The Nuclear Decommissioning Authority (NDA) will have its annual funding for Dounreay capped at £150million, meaning there will be a renewed focus on improving efficiencies and looking for new technologies to help it meet its target completion date of 2025.

Peak spending was originally envisaged to be closer to £200million per year.

Nuclear energy was in its infancy in the 1950s when the centre of fast reactor research and development was built at Dounreay to test new ways of generating electricity from uranium and plutonium. Back then, the focus was on developing a clean and efficient form of energy to power a country that under the shadow of the Cold War.

Today, Dounreay is still at the forefront of a growing sector, but this time it is leading the development of decommissioning – or the process of cleaning out and dismantling. The complex on Scotland’s north coast includes three nuclear reactors, chemical plants for manufacturing and processing new and used nuclear fuel and waste stores and disposal sites.

Dounreay Site Restoration Limited (DSRL) has managed the site since it took over from the UK Atomic Energy Authority in 2008. Work has involved more than 50 companies and provided about 3,000 jobs across Scotland and in Caithness and north Sutherland, where it accounts directly for 20% of all employment. So far more than 100 redundant buildings, many with a history of radioactive and chemical use, have been dismantled.

The most recent development was the demolition of the Crit Lab, a research cell where plutonium and uranium were taken to the point of nuclear reaction and assessed on how they performed. The lab was abandoned in the 1960s and became very dirty; it has since taken 20,000 separate entries in moon suits to clean the lab to the point where bulldozers could move in and flatten it, which occurred on target last year.

The iconic steel sphere also remains at the centre of the decommissioning process as there is another 15 years of work required to strip the reactor and vessels inside. Of the 1,700 tonnes of liquid metal left inside its pipe work, the last 45 tonnes are the most hazardous and require special plant to process. The first run of the plant, commissioned in 2008 to deal with this high level waste, has been completed and was followed by a planned maintenance; the next run is now underway.

The plant is running batches of the liquid metal through a chemical process to neutralise its alkalinity. This solution is still contaminated with large amounts of radioactive caesium, so it is passed through a second plant to clean the radioactive component. It will take until 2012-2013 to completely destroy the liquid metal in the reactor.

Robotics, used to cut out the remaining uranium and plutonium, are a technology that has been ‘taken off the shelf’. Colin Punler, Communications Manager, said this is an example of DSRL utilising available and proven technology wherever possible. “Clean-up teams are using robotic equipment of the kind found in car factories and the North Sea to package waste, to clean up radioactive waste on the seabed and for packaging up the uranium and plutonium that comes out of the sphere,” Punler said.

Skills are another asset that has been gleaned from other sectors. “The skills sets needed for decommissioning activities at Dounreay are not terribly different to those needed for offshore oil and gas,” he said. “The main difference is that we have to bolt on health physics issues caused by radiation; in terms of engineering, environmental sciences and regulatory knowledge, the requirements are very similar.”

While the priority is to dismantle and clean the site at Dounreay, ensuring that the 2,000 skilled employees are able to transfer their skills to other industries has also been built into the plan. “There is a team that looks at which other industries could benefit, such as oil and gas as well as renewables,” Punler said. “A lot of work is going into mapping their skill needs and seeing how we can match up the release of surplus skills as more of the site is demolished.”

Decommissioning has now become a major feature in the design of new nuclear projects, which has been a lesson leant at Dounreay. Punler said that in the 1950s little thought was given to how the facilities would be disassembled – the priority was providing electricity under the threat of the Cold War. “Now sustainability is the buzzword,” he said. “By finding ways to safely take apart the old reactors it’s helping the industry to support the growth of the sector in the future.”

Thought is also being given to how the site will be left once the decommissioning process has been completed. A heritage strategy is being developed to consider how future generations will interpret Dounreay’s past not only through buildings but through knowledge and records left behind. Punler said the public is being asked to consider what should be the cultural legacy of the site through a draft strategy which has just undergone                                                          consultation.

“Recommendations are due to be made to NDA this summer on what kind of work needs to be done, such as whether we keep the sphere and who looks after the site when we are gone,” he said. “Should we keep the sphere because of the emotional attachment? Is it a landmark and symbolic of a different era? We have to consider that it is so contaminated with radioactivity that it would take a huge sum of money to get contamination levels down and maintain the structure. What do you do with a giant steel sphere on land that will not be released until the year 2300?”

Keeping the sphere is not the only issue. There are also several thousand tonnes of radioactive waste stored very close by, which would mean substantial security and safety issues if the site was made open to the public. The consultation process will also ask for views on other options such as a fibre glass replica. “The process closed in March and has generated a good amount of discussion,” Punler said.

Helen King