Education and Training Series #44: Molten Salt Reactor Safety Evaluation – A US Perspective

These webinars, organised by the GIF Education and Training Working Group are streamed live monthly. The recordings and slide decks are accessible after the webinar on this website. These webinars cover a very broad range of technical and policy related topics. At the end of 2023 they have been viewed by more than 15000 people (approximately half of the views during the live streams and the other half views being of the archives on the public GIF website). In total, the GIF webinars have reached Generation IV enthusiasts, scientists, and engineers in more than 80 countries.

These webinars are organised and hosted by the GIF Education and Training Working Group (ETWG). 

Reactor safety is evaluated to demonstrate that a plant’s operation does not present significant additional risk to the life and health of the public. Reactor safety evaluation historically focused on maintaining adequate containment of radionuclides during the maximum credible accident. However, as progressively larger light water-cooled reactors (LWRs) were developed in the 1960s, the increased potential for catastrophic accidents necessitated expanding the safety adequacy from the containment of radionuclides under all conditions to the prevention of accidents and the mitigation of their consequences. Either a deterministic or probabilistic pathway could be taken to demonstrate the safety adequacy for US molten salt reactors (MSRs). The deterministic pathway relies on adapting accepted minimum design criteria for LWRs to MSRs, whereas the probabilistic pathway relies on adequately modeling the risks of MSR accidents to discern what can occur, how likely it is to occur, and the consequences of its occurrence. MSR designs as envisioned have a readily apparent high degree of passive safety. Their combination of low pressure, low stored energy within containment, negative reactivity feedback, and effective passive decay heat removal substantially reduces the potential for cascading and escalating events. This MSR resiliency opens a third demonstration pathway that refocuses safety adequacy on containment of credible accidents, precluding the need for complete probability information. This approach would be especially useful for early prototype plants which lack sufficient performance data to take advantage of higher fidelity, data-driven risk modeling. This webinar will describe the current status and comparative advantages of the three alternative MSR safety adequacy demonstration pathways.