For comparison, the largest PWR's now under construction will convert the same thermal power to 1.6 GW of electricity, i.e., 500 MW less. One could consider using a portion of the extra 500 MW of electrical power resulting from the greater thermal conversion efficiency to operate the HMSR's driven DT fusion source of energetic neutrons.

Because simulations showed that less than 1% of the MSR power is adequate for the HMSR, no more than 50 MW of average DT fusion power is needed for a 5 GWth HMSR if all fusion neutrons are absorbed in the molten salt. 

A hybrid molten salt reactor includes a source of energetic neutrons, the energetic neutrons having a typical energy per neutron of 14 MeV or greater, a critical molten salt reactor, and a molten salt comprising a dissolved mixture of fissile actinides and fertile actinides. The molten salt circulates in a loop through the reactor vessel and around the source of energetic neutrons. The fissile actinides and fertile actinides sustain an exothermic nuclear reaction in which the actinides are irradiated by the energetic neutrons, the energetic neutrons inducing subcritical nuclear fission, and undergo critical nuclear fission when circulating through the critical molten salt reactor. A portion of the daughter neutrons generated by nuclear reactions are captured by the fertile actinides in the molten salt and induce transmutation of the fertile actinides into fissile actinides and sustain critical fission chain reactions in the molten salt reactor.