The decommissioning of the Dounreay nuclear power plant is a massive undertaking. Builder & Engineer reports.
Interesting and challenging times lie ahead for the United Kingdom Atomic Energy Authority’s Dounreay site. Decommissioning of the plant is being accelerated, a move that will require extensive planning of the major works to come.
The nuclear industry was brought to this picturesque site on the north coast of Scotland in the mid-1950s, when the Government established the United Kingdom Atomic Energy Authority (UKAEA) to develop uses of nuclear energy.
Dounreay was identified as the ideal location for its new experimental reactor. No time was wasted and construction of the Dounreay Materials Test Reactor (DMTR) started in 1955. The DMTR was shut down in 1969, but by this time the Dounreay Fast Reactor (DFR) had been up and running for ten years.
The third and final reactor on the site was the Prototype Fast Reactor (PFR), which started operating in 1974 and ran until 1994.
A variety of laboratories and chemical plants were also built to handle the fuel for these reactors and various facilities were developed for the chemical treatment, storage and, where appropriate, disposal of nuclear waste.
For many years, Dounreay was the most advanced nuclear establishment of its kind in the world.
But today UKAEA faces the challenge of decommissioning the site and dealing with the nuclear waste and materials that have arisen after 40 years of nuclear operations. In doing this, more radioactive waste will be created and have to be managed.
The mission to restore the environment will take 50 to 60 years and will involve 1,500 different activities – this is why the UKAEA has drawn up a comprehensive and integrated plan to address the restoration of the Dounreay site.
The Dounreay Site Restoration Plan (DSRP) is the most detailed plan ever produced for the decommissioning of a nuclear site anywhere in the world.
Dounreay’s historic step in becoming the first nuclear plant to publish its entire programme of work for public scrutiny was only the first step towards improving communications with its many stakeholders.
An extensive series of discussions and presentations to stakeholders about the plan has been followed up by a communications strategy that includes a commitment to consult the public over options for dealing with particular wastes.
The DSRP will allow UKAEA to adapt and respond to unexpected issues and take advantage of new opportunities and technical advances as they emerge.
Decommissioning this nuclear site will not only involve taking buildings down but periods of heavy construction too. In order for all the major radiological hazards to be eliminated within 25 years, up to 20 new facilities will need to be constructed to treat waste and process nuclear materials.
The plan breaks down the work into five phases, each of about 10 to 15 years spread over the whole time frame of 50 to 60 years.
As well as the continuation of decommissioning, stage one will see the construction of many of these new facilities by contractors.
Working alliances have already been established for some of the major tasks in stage one decommissioning of PFR and DFR.
Local company JGC Engineering and Technical Services, Babtie, Ingenco and Alstec have formed an alliance, worth up to £15 million, with UKAEA to deal with sodium residues over the next three-to-five-year phase of decommissioning PFR.
Much work has already been carried out. All the nuclear fuel has been removed from the reactor after it closed down in 1994 and a £17 million plant has been built to dispose of the bulk coolant.
The next phase of decommissioning will clean out the last traces of the liquid sodium metal that was used to cool the reactor core.
An alliance is being formed to remove the last fuel from the Dounreay Fast Reactor. Six companies form the DFR Primary Circuit Decontamination Alliance that will undertake the £30 million decontamination of the reactor vessel and pipework. They are Halcrow, Interserve, Edmund Nuttall, Mitsui, NNC and Framatome.
They will use robots inside the concrete vault of the reactor to cut up and remove more than 9km of contaminated pipework. This phase of work will take until at least 2013. “This is a milestone in the site restoration plan,” said Dounreay site director Peter Welsh.
“When this alliance finishes its task, we will have successfully completed the first and most crucial stage of decommissioning a reactor. This represents one of the major engineering and environmental challenges on this site.”
UKAEA expects that some £10 million of the Primary Circuit contract value will go to locally-based companies and that an initial 50 jobs will be created or retained locally.
A key objective of the alliance will be the transfer of specialist skills, such as robotics, from major contractors to local firms. This will improve their ability to compete for future decommis-sioning work at Dounreay and elsewhere in the world.
The decommissioning work at Dounreay injected around £61 million to the local economy of Caithness during 2000/01.
Dounreay spent £80 million on contracts. Of this sum, £4.2 million went to companies in Caithness, £600,000 to the rest of the Highlands and Islands, £8.5 million to the rest of Scotland and £66 million to English companies. Caithness firms also picked up some £30 million in sub-contracts.
“Decommissioning provides an excellent opportunity for UK companies to undertake the necessary clear up work and UKAEA is working closely with Highlands and Islands Enterprise and Caithness and Sutherland Enterprise to maximise the benefits of decommissioning Dounreay to the local economy,” said an UKAEA spokesman.
The remote location in the north of Caithness makes recruitment more difficult at Dounreay than at UKAEA’s other sites: Windscale, Risley, Culham, Harwell and Winfrith. Nevertheless, the company has successfully recruited around 300 additional staff over the last few years.
The intense periods of construction and decommissioning will make the decommissioning project one of the largest engineering and construction challenges in Scotland, requiring a great deal of resources, both financial and human.
“Restoring our environment and addressing the legacies of our operational past will cost in excess of £4 billion and take many years to achieve,” says Welsh. “Our expenditure has almost doubled in the last few years and is now in the order of £140 million to £150 million per annum – a level we anticipate will continue into the next decade.”
There are three main roles for contractors and consultants on the project – providing technical support, implementing the work and supplying routine services.
“For companies, large and small, decommissioning is a major opportunity – and not just at Dounreay,” said Welsh. “I believe the skills and experience that will build up as the decommissioning progresses here will be sought after world-wide.”
For smaller companies, there are major opportunities through alliances. “This is the gateway through which smaller businesses can grow and expand in what will become a massive global marketplace,” he said.
UKAEA is growing a core of technical, project manage-ment, risk analysis, safety, health and environmental expertise to manage the decommissioning work.
All contracts are advertised through the UKAEA website and those valued at more than £150,000 are listed in the Official Journal of the European Union. UKAEA will normally invite several bidders to present detailed solutions, which are assessed by expert technical and cost panels.
Firms are evaluated by their track record, technical and financial robustness, safety and quality record, manpower and problem-solving capabilities. Such a wide range of skills is vital on a project as complex as the decommis-sioning of a major nuclear power station.