ML23117A005
| ML23117A005 | |
| Person / Time | |
|---|---|
| Site: | 99902069, Hermes |
| Issue date: | 05/01/2023 |
| From: | Ballinger R Advisory Committee on Reactor Safeguards |
| To: | David Petti Advisory Committee on Reactor Safeguards |
| References | |
| Download: ML23117A005 (1) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION ADVISORY COMMITTEE ON REACTOR SAFEGUARDS WASHINGTON, DC 20555 - 0001 May 1, 2023 MEMORANDUM TO: David Petti, Lead Kairos Power Licensing Subcommittee Advisory Committee on Reactor Safeguards FROM: Ronald Ballinger, Member }ec?o5~
Advisory Committee on Reactor Safeguards
SUBJECT:
INPUT FOR ACRS REVIEW OF KAIROS NON-POWER REACTOR HERMES CONSTRUCTION PERMIT APPLICATION- DRAFT SAFETY EVALUATION FOR CHAPTER 3, "DESIGN OF STRUCTURES, SYSTEMS AND COMPONENTS" In response to the Subcommittee's request, we have reviewed the NRC staff's safety evaluation (SE) with no open items, and the associated section of the applicant's Preliminary Safety Analysis Report (PSAR), for Chapter 3, "Design of Structures, Systems and Components." The following is our recommended course of action concerning further review of this chapter and the staff's associated safety evaluation.
Background
Chapter 3 of the PSAR do identifies and describes the principal design criteria for the structures, systems, and components (SSC) that are required to ensure reactor facility safety and that
- prevent uncontrolled releases of radioactivity that would endanger the safety of the public. The primary safety feature of the Hermes design is the unique combination of TRISO fuel and Flibe reactor coolant, while other safety-related systems support maintaining the fuel and coolant configuration within acceptable limits. These SSCs include the safety-related portion of the Reactor Building structure, the reactor vessel and internals, the reactor control and shutdown system, and the decay heat removal system.
Chapter 3 was developed following the guidelines in NUREG-1537, "Guidelines for Preparing and reviewing Applications for the Licensing of Non-Power Reactors," and applicable American Society of Civil Engineers (ASCE) and Seismic Engineering Institute standards, as listed in the references. It focuses on the following areas: (1) principal design criteria (PDC) and applicable regulatory requirements, (2) meteorological damage, (3) water damage, (4) seismic damage, (5) plant structures, and (6) associated systems and components.
While sufficient information is provided related to the above areas that allows assessment of the construction permit application , additional detail will be necessary for evaluation of the application for an operation license.
SER Summary Chapter 3 of the Hermes construction permit (CP) SE describes and discusses the staff technical review and evaluation of the preliminary design of the Hermes SSCs as presented in Chapter 3 of the Hermes PSAR. For its evaluation the staff used the guidance from NUREG-1537, "Guidelines for Preparing and Reviewing Applications for the Licensing of Non-Power Reactors," Parts 1 and 2, and the guidance from RG 1.232, "Guidance for Developing Principal Design Criteria for Non-Light Water Reactors," as relevant to this application. Chapter 3 has "connections" with several of the other chapters in the overall SE. Additional information related to key SSCs are provided in these chapters.
Also, the PSAR and associated SE should be considered in conjunction with Kairos Technical Reports KP-TR-004-P , "Regulatory Analysis for the Kairos Power Fluoride Salt-Cooled High Temperature Reactor,"< 1> and KP-TR-003-NP-A, "Principal Design Criteria for the Kairos Power Fluoride Salt-Cooled High Temperature Reactor. "< 2> The staff's SE for the PDC Topical Report (TR) imposed four limitations and conditions, which pertain , in general, to the following: (1) coolant, fuel, and system conditions that differ from the Kairos Power Fluoride Salt-Cooled High Temperature Reactor (KP-FHR), (2) manufacturing license related, (3) consistency of the design with then existing guides (NEl-18-04, RG 1.233) at the time of submittal, and (4) the use of the term "safety related " and "non-safety related ." The staff evaluated the limitations and conditions identified in the PDC TR to confirm that these were either not applicable or met and evaluated as part of the Hermes PSAR. Some of major differences between KP-FHR and Hermes, as related to limitations and conditions #3 & #4 are:
- (L&C #3) The Hermes licensing does not use the NEI 18-04 probabilistic approach for identification of licensing basis events, SSC classification and special treatment, and evaluation of defense-in-depth (DID). Kairos instead uses NUREG-1537 deterministic evaluations for postulated events, the single failure criterion , and the maximum hypothetical accident to evaluate plant safety and classify SSCs. Since limitation and condition 3 allows NRG-approved deviations from the guidance in NEI 18-04, the staff finds Kairos's use of guidance in NUREG-1537 instead of NEI 18-04 to be acceptable .
- (L&C #4) Kairos defines safety-related SSCs solely using the definition of 10 CFR 50.2 as the probabilistic approach of NEI 18-04 is not used. The safety-related SSCs definition of 10 CFR 50.2 is used with exception of a departure from the use of the term "reactor coolant pressure boundary. In the Hermes design, the reactor coolant boundary, except for the pressure vessel , is not credited for fission product retention. As such, the vessel is classified as safety-related while the remainder of the reactor coolant boundary is classified as non-safety related . The staff finds the classification acceptable.
The other Hermes PDC relevant departures from the PDC TR are also related for not using the guidance of NEI 18-04 or RG 1.233: the term "safety-related" is substituted for the term "safety significant, " and the term "postulated events" is substituted for "anticipated operational occurrences" and "accidents." The staff finds these substitutions acceptable.
