Dounreay Fast Reactor
The fast reactor at Dounreay was the first reactor to commence construction and the second operational reactor. It achieved criticality on 14 November 1959 and produced an electrical output of 14 MWe. Power was exported to the national grid from 14 October 1962 to 1977, when the reactor was taken offline for decommissioning. During its 15 year lifespan, the Dounreay Fast Reactor produced over 600 million kWh of electricity.
The Dounreay Fast Reactor was a loop-type fast breeder reactor, cooled by primary and secondary NaK (sodium-potassium alloy) circuits, with 24 primary coolant loops. The reactor core was initially fueled by uranium metal fuel stabilized with molybdenum and clad in niobium. The core was later used to test oxide fuels for Dounreay’s prototype fast reactor and provide experimental space to support overseas fast reactor fuel and materials development programs.