ML25181A199
| ML25181A199 | |
| Person / Time | |
|---|---|
| Site: | 99902049 |
| Issue date: | 08/05/2025 |
| From: | Victoria Huckabay NRC/NRR/DNRL/NLIB |
| To: | Jardaneh M NRC/NRR/DNRL/NRLB |
| References | |
| Download: ML25181A199 (1) | |
Text
MEMORANDUM TO:
Mahmoud Jardaneh, Chief New Reactor Licensing Branch Division of New and Renewed Licenses Office of Nuclear Reactor Regulation FROM:
Victoria V. Huckabay, Senior Project Manager Licensing and Regulatory Infrastructure Branch Division of New and Renewed Licenses Office of Nuclear Reactor Regulation
SUBJECT:
AUDIT PLAN FOR THE REGULATORY AUDIT OF SMR-300 DESIGN BASIS ACCIDENT RADIOLOGICAL CONSEQUENCES ANALYSIS METHODOLOGY LICENSING TOPICAL REPORT By letter dated June 6, 2025, SMR, LLC, a Holtec International Company (SMR (Holtec)),
submitted Licensing Topical Report (LTR) HI-2241098, Revision 0, SMR-300 Design Basis Accident Radiological Consequences Analysis Methodology Licensing Topical Report.1,2 The U.S. Nuclear Regulatory Commission (NRC) staff accepted the LTR for review on June 26, 2025.3 As part of the LTR review, the NRC staff will conduct an audit to better understand the information submitted by SMR (Holtec). This virtual audit will be held from August 15, 2025, through August 22, 2025. There will be an entrance meeting to discuss the audit process and an exit meeting to summarize the activities and status of each item. The NRC staff will issue an audit report within approximately 90 days following the exit meeting. The audit plan is included as an enclosure to this letter.
CONTACT: Victoria V. Huckabay, NRR/DNRL 301-415-5183 1
Letter from C. Shurtleff to NRC, SMR-300 Design Basis Accident Radiological Consequences Analysis Methodology Licensing Topical Report, dated June 6, 2025, (Agencywide Documents Access and Management System (ADAMS) Accession No. ML25157A144, part of package ML25157A142).
2 Letter from C. Shurtleff to NRC. Enclosure 1, SMR, LLC, SMR-300 Design Basis Accident Radiological Consequences Analysis Methodology Licensing Topical Report, dated June 6, 2025, (ML25157A143, part of package ML25157A142).
3 Email from NRC to C. Shurtleff, NRC Form 898 Topical Report Completeness Determination: SMR 300 Radiological Consequences Methodology Topical Report, dated June 26, 2025, (ML25161A172, part of package ML25161A170).
August 5, 2025 Signed by Huckab on 08/05/25
M. Jardaneh This audit will be conducted in accordance with the guidance provided in Office Instruction LIC-111, Revision 2, Regulatory Audits.4 Docket No. 99902049
Enclosure:
Audit Plan 4 U.S. NRC, LIC-111, Revision 2, "Regulatory Audits, dated December 19, 2024 (ML24309A281).
ML25181A199 NRR-106 OFFICE NRR/DNRL/NLIB:PM NRR/DNRL/NLIB:LA NRR/DNRL/NLIB:BC NRR/DNRL/NLIB:PM NAME VHuckabay SGreen MJardaneh VHuckabay DATE 08/04/2025 08/05/2025 08/05/2025
Enclosure UNITED STATES NUCLEAR REGULATORY COMMISSION AUDIT PLAN FOR THE SMR-300 DESIGN BASIS ACCIDENT RADIOLOGICAL CONSEQUENCES ANALYSIS METHODOLOGY LICENSING TOPICAL REPORT (CAC/EPID: 000431/L-2025-TOP-0019)
Docket No. 99902049 AUDIT PLAN APPLICANT:
SMR (Holtec)
CONTACTS:
Victoria Huckabay DURATION:
August 15 to August 22, 2025 (Approximate Audit Exit)
AUDIT TEAM:
Mahmoud Jardaneh - Branch Chief (Office of Nuclear Reactor Regulation (NRR))
Kevin Hsueh - Branch Chief (NRR)
Barbara Hayes - Branch Chief (NRR)
Victoria Huckabay - Senior Project Manager (NRR)
David Garmon - Technical Reviewer (lead) (NRR)
John Parillo - Technical Reviewer (NRR)
Elijah Dickson - Technical Reviewer (NRR)
Jason White - Technical Reviewer (NRR)
Anthony Torres - Observer (NRR)
Joshua Gordon - Observer, (United Kingdom (UK), Office for Nuclear Regulation (ONR)))
Stephen Wardle - Observer, UK ONR Additional audit team members may be included as needed.
