Dounreay prepares for world’s deepest nuclear clean-up

DOUNREAY’S operators have unveiled plans to carry out the world’s deepest nuclear clean-up.

Babcock Dounreay Partnership (BDP) are next month to lodge a planning application to retrieve radioactive waste from a vertical shaft 65 metres deep and a vault nine metres into the ground at the site.

The water-filled shaft and silo were used to dispose of radioactive waste from some of Britain’s earliest experiments with nuclear energy.

An estimated 1500 tonnes of radioactive waste was consigned to the two facilities between 1957 and 1998. Their clean-out is a key part of the site closure contract awarded by the Nuclear Decommissioning Authority (NDA) to the partnership earlier this year.

BDP aims to complete both jobs by 2021, several years earlier than previous forecasts and at less cost to the NDA through innovation in areas such as waste packaging.

A BDP spokesman said that he could not comment on the estimated costs of the project. Previous proposals for the clean up of the shaft were valued at around £150 million.

The spokesman did confirm that £27 million has already been spent on the first phase of the decommissioning of the shaft which involved sealing fissures in the rocks, with another £6 million clearing the ground of redundant services. In 1977, Dounreay experienced one of its worst accidents when an explosion at the shaft caused severe damage to the superstructure and scattered low-level contamination around the entrance to the shaft.

A 60-strong team is currently working on the project, with employment levels expected to reach 200 during the construction phase between 2013 and 2016.

It is looking to use technology already proven elsewhere such as remote vehicles, cranes, shredders and remotely-operated grabs to carry out the clean-up.

They will solidify the processed waste in a type of container made from steel, lead and concrete which will provide shielding from harmful radiation and remove the need to build a heavily-shielded store for the previous design of containers, saving tens of millions of pounds

Twenty companies will be involved in contracts ranging from the design and build of mechanical systems such as cranes to the procurement of robotics capable of operating in high-radiation zones, major construction, plant decommissioning and back-filling.

Project director Bo Wier said that emptying the shaft and silo at Dounreay is one of the biggest clean-up challenges in Europe and one of the priorities for the NDA. "We believe we can deliver the decommissioning on an earlier timescale and at lower cost than previously thought by combining proven, off-the-shelf technology with innovation in design," he said.

"By 2021, we aim to have all the waste safely packaged for long-term storage above ground and both facilities left in a condition that do not pose a hazard to future generations.

"This is significantly earlier than previous estimates and offers substantial cost savings to the NDA."

Subject to consent, construction work is scheduled to begin in the second half of 2013 and take up to three years complete.

Retrieval of waste is expected to take 18 months to complete at the silo and 30 months at the shaft, before both facilities are back-filled with concrete. DSRL have confirmed that they plan to hold an event for the supply chain in the near future to map out procurement opportunities.

Public display of the plans will be on display at Reay Village Hall on September 11, and at Dounreay.com in Thurso on September 13 before making a formal application to Highland Council next month.