Thorium, the Green Nuke

Aerospace engineer Kirk Sorensen became interested in nuclear energy by reading records of experiments done by Alvin Weinberg and his team after World War II at the Oak Ridge Nuclear Plant. What really captured Sorenson's attention was the promise of thorium, which has advantages over uranium as a nuclear fuel. Uranium worked best for nuclear weapons, but it is rare, dangerous, and produces lots of nuclear waste.

When he took over as head of Oak Ridge in 1955, Alvin Weinberg realized that thorium by itself could start to solve these problems. It’s abundant — the US has at least 175,000 tons of the stuff — and doesn’t require costly processing. It is also extraordinarily efficient as a nuclear fuel. As it decays in a reactor core, its byproducts produce more neutrons per collision than conventional fuel. The more neutrons per collision, the more energy generated, the less total fuel consumed, and the less radioactive nastiness left behind.

Even better, Weinberg realized that you could use thorium in an entirely new kind of reactor, one that would have zero risk of meltdown. The design is based on the lab’s finding that thorium dissolves in hot liquid fluoride salts. This fission soup is poured into tubes in the core of the reactor, where the nuclear chain reaction — the billiard balls colliding — happens. The system makes the reactor self-regulating: When the soup gets too hot it expands and flows out of the tubes — slowing fission and eliminating the possibility of another Chernobyl. Any actinide can work in this method, but thorium is particularly well suited because it is so efficient at the high temperatures at which fission occurs in the soup.

Sorenson is leading a campaign to revive thorium as a nuclear fuel by bringing scientists and engineers together on his blog called Energy From Thorium. A bill is now before congress to provide funds for thorium research. At least one commercial company is already using thorium. Could this be the element that saves nuclear power? Link -via reddit

(image credit: Thomas Hannich)

This isn't the only one out there. Toshiba has a small reactor that uses lithium-6
"The 200 kilowatt Toshiba designed reactor is engineered to be fail-safe and totally automatic and will not overheat. Unlike traditional nuclear reactors the new micro reactor uses no control rods to initiate the reaction. The new revolutionary technology uses reservoirs of liquid lithium-6, an isotope that is effective at absorbing neutrons. The Lithium-6 reservoirs are connected to a vertical tube that fits into the reactor core. The whole whole process is self sustaining and can last for up to 40 years, producing electricity for only 5 cents per kilowatt hour, about half the cost of grid energy."