The Nuclear Decommissioning Authority

New ventilation system for Dounreay

06 August 2009

 

A new ventilation system has been installed at Dounreay as part of the next stage of the decommissioning process.

The network of fans, electrical infrastructure, supports, ducts, chambers and stacks will vent the airflow during the next stages of cleaning out and dismantling the key plants that made up the Fuel Cycle Area.

During the 1950s the Fuel Cycle Area was where nuclear fuels were assembled, dissolved, examined and re-assembled in support of Britain's research and development of nuclear energy.

Decommissioning the Fuel Cycle Area is expected to cost £550 million and involves dismantling sealed facilities that are contaminated with some of the most hazardous radioactive debris.

Some of these plants have already been cleaned out and one, the former fuel fabrication plant, has been demolished – the first plant of its type ever successfully decommissioned in Scotland.

The installation of a modern ventilation system will allow teams of decommissioning staff to complete the clean-out and demolish the rest of the facilities by 2025.

Currently each of the dozen buildings that make up the heart of the Fuel Cycle Area has its own ventilation system with high integrity fans and ductwork, extracting contaminated air through high efficiency filters and exhausting into common ducts which terminate in the existing 55m high, 4.5m diameter vent stack.

By next March, the existing stack will have been replaced by a new system comprising two 30-metre high vent stacks, each two metres in diameter, fed by duty/standby inverter-driven 90kW & 132kW fans connected to the existing common ducts. The variable duty provided by inverter control will meet the decreasing ventilation needs as the facilities are demolished sequentially over the coming years.

Randall Bargelt, the NDA's Regional Director, said:

"This new ventilation system will allow the next stage of decommissioning to progress. It is another significant step in reaching our final goal as this project is an essential enabler to the decommissioning of Scotland's only nuclear fuel processing plants at Dounreay."