When we think about generating nuclear power, the immediate image that springs to mind is of a large nuclear reactor, always somewhere near the coast, producing between 1,000 and 2,000 megawatts (MW) of power – enough energy to power millions of homes.
High capital cost is one of the reasons why it is becoming harder to finance and invest in new large scale nuclear plants and that, in many people’s eyes, makes large scale nuclear difficult to justify as competitive with other forms of generating power. Another argument is about time. The last nuclear power station to be built in Britain – Sizewell B – was finished over 20 years ago and although we’re closer than ever to a new one getting underway, it’ll be into the 2020s before a new nuclear power plant will be up and running.
Small modular reactors, more commonly known as SMRs, could therefore play an important role in the future of nuclear.
Defined by the International Atomic Energy Agency (IAEA) as under 300MW, SMRs are by their nature, smaller and more flexible to site. As well as decreased site infrastructure construction and cost reductions because of their modular nature, staggering construction of units could mean a more gradual level of investment as the capacity builds up module by module, better matching capacity to requirement.
The other major benefit of a modular reactor is that they can be deployed at a wider range of sites than large scale nuclear reactors – assuming the SMR gains all the necessary consents and licenses – and has applications as an alternative energy source in regions where grid capacity is weak or non-existent, remote locations with sparse populations, or larger energy-using industrial applications such as for the chemical industry or at desalination plants.
Much less water is needed to cool an SMR than a conventional large scale reactor, and this has potential applications as heated water from an SMR can be pumped into district heating schemes.
This begs the sixty-four million dollar question: why haven’t we built any yet?
Economies of scale have meant that for larger power plants the pound per megawatt ratio is reduced the bigger the plant gets. For SMRs, scale would be found in economies of mass production as they are turned out in factories in large numbers, but the technology would still have to prove it can generate electricity at a reasonable price. Technical challenges about how to exactly do that is something developers are still working on.
There are some examples from around the world that show development of demonstration projects well under way – from Russia, Korea, China and the USA (although there’s been a bit of a stumble in the latter due to the impact of the shale gas boom), many companies are working on many different designs.
In the UK, Atkins has for some time been involved in work to help make the SMR a reality including our contribution to a recent Energy Technologies Institute study on the role for nuclear within a low carbon economy. Our country’s nuclear pedigree and desire to regain our position as a pioneering nuclear nation has led to some interesting designs and developments of our own. Several UK based companies, and the government, are either conducting feasibility studies or developing micro-reactor concepts and we’re excited to see where the next stages of work will take the industry.
Aside from regulatory hurdles, perhaps the biggest issue with SMRs really lies around acceptability. Support for nuclear power varies wildly from country to country. In the UK, support hovers at around 40% (source: The Guardian) and is much higher at 68% in the USA (source: World Nuclear News), whilst a return to nuclear power in Japan is staunchly opposed by 70% of people there (source: Washington Post). So would the public be open to having a small nuclear reactor in their backyard providing direct power and maybe also heating to their community? Do we want one in the basement of our office block? Are there moral implications of putting small nuclear reactors into remote communities?
If these and other questions can be answered, there may be a big future for small nuclear.