Caithness Map :: Links to Site Map Great value Unlimited Broadband from an award winning provider  

 

57,000 Tonnes Of Hazardous Materials Finally Dealt With At Dounreay

6th April 2012

Dounreay today completed the destruction of one of the most hazardous legacies of Britain's earliest atomic research.
A purpose-built chemical plant processed the last of 57,000 litres of liquid metal lifted from the primary cooling circuit of the experimental fast breeder reactor.

The coolant - an alloy of sodium and potassium (NaK) - was a major chemical and radiological hazard. An estimated 1000 trillion becquerels of caesium-137 was removed from the coolant during the chemical process that turned the 57 tonnes of liquid metal into 20,000 tonnes of salty water and took four years to complete.

Scotland's Cabinet Secretary for the Environment Richard Lochhead saw the last batches being processed.
He said: "This is a tremendous achievement and another example of how the highly skilled Dounreay workforce is delivering a world-class clean-up operation at one of the most complex nuclear sites in Europe.

"The Scottish Government welcomes today's announcement that Dounreay have successfully destroyed 57,000 litres of highly radioactive liquid metal from the Dounreay Fast Reactor."

The Nuclear Decommissioning Authority said it was "extremely pleased" the liquid metal no longer posed a hazard.
"This was very high on the list of hazards we wanted reduced across our whole estate," said Nigel Lowe, head of the NDA's Dounreay programme. "It's a significant achievement for Dounreay and joins a long list of examples whereby the site has delivered on key objectives and technical challenges."

The reactor - built in the 1950s - was one of only two ever built in Britain to run on liquid metal. Two cooling circuits connected by heat exchangers were filled with more than 161,000 litres of liquid metal.

More than 100,000 litres of NaK from the secondary circuit was destroyed when the reactor shut down in 1977.
Work on the primary circuit - a labyrinth of pipes 9 kilometres in length - stopped in the early 1980s when higher levels of radioactive contamination were detected.

The primary circuit contained 57,000 litres of NaK that flowed over the fuel pins in the reactor core.
The "open vent" design of the fuel cladding allowed the liquid metal to come into direct contact with the fuel, contaminating the primary coolant with huge levels of soluble radioactive caesium. Radiation measurements of the primary coolant showed the presence of 1000 trillion becquerels of caesium-137.

The high level of radioactive contamination added to the chemical hazard of alkali metal that reacts in contact with air or water. Its destruction remained on hold until a decade ago when work started on the construction of a purpose-built clean-up plant. The plant was designed to lift the liquid metal in small batches, neutralise the alkalinity with acid and extract the caesium via ion exchange.

In September 2007, the first of a total of 354 batches was lifted from the reactor. Each batch underwent chemical neutralisation to convert the alkali metal to a salty water before being passed through ion exchange columns that trapped the caesium. Designers thought the plant would decontaminate the effluent by a factor of 1000. Decontamination rates of up to 4 million were achieved during the operation, reducing levels of radioactivity in the effluent to below the limit of detection.

The resin columns used to trap the caesium will now be cemented up and managed as higher-activity waste.
"It's been a fantastic achievement by the whole team to deliver this milestone a year ahead of schedule and to higher environmental standards than anyone thought possible at the design stage," said Andy Swan, the engineer in charge of the reactor decommissioning.

"This stuff was highly volatile and highly radioactive. The chemical and radiological hazards combined to make this a real danger to the workers involved, so we needed to be certain they were protected at every step of the process until the hazard was destroyed. Their safety record throughout this operation was excellent."

Destruction of the liquid metal was among the strategic national priorities of the Department of Energy and Climate Change, which sponsors the Nuclear Decommissioning Authority.

With the reactor vessel empty of liquid metal, attention now turns to cleansing the residual traces from the primary circuit pipework and destroying small pockets in other vessels. When complete, a robotic arm will reach into the reactor vessel and begin removing the burst fuel pin and almost 1000 breeder elements still positioned around the core.

