The £20 billion Hinkley Point C nuclear power station in Somerset won’t open until at least 2025, and by then, it could already be a relic.
The eye-watering cost of such large projects has led to an explosion of interest in alternative nuclear technology – small modular reactors (SMRs). While traditional nuclear plants are designed to generate several gigawatts of electricity – enough to power millions of homes – these mini nuclear reactors aim for much more modest outputs of up to 350 megawatts.
In June, the UK government pledged £56 million for research into advanced versions of these smaller-scale power plants. This week, an independent expert review commissioned by the government recommended that SMRs be offered the same subsidies given to offshore wind projects. That’s potentially a big deal for the nuclear power industry and an equally big headache for projects on the scale of Hinkley Point C.
“Until recently, there was this idea that way to reduce cost is to make things bigger,” explains Giorgio Locatelli from the school of civil engineering at the University of Leeds. “Large reactors try to bring the cost down by maximising economies of scale, but SMRs try to do it with economies of multiples.”
The parts are small enough to be transported by truck or train, which means they can maximise the use of factory-built components instead of creating everything on site, which brings down the cost. The smaller scale also helps spread risk and makes attracting financing easier. Instead of gambling tens of billions on what could turn out to be a massive white elephant, SMRs allow governments or electricity companies to experiment – they can build one small reactor, and then use what they’ve learnt from that process immediately.
The proceeds from one SMR going online can also help fund subsequent projects – a route closed off for large, decades-long schemes such as Hinkley Point C, which has been heavily criticised for its funding model. It’s easier to find investors when the payoff is that much sooner.
“SMRs will play a major part in the future of nuclear,” says Robert Plana, chief technical officer at Assystem Energy & Infrastructure, one of the world’s biggest nuclear companies. The only problem? No one has actually built one yet.
Although smaller-scale reactors have been around for decades, floating in the seas on nuclear submarines, they are uncharted territory for civil engineers, where the energy requirements are higher, and the budgets relatively constrained.
Some companies, including Rolls-Royce and Westinghouse, are working on pressurised water reactors (PWR) that are similar to the technology used both in nuclear submarines and most large-scale power plants today. Others are developing alternative technologies that could prove more effective. Oregon-based NuScale power is developing a light-water reactor, for example, while a number of others are exploring the potential of using molten salt as a coolant. “In theory molten salt is much better than PWR,” says Locatelli. “The problem is we need to build them to prove that they are reliable.”
There's a trade-off. SMRs based on existing technology will be easier to build, and ready more quickly. New technologies might be more efficient, but given the breakthroughs required, it could take decades before they're ready to start generating power.
In Britain, a skills shortage could exacerbate the problem. “The UK is already in desperate need for talent to complete current nuclear projects,” says Plana. He estimates that to build enough SMRs to generate seven gigawatts of electricity, the country would need an extra 40,000 skilled workers.
The best approach is likely to be a mixed one: SMRs based on established technologies in the short-term, accompanied by heavy investment in new approaches, as well as a mixture of small and large-scale nuclear projects. “It’s important to note that this is not about a competition between big gigawatt reactors and small reactors, we recognise there is room for both large and small nuclear in the UK’s energy mix,” says Fiona Reilly, who helped develop a government framework for creating a market for SMRs, which was published earlier this week.
The last of the UK’s currently operational nuclear power plants will be decommissioned in 2035. They need to be replaced with something, or the country will be left relying on gas to provide power on demand - known as dispatchable power - on days when there’s no wind or sunshine. “If something happens to the supply of gas, we are without dispatchable power,” says Locatelli.
SMRs could be an important part of the solution. “You need renewables, you need nuclear, you need to invest in fusion and molten salt,” adds Locatelli. “If every UK citizen pays £10 a year to invest in future technology, we will have the budget to do all this research.”