The idea of using thorium as a nuclear power reactor fuel has been around since the 1960s but there are no commercial thorium reactors in operation today.
Some of the potential benefits of a thorium reactor include production of tiny amount of waste with half life of thirty years, abundance and low radioactivity of thorium, cannot melt down, is not under high pressure, can burn waste from conventional power reactors, can be self-regulating, requires less cooling water than light-water reactors, and more difficult to use for nuclear weapons production than conventional reactors fuel and waste.
Some of the problems with thorium reactors include non-renewable fuel, still produces hazardous waste, can still be used to make nuclear weapons, uses complex and different technology that must be developed, could be terrorist target, conceived of as a centralized plant, competes with renewables for investment dollars, still requires highly fissile materials to act as primer, fuel can be more expensive to produce, waste is more dangerously radioactive in the short term, requires materials that can withstand temperatures higher than conventional light water reactors.
Steven Ashley, a writer for New Scientist had this to say about thorium reactors, "because nuclear power was traditionally tied up with nuclear weapons research, thorium was abandoned. Except for one test reactor that has been under construction in India since 2004, the last research into thorium reactors took place 45 years ago." Nonetheless, "Molten salt reactors are expected to be very well suited for using thorium as a fuel. The unique fluid fuel can incorporate thorium and U-233 fluorides as part of a salt mixture, to melt at very high temperatures."
While U.S. is not focused on researching and developing thorium power reactors, there is a startup in Utah that wants to build a thorium reactor for local utilities. India has beaches of thorium sand and a great need for more electricity. China and Russia are both researching thorium as part of their broad dedication to developing advanced nuclear technologies. Canada is working on building a thorium reactor. Researchers in the Netherlands are making progress in their development of a thorium reactor.
Researchers at the Nuclear Research and Consultancy Group (NRG) in the Netherlands are experimenting with thorium reactors. The Chairman of the Thorium MSR (molten salt reactor) Foundation posted a comment in Medium that said "On August 10, 2017, a set of concentric sealed tubes was entered into the core of the High Flux Reactor in Petten, Netherlands. In the smallest of these tubes sits an even smaller set of four graphite crucibles, containing a mixture of salts: lithium fluoride and thorium fluoride."
The NRG is an “internationally operating nuclear service provider.” They produce commercial isotopes, research nuclear technology, consult on nuclear safety and reliability and provide radiation protection services. They are working on the Salt Irradiation Experiment (SALIENT) at their laboratory in Petten.
The post from the lab in Medium said, “SALIENT is a way to build up experience with the use of fission fuel in the form of a molten salt. That hasn't been done for decades and we're also doing it to train ourselves. It's important to notice that SALIENT is not a single experiment but really a series, and we'll build that up step by step. On the other hand, it is fundamental research, in which we look at the behavior of salt and the fission products that are formed in the salts.”
Ashley, the science writer says, “The next step is to study tough metal alloys and other materials that can survive the bombardment. Later research will examine how to deal with the waste from a molten salt thorium reactor. While safer than the long-lived products from a standard nuke, these will still need special disposal. The next step is to study tough metal alloys and other materials that can survive the bombardment.”
With abundant fossil fuels and dropping prices for renewables, it may be too late for thorium nuclear power.
