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Read part one, "Power Play: The small solution to the world's big nuclear energy problem."
The idea of compact nuclear energy – or small modular reactor (SMR) technology – is experiencing a resurgence largely because of the cost of building large power plants.
That’s according to some of the big companies in the sector and academics such as Sir Steven Cowley, an expert in nuclear fusion. While there are clear advantages to large reactors, says Cowley, projects such as the £20bn Hinkley Point C illustrate the capital required and the risks involved if “suboptimal decisions” are made. Building smaller reactors in much the same way as jet engines or cars are made will allow engineers to drive quality into the products and to drive out the bugs. In fact, the greatest benefit of the renewed interest in SMR research is learning, says Cowley.
“They’ve built thousands and thousands of cars, learning along the way. But with large-scale nuclear plants, until now, we’ve made one of a kind, with very little learning. With SMRs, you evolve the kind of economy of manufacturing you see in the car or aircraft industries.”
Who should know this better than Rolls-Royce, which is leading a group exploring the idea of shrinking entire power plants, not just reactors. The company’s executive vice-president, David Orr, says this approach offers many benefits.
“We have seen timeline and financing challenges with large-scale nuclear projects, so the market is responding with alternatives that can provide lower barriers to entry, greater standardisation, more speed and lower costs,” says Orr.
“Our design is compelling because once it is licensed it requires no taxpayer funding for construction and this means that private companies can then make this electricity accessible quickly and cheaply.”
For Cowley, the future of nuclear energy and SMRs resembles a relay race. Today’s runners who carry the baton represent fission technology. He says it would be more practical to focus on a handful of existing technologies – such as light-water/pressurised-water reactors – instead of having too many runners clogging up the lanes. “You don’t want too many technologies. By making a lot of the same you bring down costs.”
By the middle of the century, the baton can be passed to fusion energy, which, says Cowley, is “the perfect way to make energy” – it’s safer and cleaner.
“With fusion, we don’t have all the physics and engineering figured out,” he says. “We’d like to bring down the size of the experiments and lower the risk.”
Cowley is director of the Princeton Plasma Physics Laboratory, which is focusing on shrinking fusion experiments and is about to start rebuilding its NSTX Upgrade spherical tokamak, which holds the world record for reaching 70m degrees Celsius. Its sights are now set on breaking through the 100m degrees barrier.
The trouble for runners carrying the fusion baton is that there are additional hurdles in the way. Engineering new super-powerful magnets is one, solving the net energy gain conundrum is another. As is getting smarter with the physics and experimenting with various configurations of tokamaks. The UK Atomic Energy Authority’s research lab at Culham is busy in this field with its MAST Upgrade tokamak, as are various universities and companies.
The race is on to build the first SMR. These small power plants will offer states the option to make smaller bets on nuclear energy. With many existing reactors ready for retirement around 2030, it’s important to get SMR development right if nuclear is to remain in the global electricity mix.
Content published by Professional Engineering does not necessarily represent the views of the Institution of Mechanical Engineers.