ML21056A022
| ML21056A022 | |
| Person / Time | |
|---|---|
| Site: | 99902049 |
| Issue date: | 05/21/2021 |
| From: | Gregory Cranston NRC/NRR/DNRL/NRLB |
| To: | Michael Dudek NRC/NRR/DNRL/NRLB |
| Cranston G - NRLB | |
| Shared Package | |
| ML21056A023 | List: |
| References | |
| HI-2201064R1, ML20356A016) | |
| Download: ML21056A022 (6) | |
Text
May 21, 2021 MEMORANDUM TO:
Michael I. Dudek, Branch Chief New Reactor Licensing Branch Division of New and Renewed Licenses Office of Nuclear Reactor Regulation FROM:
Gregory V. Cranston, Senior Project Manager /RA/
Division of New and Renewed Licenses New Reactor Licensing Branch Office of Nuclear Reactor Regulation
SUBJECT:
SUMMARY
OF THE FEBRUARY 17, 2021, PUBLIC MEETING TO DISCUSS THE HOLTEC INTERNATIONAL SMALL MODULAR REACTOR SMR-160 LICENSING TOPICAL REPORT ON ELIMINATION OF LARGE BREAK LOSS-OF-COOLANT ACCIDENT AND ESTABLISHMENT OF LOCA ACCEPTANCE CRITERIA On February 17, 2021, a Category 1 public meeting was held between the U.S. Nuclear Regulatory Commission (NRC) staff and SMR), LLC (a Holtec International Company) for Holtec to provide an overview of proposed changes to their Licensing Topical Report HI-2201064R1, Elimination of Large Break Loss of Coolant Accident (LOCA) and Establishment of LOCA Acceptance Criteria, (Agencywide Documents Access and Management Systems (ADAMS) under Accession No. ML20356A016). Participants included personnel from the NRC, Holtec, and members of the public.
The public meeting notice can be found in ADAMS under Accession No. ML21028A769. This meeting notice was also posted on the NRCs public Web site.
Enclosed are the meeting agenda (Enclosure 1), list of attendees (Enclosure 2), and meeting summary (Enclosure 3). Holtecs presentation slides can be accessed via ADAMS Accession No. ML21048A088.
Docket No. 99902049
Enclosures:
- 1. Meeting Agenda
- 2. List of Attendees
- 3. Meeting Summary CONTACT:
Gregory Cranston, NRR/DNRL 301-415-0546
PKG: ML21056A023 HOLTEC SLIDES: ML21048A088 HOLTEC MEETING NOTICE: ML21028A769 MEMO: ML21056A022
SGreen*
MDudek*
DATE 05/20/21 02/25/21 05/21/21
PUBLIC MEETING TO DISCUSS THE HOLTEC INTERNATIONAL SMALL MODULAR REACTOR SMR-160 LICENSING TOPICAL REPORT ON ELIMINATION OF LARGE BREAK LOSS-OF-COOLANT ACCIDENT AND ESTABLISHMENT OF LOSS-OF-COOLANT ACCIDENT ACCEPTANCE CRITERIA February 17, 2021 Meeting Agenda Time Topic Organization 1:00 p.m. - 1:10 p.m. Introductions and Opening Remarks NRC/Holtec 1:10 p.m. - 1:35 p.m. SMR-160 Licensing Topical Report (LTR)
Presentation - Open Session Holtec 1:35 p.m. - 1:40 p.m. Public comments Public/NRC 1:40 p.m. - 1:45 p.m. Break All 1:45 p.m. - 2:45 p.m. SMR-160 LTR Presentation and Discussion -
Closed session Holtec/NRC 2:45 p.m.
Adjourn All
PUBLIC MEETING TO DISCUSS THE HOLTEC INTERNATIONAL SMALL MODULAR REACTOR SMR-160 LICENSING TOPICAL REPORT ON ELIMINATION OF LARGE BREAK LOSS-OF-COOLANT ACCIDENT AND ESTABLISHMENT OF LOSS-OF-COOLANT ACCIDENT ACCEPTANCE CRITERIA February 17, 2021 List of Participants Name Affiliation Anton, Stefan Holtec Bullard, Chuck Holtec Hickey, Kevin Holtec Marcille, Thomas Holtec Morin, Tammy Holtec Rajkumar, Joseph Holtec Trotta, Richard Holtec Barrett, Antonio NRC Brown, Christopher NRC Buford, Angela NRC Chowdhury, Prosanta NRC Cranston, Gregory NRC Dudek, Michael NRC Gonzalez, Hipo NRC Honcharik, John NRC Li, Yueh-Li (Renee)
NRC Lu, Shanlai NRC Mitchell, Matthew NRC Nolan, Ryan NRC Patton, Rebecca NRC Reichelt, Eric NRC Scarbrough, Thomas NRC Sugrue, Rosemary NRC Tsao, John NRC Wittick, Brian NRC Burg, Rob Engineering Planning and Management, Inc.
