ML24332A112

Memo - Summary of Meeting Held on November 7, 2024 with TRISO-X Chemical Safety Request for Additional Information

ML24332A112
Person / Time
Site:	Triso-X
Issue date:	01/02/2025
From:	Rudd J NRC/NMSS/DFM/FFLB
To:	James Downs NRC/NMSS/DFM/FFLB
Shared Package
ML24332A111	List: ML24332A112 ML24332A113
References
EPID L-2022-PMP-0005
Download: ML24332A112 (1)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 MEMORANDUM TO: James Downs, Chief (Acting)

Fuel Facility Licensing Branch Division of Fuel Management Office of Nuclear Material Safety and Safeguards FROM:

Joseph Rudd, Project Manager Fuel Facility Licensing Branch Division of Fuel Management Office of Nuclear Material Safety and Safeguards

SUMMARY

OF MEETING ON NOVEMBER 7, 2024, WITH TRISO-X LLC, TO ALIGN ON CHEMICAL SAFETY REQUEST FOR ADDITIONAL INFORMATION-9, LOW ESITAMTES OF INDOOR CHEMICAL CONCENTRATION, METHODOLOGY, (ENTERPRISE PROJECT IDENTIFIER L-2022-PMP-0005)

The U.S. Nuclear Regulatory Commission (NRC) hosted a closed Microsoft Teams meeting to with TRISO-X, LLC (TRISO-X) on November 7, 2024, from 2:00 p.m. until 3:30 p.m. The purpose of the meeting was to discuss technical clarifications related to the chemical safety portion of the TRISO-X license application (LA) related to the NRC request for additional information (RAI) issued via letter dated October 10, 2023 (Agencywide Documents Access and Management System [ADAMS] Accession No. ML23265A264). TRISO-X provided their responses to the RAIs via letter dated December 9, 2023 (ML23343A002), in which TRISO-X adequately addressed RAIs 1-8, and 10. This call was to discuss further technical details regarding RAI-9, Low estimates of indoor chemical concentration, methodology.

TRISO-X presented alternative calculational methods for estimating the hazardous material concentrations that workers would experience following an accidental release. One calculation assumed a constant release rate into an expanding mixing zone while a worker exited the area of the release. The NRC staff provided feedback during the meeting that this methodology appears reasonable for estimating hazardous material concentrations that a worker near the release point would experience. The second method was one presented earlier which assumed instantaneous release of different quantity accompanied by instantaneous dilution of the release quantity through the available room volume.

CONTACT: Matt Bartlett, NMSS/DFM 301-415-7154 January 2, 2025 Signed by Rudd, Joseph on 01/02/25

J. Downs 2

The addition of the first method mentioned above (i.e., dynamic analysis of an ongoing release into a smaller volume) into an update of the TRISO-X chemical consequence estimation methodology section of the LA would provide TRISO-X with an additional option to estimate worker consequences, particularly for a worker who might be near the hazardous material release point. The two approaches provide TRISO-X with options to adequately approximate the physical processes that would influence the concentrations that a worker could experience.

Revising the chemical consequence assessment methodology to include both analytical approaches will provide flexibility when assessing chemical hazards with different accident sequence details (e.g., worker location, room size, ventilation, localized mixing, etc.). The individual consequence analysis will support the NRC staffs review if each analysis includes a discussion of (1) the basis, reasonableness and conservatism of the parameters used in the specific calculation and (2) the reasonableness and conservatism of the overall case-specific results.

The additional approach presented during this call, combined with the existing approach in the LA support resolution of the issues raised in RAI-9 and improves the NRC staffs ability to make findings of adequate protection during the review TRISO-Xs assessment of chemical hazards.

The NRC staff will review the implementation of the revised methodology to be submitted in the updated LA and review the details in a sample of chemical consequence calculation packages during the horizontal and vertical slice review.

A list of participants is provided as Enclosure 1.

Docket No. 07007027

Enclosures:

1.

Participant List (public) cc: trisox@listmgr.nrc.gov

ML24332A111(pkg), ML24332A112(memo), ML24332A113(encl)

OFFICE NMSS/DFM NMSS/DFM NMSS/DFM NAME JRudd MBartlett JGoodridge DATE 12/2/2024 12/20/2024 12/20/2024 OFFICE NMSS/DFM NMSS/DFM NMSS/DFM NAME TGovan JDowns JRudd DATE 12/23/2024 12/31/2024 1/2/2025