The concept dates to the 1950s, and was briefly advocated by Hans Bethe during the 1970s, but detailed studies of the economics of the systems suggested they could not compete with existing fission reactors, even in theory.
The concept dates to the 1950s, and was strongly advocated by Hans Bethe during the 1970s. In 1979, detailed studies of the neutron economics of the systems suggested they could not compete with existing fission reactors, even in theory.