EnergyExploring power of thorium for improved nuclear design
An international project aims to develop a radical new type of nuclear power station that is safer, more cost-effective, compact, quicker, and less disruptive to build than any previously constructed. Funded by the U.K. Engineering and Physical Sciences Research Council (EPSRC), a team at the University of Cambridge is exploring whether the element thorium could help to meet the new design’s fuel needs. As well as being three to four times more abundant than uranium, thorium could potentially produce electricity more fuel efficiently and therefore more cheaply.
The United Kingdom is playing a key role in an international project to develop a radical new type of nuclear power station that is safer, more cost-effective, compact, quicker, and less disruptive to build than any previously constructed.
Funded by the Engineering and Physical Sciences Research Council (EPSRC), as part of the RCUK Energy Program, a team at the University of Cambridge is exploring whether the element thorium could help to meet the new design’s fuel needs. As well as being three to four times more abundant than uranium, thorium could potentially produce electricity more fuel efficiently and therefore more cheaply.
An EPSRC release reports that the aim of the overall project, initiated by the US Department of Energy and led by Georgia Institute of Technology, is to design a power plant whose size would be reduced and safety enhanced by breaking with convention and integrating the main heat exchangers inside the secure pressure vessel where the nuclear reactions take place. This innovation gives the design its name: Integral Inherently Safe Light Water Reactor (I2S-LWR).
Dr. Geoff Parks, who is leading the Cambridge team, says: “The fact that we are part of such a pioneering international project not only reflects the UK’s enduring reputation in nuclear science and engineering — it also provides a platform for the United Kingdom to develop a new suite of relevant, globally marketable skills for the years and decades ahead. If all goes to plan, construction of the first I2S-LWRs could begin in around ten years, making deployment of nuclear power more practical, more cost-effective and more publicly acceptable worldwide.”
The I2S-LWR, which could also be constructed off-site, module by module, and then quickly assembled on site, would be suitable for deployment worldwide. In this country, it could contribute to a new era of nuclear power that helps the United Kingdom meet its carbon reduction targets and energy security objectives; no new nuclear power station has been built here since Sizewell-B began generating in 1995. With a power rating of around 1GW, the output from the I2S-LWR would be comparable with Sizewell B’s 1.2GW rating, but the station should be significantly less costly in real terms.
The EPSRC says that the EPSRC-funded part of the project will help the United Kingdom reinvigorate its technical expertise in civil nuclear power and attract a new generation of engineers and scientists to the field. Expertise of this kind will be crucial to securing the U.K. nuclear future but has significantly diminished during the 20-year ‘nuclear hibernation’ where no new nuclear power stations have come on stream.
The Cambridge team will focus on how thorium, which can be converted into the isotope uranium-233, could be used alongside uranium silicide to fuel the I2S-LWR. The team will assess the question not just from the perspective of fundamental nuclear reactor physics but also in terms of the scope to achieve high fuel-to-power conversion efficiency and to recycle spent nuclear fuel - key issues impacting the cost-effectiveness of the thorium fuel option.
Background
The 3.5-year project, “Integral Inherently Safe Light Water Reactor (I2S-LWR)” GOW EP/K033611/1, has received around £279,000 in EPSRC funding and is due to run until January 2017.
The I2S-LWR would be a type of pressurized water reactor (PWR), a technology well-established around the world. Examples include Sizewell-B power station on the Suffolk coast.
In a PWR, heat is taken away from the nuclear core by a primary coolant and then transferred to a secondary coolant which is raised to steam. This steam is then used to drive turbines and generate electricity.
Nuclear power currently produces around one-sixth of the U.K. electricity. Most existing nuclear power stations in this country are scheduled to close by 2023. The coalition government’s vision is that nuclear power should continue to play an important role in the U.K. energy mix, with energy companies building new power stations subject to the normal planning process and without public subsidy.
Conventionally, nuclear power stations use uranium oxide as their main fuel. Uranium silicide’s higher density and better thermal conductivity mean it could potentially deliver superior power production performance, resulting in lower-cost electricity.
