Wednesday, January 21, 2009

thorium cycle

Oil Drum | Excitement has recently been rising about the possibility of using thorium as a low-carbon way of generating vast amounts of electricity. The use of thorium as a nuclear fuel was extensively studied by Oak Ridge National Laboratory between 1950 and 1976, but was dropped, because unlike uranium-fueled Light Water Reactors (LWRs), it could not generate weapons' grade plutonium. Research on the possible use of thorium as a nuclear fuel has continued around the world since then. Famed Climate Scientist James Hanson, recently spoke of thorium's great promise in material that he submitted to President Elect Obama:

The Liquid-Fluoride Thorium Reactor (LFTR) is a thorium reactor concept that uses a chemically-stable fluoride salt for the medium in which nuclear reactions take place. This fuel form yields flexibility of operation and eliminates the need to fabricate fuel elements. This feature solves most concerns that have prevented thorium from being used in solid-fueled reactors. The fluid fuel in LFTR is also easy to process and to separate useful fission products, both stable and radioactive. LFTR also has the potential to destroy existing nuclear waste.

(The) LFTR(s) operate at low pressure and high temperatures, unlike today’s LWRs. Operation at low pressures alleviates much of the accident risk with LWR. Higher temperatures enable more of the reactor heat to be converted to electricity (50% in LFTR vs 35% in LWR). (The) LFTR (has) the potential to be air-cooled and to use waste heat for desalinating water.

LFTR(s) are 100-300 times more fuel efficient than LWRs. In addition to solving the nuclear waste problem, they can operate for several centuries using only uranium and thorium that has already been mined. Thus they eliminate the criticism that mining for nuclear fuel will use fossil fuels and add to the greenhouse effect.