UK's 10,200-ton nuclear submarines to get Rolls-Royce reactors

Rolls-Royce Submarines has entered a £400 million long-term partnership with engineering firms Assystem, AtkinsRéalis, and Frazer-Nash to support the UK’s expanding nuclear-powered submarine programs under the AUKUS trilateral security pact with Australia and the United States. This Capability Assured Strategic Partnership (CASP) aims to strengthen the industrial base behind the Royal Navy’s future fleet and the wider Defense Nuclear Enterprise amid rising demand. The collaboration builds on over 20 years of cooperation and focuses on delivering next-generation nuclear propulsion systems, including the enhanced PWR3+ pressurized water reactor and single pumpjet propulsion for the upcoming SSN-AUKUS class submarines. The SSN-AUKUS program, confirmed in the UK Strategic Defence Review of June 2025, plans to replace the Royal Navy’s Astute-class submarines with up to 12 new vessels beginning in the late 2030s, alongside at least eight submarines for the Royal Australian Navy in