PUBLIC MEETING TO DISCUSS THE HOLTEC INTERNATIONAL SMALL MODULAR REACTOR SMR-160 LICENSING TOPICAL REPORT ON ELIMINATION OF LARGE BREAK LOSS-OF-COOLANT ACCIDENT AND ESTABLISHMENT OF LOSS-OF-COOLANT ACCIDENT ACCEPTANCE CRITERIA February 17, 2021 Meeting Summary On February 17, 2021, a Category 1 public meeting was held between the U.S. Nuclear Regulatory Commission (NRC) staff and SMR, LLC (a Holtec International Company) for Holtec to provide an overview of proposed changes to their licensing topical report (LTR) HI-2201064R1, Elimination of Large Break Loss-of-Coolant Accident (LOCA) and Establishment of LOCA Acceptance Criteria, (Agencywide Documents Access and Management Systems (ADAMS) under Accession No. ML20356A016). The meeting was divided into a public portion and a closed portion.
The public meeting commenced with opening remarks and an introduction of participants.
Holtec then commenced their presentation on the topics described below. After the public portion of the meeting, the public was given an opportunity to provide comments. There were no public comments. The public meeting was followed by a closed session to discuss the same topics in areas which included proprietary information.
The LTR, associated with the Holtec small modular pressurized-water reactor SMR-160, is currently being reviewed for acceptance by the NRC. The objective of the LTR is for Holtec to gain NRC approval that, by following American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code,Section III, Subsection NB, a postulated break in the combined vessel connection (steam generator to reactor pressure vessel) can be considered a no-break zone, thereby eliminating the requirement for the SMR-160 to include a large break LOCA as a design basis-accident (DBA).
Holtec presented that the use of ASME B&PV Code can be interpreted to allow the combined vessel connection to be constructed as a vessel or a pipe. Per Holtec, the ASME B&PV Code allows the owner to select the preferred designation and that either designation can be acceptable.
Per Holtec, their approach is to designate the reactor pressure vessel (RPV), steam generator (SG), pressurizer, and RPV/SG combined connection as one continuous vessel, referred to as the combined vessel, in accordance with the ASME B&PV Code,Section III, Subsection NB.
The RPV/SG combined connection is a communicating chamber joining the RPV to the SG.
The connecting welds are in compliance with NB-3350. Holtec discussed the geometry of the RPV/SG connection.
Holtec stated that all SMR-160 reactor coolant pressure boundary piping is postulated to break, and the break is evaluated as a LOCA as part of the SMR-160 DBAs. NRC Branch Technical Position (BTP) BTP 3-4, Postulated Rupture Locations in Fluid System Piping Inside and Outside Containment (ADAMS Accession No. ML16085A315), which contains the NRC position on pipe rupture postulation for Class 1 piping, was discussed for applicability. Holtec presented that BTP 3-4 is based on actual piping failures that have occurred and allows leak-before-break to eliminate the postulation of a pipe break to meet NRC General Design Criterion 2 4, Environmental and Dynamic Effects Design Bases, of Title 10 of the Code of Federal Regulations, Part 50, Domestic Licensing of Production and Utilization Facilities. Per Holtec, BTP 3-4 does not require postulation of a Class 1 vessel rupture, nor is there other regulatory precedence for postulating a Class 1 vessel rupture as a DBA. And, initiating event frequencies for pressure vessel ruptures are highly dependent on pressurized thermal shock per NUREG-1829 (Estimating Loss-of-Coolant, Accident (LOCA) Frequencies Through the Elicitation Process). Event frequencies are well below the threshold for DBA and therefore, by design, there is an extremely low probability of a Class 1 pressure vessel rupture occurring.
Holtec stated that their design will fully comply with ASME B&PV Code NB-3200 and NB-3300, that stress intensities will not exceed limits in Section III, Mandatory Appendix XIII, and that fatigue analysis will be performed in accordance with ASME XIII-3500 (with a cumulative usage factor that shall not exceed 1.0).
Therefore, Holtecs position is that ruptures in the combined vessel are considered a Beyond Design Basis Accidents and will be analyzed with a probabilistic risk assessment.
NRC requested that Holtec provide additional justification in the LTR as to the basis for eliminating the possibility of a break at the pipe to vessel or vessel-to-vessel weld. Also, NRC requested that additional information be provided in the LTR as to how the applicant will demonstrate compliance.
Holtec stated that they would provide additional information in their LTR and submit a revision to the LTR.