Van-sized robot to hunt radiation

A remotely-controlled pipe crawler has already been used at Dounreay

A remotely operated vehicle (ROV) the size of a transit van is to be built to help clean radioactive particles from the seabed near a nuclear site.

Last year, contractors used an ROV to make an undersea search near Dounreay in Caithness. It found 115 particles.

Dounreay Site Restoration Limited (DSRL) has agreed a three-year contract with a specialist offshore company to continue the programme.

Up to 700 radioactive fragments could be found by the machine, DSRL said.

A number of robotic machines have been built to aid in the demolition of Dounreay, a former experimental power site.

Devices have included a remotely-controlled pipe crawler, built at a cost of £100,000.

Cutting gear

In development is the 75-tonne Reactorsaurus. It is due to be built by 2013 to tear out the insides of the site's Prototype Fast Reactor.

Its robotic arms will reach 16m down into the reactor vessel.

Activated from a central control room, these arms will use diamond wire and disks, hydraulic shears, oxy/propane and plasma cutting gear to slice up the reactor's innards.

Six radiation-tolerant cameras will relay images and sound back to the control room.

The seabed is a key area of the clean-up work.

Radioactive hot spots have been discovered on the beaches and seabed around the plant for years.

They are believed to come from historic discharges of waste from the site.

Tracked wheels

Land and Marine Project Engineering, based in Cheshire, has been awarded the contract to build the new ROV and carry out search and recovery operations.

The ROV to be used will be a bespoke piece of equipment derived from underwater vehicles used in the North Sea oil industry.

Tracked wheels will allow it to crawl across the seabed and it will be equipped with a radiation detection system capable of sweeping a 2m-wide strip at a time.

The seabed scan can only take place during the summer because of sea and weather conditions and is carried out in depths of about 30m.

It will involve crews living aboard a 60m barge with operations continuing 24 hours a day.