Manufacturer Rolls-Royce has said it plans to install and operate factory-built power stations, which could be generating power in the UK by 2029.
Mini nuclear stations can be mass manufactured and delivered in chunks which makes costs more predictable. Nevertheless critics say the UK should quit nuclear power altogether and should concentrate on cheaper renewable energy instead.
Environmentalists are divided over nuclear power, with some stating it is dangerous and expensive, and others say that to achieve net zero emissions by 2050, all technologies are needed.
However, the industry is confident the mini reactors can compete on price with low-cost renewables such as offshore wind. Rolls-Royce is leading a group to build small modular reactors (SMRs) and install them in former nuclear sites in Cumbria or Wales, with 10 to 15 stations in total in the UK. They are about 1.5 acres in size, sitting in a 10-acre space, a 16th of the size of a major power station such as Hinkley Point. SMRs are so small that technically every town could have its own reactor, but using existing sites avoids the problem of how to secure them against terrorist attacks.
It is a rare positive from the nuclear industry, which has struggled as the cost of renewables has plummeted. In the past few years, major nuclear projects have been abandoned as companies Toshiba and Hitachi pulled out due to lack of funding. Also the construction of Hinkley Point could cost £3 billion more than was expected.
Paul Stein, the chief technology officer at Rolls-Royce, said "the trick is to have prefabricated parts where we use advanced digital welding methods and robotic assembly and then parts are shipped to site and bolted together".
He believes the approach would dramatically reduce the cost of building nuclear power sites, which would lead to cheaper electricity.
However Paul Dorfman, from University College London, commented "the potential cost benefits of assembly line module construction relative to custom-build on-site construction may prove overstated".
He warned that production line mistakes can lead to generic defects that spread throughout an entire fleet of reactors, and are costly to fix. It is "far more economic to build one 1.2 GW unit than a dozen 100 MW units".
Rolls-Royce is hoping to overcome the cost barrier by selling SMRs abroad to achieve economies of scale.
Critics have warned that SMRs will not be ready in substantial numbers until the mid 2030s, by which time electricity needs to be carbon-free in the UK already, to meet climate change targets.
