New stacks set to rise above Dounreay

Dounreay’s skyline is set to change again when two new ventilation stacks – each the size of a jet airliner’s fuselage – are moved into position.

The two, 30-metre high chimneys will rise above the Fuel Cycle Area in the latest phase of a £7.4 million contract to modernise the ventilation system serving the site’s former chemical works.

The stacks will vent airflows during decommissioning of some of the most hazardous facilities at the site.

More than 300 tonnes of steel has been fabricated into a network of ducts, chambers and stacks.

The new system has arrived at site in 150 lorry-loads and each part moved carefully into position to be welded together.

“This area of the site is very congested with buildings close together, so just getting the stacks into the right position to be lifted into place has been like threading the eye of a needle,” explained project manager Iain Lyall.

Each stack is 30 metres high and 2-3 metres wide – equivalent to the body of a Boeing 737 airliner.

Once commissioned, they will replace the 55m high concrete chimney that dates from the 1950s.

The main contractor is JGC Engineering and Technical Services.