usable energy, as the average energy expenditure per neutron produced ranges around 30 MeV (1 GeV beam producing a bit over 30 neutrons in the most productive targets), while fission produces on the order of 200 MeV per actinide atom that is split. Even at relatively low energy efficiency of the processes involved, net usable energy could be generated while being able to use actinides unsuitable for use in conventional reactors as "fuel".

Production of neutrons at a spallation neutron source