20 Feb (NucNet): A hi-tech “worm” is probing a subterranean pipeline used to discharge radioactive effluent from Dounreay, the UK’s former centre of fast reactor research and development, between 1957 and 1992.
The 100,000-pound (142,000 US dollars, 113,000 euro) pipe crawler has sent back video and radiation readings during its five-day journey some 45 metres underground.
The data will be analysed by a project team investigating how to leave the disused system in a safe condition as part of the site clean-up.
A bundle of four cast iron pipes, each 23cm in diameter, was laid in the 1950s to discharge effluent from the fast reactor experiment. It was connected on the surface at one end to two disused tanks where effluent drained from the reactors, chemical plants and waste facilities.
The pipeline bundle descends towards the sea to a tunnel excavated 25 metres beneath the seabed. At the end of the tunnel, some 600 metres offshore, the pipeline terminated in a diffuser attached to vertical risers that exited on the seabed 20 metres beneath the waves.
The pipes were encased in a thick concrete sleeve that runs along one side of the tunnel. When construction finished in 1957, the tunnel was abandoned and allowed to flood.
“The remotely-operated vehicle will allow us to inspect the inside of the pipes,” said Martin Howse, project manager with Dounreay Site Restoration Ltd. “We are looking for signs of structural degradation, trapped debris and radioactive contamination.”
Details of decommissioning work being carried out at Dounreay are available on the DSRL web site (www.dounreay.com).
>>Related reports in the NucNet database (available to subscribers)
Next Phase Of Dounreay Reactor Clean-out Under Way (World Nuclear Review No. 21, 26 May 2006)
Green Light For Dounreay Intermediate-Level Waste Facility (World Nuclear Review No. 4, 26 January 2007)
