ML24155A168
| ML24155A168 | |
| Person / Time | |
|---|---|
| Site: | 99902094 |
| Issue date: | 07/25/2024 |
| From: | Holly Cruz NRC/NRR/DANU/UNPL |
| To: | Brooks C University of Illinois |
| Edward Helvenston, NRR/DANU | |
| References | |
| EPID L-2023?NFN?0013 | |
| Download: ML24155A168 (1) | |
Text
Dr. Caleb S. Brooks, Associate Professor Department of Nuclear, Plasma, and Radiological Engineering University of Illinois at Urbana-Champaign Talbot Laboratory, Room 111C, MC-234 104 South Wright St.
Urbana, IL 61801
SUBJECT:
UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN - SAFETY EVALUATION FOR TOPICAL REPORT RELATED TO PRINCIPAL DESIGN CRITERIA (EPID: L-2023-NFN-0013)
Dear Dr. Brooks:
By letter dated November 15, 2023 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML23319A407), the University of Illinois at Urbana-Champaign (UIUC) submitted the topical report (TR) University of Illinois Urbana-Champaign High Temperature Gas-cooled Research Reactor: Micro Modular Reactor (MMRTM) Principal Design Criteria, Release 1 (i.e., Revision 0), for U.S. Nuclear Regulatory Commission (NRC) staff review. On April 5, 2024, the NRC staff held a public meeting with UIUC to discuss NRC staff questions related to the UIUC TR (see public meeting summary dated May 8, 2024 (ML24128A254)). In response to the public meeting, by letter dated April 10, 2024 (ML24101A413), UIUC submitted Release 2 (i.e., Revision 1) of the TR.
The NRC staffs safety evaluation (SE) for the TR, Release 2, is enclosed. The enclosed SE will be made publicly available.
The NRC staff requests that UIUC publish an accepted version of the TR within 3 months of receipt of this letter. The accepted version should incorporate this letter and the enclosed SE after the title page. The accepted version should include a "-A" (designating accepted) following the TR identifier.
July 25, 2024
C. Brooks If you have any questions, please contact Edward Helvenston at (301) 415-4067, or by email at Edward.Helvenston@nrc.gov.
Sincerely, Holly D. Cruz, Acting Chief Non-Power Production and Utilization Facility Licensing Branch Division of Advanced Reactors and Non-Power Production and Utilization Facilities Office of Nuclear Reactor Regulation Project No.: 99902094
Enclosure:
As stated cc: via GovDelivery Subscribers Signed by Cruz, Holly on 07/25/24
ML24155A168 NRR-106 OFFICE NRR/DANU/UNPL/PM NRR/DANU/LA NRR/DANU/UTB1/BC NAME EHelvenston NParker GOberson DATE 06/11/2024 06/12/2024 07/02/2024 OFFICE OGC/NLO NRR/DANU/UNPL/BC(A)
NAME JEzell HCruz DATE 07/25/2024 07/25/2024
Enclosure UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN - SAFETY EVALUATION OF RELEASE 2 OF TOPICAL REPORT UNIVERSITY OF ILLINOIS URBANA-CHAMPAIGN HIGH-TEMPERATURE GAS-COOLED RESEARCH REACTOR: MICRO MODULAR REACTOR (MMRTM) PRINCIPAL DESIGN CRITERIA (EPID: L-2023-NFN-0013)
APPLICANT INFORMATION Applicant:
University of Illinois at Urbana-Champaign Applicant Address:
