Rolls-Royce is in early-stage talks with potential commercial customers for its planned micro nuclear reactor, a technology it hopes will also provide power for space missions.
Jake Thompson, director of novel nuclear and special projects at Rolls-Royce, said the company was exploring opportunities to deploy the reactor “across data centres, mining and remote communities”.
Better known for its civil aircraft engines and for building the reactors that have propelled Royal Navy submarines for the past six decades, Rolls-Royce wants to capitalise on its nuclear expertise.
With global interest in small reactors growing quickly, the company believes there is a business case for micro reactors for both terrestrial and space applications.
“Energy demands are set to increase rapidly — essentially the world will need everything that we can bring to bear,” said Thompson, who has been a nuclear engineer at the company for 18 years.
Compared with small modular reactors (SMRs) which are seeing demand from technology groups such as Google to deliver low-carbon electricity for data centres, micro nuclear reactors use different technologies and have a much smaller power output. Their compact size also makes them transportable.
For Rolls-Royce, the business is separate from the unit which is looking to build a fleet of SMRs, including in the UK.
Rolls-Royce began work on the technology for a micro reactor three and a half years ago, joining forces with the UK Space Agency in 2021 to study how nuclear power could be used as part of space exploration.
The focus at Rolls-Royce, said Thompson, has been on how to make a reactor that is “really small, small enough so you could load it on to a rocket and send it into space”.
Nuclear power is seen as an “essential enabler” in space exploration, said Thompson. “People want to do more things, have more things in space. All of that requires more energy. On the dark side of the moon, you can’t generate that energy through solar power.”
The space agency has invested £9.46mn in grant funding to date towards the demonstration of a lunar modular nuclear reactor, matched by funding from Rolls-Royce.
The company said it will have a deployable reactor by the “early 2030s”. A big prize would be a contract with Nasa, whose Artemis programme aims to establish a human presence on the lunar surface by 2031.
“We believe once governments and the Artemis missions have re-established human presence on the moon, commercial services will follow that,” said Thompson, adding that “every operation on the moon will require power”.
Nuclear power in space is not a new idea. The US spent considerable effort in the 1960s on an experimental reactor, Snap-10A, which was sent into orbit. It stopped working after 43 days but remains in polar orbit. Radioactive batteries have also powered numerous vehicles, including the Voyager spacecraft.
The bet today by governments and companies is that advances in technology can offer something more powerful. Russia’s space agency, Roscosmos, announced earlier this year it would build a lunar reactor with the China National Space Administration by 2035 to power a joint base on the moon.
Rolls-Royce, as part of a separate initiative with the UK Space Agency, is also working with BWX Technologies of the US to look at different nuclear applications in space.
Other companies vying for a role in the burgeoning market include Lockheed Martin and Westinghouse. Both companies were selected by Nasa two years ago to develop design concepts for a reactor for use on the moon.
At Rolls-Royce’s site in Bristol, the programme’s 100-strong team has been working on the concept development phase of the reactor, as well as on the manufacturing and testing of prototype components.
Unlike conventional pressurised water reactors that are often used in large nuclear power plants and which Rolls-Royce plans to deploy for its SMR initiative, the micro reactor is a “high-temperature gas-cooled reactor”. In this design, gas instead of water is used as a coolant, allowing for much higher temperatures.
The hot gas is then used to drive turbines that generate electricity. The company recently successfully tested an electrically-heated version of the process to demonstrate the hot gas driving a turbine to generate electricity. There is “not another facility in the world doing that kind of testing right now,” said Thompson.
The reactor uses highly enriched uranium fuel. Made up of very small spheres of uranium, these are coated in protective layers of carbon and graphite to create “really strong and high-temperature resistant individual fuel particles,” said Thompson.
One reactor core is expected to last about 10 years. On Earth, Rolls-Royce could re-fuel the reactor but is unlikely to do so in space. Thompson said it would work closely with the UK government on safe storage and disposal routes.
The two variants will differ in size and power output. The terrestrial variant, with a power output of between 5MW-20MW, is expected to fit into a shipping container that could be deployed to remote industrial locations or military installations where access to fossil fuels or reliable renewable power is limited.
The space reactor needs to be lightweight and just as durable. Nasa’s requirement is for a reactor to weigh 6,000kg or less. The concept is about the size of a family car and would produce “hundreds of kilowatts,” said Thompson.
The company is mindful of the potential dangers. Thompson said the reactor would be designed so that it would only turn on when it gets to the lunar surface. During transit on the rocket the nuclear fuel inside would be inert.
Stephen Thomas, emeritus professor of energy policy at the University of Greenwich, points out that while there is a “lot of ambitious talk about new nuclear designs . . . most of the applications have been talked about for 50 years, [from] ships to aircraft and now space stations”.
Commercial applications for remote sites, added Thompson, were “very limited . . . and whether micro reactors are the best way to meet the demands are very far from clear for me”.
Nick Cunningham, analyst at Agency Partners, is similarly not convinced of the use of micro reactors for isolated communities, but believes there are opportunities in space, albeit a “bit of a niche market”.
There are “two good uses for reactors — submarines and spacecraft,” he said. “They cannot be replaced for submarines . . . and they are really good for deep space probes and perhaps lunar stations if they are not in direct sunlight.”
