Identification and Resolution of Gaps in Mechanistic Source Term and Consequence Analysis Modeling for Molten Salt Reactors Salt Spill Scenarios

State of Knowledge on Aerosols and Bubble Transport for Mechanistic Source Term Analysis of Molten Salt Reactors

“…The bubbles may be formed from noble gas fission products present in the fuel salt or from gas that has been entrained in spilled or agitated molten salt. The formation of aerosols from molten salt bubble bursting is not well studied [107] and received a high priority ranking pertaining to the release of radionuclides in the recent MSR campaign PIRT [104]. The rupture of molten salt surface bubbles can be simulated experimentally by bubbling a hot non-condensable gas into a static pool of molten salt.…”

“…A comparison between aerosols that form by vapor nucleation above static molten salt pools and spilled molten salt pools would indicate whether agitation due to spilling has any effect [107]. Recent experiments at Argonne that involved spilling small amounts of FLiNaK doped with cesium and iodine as surrogate fission products into a stainless steel catch pan showed that the composition of the aerosols particles that were collected did not reflect the composition of FLiNaK but instead was made up of cesium and iodine [31].…”

Conceptual Design of Engineering-Scale Molten Salt Spill Tests to Support Molten Salt Reactor Licensing

“…Integral effects tests that provide insight into coupled processes that govern the behavior of spilled molten fuel salt and the dispersal of radionuclides during a salt spill accident were recently identified as high priority experiments needed to fill gaps in mechanistic source term models for MSRs (Shahbazi and Grabaskas, 2021). In addition, such integral effects tests are required to provide validation datasets for accident progression models (Leute et al, 2021;Smith et al, 2021). It is important that experimental data used for systems-level code validation be generated at the same spatial and temporal scales as the facilities that the code will be used to model.…”

Integrated Process Testing of MSR Salt Spill Accidents

“…Tests addressing individual processes can provide the mechanistic detail that is required for model development, but results from integral effects tests are needed to quantify the coupling between the thermohydraulic behavior of the molten salt and radionuclide dispersal during a salt spill accident (Shahbazi and Grabaskas, 2021). The validation of systemslevel accident progression codes (e.g., MELCOR; Humphries et al, 2018) will require experimental data generated from integral effects tests that are conducted at a large enough scale to ensure that the results are representative of full-scale accidents (Leute et al, 2021;Thomas, 2023).…”