Professor Bob Cywinski presented a case for the use of thorium in nuclear reactors for power generation. It was delivered in a manner that was logical and easily understandable, even to the non-scientific members of our club. In brief the case is set out below.
World energy consumption is rising. The CO2 emitted is causing climate change and global warming. Most experts agree that renewable sources, even combined with efficiency savings, cannot meet the demand.
Nuclear power, fuelled by Uranium, provides a low-carbon way to meet energy needs. But there are problems and public resistance, particularly on issues of safety, waste management and proliferation. However using thorium as nuclear fuel instead of uranium can help to solve all three issues: thorium reactors can be run in subcritical mode: when switched off they stay off; the waste from Thorium reactors decays after a few hundred years – rather than after hundreds of thousands; it is very difficult to divert a thorium reactor to military use, particularly because little or no plutonium is produced in the fuel cycle.
Additionally the world has a lot of thorium – it is as abundant as lead – and it is found widely in politically friendly countries. Indeed there is sufficient thorium to provide our energy needs for tens of thousands of years. Moreover thorium fuel rods would last for years, rather than months in a reactor, so there is less refuelling than with uranium. Equally importantly, legacy radioactive waste from existing reactors can be mixed with thorium and burnt as fuel, thereby turning a liability into an asset.
This is not just speculation. Thorium reactors have run in the past for many years. China and India are increasing funding for Thorium power. It’s a fast moving field and there is an opportunity for the UK to tap into its expertise by investing in the research necessary to position UK industry to build the new power stations.
This talk introduced some of the ways that thorium could be deployed: as a fuel in conventional reactors; through molten salt reactor technology; and as fuel in an accelerator driven subcritical reactor (ADSR) or Energy Amplifier in which the neutrons necessary to drive the fertile to fission conversion of thorium, and the fission process itself are provided by spallation.
The ADSR is of particular interest at the University of Huddersfield, where we are developing new and advanced accelerator technology not only capable of driving an ADSR but also providing compact accelerators for proton cancer therapy and medical radioisotope delivery.
Having listened to the talk the majority of our members saw the use of thorium as a ‘win win’ situation and there were many enthusiastic questions from the floor.