Rolls-Royce has signed two landmark trilateral memorandums of cooperation with the UK National Nuclear Laboratory (UKNNL) and the Japan Atomic Energy Agency (JAEA) to rapidly co-develop next-generation nuclear technology. The agreements were signed at 10 Downing Street during a diplomatic visit by Japanese Prime Minister Sanae Takaichi.
They represent the first real-world activation of the UK government’s newly established Advanced Nuclear Framework, which seeks to build an efficient pipeline for commercial, privately funded nuclear ventures. The partnership combines British and Japanese expertise to accelerate the research, development, and deployment of two critical technologies – high-temperature gas-cooled advanced modular reactors (AMRs) and Tri-structural Isotropic (TRISO) coated particle fuel (CPF/TRISO).
Japan brings crucial operational experience from its High Temperature Engineering Test Reactor, which has run since 1998. Meanwhile, UKNNL hosts the UK’s only specialised facility capable of producing CPF kernels at its Preston laboratory.
Unlike large-scale or small modular reactors (SMRs) built primarily for grid electricity, these compact AMRs are tailor-made to provide flexible, low-carbon heat and power directly to off-grid industrial estates, data centres, and military bases.
This agreement is part of a larger £18bn ($24bn) UK-Japan technology and investment push, which spans offshore wind energy, quantum computing, semiconductors, and joint defence initiatives. The immediate phase focuses on progressing workforce skills programmes, coordinating the domestic nuclear supply chain, and providing Rolls-Royce with access to specialised international testing facilities. Backed by previous government funding allocations, the ultimate goal of the UK-Japan framework is to have an operational AMR demonstration project up and running by the mid-2030s.
Our two agreements with UKNNL and JAEA are a milestone moment for the UK’s nuclear sector,” said Rolls-Royce Group President Chris Cholerton. “Strengthening existing relationships between our nations and combining our broad nuclear capability, they will enable us to jointly address technical challenges and accelerate the development of advanced modular reactors and their advanced coated particle fuel, to deliver industrial growth, skilled jobs and energy security for our nations.”
Building on the success of Rolls-Royce SMR in the Great British Energy – Nuclear selection process, Rolls-Royce is looking to broaden its nuclear portfolio and explore opportunities in the AMR market. Differentiated in reactor technology, size and power output from the Rolls-Royce SMR, the Rolls-Royce AMR still benefits from the same innovative modular design and build certainty.
JAEA President Masanori Koguchi welcomed the collaboration with UKNNL and Rolls-Royce. “I hope that through our expertise in high temperature gas reactor technologies, this collaboration will lead to their early deployment, a significant step towards net zero,” he said.
Julianne Antrobus, CEO of UKNNL, said: “Advanced nuclear technologies have the potential to deliver clean, safe and reliable energy, stimulating economic growth while supporting the decarbonisation of industries that millions of people work in. Getting these technologies deployed is an economic and social opportunity that the UK is well placed to seize.
She added: “The UK government’s Advanced Nuclear Framework exists to give industry a clear route to access the world-class expertise that UKNNL offers. Being contracted by Rolls-Royce to support this vital work is a strong signal that the framework is delivering and that UKNNL is playing its part in bringing the sector together.”
