A Collaborative National Center for Fusion & Plasma Research

Hybrid Molten Salt Reactor (HMSR): Method and System to fully fission actinides for electric power production without fuel enrichment, fabrication, or reprocessing

A method for integrating an external source of high-energy neutrons with a conventional moderated high conversion ratio molten salt reactor, thereby creating a self-contained hybrid system which fissions any supplied actinides to produce heat suitable for efficient electricity production.  The molten salt which flows through the critical fission reactor carrying a dissolved mix of both fissile and fertile actinides also flows through a blanket of tanks surrounding the external neutron source.  A coupled set of nuclear reactions initiated in the molten salt mixture by the high energy neutrons converts fertile actinides into fissile actinides at a pace counterbalancing the reactor's net consumption of fissile actinides.  Associated feedback controls adjust the external energetic neutron source power relative to reactor power to control fissile actinide inventories, thus maintaining reactivity so that reactor power can follow load power demand via the negative temperature coefficient and if needed via control rod motion.  A mixture of fresh actinides may be continuously added to the molten salt to replace fissioned actinides and thus extend system operation.  If fission products are also continuously removed so that their inventories in the molten salt are kept stabilized at low enough concentrations to maintain molten salt reactor criticality, then operation of the present HMSR invention can be extended indefinitely without any need to ever shut down for refueling.  In that case the hybrid system's fission utilization of actinides reaches 100% and its waste stream contains only fission products without any actinides


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Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University.

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