104 South Wright St.
Urbana, Illinois 61801 Docket /Project No(s).:
99902094 APPLICATION INFORMATION Submittal Date: November 15, 2023 Submittal Agencywide Documents Access and Management System (ADAMS) Accession No.: ML23319A407 (Reference 1)
Supplement ADAMS Accession No.: ML24101A413 (Reference 2)
Brief Description of the Topical Report: The topical report (TR) University of Illinois Urbana-Champaign High Temperature Gas-cooled Research Reactor: Micro Modular Reactor (MMRTM)
Principal Design Criteria, Release 2 (i.e., Revision 1) (Reference 2), describes the principal design criteria (PDC) for the University of Illinois at Urbana-Champaign (UIUC) Micro Modular Reactor (MMR) research reactor. TR sections 1.0, 1.2, and 5.0 state that the UIUC MMR, designed by Ultra Safe Nuclear Corporation (USNC), would use these PDCs to satisfy Title 10 of the Code of Federal Regulations (10 CFR) 50.34(a)(3)(i), which requires that applications for a construction permit (CP) include the PDCs for a proposed facility in the preliminary safety analysis report (PSAR) submitted with a CP application. TR section 1.0 states that details of how the MMR design satisfies the PDCs will be described in future licensing submittals. A preliminary high-level description of the planned UIUC MMR design is given in the TR section 2.0 to provide context for the development and UIUCs request for approval of appropriate PDCs. Specifically, the design consists of a modular high temperature gas-cooled reactor (MHTGR) fueled with a tri-structural isotropic (TRISO) based fuel form referred to as Fully Ceramic Micro-encapsulated (FCM) fuel. TR section 1.0 states that the PDCs in the TR are based on the key design features of the USNC MMR technology as well as the MHTGR design criteria provided in U.S. Nuclear Regulatory Commission (NRC) Regulatory Guide (RG) 1.232, Guidance for Developing Principal Design Criteria for Non-Light-Water Reactors, Revision 0 (Reference 3).
For additional details on the submittal, please refer to the documents located at the ADAMS Accession numbers identified above.
EVALUATION CRITERIA As discussed in UIUCs Regulatory Engagement Plan (REP) submitted to the NRC by letter dated June 26, 2023 (Reference 4), UIUC plans to apply to license its MMR under the provisions of 10 CFR 50.21(c), as a class 104(c) research reactor. Specifically, UIUC plans to submit CP and operating license applications to the NRC in the future to request authorization for construction and operation, respectively, of the UIUC MMR. The regulations in 10 CFR 50.34 require that applicants for construction permits and operating licenses include a PSAR and a final safety analysis report, respectively, and describe the information that shall be included in these reports. The regulation in 10 CFR 50.34(a)(3)(i) requires, in relevant part with respect to the PDC TR, that CP applicants establish PDCs. The regulation in 10 CFR 50.34(a)(3)(i) also states that 10 CFR Part 50, Appendix A, establishes minimum requirements for the [PDCs] for water-cooled nuclear power plants and provides guidance to applicants for [CPs] in establishing [PDCs] for other types of nuclear power units. However, according to the PDC TR, the UIUC MMR would be a research reactor, and would also not be a water-cooled reactor.
Therefore, the NRC staff finds that the specific PDC requirements (i.e., general design criteria) in Appendix A to 10 CFR Part 50 would not apply to the UIUC MMR. As such, UIUC is not required to meet the GDC in Appendix A to Part 50. UIUC would still be required, however, to submit PDCs along with a Part 50 CP application.
NUREG-1537, Guidelines for Preparing and Reviewing Applications for the Licensing of Non-Power Reactors (Reference 5), Part 1, Format and Content, and Part 2, Standard Review Plan and Acceptance Criteria, provide guidance for preparing and reviewing, respectively, applications for non-power reactors, including research reactors. The most relevant guidance with respect to this TR is contained in chapter 3, Design of Structures, Systems, and Components, of Parts 1 and 2. In this chapter, NUREG-1537 describes, in part, the identification and development of principal architectural and engineering design criteria for the structures, systems, and components (SSCs) that ensure reactor facility safety and protection of the public.
Guidance regarding non-light-water-reactor (non-LWR) design criteria is contained in RG 1.232, Revision 0 (Reference 3). RG 1.232 outlines example PDCs formulated to be generally applicable to non-LWR designs. Appendix C of RG 1.232 contains a set of PDCs specifically tailored to MHTGR designs, such as the UIUC MMR. In the PDC TR, UIUC references the guidance in RG 1.232 and largely adopts the PDCs in appendix C of RG 1.232, with a limited number of changes to reflect certain aspects of the MMR design. While the example PDCs in RG 1.232 were developed with a focus on nuclear power reactors, the NRC staff considers the guidance adequate for use in developing research reactor PDCs and considers RG 1.232 to be appropriately consistent with the guidance in NUREG-1537. RG 1.232 is therefore appropriate to use to demonstrate that PDCs meet the requirements of 10 CFR 50.34(a)(3)(i) as applicable to research reactors.
