kelli, Nuclear Energy Institute Weglian, John E, EPRI
Slides
The slides are available in ADAMS and were posted publicly prior to the meeting.
NEI slides ML24249A201
Meeting slides ML24250A101