Configuring Material Balance Areas for Effective MC&A in Liquid-Fueled Molten Salt Reactors

To develop an effective MC&A system for liquid-fueled MSRs, an appropriate internal control structure of MBAs and/or ICAs must be defined. Three possibilities—one with three MBAs, one with two MBAs, and one with a single MBA—have been discussed here; each option has its own benefits and challenges. When considering the best MBA structure for such a facility, designers should consider when and how the SNM within the reactor’s physical boundary should be quantified and reported. Reporting options and MBA structures go hand in hand because the MBA structure will inform where inventories that need to be reported into NMMSS are taken, and the reporting options could dictate where MBAs should be drawn (i.e., whether there should be an MBA around the reactor’s physical boundary). For example, SNM quantities could be measured during operation and reported in NMMSS, and computational codes could be used to predict SNM quantities, although the related unknown uncertainties may make this option better in the future once the relevant codes have been validated.