SECY-18-0096, Functional Containment Performance Criteria for Non-Light-Water-Reactors (Reference 6), which the Commission approved in SRM-SECY-18-0096 (Reference 7), details criteria that describe how advanced reactor designs may justify the use of a functional containment consisting of multiple barriers to limit the release of radioactive materials, in lieu of a traditional LWR-style containment design. As discussed in TR sections 2.0 and 4.0, the UIUC MMR design relies on this functional containment approach and the associated PDCs reflect this concept.
The regulations in 10 CFR Part 20 establish standards for protection against ionizing radiation resulting from NRC-licensed activities. Based on UIUCs proposed PDCs, the NRC staff expects that in future licensing submittals the UIUC MMR design, including analyses of SSCs identified to mitigate postulated accident conditions, will be assessed against criteria that will be established by UIUC to ensure that applicable regulatory limits regarding radiological consequences (e.g., dose limits in 10 CFR Part 20) will be met.
TECHNICAL EVALUATION Scope of Review TR section 2.0 describes the proposed design of the UIUC MMR facility and TR section 3.0 describes the methodology used in developing the PDC for the described design. The NRC staff notes that these sections provide meaningful context for the PDCs proposed in TR section 4.0 and further outlined in appendix A to the TR, which provides a comparison and highlights differences between the example MHTGR PDCs (i.e., MHTGR-DCs) in appendix C of RG 1.232 versus the proposed UIUC MMR PDCs. However, the NRC staffs review and conclusions in this safety evaluation (SE) pertain specifically to the proposed PDCs provided in TR section 4.0 and listed in appendix A of the TR. The NRC staff makes no determinations regarding the acceptability of the preliminary design described in TR section 2.0, the PDC development information detailed in TR section 3.0, or information in other sections of the TR other than the PDCs themselves. The NRC staff also does not make any determinations regarding the proposed designs adherence to the PDCs. This review scope aligns with the action that UIUC requested in PDC TR section 1.4.
UIUC MMR Design Features This SE section generally summarizes the preliminary design of the planned UIUC MMR for context. This section does not evaluate or make any determination regarding the acceptability of the design itself.
As discussed in TR section 2.0 and UIUCs REP submitted June 26, 2023 (Reference 4), the proposed UIUC MMR would be a 10 megawatt-thermal, uranium fueled, MHTGR that is normally cooled by helium gas that transfers the generated power to a secondary molten salt loop. The reactor core consists of uranium oxy-carbide fueled TRISO particles embedded in a silicon carbide matrix, forming FCM pellets. The FCM pellets will be stacked within solid graphite blocks to make up the fueled reactor core sections. Helium gas will be pumped through the core to transfer the heat generated to a secondary heat transfer system that consists of an intermediate heat exchanger with a molten salt loop.
TR section 2.0 states that the reactor and core SSCs will be designed such that safety-related core cooling can be adequately achieved through passive means that do not require helium coolant, electrical power, or operator action. The NRC staff notes that, based on the proposed PDCs, the design would ensure that specified acceptable radionuclide release design limits (SARRDLs) will be met through reliance on inherent reactivity feedback, functional containment provided by the FCM fuel form, and passive transfer of heat from the reactor core through the vessel, surrounding below-grade building (citadel), and other associated passive SSCs to the surrounding environment.
UIUC MMR PDCs PDC TR sections 4.1 through 4.5 list the proposed PDCs for the UIUC MMR. Further, appendix A of the PDC TR provides a direct comparison between the proposed UIUC MMR PDCs and the example MHTGR PDCs (i.e., MHTGR-DCs) provided in appendix C of RG 1.232.
Appendix A of the TR also discusses any departures from the RG 1.232 PDC verbiage that UIUC proposed in its MMR PDCs.
UIUC MMR PDCs with Minimal or No Departure from RG 1.232 Many of the PDCs UIUC proposed for the UIUC MMR were derived directly from the RG 1.232, appendix C, example PDCs for MHTGRs and are therefore identical to the RG PDCs or contain minor verbiage adaptations to reflect the MMR design. The NRC staff evaluated each proposed PDC for its applicability to the specific UIUC MMR design and evaluated whether the underlying safety bases for PDCs documented in RG 1.232 remained applicable for each in the context of the preliminary UIUC MMR design summarized earlier in this SE. The NRC staff finds that the following UIUC MMR PDCs are acceptable because they are applicable to the UIUC MMR design and because the underlying safety bases documented in RG 1.232 remain applicable and valid: 1, 2, 3, 4, 5, 10, 11, 12, 13, 14, 16, 18, 20, 21, 22, 23, 24, 25, 28, 29, 30, 31, 32, 34, 36, 37, 44, 45, 46, 60, 61, 62, 63, 64, and 72.