 

Related Businesses

 

Related Articles

NDA Innovation Competition Winners Have Been Announced - £3.9 MillionThumbnail for article : NDA Innovation Competition Winners Have Been Announced - £3.9 Million
14 successful companies have been awarded contracts to come up with innovative approaches to remotely sort and segregate radioactive waste.   The ‘Sort and Seg' innovation competition, worth £3.9 million in total, was launched in July 2020.  
NDA Appoints Lawrie Haynes As New Chair Designate For DounreayThumbnail for article : NDA Appoints Lawrie Haynes As New Chair Designate For Dounreay
David Peattie, Chief Executive Officer of the Nuclear Decommissioning Authority, has announced the appointment of Lawrie Haynes as Chair Designate of Dounreay Site Restoration Ltd.  (DSRL).  
Odds Are On The Monte Carlo System - DounreayThumbnail for article : Odds Are On The Monte Carlo System - Dounreay
Dounreay features in a new leaflet from the Nuclear Decommissioning Agency showing recent research, development and innovation.  See the leaflet link at the bottom of this page to read about some of the other investments by the NDA.  
£12m UK-Japan Robotics Deal For Fusion Energy And Nuclear Decommissioning ResearchThumbnail for article : £12m UK-Japan Robotics Deal For Fusion Energy And Nuclear Decommissioning Research
UK-Japan relationship in nuclear science boosted by robotics and automation.   Britain and Japan have signed a research and technology deployment collaboration to help automate nuclear decommissioning and aspects of fusion energy production.  
Nuclear Decommissioning Agency Update - New Transport and Waste DivisionsThumbnail for article : Nuclear Decommissioning Agency Update - New Transport and Waste Divisions
Issued by David Peattie, Group CEO and Accounting Officer, NDA.   I am pleased to be able to share with you some significant developments within the NDA around our transport and waste businesses, further underlining our One NDA approach to working more collaboratively and efficiently to clean up the UK's earliest civil nuclear sites.  
Multi-million Design Contract Secured For Dounreay Waste Repackaging FacilityThumbnail for article : Multi-million Design Contract Secured For Dounreay Waste Repackaging Facility
The Decommissioning Services Framework (DDF) Alliance, led by Cavendish Nuclear and supported by KDC Contractors (Veolia) and BAM Nuttall (BAM), has been successfully awarded a contract for the design of a new waste repackaging facility at the Dounreay nuclear site.   The programme of work is expected to run until early 2022 and forms part of Dounreay Site Restoration Limited's (DSRL's) Decommissioning Services Framework.  
Mark Rouse appointed as Managing Director of DounreayThumbnail for article : Mark Rouse appointed as Managing Director of Dounreay
Dounreay Site Restoration Limited (DSRL) has announced the appointment of Mark Rouse as its Managing Director.   Mark took up the position of Managing Director in March 2020 but will now move from the current parent body organisation to Dounreay Site Restoration Limited to continue leading the business when it becomes an NDA subsidiary on 1 April 2021.  
Significant Milestone Reached With Concrete 'mega Pour'Thumbnail for article : Significant Milestone Reached With Concrete 'mega Pour'
Work on Dounreay's newest radioactive waste store went up a storey last week, with the completion of a ‘mega' concrete pour.   The construction project was one of the first to re-start work on 22 June, following the easing of lock down restrictions.  
The12-week public consultation on the NDA's Draft Strategy is about to closeThumbnail for article : The12-week public consultation on the NDA's Draft Strategy is about to close
The public consultation on the NDA's Draft Strategy 4 closes at 5pm on Sunday 8th November 2020.   Because of the current Government guidance around social distancing during the COVID-19 pandemic, we have created a virtual consultation exhibition to give members of the public a chance to delve into the key themes, before making a response.  
Contract For World's Deepest Nuclear Clean-up Awarded At DounreayThumbnail for article : Contract For World's Deepest Nuclear Clean-up Awarded At Dounreay
Dounreay has awarded a major contract as the world's deepest nuclear clean-up job gets underway.   Dounreay Site Restoration Ltd (DSRL), on behalf of the Nuclear Decommissioning Authority, awarded the £7.5 million contract for "advanced transition works" at the 65 metre deep shaft and silo to Nuvia and its partner Graham Construction, through the site's decommissioning framework following a competitive tendering process.