The sphere
Unlike modern reactors that are situated in bedrock, the 60MW system of the Dounreay Fast Reactor was installed above ground.
The reactor vessel sits in the bottom half of the sphere and is contained inside a biological shield made of concrete.
In the 1950s, a sphere was considered to be the strongest means of containing any build-up of explosive forces that breached the primary containment around the reactor.
The sphere is made up of plates of mild steel that were welded into the shape of a sphere.
Its distinctive silhouette is recognised internationally as a symbol of 1950s technological achievement. In the early 1960s, it featured in a series of special edition stamps promoting Britain’s “white heat of technology”.
The future of the sphere once the reactor itself has been dismantled and removed is the subject of debate.
Its prominence in industrial history has been recognised by Historic Scotland, the agency responsible for conservation of built heritage.
But the sphere itself is contaminated with low levels of radioactivity. It requires continual maintenance to counter the effects of corrosion and no financial provision has been made at this stage for its maintenance beyond site closure in 2025.
Early in 2008, the site appointed its first heritage officer and WS Atkins was commissioned to prepare a heritage strategy. The outcome of this work will enable decisions to be made about which aspects of Dounreay, including the sphere, should be retained for posterity.
The original controls used to run DFR remain intact
Construction nears completion
The disused control room has been partly converted to an incident control centre on standby 24 hours a day
Construction of the sphere in the 1950s