RG 1.232 Criteria Not Applicable to the UIUC MMR The guidance in RG 1.232, appendix C, has criteria that are applicable to some advanced reactor designs other than MHTGRs, as included in the other appendices of the RG, but that are considered not applicable to MHTGR designs for various reasons. Many of these criteria are not considered applicable because of specific design aspects and features of MHTGRs; for example, some of these criteria are not applicable to MHTGRs because of their reliance on a functional containment in lieu of a traditional containment structure. Consistent with the RG 1.232, appendix C guidance related to MHTGRs such as the UIUC MMR, UIUC determined that the following RG 1.232 PDCs are not applicable to the UIUC MMR: 27, 33, 35, 38, 39, 40, 41, 42, 43, 50, 51, 52, 53, 54, 55, 56, and 57. The NRC staff reviewed each of these criteria and finds that exclusion of each is appropriate in the context of the associated RG 1.232 guidance and the UIUC MMR design because they are not applicable for MHTGRs, consistent with RG 1.232, appendix C.
UIUC MMR PDCs with Departures from RG 1.232 The NRC staff determined that the remaining proposed UIUC MMR PDCs warranted specific evaluation regarding their acceptability due to differences in verbiage that the NRC staff considered to be more-than-minimal departures from the underlying RG 1.232 verbiage on which they were based. These proposed UIUC MMR PDCs, 15, 17, 19, 26, 70a, 70b, 71a, and 71b, are discussed in the SE sections below.
UIUC MMR PDC 15 - Reactor Helium Pressure Boundary Design UIUC MMR PDC 15 describes UIUCs proposed approach to reactor helium pressure boundary design. As discussed in TR appendix A, the language proposed deviates from the language in the analogous RG 1.232 MHTGR-DC 15. Specifically, UIUC added a reference to pressure relief valves to ensure the SSCs inclusion within the scope of the PDC. TR appendix A states that the verbiage was added because of conflicting definitions between the NRC and USNC terminology for the helium pressure boundary. TR appendix A furthermore states that a definition for the helium pressure boundary, as it applies to the UIUC MMR, will be provided in the planned UIUC MMR PSAR. UIUCs proposed definition for helium pressure boundary would be subject to NRC staff review, as appropriate, as part of its review of future licensing submittals. Nevertheless, the NRC staff finds that UIUCs addition of the specific SSC to ensure it is included in the scope of applicability of the PDC does not change the underlying intent of the PDC itself in any way, as the list of SSCs is exemplary in nature and not necessarily all-inclusive. The SSCs to which the PDC applies will be subject to NRC staff review, as appropriate, as part of its review of future licensing submittals. Therefore, the NRC staff finds that the underlying safety bases documented in RG 1.232 remain applicable. Accordingly, the NRC staff finds that proposed UIUC MMR PDC 15 is acceptable.
UIUC MMR PDC 17 - Electric Power Systems UIUC MMR PDC 17 describes UIUCs proposed approach to electric power systems. As discussed in TR appendix A, the proposed wording deviates from that in the analogous RG 1.232 MHTGR-DC 17. Specifically, UIUC removed significant verbiage regarding electric power systems required to perform functions important to safety because the UIUC MMR will be designed to be passive and will not require electrical power for anticipated operational occurrences (AOOs) or postulated accidents. The remaining applicable verbiage is retained, largely unchanged, including a statement specifying that the design shall demonstrate that power for important to safety functions is provided. The NRC staff finds the proposed UIUC MMR PDC 17 acceptable on the basis that, in the context of the UIUC MMR research reactor design, including its passive nature, the proposed UIUC MMR PDC 17 aligns with the guidance provided in NUREG-1537, Parts 1 and 2, sections 8.1 and 8.2, regarding normal and emergency electrical power systems. Specifically, the guidance in NUREG-1537, Part 2, section 8.2, states that emergency electrical power is required when assured power is required to maintain safe reactor shutdown to support operation of a required engineered safety feature or to protect the public from release of radioactive effluents. The NRC staff finds that UIUC MMR PDC 17meets the intent of this statement regarding power for important to safety functions. Specifically, the NRC staff expects this PDC to cover any potential important to safety functions that would require electrical power that fall outside the scope of AOOs or postulated accidents, if any are identified. In this context, the NRC staff finds that for the UIUC MMR, the proposed PDC 17 aligns with the underlying safety bases for MHTGR-DC 17, as documented in RG 1.232.
