 The reactor drives two GEC steam turbines linked to a single shaft pump jet propulsor, giving the submarines a maximum submerged speed of over .Auxiliary power is provided by a pair of 6 MW steam-turbine generators supplied by WH Allen, (later known as NEI Allen, Allen Power & Rolls-Royce), and two 905 kWb Paxman diesel generators for provision of backup power supply.British nuclear weapons are designed and developed by the UK's Atomic Weapons Establishment.