Thorium Reactor
thorium reactor
[′thȯr·ē·əm rē‚ak·tər]Thorium Reactor
nuclear reactor in which the fissionable material is uranium (233U), formed in the same reactor from thorium (232Th). Natural 232Th itself is not suitable for carrying out a nuclear chain reaction and so serves as a raw material in thorium reactors.
The isotope 233U, which undergoes fission upon interaction with both fast and slow neutrons, is first placed in the reactor after being obtained from a different reactor. As a result of the capture of a neutron formed in the fission of 233U, the thorium (232Th) nucleus, after twice undergoing beta decay, is converted into a 233U nucleus; that is, a secondary nuclear fuel is produced. The ability of thorium reactors to effect a large-scale regeneration of 233U (seeBREEDER REACTOR) increases the importance of the large natural reserves of thorium for the nuclear power industry. However, as of the mid-1970’s, the period for doubling the nuclear fuel in thorium reactors is too long (10–12 years); the reactors are used only for research.