UIUC MMR PDC 19 - Control Room or Secure Remote Monitoring Facility UIUC MMR PDC 19 describes UIUCs proposed approach to the UIUC MMR control room design and function and facility monitoring. As discussed in TR appendix A, the language proposed deviates from that in the analogous RG 1.232 MHTGR-DC 19. Specifically, the proposed verbiage reflects that no operator actions are required to maintain the reactor in a safe condition following an accident. Therefore, a control room will be provided to safely operate under normal conditions, but for accident conditions, only monitoring capability from a control room or remote monitoring facility is necessary. Additionally, in proposed UIUC MMR PDC 19, UIUC specified a more restrictive (lower) control room personnel radiation exposure limit of 2 rem, compared to 5 rem in RG 1.232 MHTGR-DC 19. The NRC staff finds that proposed UIUC MMR PDC 19 is acceptable because, considering that the UIUC MMR design does not require operator actions in response to accidents, the PDC aligns with the underlying safety bases for MHTGR-DC 19 as documented in RG 1.232 and also provides a conservative control room radiation exposure limit.
The NRC staff notes that its approval of this proposed UIUC MMR PDC does not constitute NRC staff approval of remote operations (e.g., operational control from a remote monitoring facility) of the UIUC MMR.
UIUC MMR PDC 26 - Reactivity Control Systems UIUC MMR PDC 26 describes UIUCs proposed approach to the design of reactivity control systems and/or means. As discussed in TR appendix A, the proposed language deviates from that in the analogous RG 1.232 MHTGR-DC 26. Specifically, UIUC removed the verbiage a minimum of two in the text that precedes the four numbered paragraphs in the PDC. UIUC states that it made this change to remove potential ambiguity that may lead a reader to interpret the statement as suggesting that two reactivity control systems are needed for each of the numbered paragraphs. The NRC staff notes that, although it does not consider the intent of the wording in RG 1.232 MHTGR-DC 26 to require two reactivity control systems for each of the four numbered paragraphs, the remaining verbiage in proposed UIUC MMR PDC 26 continues to effectively require that two (or more) reactivity control systems or means be provided as part of the design to satisfy the entirety of the PDC, consistent with the intent of RG 1.232. The verbiage contained in the paragraphs numbered (1) through (3) is largely unchanged between RG 1.232 MHTGR-26 and proposed UIUC MMR PDC 26. In paragraph (4), UIUC removed fuel loading from the list of example intervention activities. However, the NRC staff finds that because the removed text is only an example activity, the removal is inconsequential to the underlying intent of the PDC. Based on the discussion above, the NRC staff finds that proposed UIUC MMR PDC 26 maintains the same effective underlying intent and basis for safety as RG 1.232 MHTGR-DC 26 and remains applicable to the UIUC MMR. Therefore, the NRC staff finds that proposed UIUC MMR PDC 26 is acceptable.
The NRC staff notes that its approval of proposed UIUC MMR PDC 26 with the fuel loading text removed does not constitute NRC staff approval of any specific UIUC MMR refueling technique, approach, or strategy.
UIUC MMR PDCs 70a and 70b - Reactor Vessel and Reactor System Structural Design Basis The verbiage provided in RG 1.232 MHTGR-DC 70 contains two numbered requirements regarding the design of the reactor vessel and reactor system, to ensure integrity is maintained during postulated accidents to maintain (1) capability of passive heat removal of residual heat and (2) capability to insert control rods. As discussed in TR appendix A, proposed UIUC MMR PDCs 70a and 70b separate the two requirements of RG 1.232 MHTGR-DC 70 into two separate PDCs for organizational purposes. The NRC staff reviewed the proposed UIUC MMR PDCs 70a and 70b and finds that they adequately reflect the underlying intent of the RG 1.232 language and the underlying safety bases documented in RG 1.232 continue to appropriately apply to the UIUC MMR. Therefore, the NRC staff finds that the proposed UIUC MMR PDCs 70a and 70b are acceptable.
