Rolls-Royce PWR - PWR1

PWR1

The first British naval reactor, the PWR1, utilising a core based on a Westinghouse design (though built entirely by Rolls-Royce) and a larger reactor assembly of purely British design went critical in 1965. Technology transfers under the 1958 US-UK Mutual Defence Agreement eventually made Rolls-Royce entirely self-sufficient in reactor design in exchange for a "considerable amount" of information regarding submarine design and quietening techniques being passed on to the USA.

Rolls Royce and Associates at Derby became the centre for design and manufacture of the reactors. The Ministry of Defence's Vulcan Naval Reactor Test Establishment, at Dounreay, tested each reactor prior to its installation in nuclear submarines.