Demonstration of MELCOR and MACCS Capabilities for Molten Salt Reactor Decay Heat Removal During both Normal Operations and Salt Spill Scenarios

Progress on Near-Term Tasks for the Development of Advanced Reactor Mechanistic Source Term Modeling and Simulation Tools

“…Along with the long-term development objectives previously presented [1], these near-term tasks represent important focus areas that should continue to be investigated to further development of the MST tools that will be useful in establishing the accident source terms of MSRs and FHRs during licensing activities. Examples of such tools that may be used include the suite of NEAMS codes that cover many different modeling phenomena [42], the reactor physics suite of codes SCALE [7,8,43,44], and the severe accident analysis codes MELCOR and MACCS [7,11,45].…”

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

“…In addition, existing nuclear accident analysis models will need to be significantly modified (or newly developed) to account for features of MSRs that are fundamentally different from those of the commercial reactor fleet of light water reactors (LWRs). For example, MELCOR is a systems-level safety analysis code originally developed for LWRs that is currently being updated to accommodate advanced reactor types including MSRs (Humphries et al, 2018;Smith et al, 2021).…”

“…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.…”

Modeling Molten Salt Spreading and Heat Transfer using MELTSPREAD – Model Development Updates

“…Accident progression codes such as MELCOR will likely be employed by MSR developers to model accident sequences as part of the licensing process. The application of MELCOR to postulated MSR accidents is documented (Humphries et al, 2018;Kalilainen et al, 2020;Nichenko et al, 2022;Smith et al, 2021). The spreading and freezing of spilled molten salt will need to be incorporated into the accident progression code due to its importance to a salt spill accident sequence.…”