Plutonium and Mox nuclear fuel

Government’s doomed £6bn plan to dispose of nuclear waste,  The Independent, 11 April 11“……Q & A: Why has it come to this?

Q: What is Britain’s “plutonium mountain”?

A: It is the nation’s stockpile of radioactive plutonium, kept as plutonium dioxide powder, packed into special drums stored at Sellafield in Cumbria. A further, smaller amount is stored at the Dounreay nuclear facility in Scotland, the site of the doomed nuclear fast-breeder reactor programme.

Q: Why is the plutonium stockpile so big?

A: This is civilian plutonium, not military. It is largely the result of a decision in the 1960s to extract the plutonium from spent nuclear fuel for use in fast-breeder reactors, which were never built commercially. Britain continued to accumulate civilian plutonium, currently amounting to 84 tonnes, along with foreign-owned plutonium, currently 28 tonnes. The final British-owned plutonium stockpile will be 109 tonnes, once fuel reprocessing from existing nuclear reactors has been completed.

Q: Why do we need to do anything with it?

A: Plutonium remains radioactive for many thousands of years – just how long depends on which isotope. Experts say that doing nothing with the stockpile is not an option – the current methods of storage will eventually become unsafe in decades to come. Plutonium either has to be put into long-term storage, with a view of permanent disposal at some future point in cement or glass blocks, or used in some way that makes it “safer”, such as incorporating it into Mox fuel that is used in a reactor.

Q: Is converting plutonium to Mox fuel safe?

A: Plutonium is an extreme health risk if it gets inside the body – it emits alpha particles which are highly dangerous if they penetrate the skin because they damage the DNA of cells and cause cancer. It is also a security risk because of its use in nuclear weapons and “dirty” bombs. By converting it to Mox fuel, and irradiating this fuel in reactors, some experts believe that plutonium will, ironically, become safer because, being more radioactive, it will be more difficult to handle. Opponents argue that manufacturing Mox necessarily increases security risks not least because of the transport of Mox fuel rods, and even plutonium dioxide, which can be subject to terrorist attacks of accidents.

Q: Is it easy to use Mox fuel in nuclear reactors?

A: Some reactors do use Mox, but only as a small percentage (less than 30 per cent) of the total fuel. The rest of the fuel is conventional uranium oxide. Supporters of Mox suggest that the new generation of nuclear reactors to be built in Britain could burn Mox fuel and thereby be used to diminish the plutonium stockpile. However, the new reactors have been licensed to burn uranium-only fuel and none of the reactor designs being considered has been “just”justified” for Mox, which in any case remains far more expensive than conventional uranium fuel.
Government’s doomed £6bn plan to dispose of nuclear waste – Science, News – The Independent

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