Thorium Reactors:

Back to the Dream Factory

by Gordon Edwards, July 13, 2011

The Nuclear Dream Factory

Every time a nuclear power reactor idea doesn't work out, and ordinary people get down-hearted and start to doubt the magnificence and benificence of nuclear energy, nuclear proponents rush back to their well-stocked dream factory to fetch another idea -- one that is sufficiently unfamiliar and sufficiently untested that ordinary people have no idea whether it is good or bad, safe or dangerous, feasible or foolish, or whether the almost miraculous claims made about it are true or false.

Just a few years ago, nuclear proponents were pushing Generation 3 reactors -- enormous plants that would generate huge amounts of electricity, yet be cheaper and faster to build than earlier models, as well as being safer and longer-lived.

Then Areva ran into a blizzard of problems trying to build one of these behemoths in Finland -- the cost soaring by billions, the construction time stretched by years, and fundamental safety-related design problems surfacing late in the game. Check and mate.

Undaunted, nuclear proponents quickly executed a 180-degree turn and are now promoting small reactors which can be mass-produced by the thousands and sprinkled on the landscape like cinnamon on toast. Pebble-bed reactors, molten-salt reactors, thorium reactors, have been paraded before the public with as many bells and whistles as the nuclear industry can muster, to distract people's gaze away from the construction fiascos, the litany of broken promises from the past, the still-unsolved problems of nuclear waste and nuclear weapons proliferation, and the horror that is Fukushima.

The following paragraphs are written to dispel some of the mystique surrounding the idea of "thorium reactors" -- a very old idea that is now being dressed up in modern clothes and made to seem like a major scientific breakthrough, which it is not.

Thorium is not a nuclear fuel

The fundamental fact about thorium is that it is NOT a nuclear fuel, because thorium is not a fissile material, meaning that it cannot sustain a nuclear fission chain reaction.

In fact the ONLY naturally occurring fissile material is uranium-235, and so -- of necessity -- that is the material that fuels all of the first-generation reactors in the entire world. Thorium cannot replace uranium-235 in this regard. Not at all.

Thorium is a "fertile" material

But thorium-232, which is a naturally occurring radioactive material, is about three times as abundant as uranium-238, which is also a naturally occurring radioactive material. Neither of these materials can be used directly as a nuclear fuel, because they are not "fissile" materials.

However, both uranium-238 and thorium-232 are "fertile" materials, which means that IF they are placed in the core of a nuclear reactor (one that is of necessity fuelled by some other material -- a fissile material), some fraction of those fertile atoms will be transmuted into man-made fissile atoms.