Thorium Reactor

thorium reactor

[′thȯr·ē·əm rē‚ak·tər] (nucleonics) A nuclear reactor in which thorium surrounds the central enriched uranium core to give breeder operation.

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.