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Dirty cell clean up goes through the roof

Dirty cell clean up goes through the roof

The x-ray cell in one of Dounreay’s redundant fuel cycle facilities has been stripped out, earning the decommissioning team a performance-based incentive.

Its an important part of the post-irradiation examination facility’s clean-out programme, due to be completed in October 2012.

During its lifetime the facility examined irradiated fuel and other fissile materials from research reactors at Dounreay, elsewhere in the UK and abroad.

The facility was in virtually constant use from its construction in 1959 until it was shut down in 1996. It played a major role supporting the reactor operations at Dounreay.

An extensive period of remote decontamination was required to reduce the background radiation in the cell to levels to allow man entry. A mixed team of workers from DSRL, Doosan Babcock and NDSL were then able to enter the cell to assist with the removal operations.

The roof of the heavily shielded cell was constructed of two layers of removable reinforced concrete blocks. Several of these were removed to create a path for the bulky equipment to be winched out.

The x-ray equipment was remotely disconnected using manipulators, slung under the building crane and carefully lifted out of the cell through the hole in the roof.

Each piece of equipment was packaged before being placed in an industrial container for disposal as low level waste.

DSRL project manager Colin Paterson commented on the skill of the team carrying out the work.

“They were able to disconnect the equipment remotely from the in-cell fixtures, using manipulators,” he said. “This meant that we could get the job done with far less dose to the operators than if they had physically gone into the cell to do the complete task.”