Domestic Safeguards Material Control and Accountancy Considerations for Molten Salt Reactors

Planning for Material Control and Accountancy at Liquid Fueled Molten Salt Reactors

“…Because such diverse designs exist within the class of liquid-fueled MSRs in different stages of development, representative design feature examples are referenced. The following design features will be relevant from an NRC MC&A perspective F (adapted from [10]).…”

“…Such wide variation across different liquid-fueled MSR design concepts makes it impossible to generalize a MC&A approach to meet specified objectives. Table 2 (adapted from [11]) is a list of some of the design features of liquid-fueled MSRs that have been identified as MC&A-relevant.…”

Domestic MC&A Recommendations for Liquid-Fueled MSRs

“…Although liquid-fueled MSR operators will likely need to shut down the MSR and perhaps drain the irradiated salt at some periodicity to perform maintenance, the frequency for maintenance is extremely unlikely to be less than or equal to 12 months [7]. A few liquidfueled MSR designers who have publicly spoken on the subject suggest plans for equipment replacement at a frequency of ≥4 years [10]. Full, static physical inventories (i.e., requiring the reactor to be shut down and the fuel salt drained from the system) likely could not be performed at the frequency required by 10 CFR Part 74.…”

“…The recommendation is that the license applicant propose to leverage the NRC's graded approach for MC&A requirements to incorporate different levels of MC&A rigor into different process streams, based on the category of the material. Other characteristics of the process stream in which SNM is contained, such as the radioactivity levels, concentration of SNM within the material, and the accessibility of the SNM could provide justification for reducing the material categorization [10].…”

“…This report builds on previous research and is organized to facilitate efficient location of a reference, definition, or relevant subject matter expert guidance [7,8,9,10,11,12,13]. The main research findings are provided first and are intended to identify and describe the challenges and differences that a liquidfueled MSR may face under current licensing regulations.…”