I.
BACKGROUND AND AUDIT BASIS By letter dated June 6, 2025, SMR, LLC, a Holtec International Company (SMR (Holtec)),
submitted LTR HI-2241098, Revision 0, SMR-300 Design Basis Accident Radiological Consequences Analysis Methodology Licensing Topical Report. The NRC staff accepted the LTR for review on June 26, 2025.
This audit will be conducted in accordance with the guidance provided in the Office Instruction LIC-111, Revision 2, Regulatory Audits.
II.
OBJECTIVES The NRC staff will seek clarification, gain understanding, and verify information related to the subject LTR. The audit will identify if information is needed to support a regulatory finding so it can be placed on the docket. Additionally, review and discussion of the audit material will help focus any subsequent requests for additional information.
III.
REGULATORY AUDIT SCOPE The audit team will examine supporting documentation provided by SMR (Holtec) in the online portal and hold discussions during virtual meetings. Audit topics include the initial information needs described below and any additional items identified during the audit.
IV.
INFORMATION AND OTHER MATERIAL NECCESSARY FOR THE REGULATORY AUDIT In Section 4.3.1.2 of the LTR, SMR (Holtec) provides as a basis for acceptability of containment flood-up pool pH of 6 (vice the prescribed value of 7 in guidance) that the iodine evolution to elemental iodine is significantly less than 4.85%. The assumption of 4.85% in Regulatory Position 3.5 of Regulatory Guide (RG) 1.183, Revision 15 represents the elemental iodine that is released from the gap and fuel pellets not considering elemental iodine that would re-evolve in the pool. This value is predicated on the containment flood-up pool pH being 7. At lower pH levels, iodine from the pool water would re-evolve at a rate that is dependent on the pH level as described in NUREG/CR-59506. This re-evolved iodine would add to the value assumed in RG 1.183, Position 3 for elemental iodine and would thus adversely impact resultant radiological doses.
The NRC staff views the long-standing limitation on containment flood-up pool pH level of greater than or equal to 7 as a conservative margin above the analytic values presented in Figure 4-1 in the LTR, as reproduced from NUREG/CR-5950, Figure 3.1. To support developing a risk-informed evaluation for SMR (Holtec)s proposal, the NRC staff would like to understand the basis and considerations for the containment flood-up pool pH value (e.g., margin that would be available from the elemental iodine re-evolution point and SMR (Holtec)s need for using this alternative approach rather than following long-standing guidance). Therefore, please provide additional information on the basis for the requested change in the minimum containment flood-up pool pH level. In addition, please provide information describing why this change is necessary for the SMR-300 design.
V.
SPECIAL REQUESTS The NRC staffs requests that SMR (Holtec) provide subject matter expert(s), if necessary, to discuss the details of the audit material.
VI.
LOGISTICS AND DELIVERABLES Entrance Meeting:
August 15, 2025 Exit Meeting:
August 22, 2025 (date approximate)
The audit team will hold audit calls and/or meetings with SMR (Holtec) as necessary to understand audit material. The team will inform SMR (Holtec) of any emerging information needs.
5 Regulatory Guide 1.183, Alternative Radiological Source Terms for Evaluating Design Basis Accidents at Nuclear Power Reactors, Revision 1, dated October 2023 (ML23082A305).
6 NUREG/CR-5950 (ORNL/TM-12242), Iodine Evolution and pH Control, Revision 3, dated October 1992 (ML063460464).
An audit report will be issued within 90 days following the exit meeting. The NRC point of contact for this audit is Victoria Huckabay at Victoria.Huckabay@nrc.gov.