SUBJECT: M.S. Thesis Presentation
BY: Matthew Mitchell
TIME: Wednesday, April 17, 2024, 11:00 a.m.
PLACE: Boggs Building, 3-39
TITLE: Modeling and Sensitivity Studies for Radioisotope Signatures of Molten Salt Reactors (MSRs)
COMMITTEE: Dr. Steven R. Biegalski, Chair (NRE)
Dr. Bojan Petrovic (NRE)
Dr. Derek A. Haas (NRE)


Developments of MSR technologies are making rapid progress across the globe. MSRs are a type of Generation IV system chosen by the Gen IV International Forum (GIF) as being one of the most feasible Advanced Reactor Technologies (ART) for research and development. US companies have various planned designs driven by commercial interest and intend on licensing MSRs through the Nuclear Regulatory Commission (NRC). These reactor designs involve properly controlling radionuclides through off-gas systems. This work examines radioisotope emissions and assesses treaty detection technology to be used for monitoring the interference of human-made events.
The research in this thesis analyzes various reactor activities with SCALE models on the nuclear forensic signals possible from a MSR in operation. Multiple Isotope Ratio Comparison (MIRC) plots are used to compare the activities of monitored radioisotopes of high interest in an MSR to the signatures of a highly enriched uranium (HEU) pulse.
The sensitivity studies performed to determine the nuclear forensic signals of MSRs in operation is the main focus of this thesis. It is defined in detail the depletion analysis executed using the t6-depl sequence in TRITON and the point depletion and decay calculations using ORIGEN with a FLiBe fuel salt. MSR emissions from certain reactor applications may significantly overlap with signals produced in a HEU event and changing irradiation time, using hold tanks, and changing off-gas removal rates can significantly shift the radioisotope signatures away from a HEU pulse to avoid considerable global effects on the International Monitoring System (IMS).