Small modular reactors aren’t a new concept but they’re an idea whose time has come. With large nuclear plants looking increasingly unaffordable, small modular reactors offer a flexible and cost-effective way to meet the growing demand for low-carbon power.
Increasingly countries are looking to include nuclear power as part of their energy mix because it’s the only low-carbon form of base-load generation in many regions – and it doesn’t rely on the wind blowing or the sun shining. Historically, increasingly large nuclear reactors provided this and realised economies of scale. But without state backing of sovereign wealth fund investment, these plants are now almost unaffordable.
What’s more, many countries lack suitable sites. Access to cooling water is a major factor and in countries like Malaysia and Indonesia the transmission grid infrastructure doesn’t exist or they simply don’t have the space required. These and other countries are facing demand that’s growing at 8-10% per year and can’t wait the decade or more it takes to bring a couple of Gigawatts of generation online. They need something that can give them 400-500MW more each year.
Small modular reactors are the answer in these situations. The larger of these are 200-300MW (about a tenth of the size of the proposed new plant at Hinkley Point C in the UK). Current designs use proven pressurised water reactor technology. Their size makes them quicker and easier to build. And they offer the prospect of bringing capacity online gradually.
Looking further ahead, small modular reactors could help countries like the UK meet their commitment to low-carbon generation. By 2050, the UK’s grid capacity will need to double from 80GW to 160GW as transport goes electric. Meeting this through low-carbon generation could involve a five-fold increase in nuclear power – from 15GW to 75GW.
There aren’t enough suitable sites available to house all the large-scale nuclear plants this step change would require because of technical constraints such as access to cooling water. But there are inland sites such as the former nuclear research centres at Winfrith and Harwell that could easily accommodate smaller modular reactors of a few hundred megawatts.
This approach also has potential on a smaller scale to respond to our changing global needs. Smaller reactors of 50MW could offer a low-carbon way to power data centres, which currently account for around 2% of global energy consumption. They could also power desalination plants to meet increasing demand for potable water in places like the Middle East. Indeed, Russia already uses a small modular reactor to power a desalination plant on the Black Sea Coast.
Even smaller modular reactors of 10-50MW could one day replace gas plants at the heart of combined heat and power plants. Small modular reactors have been providing combined heat and power for the remote Russian community of Bilibino up in the Arctic Circle since 1976. And the generation four systems in development have much smaller emergency planning zones so they don’t have to be built in remote locations.
Nuclear batteries take things a step further, with a small modular reactor contained within a transportation flask. This provides a plug and play solution that seals the reactor and its waste away until the end of the plant’s life, when it can be safely disposed of.
So could all this mean that small modular reactors’ time has come? I think so, particularly if public opinion backs the nuclear option. And studies by the UK Energy Research Centre show opposition to nuclear power in Britain has fallen since 2005 despite the Fukushima accident.