Dounreay update: Another relic to be consigned to history.

Dounreay, UK - Another relic of Dounreay¹s past is about to be consigned to history. The original ventilation stack from the Dounreay Fast Reactor is about to be decontaminated and cut up. Measuring 28 metres in length and weighing almost 24 tonnes, the stack served as the exhaust for the ventilation system in DFR during its operational days.

It was taken down at the turn of the century when the DFR decommissioning team needed a more modern ventilation system. A replacement stack costing £750,000 - designed to replicate the silhouette of the original reactor was installed in its place.The redundant chimney, meanwhile, was sealed and placed in storage at the decontamination area towards the eastern end of the site. A waste team has now begun work scrapping it.

The first step was to get JGC and Simpson¹s crane to lift the 24-tonne chimney into a position where workers can go inside and decontaminate. They¹ll use another redundant piece of reactor hardware the air lock entry chamber removed from DMTR as a containment barrier. Once it¹s decontaminated, the stack will be cut up and packaged as low-level waste.

DFR was Britain’s first fast breeder reactor, playing an important part in international fast reactor research. It demonstrated that a safe and easily operable reactor of this type could be built for electrical power station use.

Housed inside a steel sphere, it was built to test the concept and, in 1961, became the first fast reactor in the world to provide electricity to the national grid. At this time its 14MW output was enough to power a small town the size of Thurso.

Key facts:

* Construction: 1955-1958

* Output:: 14MW (electrical) - 60MW (thermal)

* Operation:- 1959-1977

* Decommissioning Completion: 2024

Decommissioning progress to date:

- All reactor fuel, except one experimental assembly, and around one third of the uranium breeder blanket surrounding the core removed.

- Pipe-bridge between reactor and heat exchanger removed.

- New ventilation system installed and strip-out of redundant 50-year-old ducting underway.

- Removal and demolition of steam-raising plant, turbine and building.

- All secondary liquid metal coolant removed and destroyed (110 tonnes).

- Fuel storage pond furniture and sludge removed.

- Removal of large reactor components ongoing.

- Construction of new liquid metal sodiumpotassium disposal plant complete and active operation started.

- Goliath crane refurbished and operational for dismantling plant.

- Removal of redundant ductwork and associated equipment and pipework underway.

- Construction of new plant to remove remaining breeder material from reactor.