Article by Rose Linihan, student of Xaverian College (Manchester) and winner of the British Science Association’s 2017 Science Journalism contest.
The United Kingdom currently faces nuclear threat. And no, not that kind. There is in fact a potential energy crisis on its way, involving huge energy shortages and 100,000 tonnes of nuclear waste, to be precise.
There are currently nine nuclear power stations here in the UK, providing 22% of our total electricity. The Government have decided they want nuclear power to continue to provide a portion of our energy, alongside other low-carbon options. The general public conception of nuclear power is notoriously bad, and yet nuclear power is very effective. It’s a low-carbon way of producing the energy needed to power everything in the UK, from our toasters to TVs, and radioactivity is all around us – there’s even radioactivity in bananas!
Nuclear energy itself is produced by a process called fission, whereby a very unstable isotope of an element called uranium is split into two smaller radioactive nuclei and 2 or 3 neutrons are released and lots of energy. In a nuclear reactor, uranium fuel is surrounded by graphite (material that used to be in pencils) moderators and keep the reaction under control by slowing the neutrons down so they’re at the optimum speed for a further reaction to occur. After it has done its job inside the nuclear reactor, this graphite is known as nuclear waste.
However, our current reactors are now old and so require decommissioning and replacing with new and more advanced models, or else there will be a national energy shortage. Which leaves the us with the problem of the 100,000 tonnes of radioactive nuclear waste. Not to mention 300,000 tonnes worldwide. The NDA (Nuclear Decommissioning Authority) is responsible for decommissioning nuclear waste and their present plan of how to do this is to wait 100 years and then bury the waste in a geological disposal facility. Another option is to go down a similar route to US whereby waste is shipped in containers and the stored in underground tunnels by machines. These options are both very expensive, costing a whopping £20 billion, not to mention being very time consuming and the fact that suitable geological sites are rare. So what do we do? Dump it at the bottom of the ocean? Bury it somewhere? Launch it into space? Or something else…
Alex Theodosiou is a post-doctoral research associate at Manchester University, working in the field of nuclear decommissioning as part of the Nuclear Graphite Research Group. They work as part of a consortium to come up with novel methods of tackling the nuclear waste crisis. Alex is currently researching the thermal treatment of nuclear graphite by reacting it with oxygen at high tempuratures to produce carbon dioxide. This carbon dioxide can then be managed using carbon capture techniques such as liquefication. Alex says ‘This will lead to a massive volume reduction in the graphite inventory and should help reduce overall costs involved with decommissioning, as well as reduce the lengthy timescales currently predicted.’ It could also have wider applications such as nuclear weapon disposal.
Alex’s laboratory work is small scale and involves using a few grams of nuclear grade graphite and heating it with a tube furnace under various conditions, before using a gas analyser to monitor the species formed. This lab data can then be transferred to an industrial scale by partner companies who use a plasma furnace and greater volumes of graphite, to produce results on 1000x the scale.
Alex and his colleages hope that together they can develop a commericially viable decommissioning strategy for the nuclear sector, to propose to the NDA to hopefully win the war against nuclear waste!
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