Deadly legacy of Dounreay destroyed

Significant progress has been made in destroying one of the "most hazardous legacies" of Britain's 20th-century nuclear research programme, according to the Nuclear Decommissioning Authority (NDA).

A clean-up operation funded by the NDA has destroyed more than half of the 57,000 litres of liquid metal used as a coolant at Dounreay, the former nuclear power plant in Caithness.

Its reactor was shut down in 1994 and work to decommission the site has been under way since then.

The NDA's annual report states: "Dounreay has turned in an outstanding performance on the destruction of the sodium-potassium coolant, the largest single hazard left over from the fast-reactor research programme and the second-highest hazard on our estate."

A purpose-built chemical treatment plant destroyed the substance, according to the report.

The metal was so radioactive that its removal is rapidly bringing down radiation levels inside the reactor.

Dounreay was the only place in Britain to use liquid metal instead of gas or water in cooling systems.