Japanese team finds way to drastically cut danger of radioactive waste

14 Nov 2017

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A team of researchers in Japan has found a way to cut the dangerous half-life of radioactive waste from hundreds of thousands of years to just hundreds.

While major nations across the world are de-escalating their nuclear fission plants in favour of cleaner, renewable energies, the leftover radioactive waste will pose a safety challenge for hundreds of thousands of years.

That is why massive underground tombs have been built in places such as Finland to keep it as far as possible away from humans and any natural life. However, more scientific options have been proposed.

Among them is a method known as partitioning and transmutation, which involves separating the nuclear fuel into minor actinides – other elements aside from plutonium and uranium – and the nuclear waste.

Both the minor actinides and nuclear waste are then converted into short-lived nuclides, but this is costly, cumbersome and, in some cases, ineffective.

But now, a team of researchers in Japan’s Tokyo Institute of Technology has found a more efficient way to dispose of nuclear waste, and it reduces its timeframe of potential harm – known as its half-life – drastically.

Can even generate energy

In a paper published to Scientific Reports, the research team showed that it is possible to convert radioactive material into short-lived nuclides by absorbing neutrons in the periphery of a core in a small, fast reactor, rather than the core itself.

Then, the team led by Satoshi Chiba added a ‘relaxant’ to the fast reactor called yttrium deuteride, which actually speeds up the cleaning of nuclear waste in the radial blanket and shield regions of the reactor.

This creates a situation where the absorption rate is faster than in a reactor, which means nuclear waste can be made safe after hundreds of years, rather than hundreds of thousands of years.

Using this method, the team believes that it can convert 17,000 tonnes of waste currently sitting in storage in Japan in 10 fast spectrum reactors.

Even more beneficial is the fact that this method can also be used to generate electricity after its initial use in the fission reactor.

Colm Gorey was a senior journalist with Silicon Republic