Whatever your opinions on nuclear energy it’s unlikely to go away. Fossil fuels contribute to greenhouse gases, and are becomingly harder to exploit; energy security is an increasingly vexatious issue, and many renewable energy sources, although valuable, are often intermittent in their output. There’s no doubt we need an alternative to oil, coal and gas. And nuclear, love it or loathe it, is part of the mix.
The chief criticism against nuclear energy is the waste products which are left behind. Conventional nuclear reactors use uranium-235 as a fuel, which is only obtained by enrichment from another isotope of uranium. U-235 is therefore extremely rare and unfortunately produces plutonium as a waste product.[1]
There is an alternative to uranium, and this is thorium. It has a number of advantages over uranium which make one wonder why uranium was ever the fuel of choice to start with. Thorium is abundant in the earth’s crust[2], doesn’t require enrichment, can’t be weaponized, and only produces a small amount of radioactive waste, which decays in 200 years. And best of all, because thorium can’t sustain a nuclear chain reaction, a plant cannot go into nuclear meltdown.
If thorium is such a wonder fuel why is uranium still the fuel of choice? The answer goes back to the 1940s. Nuclear energy is a spin-off technology from nuclear weapons research. During WWII America launched the Manhattan project, an attempt to build an atomic bomb. Plutonium is the key to the nuclear fission reaction, so the vast majority of research and development focused on uranium and plutonium. During the 50s research was carried out on thorium, but died out pretty much completely in the 70s when America started a massive programme of building nuclear power stations –using uranium as a fuel. Research into thorium faded into the background.
But now thorium is starting to creep back onto the agenda. It’s been found that thorium can be dissolved in fluoride salts. A liquid fluoride thorium reactor, or LFTR would be 50% more efficient than a uranium reactor, with few of the drawbacks. These figures are raising eyebrows in some countries, notably India, China and Russia, who are starting to research building LFTRs. In fact China is already starting to hold back on mining thorium, keeping it in reserve in case they need it as a fuel.
Thorium is a perfect example of a superior technology which was beaten by an inferior one (think Betamax and VHS). It’s down to its inability to make nuclear bombs which led to its downfall; but perhaps thorium will now come to the fore as the element which can make nuclear power palatable to the public.