Australia to export uranium to that country, although actual sales are apparently a long way off. Almost simultaneously, the Prime Minister announced that Australia would no longer sell uranium to Russia. Russia is a declared nuclear state, it acknowledges that it has nuclear weapons, and it has signed the Nuclear Non-Proliferation Treaty (NPT), while India in an undeclared nuclear state and has not signed the NPT. This would seem a little strange were it not for the fact that Russia and its president have been cast as everyone’s villains, and because Australia wants to strengthen its trade links with India. The agreement has taken a long time to work out because Australia now only exports uranium to countries that will use it for electricity generation, although it did provide material for US and British nuclear weapons before 1971, and because India is not a party to the NPT (Australia is) and hence is not bound by the constraints of that treaty. The reason why a country who wants to sell uranium only for power generation needs to be careful is that naturally-occurring uranium is the starting point for deriving the material used in nuclear weapons as well as for civilian power reactors. The purpose of this post is to give a little background about this issue.
A nuclear weapon is one whose mechanism, or ‘explosive principle’, comprises the breaking apart (fission) or the production (fusion) of certain nuclei. All chemical elements, the atoms that are the building blocks of molecules, have a nucleus, tiny in size with respect to the atom, together with a surrounding ‘cloud’ of electrons. Until the advent of nuclear weapons, weapons designers were restricted to exploiting chemical reactions, reactions that involved only the rearrangement of electrons. Nuclear fission and fusion reactions are very hard to produce, but they are very much more vigorous than chemical reactions; hence the terrifying power of nuclear weapons. A nuclear fusion reaction, in which energy is liberated when light atoms fuse together to form heavier ones, can only be produced by a nuclear fission reaction, in which energy is liberated when heavy atoms break apart. So in the most powerful nuclear weapons, the so-called thermonuclear weapons, fusion reactions are induced or triggered by fission reactions. Put another way, thermonuclear weapons presuppose the existence of fission nuclear weapons, such as the ‘atomic bombs’ dropped on Hiroshima and Nagasaki. The heavy atoms that are used in atomic bombs are either uranium or plutonium. But plutonium does not occur naturally and is only produced in a nuclear reactor, a device that is able to produce controlled fission reactions in uranium. In this sense, all nuclear weapons ‘presuppose’ uranium.
The right kind of uranium needs to be concentrated in order to produce an uncontrolled nuclear explosion, and this is why naturally-occurring uranium deposits do not blow up. The latter is in the form of an oxide, which means that uranium atoms are dispersed in the ore, and moreover the ‘right kind’ of uranium comprises only 0.7% of the total. Uranium atoms come in two forms, or isotopes, only one of which, the one that occurs naturally on average only 7 times in 1000, fissions (under appropriate conditions). “Enrichment” refers to a process whereby the proportion of the right kind of uranium is increased in a given sample. There are several ways to do this and the methods are now well-understood but still quite technically difficult. Nuclear reactors normally require uranium enriched to between 3 and 5%, whereas nuclear weapons require enrichment of over 80%. The enriched fuel rods in a power reactor therefore contain mostly uranium of the ‘wrong kind’. However, as controlled fission takes place, some of this uranium is converted into plutonium, which is also fissions and which is the most common material used for the fission triggers in thermonuclear weapons. It was a plutonium bomb that destroyed Nagasaki.
It is quite possible for a country to buy nuclear reactors and have their fuel rods supplied, without developing the technology either to enrich uranium or reprocess the spend fuel rods and recover plutonium. However, for a country that is able to perform the latter tasks, a country like India for example, the boundary between the manufacture of material for civilian power generation and material for nuclear weapons, and the boundary between the latter and reprocessing fuel rods as nuclear waste, becomes blurred. It is entirely possible, for example, for one and the same enrichment facility to produce fuel rods and weapons grade uranium. And it is entirely possible for a reprocessing facility to remove plutonium from spent fuel – this is done chemically – and render the remainder if a form suitable for storage. If Australia supplies uranium to India, the only way to ensure that some it does not become highly enriched, or be reprocessed as plutonium, is to put in place a rigorous accounting system, whereby it can be verified that all the uranium is used for fuel rods and none of it is reprocessed to recover plutonium. I assume the reason why the trade agreement has taken so long was that such a system was hard to set up. But of course even if Aussie uranium is only ever used to generate power, this could still free up uranium obtained by India from other sources for nuclear weapons, and so indirectly support the Indian nuclear weapons programme and make us all that little bit less secure.