The word "thorium" is correct and usable in written English.
You can use it when talking about a naturally occurring radioactive element, usually found in monazite sands. For example, "Thorium is an alternative fuel source that produces substantially less radioactive waste than traditional uranium-based fuels."
Overall, the half-life of a liquid-fuel reactor's byproducts is measured in hundreds rather tens of thousands of years.The liquid-fluoride thorium reactor, developed at Oak Ridge National Laboratory in Tennessee during the late 1960s, ran successfully for five years before being axed by the Nixon administration.
The team plan to fire up a prototype thorium reactor in 2015.
By contrast thorium, once extracted from its ore, is reactor-ready.It does, it is true, need a seed of uranium or plutonium to provide neutrons to start the ball rolling.
However, unlike fissile uranium, natural thorium must be "seeded" with external neutrons in order to get it to fission.
Being plentiful and cheap, thorium is the only fuel that stands a chance of generating electricity as cheaply as burning coal.
The Chinese Academy of Sciences claims the country now has "the world's largest national effort on thorium", employing a team of 430 scientists and engineers, a number planned to rise to 750 by 2015.
The Indira Gandhi Centre for Atomic Research already runs a small research reactor in Kalpakkam, Tamil Nadu, and the Bhabha Atomic Research Centre in Mumbai plans to follow this up with a thorium-powered heavy-water reactor that will, it hopes, be ready early next decade.China's thorium programme looks bigger.
The American effort was abandoned after the Nevada tests.The gamma-ray problem is created by a quirk of the process that turns thorium into 233U.
There is less than a hundredth of the quantity and its radioactivity falls to safe levels within centuries, instead of the tens of millennia for light-water waste.Paradoxically, though, given thorium's history, it is the difficulty of weaponising thorium which many see (as it were) as its killer app in civil power stations.
