Kier, X-energy, and Cavendish Nuclear have entered into a Memorandum of Understanding (MoU) to work together on advancing the next era of nuclear reactors in the UK.

The companies will explore opportunities around the deployment of a fleet of Xe-100 Generation IV Advanced Reactors in the UK following the award today of a grant to X-energy and Cavendish Nuclear from the Government’s Future Nuclear Enabling fund.

The Government's award of £3.34 million will be matched by X-energy, providing a total fund of £6.68m.


The MoU establishes the basis for Kier to carry out a constructability assessment for the Xe-100 in the UK, adopting lessons learnt from studies in the US and Canada.

The High-Temperature Gas-cooled ‘pebble bed’ Reactor is designed to have a substantial proportion of modules prefabricated in factory conditions and transported to site for assembly, allowing for a construction time of three to four years.

The MoU supports X-energy and Cavendish Nuclear’s supply chain development, with the companies seeking to have more than 80% of their project requirements met eventually by British companies.

Each Xe-100 is capable of producing 200MW of high temperature heat and steam for clean industrial applications as well as 80MW of electricity. There are plans for around 40 in the UK.

The intrinsically safe 'pebble' fuel form acts as a containment vessel, reducing the need for large and complex safety structures. It also means the emergency planning zone is restricted to the site boundary, allowing for more flexibility in siting.