ML24255A014

Letter - Terrapower, LLC - Summary Report on the Regulatory Audit of Topical Report, TP-LIC-RPT-0004, Design Basis Accident Methodology for In-Vessel Events Without Radiological Release Topical Report, Revision 0

ML24255A014
Person / Time
Site:	99902100
Issue date:	11/27/2024
From:	Stephanie Devlin-Gill Office of Nuclear Reactor Regulation
To:	George Wilson TerraPower
References
EPID L-2023-TOP-0050
Download: ML24255A014 (3)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 November 27, 2024 George Wilson Vice President, Regulatory Affairs TerraPower, LLC 15800 Northup Way Bellevue, WA 98008

SUBJECT:

TERRAPOWER, LLC -

SUMMARY

REPORT ON THE REGULATORY AUDIT OF TOPICAL REPORT, TP-LIC-RPT-0004, "DESIGN BASIS ACCIDENT METHODOLOGY FOR IN-VESSEL EVENTS WITHOUT RADIOLOGICAL RELEASE," REVISION 0 (EPID NO. L-2023-TOP-0050)

Dear George Wilson:

By letter dated September 29, 2023, TerraPower, LLC (TerraPower) submitted topical report (TR) TP-LIC-RPT-0004 Design Basis Accident Methodology for In-Vessel Events without Radiological Release, Revision 0 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML23272A260) to the U.S. Nuclear Regulatory Commission (NRC) staff. The TR summarizes the approach taken to satisfy the guidance outlined in Regulatory Guide 1.203, Transient and Accident Analysis Methods, Revision 0 (ML053500170), regarding the evaluation model development and assessment process for in-vessel design basis accident events without radiological release in the Natrium reactor. On October 31, 2023, the NRC staff found that the material presented in the TR provides technical information in sufficient detail to enable the NRC staff to conduct a detailed technical review (ML23303A165).

Enclosed is a summary report on the regulatory audit conducted by the NRC staff in connection with its ongoing review of the TR. The audit followed the plan dated March 5, 2024 (ML24064A195). By letter dated October 11, 2024, TerraPower submitted a revision to the subject TR, NAT-9390, Design Basis Accident Methodology for In-Vessel Events without Radiological Release, Revision 2 (ML24295A202), which incorporated changes to the TR to address questions discussed during the audit.

The audit summary report does not make any licensing conclusions or findings, but it is part of the administrative record of the NRC staffs review of the TR and may provide information supporting the NRC staffs safety evaluation. No requests for additional information were identified as part of the audit and there are no open items resulting from the audit. The report constitutes the final report on the audit.

If you have any questions regarding this matter, please contact me at (301) 415-5301 or via email at Stephanie.Devlin-Gill@nrc.gov.

Sincerely,

/RA/

Stephanie Devlin-Gill, Senior Project Manager 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: ML24255A028 Letter: ML24255A014 Public

Enclosure:

ML24255A017 Non-Public

Enclosure:

ML24255A024 OFFICE NRR/DANU/UAL1:PM NRR/DANU/UAL1:PM NRR/DANU/UAL1:LA NAME KWagner SDevlin-Gill DGreene DATE 09/12/2024 09/13/2024 09/17/2024 OFFICE NRR/DANU/UTB2:BC NRR/DANU/UAL1:BC NAME CdeMessieres JBorromeo DATE 11/19/2024 11/27/2024