ML24061A113
| ML24061A113 | |
| Person / Time | |
|---|---|
| Site: | 99902069 |
| Issue date: | 03/11/2024 |
| From: | Cayetano Santos NRC/NRR/DANU/UAL1 |
| To: | Jessup W NRC/NRR/DANU/UAL1 |
| References | |
| Download: ML24061A113 (1) | |
Text
March 11, 2024 MEMORANDUM TO:
William Jessup, Chief Advanced Reactor Licensing Branch 1 Division of Advanced Reactors and Non-Power Production and Utilization Facilities Office of Nuclear Reactor Regulation FROM:
Cayetano Santos Jr., Senior Project Manager Advanced Reactor Licensing Branch 1 Division of Advanced Reactors and Non-Power Production and Utilization Facilities Office of Nuclear Reactor Regulation
SUBJECT:
SUMMARY
OF FEBRUARY 20, 2024, MEETING WITH KAIROS ON CRITICALITY SAFETY FOR THE HERMES 1 TEST REACTOR AND A DRAFT CORE DESIGN METHODOLOGY TOPICAL REPORT Meeting Information:
Applicant: Kairos Power LLC (Kairos)
Project No.: 99902069 Meeting Type: Partially Closed Observation Meeting Public Meeting Notice: Agencywide Documents Access and Management System (ADAMS)
Accession No.: ML24039A165 Applicant Presentation Slides: ML24046A145 and ML24046A146
Contact:
Cayetano Santos, NRR/DANU (301) 415-7270 CAYE TANO SANT OS Digitally signed by CAYETANO SANTOS Date:
2024.03.11 09:28:49
-04'00'
W. Jessup 2
Meeting Summary:
On February 20, 2024, a partially closed observation meeting was held between the U.S.
Nuclear Regulatory Commission (NRC) staff and representatives of Kairos Power, LLC (Kairos) at NRC Headquarters, One White Flint North, 11555 Rockville Pike, Rockville, Maryland. The purpose of the meeting was to discuss: (1) criticality safety analysis methods for the Hermes non-power reactor and (2) a draft topical report (TR) on core design methods for the Kairos Power Fluoride Salt-Cooled High Temperature Reactor.
Topic 1: Criticality Safety Analysis Methods for Hermes 1 Test Reactor Facility Kairos representatives provided an overview of the Hermes 1 pebble handling and storage systems and summarized the criticality safety analyses methods that will be used to ensure subcriticality of the fuel handling and storage operations at the Hermes 1 test reactor facility (ML24046A145).
Below is a summary of the comments and discussions:
The NRC staff noted that the review of an upper subcritical limit (USL) of 0.90 may be difficult without formal code validation, especially given the limited data applicable to high-assay low-enriched uranium (HALEU) fuel. Kairos representatives stated the technical justification is expected to show that the 10%
margin is sufficient.
The NRC staff asked about the fuel pebble packing fraction assumed in the analysis model. Kairos representatives stated that the analysis model assumes a random spherical packing fraction of 65%. A typical value of spherical random packing fraction in the scientific literature is 64%, while the maximum theoretical ordered packing fraction is 75%.
Members of the public were in attendance but voiced no comments or questions.
Discussions between the NRC staff and Kairos representatives continued during a closed meeting to discuss proprietary information.
Topic 2: Draft Core Design Methodology Topical Report Kairos representatives provided an outline of the draft TR, identified the three methods used to analyze the physical behavior of the core (i.e., discrete element methods, neutronics, and thermal hydraulics), and described the various tools used to implement each of these methods. Kairos plans to submit the core design TR for the NRC staff review by the end of the first quarter of 2024 with a requested approval date within one year. Kairos also plans to submit another TR on safety analysis methods (ML24046A146).
Below is a summary of the comments and discussions:
The NRC staff asked about the startup testing process for the Hermes test reactor facility. Kairos representatives stated that initially, the core will be loaded with graphite pebbles in a molten salt coolant (Flibe). The first criticality would be accomplished by slowly replacing graphite pebbles with fuel pebbles. The reactor
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would then be shut down and filled with the ratio of fuel and graphite pebbles needed to achieve the first criticality. Next, the reactor will be restarted by pulling control rods. During this second approach to criticality, various startup tests will be conducted.
The NRC staff noted that a clear description and explanation of how the various tools used in core design analyses interact and communicate with one another would be helpful. Kairos representatives stated that they would consider this comment in preparing the final report.
Members of the public were in attendance but voiced no comments or questions.
Discussions between the NRC staff and Kairos representatives continued during a closed meeting to discuss proprietary information.
Enclosure:
List of Attendees cc: Kairos Power FHR Kairos Power Hermes Kairos Power Hermes 2 via GovDelivery
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SUBJECT:
SUMMARY
OF FEBRUARY 20, 2024, MEETING WITH KAIROS ON CRITICALITY SAFETY FOR THE HERMES 1 TEST REACTOR AND A DRAFT CORE DESIGN METHODOLOGY TOPICAL REPORT DATED: March 11, 2024 DISTRIBUTION:
PUBLIC RidsACRS_MailCTR Resource RidsNrrDanuUal1 Resource RidsNrrDanu Resource CdeMessieres, NRR WJessup, NRR CSantos, NRR DGreene, NRR SDevlin-Gill, NRR PSawant, NRR ASiwy, NRR MOrenak, NRR MHiser, NRR BAdams, NRR BParks, NRR JSchaperow, NRR JKaizer, NRR LKingsbury, NRR RBrusselmans, NRR ABielen, RES ABarto, NMSS JMunson, NMSS ADAMS Accession Number: ML24061A113 NRR-109 OFFICE NRR/DANU/UAL1:PM NRR/DANU/UAL1:LA NRR/DANU/UAL1:BC NRR/DANU/UAL1:PM NAME CSantos DGreene WJessup (SDevlin-Gill)
CSantos DATE 3/1/2024 3/6/2024 3/7/2024 3/11/2024 OFFICIAL RECORD COPY
Enclosure List Of Attendees Summary of February 20, 2024, Meeting with Kairos on Criticality Safety for the Hermes 1 Test Reactor and a Draft Core Design Methodology Topical Report February 20, 2024 Name Organization Cayetano Santos U.S. Nuclear Regulatory Commission (NRC)
Pravin Sawant NRC Alex Siwy NRC Andrew Bielen NRC Michael Orenak NRC Matthew Hiser NRC Andrew Barto NRC Ben Adams NRC Benjamin Parks NRC Candace de Messieres NRC Jason Schaperow NRC Jeremy Munson NRC Joshua Kaizer NRC Lance Kingsbury NRC Roel Brusselmans NRC William Jessup NRC James Tomkins Kairos Power, LLC (Kairos)
Nicole Schlichting Kairos Drew Peebles Kairos Nader Satvat Kairos Brandon Haugh Kairos Giacomo Busco Kairos Richard Hernandez Kairos Chris Campbell Kairos Darrell Gardner Kairos Etienne Demarly Kairos Fanny Vitullo Kairos Jeff Schmidt Kairos Michael Ellett Kairos Brian Jackson Kairos Jana Bergman Member of the Public Shane Scanlon Member of the Public Matthew Presson Member of the Public Kris Cummings Member of the Public Max Fratoni Member of the Public Carol Campbell Member of the Public Pat Everett Member of the Public