Rolls-Royce charts SSN-AUKUS reactor progress

A model of SSN-AUKUS on display at DSEI 2025. (Janes/Neil Dee)

Rolls-Royce has provided an update on the progress of its new nuclear reactors for the future SSN-AUKUS-class submarines for the UK Royal Navy (RN) and Royal Australian Navy (RAN).

Speaking in a session on SSN-AUKUS at the Defence and Security Equipment International (DSEI) 2025 exhibition held in London from 9 to 12 September, a Rolls-Royce representative said the company has already commenced production of boat two SSN-AUKUS reactor components at its Raynesway site in Derby, while boat six's and seven's major materials have been released into the supply chain. Speaking to Janes later in the day and via email, Rolls-Royce said while the build order of boats for the United Kingdom and Australia is yet to be confirmed, boat components for both countries are in the early stages of manufacturing.

A model of SSN-AUKUS was displayed on Rolls-Royce's stand at DSEI 2025 alongside a model of the RN's future Dreadnought-class nuclear-powered ballistic missile submarine (SSBN). The latter will feature Rolls-Royce's PWR 3 (Pressurised Water Reactor 3), while SSN-AUKUS will have an enhanced variant referred to as PWR 3+. In both classes, the reactor will power a single pumpjet propulsor. The UK Strategic Defence Review, published in June 2025, confirmed that up to 12 SSN-AUKUS-class attack submarines are to replace the Astute class in RN service from the late 2030s. A further eight or more SSN-AUKUS-class submarines will also enter Australian service by the 2040s.