UIUC MMR PDCs 71a and 71b - Citadel Design Basis As discussed in TR appendix A, similar to PDC 70, UIUC split the RG 1.232 MHTGR-DC 71 language into proposed UIUC MMR PDCs 71a and 71b for organizational purposes.
Additionally, UIUC modified the language from the RG slightly to replace reactor building with citadel to reflect the MMR design terminology. The NRC staff reviewed the proposed UIUC MMR PDCs 71a and 71b and finds that they adequately reflect the underlying intent of the RG 1.232 language, and the underlying safety bases documented in RG 1.232 continue to appropriately apply to the UIUC MMR. Therefore, the NRC staff finds that the proposed UIUC MMR PDCs 71a and 71b are acceptable.
LIMITATIONS AND CONDITIONS Approval of this TR for incorporation by reference to support licensing application(s) for construction and/or operation is limited to the MMR design located at the University of Illinois at Urbana Champaign, as the design is generally described in the subject topical report, licensed under the provisions of 10 CFR 50.21(c), as a class 104(c) research reactor. Any departure from the design, or licensing approach described in the TR would require justification in the referencing licensing action and would be subject to NRC review for acceptability.
CONCLUSION The NRC staff concludes that the UIUC TR University of Illinois Urbana-Champaign High-Temperature Gas-Cooled Research Reactor: Micro Modular Reactor (MMRTM) Principal Design Criteria, Release 2 (Reference 2), section 4.0 and appendix A, describe an acceptable list of PDCs that can be used to meet the requirements of 10 CFR 50.34(a)(3)(i) in support of future licensing actions associated with the construction and operation of the proposed UIUC MMR. The NRC staff based this conclusion on the following findings:
The proposed UIUC MMR technology is largely similar to that of the MHTGR described in the applicable regulatory guidance for generating MHTGR PDCs in RG 1.232, appendix C. The UIUC MMR PDCs were generated using, and closely align with, this guidance.
Each UIUC MMR PDC is applicable to the UIUC MMR design and meets the underlying intent of the applicable RG 1.232 guidance, in the context of the specific UIUC MMR design.
UIUCs determinations regarding RG 1.232 criteria that are not applicable to the UIUC MMR are appropriate and are consistent with the intent of the applicable RG 1.232 guidance, in the context of the UIUC MMR design.
REFERENCES 1.
Letter from UIUC to NRC, Submittal of University of Illinois Urbana-Champaign High Temperature Gas-cooled Research Reactor: Micro Modular Reactor (MMRTM) Principal Design Criteria Topical Report, dated November 15, 2023 (ML23319A407).
2.
Letter from UIUC to NRC, Submittal of University of Illinois Urbana-Champaign High Temperature Gas-cooled Research Reactor: Micro Modular Reactor (MMRTM) Principal Design Criteria Topical Report, Release 02 (Revision 1), dated April 10, 2024, dated April 10, 2024 (ML24101A413).
3.
NRC Regulatory Guide 1.232, Guidance for Developing Principal Design Criteria for Non-Light-Water Reactors, Revision 0, dated April 2018 (ML17325A611).
4.
Letter from UIUC to NRC, USNRC Project No. 99902094: UIUC Regulatory Engagement Plan revision submission, dated June 26, 2023 (ML23178A259).
5.
NUREG-1537, Guidelines for Preparing and Reviewing Applications for the Licensing of Non-Power Reactors, Part 1, Format and Content, and Part 2, Standard Review Plan and Acceptance Criteria, dated February 1996 (ML042430055 and ML042430048).
6.
SECY-18-0096, Functional Containment Performance Criteria for Non-Light-Water-Reactors, dated September 28, 2018 (ML18114A546).
7.
SRM-SECY-18-0096, Staff Requirements - SECY-18-0096 - Functional Containment Performance Criteria for Non-Light-Water-Reactors, dated December 4, 2018 (ML18338A502).
Principal Contributors: D. Beacon, NRR L. Kingsbury, NRR Date: July 25, 2024