Toxic hazard levels are dropping fast

Toxic hazard levels are dropping fast

The Dounreay plant that destroys the largest single hazard left over from the fast reactor experiment is working full throttle and has destroyed the equivalent of approximately 19,000 litre bottles of the liquid metal.

As well as a large percentage of the site’s total hazard this is one third of the Dounreay Fast Reactor’s own inventory, which means the breeder elements contained within the vessel are closer to being removed as the reactor is finally dismantled.

The safe destruction of the 160 kg batches of the radiologically contaminated liquid metal coolant (NaK) from the primary circuit is a crucial part of the site decommissioning programme being undertaken on behalf of the Nuclear Decommissioning Authority.

The 57 tonnes remaining inside the reactor are heavily soiled with radioactive caesium from the fuel used in the core and its destruction is one of the national priorities of the UK Government’s Department of Energy and Climate Change.

The £15m purpose built plant lifts the highly-reactive, alkali metal from the reactor system in 160 kg batches. Each batch is reacted with water in a nitrogen atmosphere to create a hydroxide solution that is neutralised with nitric acid.

Mike Brown, reactors decommissioning unit manager, explained: “The DFR NaK is the second highest hazard for the entire NDA estate and the safe removal of this highly dangerous material is crucial to the site’s decommissioning programme.”

“The removal of the NaK from DFR has presented DSRL with many unique challenges over many years and the staff and contractors involved have been totally committed and worked extremely hard to ensure the safe and successful operation of a plant built to tackle dangerous legacies from over fifty years ago and the results now speak for themselves.”

The destruction plant is on target to destroy all 57 tonnes by 2013. This will uncover the breeder elements and enable the breeder removal to commence, which will be handled in the newly constructed containment building adjacent to DFR.