Rolls-Royce sets out defence case for modular reactor at UDT

Rolls-Royce has outlined how its Advanced Modular Reactor (AMR) could support both defence operations and wider energy resilience, with an emphasis on deployable, long-endurance power and export potential.

Speaking to the UK Defence Journal at UDT in London, Mark Cheeseman, a Programme Executive within Rolls-Royce’s AMR team, positioned the concept as a next step beyond existing small modular reactor efforts, designed to deliver more flexible power closer to demand.

“What we think comes next is a smaller power plant that can be positioned closer to larger population densities, where we can provide more flexible power that provides higher heat,” he said.

Cheeseman explained that this capability is particularly relevant for industrial use, highlighting sectors that are difficult to decarbonise.

“It can really help us to transition hard to abate industries, steel making, hydrogen production… [and] help the UK with its clean economy.”

From a defence perspective, he made clear that resilience and independence are central to the concept, particularly in environments where access to reliable power is constrained.

“The resilience that this kind of product would offer… being able to fuel for between five and seven years… is very attractive,” he said, adding that the ability to pay upfront for fuel provides cost certainty over extended periods.

He also stressed that the system is designed to be power-dense and continuously available, characteristics that align with military requirements for persistent capability.

A key differentiator, Cheeseman argued, is the use of coated particle fuel, which underpins what he described as inherent or passive safety.

“You could walk away from this reactor, and everything will be fine… it will safely come to its own controlled stop,” he said.

Cheeseman made clear that this reduces the need for the complex redundancy typically associated with large nuclear plants, enabling more flexible siting and deployment.

“You don’t need the redundancy you typically need with large reactors… you can place them closer to populations.”

He added that the design is being developed with mobility in mind, including the ability to transport units by road, which would allow deployment into remote or austere environments.

This has clear implications beyond defence, particularly in regions without established grid infrastructure.

“If you take it beyond the UK… where you have a lot of mining companies that really need electrical power… some of them don’t have a grid at all… why not deploy… an array of these smaller reactors.”

Cheeseman suggested that multiple units could be deployed together to provide scalable power and heat, ensuring continuity of industrial processes in isolated locations.

He also pointed to a broader strategic opportunity for the UK, linking the programme to domestic fuel production and export potential.

“We are working very hard as a country to produce the fuel that will be required… this will separate us from the dependence on oil and gas.”

“If we can make it right here in the UK, this can become a huge export opportunity.”

However, he was clear that the programme remains at an early stage, with further progress dependent on backing and investment.

“We’re in a concept design stage right now… it’s really important to us to make sure we have UK home-grown support for this.”

Cheeseman indicated that, with sufficient support, the programme could move towards a first-of-a-kind reactor in the mid-2030s, while noting that international competitors, particularly in the United States, are already advancing similar technologies. His remarks framed the AMR as a dual-use capability, positioned at the intersection of defence resilience, industrial decarbonisation and long-term energy security.