ML25148A386
| ML25148A386 | |
| Person / Time | |
|---|---|
| Site: | 99902076 |
| Issue date: | 06/23/2025 |
| From: | Stephen Philpott NRC/NRR/DANU/UAL2 |
| To: | Irish S Terrestrial Energy USA |
| Shared Package | |
| ML25148A349 | List: |
| References | |
| EPID L-2025-LRO-0007 | |
| Download: ML25148A386 (1) | |
Text
OFFICIAL USE ONLY - PROPRIETARY INFORMATION OFFICIAL USE ONLY - PROPRIETARY INFORMATION Simon Irish, Chief Executive Officer Terrestrial Energy USA, Inc.
537 Steamboat Road Suite 200 Greenwich, CT 06830
SUBJECT:
TERRESTRIAL ENERGY USA, INC. - U.S. NUCLEAR REGULATORY COMMISSION STAFFS FEEDBACK REGARDING THE TECHNICAL REPORT TITLED MODELING AND SIMULATION ACTIVITIES RELATED TO SOURCE TERM FOR IMSR DESIGN BASIS ACCIDENTS (EPID NO. L-2025-LRO-0007)
Dear Mr. Irish:
By letter dated February 12, 2025, (Agencywide Documents Access and Management System (ADAMS) Package Accession No. ML25055A009), Terrestrial Energy USA, Inc. (TEUSA),
submitted the technical report titled Modeling and Simulation Activities Related to Source Term for IMSR Design Basis Accidents, for the U.S. Nuclear Regulatory Commission (NRC) staffs review. TEUSA stated that the purpose of this technical report is to document the development and application of a broadly applicable modeling and simulation capability to calculate the thermal hydraulic and core physics response following postulated design basis accidents and to calculate a mechanistically derived source term for molten salt reactors (MSRs). The capability will include a methodology for determining and propagating the uncertainties in parameters of importance for fission product source terms specific for MSRs which will be accomplished using the U.S. Department of Energys (DOEs) Nuclear Energy Advanced Modeling and Simulation (NEAMS) tools.
TEUSA requested the NRC staff to review the technical report and provide feedback regarding:
The enhanced discussion of the development of the thermochemical and thermophysical data supporting the calculations, The new discussion of the calculations of the potential uncertainties present with the source term results, Enclosures 1 and 3 to this letter contain Proprietary information. When separated from Enclosures 1 and 3, this letter is DECONTROLLED.
June 23, 2025
OFFICIAL USE ONLY - PROPRIETARY INFORMATION OFFICIAL USE ONLY - PROPRIETARY INFORMATION The preliminary results of the calculated source term available for release following a postulated rupture of the off-gas line, The areas where additional documentation and justification are needed to support the approval of the future topical report that proposes the use of the combined methodology in licensing applications.
The NRC staff completed its review of the submittal and is providing its feedback and observations in Enclosure 1 (Proprietary), Enclosure 2 (Non-Proprietary), and Enclosure 3 (Proprietary) of this document.
If you have questions regarding this matter, please contact Kevin Roche at (301) 415-1554 or via email at Kevin.Roche@nrc.gov.
Sincerely, Stephen Philpott, Acting Chief Advanced Reactor Licensing Branch 2 Division of Advanced Reactors and Non-Power Production and Utilization Facilities Office of Nuclear Reactor Regulation Project No.: 99902076
Enclosures:
(1) NRC Staff Feedback and Observations for Technical Report, Modeling and Simulation Activities Related to Source Term for IMSR Design Basis Accidents (Proprietary)
(2) NRC Staff Feedback and Observations for Technical Report, Modeling and Simulation Activities Related to Source Term for IMSR Design Basis Accidents (Non-Proprietary)
(3) Preliminary Questions Regarding the Terrestrial Energy USA, Inc. Technical Report Titled:
Modeling and Simulation Activities Related to Source Term for IMSR Design Basis Accidents cc: Distribution via Terrestrial IMSR GovDelivery (Letter and Enclosure 2 only)
Signed by Philpott, Stephen on 06/23/25
Pkg: ML25148A349 Letter: ML25148A386 : ML25148A387 (Proprietary) : ML25174A182 (Non-Proprietary) : ML25148A385 (Proprietary)
NRR-106 OFFICE NRR/DANU/UAL2:PM NRR/DANU/UAL2:PM NRR/DANU/UAL2:LA NAME MVegaRodriguez KRoche CSmith DATE 05/28/2025 05/28/2025 05/29/2025 OFFICE NRR/DANU/UTB3: BC NRR/DANU/UAL2: BC (A)
NAME GOberson SPhilpott DATE 06/02/2025 06/03/2025