October 9, 2011
For Australia, The Age, nuclear is the power of last resort. Michael Bachelard October 9, 2011
“……..NEW GENERATION REACTORS. Conventional nuclear reactors use uranium, but leave behind waste, elements of which remain radioactive for thousands of years. In addition, the known reserves of high-grade uranium ore are running out. Only 80 years’ supply remains at current rates of use, and 40 years if the world doubles the number of reactors.
Various nuclear technologies are being explored to provide a new generation of reactors using much more abundant materials to generate power. The kind referred to by questioner Russell Hamstead, thorium fast-breeder reactors, will use thorium, an element that is three times more abundant than uranium. In its natural state, thorium will not produce energy because it is not ”fissile”, so it needs a trigger such as plutonium to kick off a reaction. In effect, this ”breeds” fissile material (hence the term ”breeder”).
According to Dracoulis, these reactors have the potential to be 100 per cent efficient. That is, they generate little or none of the highly radioactive waste produced by current reactors, removing another key objection to nuclear power: the problem of disposing of radioactive waste.
But thorium is not the only material that could be used in a breeder reactor: depleted uranium can also be kicked back into energy production under the right conditions. The downside is that they are very expensive and have ”never been commercial”. Superphoenix, a breeder reactor in France, took seven years from 1974 to build, but produced a small fraction of the electricity it promised to produce and was eventually closed in 1998.
Diesendorf is unconvinced about thorium particularly: ”The new technology doesn’t exist. It’s all talk, it’s all plans. India has been trying to build an incredibly complicated three-part system for thorium and if it ever works it will be much more expensive than existing reactors and even more dangerous.”