What is Thorium?
Thorium is a naturally occurring, slightly radioactive metal. It is estimated to be about three to four times more abundant than uranium in the Earth's crust.
Thorium was successfully used as an alternative nuclear fuel to uranium in the molten-salt reactor experiment (MSR) from 1964 to 1969 to produce thermal energy, as well as in several light-water reactors using fuel composed of a mixture of 232Th and 233U, including the Shippingport Atomic Power Station (operation commenced 1957, decommissioned in 1982). Currently, officials in the Republic of India are advocating a thorium-based nuclear program, and a seed-and-blanket fuel utilizing thorium is undergoing irradiation testing at the Kurchatov Institute in Moscow. Advocates of the use of thorium as the fuel source for nuclear reactors state that they can be built to operate significantly cleaner than uranium based power plants as the waste products are much easier to handle........
Thorium, as well as uranium and plutonium, can be used as fuel in a nuclear reactor. A thorium fuel cycle offers several potential advantages over a uranium fuel cycle, including greater abundance on Earth, superior physical and nuclear properties of fuel, enhanced proliferation resistance, and reduced nuclear waste production.
So how realistic is Thorium as a fuel alternative?
Lets see what the WNA say
and guess who else is starting to take an interest
Rather than copy the whole article i'll pick out the part on the developing the thorium fuel cycles main features and problems
The possibility of utilising a very abundant resource which has hitherto been of so little interest that it has never been quantified properly.
The production of power with few long-lived transuranic elements in the waste.
Reduced radioactive wastes generally.
The problems include:
The high cost of fuel fabrication, due partly to the high radioactivity of U-233 chemically separated from the irradiated thorium fuel. Separated U-233 is always contaminated with traces of U-232 (69 year half-life but whose daughter products such as thallium-208 are strong gamma emitters with very short half-lives). Although this confers proliferation resistance to the fuel cycle, it results in increased costs.
The similar problems in recycling thorium itself due to highly radioactive Th-228 (an alpha emitter with two-year half life) present.
Some concern over weapons proliferation risk of U-233 (if it could be separated on its own), although many designs such as the Radkowsky Thorium Reactor address this concern.
The technical problems (not yet satisfactorily solved) in reprocessing solid fuels. However, with some designs, in particular the molten salt reactor (MSR), these problems are likely to largely disappear.
Much development work is still required before the thorium fuel cycle can be commercialised, and the effort required seems unlikely while (or where) abundant uranium is available. In this respect, recent international moves to bring India into the ambit of international trade might result in the country ceasing to persist with the thorium cycle, as it now has ready access to traded uranium and conventional reactor designs.
Nevertheless, the thorium fuel cycle, with its potential for breeding fuel without the need for fast neutron reactors, holds considerable potential in the long-term. It is a significant factor in the long-term sustainability of nuclear energy.