In summary, there are only two SSC classifications used in the preliminary safety analysis report: "safety-related" and "non-safety related." This classification does not depend on a significance determination . Also , all 'postulated events" are evaluated regardless of their frequency of occurrence .
The PSAR and SE discuss the application and analysis of PDCs that are relevant to Hermes SSCs and any deviations, with justification, for the Hermes system.
The SE presents a detailed evaluation of meteorological, water, and seismic damage and concludes that, for the construction application, the Hermes reactor SSCs will comply with the applicable codes and standards commensurate with the safety classification.<3- 10>
In summary, the SE for Chapter 3 documents the staff's evaluation of the applicant's design for compliance with applicable regulations and standards. Based on the above determinations, the NRC staff found that the descriptions and discussions of Kairo's Chapter 3 are sufficient and meet the applicable regulatory requirements and guidance, and acceptance criteria (compliance with relevant PDCs), for the issuance of a construction permit.
Concerns We did not identify any specific deficiencies in our review. Chapter 3 has "connections" with several of the other chapters in the overall SE. We will follow relevant information as provided in these chapters.
Recommendation As lead reviewers for Hermes SE Chapter 3, we concur with the staff that information in Chapter 3 of the PSAR is adequate for this Construction Permit application. No additional actions from the staff or applicant are needed to complete our review of this chapter.
References
- 1. Kairos Power, LLC, "Regulatory Analysis for the Kairos Power Salt-Cooled, High Temperature Reactor, " KP-TR-004-NP-A, June 2022 (ML19024A483).
- 2. Kairos Power LLC, KP-TR-003-NP-A, Revision 1, "Principal Design Criteria for the Kairos Power Fluoride Salt-Cooled, High-Temperature Reactor," July 2019 (ML19212A756).
Additional References Consulted
- 1. American Society of Civil Engineers, "Seismic Design Criteria for Structures, Systems, and Components in Nuclear Facilities," ASCE 43-19. 2019.
- 2. International Code Committee, "International Building Code." 2012.
- 3. American National Standards Institute, American Nuclear Society, "Research Reactor Site Evaluation." ANSI/ANS 15.7. 1977
- 4. International Atomic Energy Agency, "Siting of Research Reactors," IAEA-TECDOC 403.
1987.
- 5. American Society of Civil Engineers, "Seismic Analysis of Safety-Related Nuclear Structures," ASCE 4-16. 2017.
- 6. American Society of Civil Engineers, Seismic Engineering Institute, "Minimum Design Loads for Buildings and Other Structures," ASCE/SEI 7-10. 2011.
- 7. International Atomic Energy Agency, "Earthquake Resistant Design of Nuclear Facilities with Limited Radioactive Inventory," IAEA-TECDOC 348. 1985.
- 8. International Atomic Energy Agency, "Consideration of External Events in the Design of Nuclear Facilities Other Than Nuclear Power Plants, with Emphasis on Earthquakes,"
IAEA-TECDOC-1347. 2003.
- 9. RG 1.76, Design-Basis Tornado AND Tornado Missiles for Nuclear Power Plants.
- 10. RG 1.221 , Design-Basis Hurricane Missiles for Nuclear Power Plants.
11 . RG 1.232, Guidance for Developing Principal Design Criteria for Non-Light-Water Reactors.
- 12. RG 1.233, Guidance for a Technology-Inclusive, Risk-Informed , and Performance-Based Methodology to Inform the Licensing Basis and Content of Applications for Licenses, Certifications, and Approvals for Non-Light-Water Reactors.
- 13. NUREG-1537, Guidelines for Preparing and Reviewing Applications for the licensing of Non-Power Reactors, Parts 1,2
- 14. RG 1.29, Seismic Design Classification for Nuclear Power Plants, Revision 6.
- 16. NEI 18-04, Risk-Informed Performance-Based Technology Inclusive Guidance for Non-Light Water Reactor Licensing Basis Development.
- 17. ACI 349-13 , Code Requirements for Nuclear Safety-Related Concrete Structures.
- 18. ANSI/ASIC N690-18, Specification for Safety-Related Steel Structures for Nuclear Facilities.
- 19. USNRC, Draft Safety Evaluation for Hermes Non-Power Reactor Preliminary Safety Analysis Report Chapter 3, February 7, 2023 (ML23065A010)
- 20. Kairos Power LLC, "Submittal of the Preliminary Safety Analysis Report for the Kairos Power Fluoride Salt-Cooled, High Temperature Non-Power Reactor (Hermes)," Revision 2, February 2023 (ML23055A672)
May 1, 2023
SUBJECT:
INPUT FOR ACRS REVIEW OF KAI ROS NON-POWER .
REACTOR HERMES CONSTRUCTION PERMIT APPLICATION- DRAFT SAFETY EVALUATION FOR CHAPTER 3, "DESIGN OF STRUCTURES, SYSTEMS AND COMPONENTS" Package No: ML23117A000 Memo Accession No: ML23117A005 Publicly Available Y Sensitive N V"Iewmg R"Ig hts: r:8J NRC U sers or ACRS O nIy I or S ee R estnc
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- via OFFICE ACRS/TSB* SUNSI Review* ACRS/TSB* ACRS*
NAME WWang WWang LBurkhart (WWang for) RBallinqer DATE 14/27/2023 14/27/2023 4/27/2023 5/01/2023 OFFICIAL RECORD COPY