ML25076A657
| ML25076A657 | |
| Person / Time | |
|---|---|
| Site: | 99902100 |
| Issue date: | 03/28/2025 |
| From: | Joshua Borromeo Office of Nuclear Reactor Regulation |
| To: | George Wilson TerraPower |
| References | |
| EPID L-2023-TOP-0024, CAC 000431 | |
| Download: ML25076A657 (3) | |
Text
March 28, 2025 George Wilson Senior Vice President, Regulatory Affairs TerraPower, LLC 15800 Northup Way Bellevue, WA 98008
SUBJECT:
TERRAPOWER, LLC - FINAL SAFETY EVALUATION OF NATRIUM TOPICAL REPORT NAT-3056, PLUME EXPOSURE PATHWAY EMERGENCY PLANNING ZONE SIZING METHODOLOGY REVISION 3 (EPID L-2023-TOP- 0024)
Dear George Wilson:
By \
letter dated March 20, 2023 (Agencywide Documents Access and Management System (ADAMS)
Accession No. ML23080A045), TerraPower, LLC (TerraPower) submitted a Topical Report (TR) NAT-3056, Plume Exposure Pathway Emergency Planning Zone Sizing Methodology, Revision 0, for the U.S. Nuclear Regulatory Commission (NRC) staffs review. The TR provides a methodology describing how the Plume Exposure Pathway (PEP) Emergency Planning Zone (EPZ) sizing is determined. The TR follows the guidance in NRC Regulatory Guide (RG) 1.242, Performance-Based Emergency Preparedness for Small Modular Reactors, Non-Light-Water Reactors, and Non-Power Production or Utilization Facilities, Revision 0 (ML23226A036).
By email dated June 12, 2023 (ML23158A203), the NRC staff informed TerraPower that the TR provided sufficient information for the NRC staff to conduct a detailed technical review. On August 11, 2023, the NRC staff transmitted an audit plan to TerraPower (ML23199A317) and subsequently conducted an audit of materials related to the TR from August 17, 2023, to September 15, 2023. By \
letter dated November 16, 2023, Revision 1 of the TR (ML23321A036) was submitted by TerraPower that addressed items discussed in the audit. On September 2, 2024, the NRC staff issued the draft safety evaluation (SE) to TerraPower (ML24242A101). In a \
letter dated October 29, 2024, TerraPower submitted Revision 2 of the TR (ML24303A147), which clarified information discussed during the Advisory Committee for Reactor Safeguards (ACRS) subcommittee (Design-Centered Review: TerraPower) meeting held on September 19, 2024 (ML24296A058).
The audit summary was issued on January 8, 2024 (ML24008A057). To provide further insight into the description of Plume Exposure Pathway EPZ sizing methodology, TerraPower submitted Revision 3 of the TR (ML24304B034) by \
letter dated October 30, 2024.
The enclosed final SE is provided to TerraPower because the NRC staff found the TR acceptable for referencing in licensing actions to the extent specified and under the limitations and conditions delineated in the TR. The final SE defines the basis for the NRC staffs acceptance of the TR.
The NRC staff requests that TerraPower submit an approved version of this TR within 3 months of receipt of this letter. The approved version should incorporate this letter and the enclosed SE after the title page. The approved version should include a -A (designating approved) following the TR identification symbol.
If you have any questions, please contact Mallecia Sutton at (301) 415-0673 or via email at Mallecia.Sutton@nrc.gov.
Sincerely,
/RA/
Joshua Borromeo, Chief Advanced Reactor Licensing Branch 1 Division of Advanced Reactors and Non-Power Production and Utilization Facilities Office of Nuclear Reactor Regulation Project No.: 99902100
Enclosure:
As stated cc: TerraPower Natrium via GovDelivery
Package: ML25076A653 Letter: ML25076A657
Enclosure:
ML25065A250 OFFICE NRR/DANU/UAL1:PM NRR/DANU/UTB2:TR NRR/DANU/UAL1:LA NAME MSutton MHart DGreene DATE 3 / 17/2025 3/18/2025 3/18/2025 OFFICE OGC NRR/DANU/UTB2:BC NRR/DANU/UAL1:BC NAME NMertz CdeMessieres JBorromeo DATE 3/10/2025 3/12/2025 3/28/2025