The GEM*STAR design was originally developed by Bowman and Vogelaar    , which uses a molten salt fuel, with graphite moderation in a subcritical configuration with supplemental neutrons provided by an accelerator driven proton spallation source. This allows for very safe operation since no criticality accidents are possible. Further, the liquid fuel and subcritical nature allow for higher burnup and more flexible fueling options. A portion of the liquid fuel is continuously removed from the system, while a feed stock of fuel is continuously added at the same rate. After sufficient time, this creates an equilibrium situation which greatly simplifies the reactor design and operation.
In 2015-2016, NSEL performed verification studies on the performance of GEM*STAR core. These studies have demonstrated the potential for achieving the aforementioned objectives. For further information click here