Odds Are On The Monte Carlo System - Dounreay
28th January 2021
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.
Before the experimental Dounreay Fast Reactor (DFR) can be dismantled, a clear understanding is required of radiation levels, and their distribution, inside the shielded vault that houses the
DFR was the world's first fast breeder reactor to supply electricity to a national grid, playing an important part in research for fuel and coolant technology.
Decommissioning the DFR is one of the UK's most significant nuclear challenges. As workforce access to DFR's interior is
impossible, measurements were taken using a variety of tools deployed through the dozens of openings. Among other
items, the vault contains graphite, tanks, vessels, heat exchangers and ring main contaminated with residual sodium potassium liquid metal coolant, NaK.
Almost 70 tonnes of highly radioactive and chemically reactive NaK were destroyed over 10 years in a purpose-built plant, and
dealing with remaining contamination is a key challenge.
Four different systems were used to collect data, including the compact N-visage gamma imaging scanner, which was developed by Cumbria-based Createc with support from the NDA's research budget and Innovate UK.
Senior Characterisation Specialist Vittoria Baldioli said: "Work to build a comprehensive picture of the vault's inventory, including radioactive hotspots, has been under way for a number of years.
"It's also important to predict how conditions will change once decommissioning starts and items are retrieved. This will enable us
to assess the possibility of future workforce access."
Data from all techniques provided large quantities of information but did not represent the entire vault. The team opted to use the Monte Carlo N-particle (MCNP) code, a powerful and highly specialised
simulation software developed by the Los Alamos national lab, used globally for safety, radiation and shielding problems.
A 3D MCNP model of DFR's vault was constructed using all available information, and gradually adjusted to achieve a match
between measured and theoretical dose rate, indicating accurate modelling of activity distribution.
The model will support decommissioning, modified when necessary, and used to determine dose rate changes outside the vault, through the effects of shielding, and inside as components are removed.
It will be of particular value for addressing contamination levels, and can also be applied at other decommissioning sites in the NDA group.
See the full leaflet HERE
Statement issue18 March 2021 by NDA, Dounreay and Sellafield. In 2013 we concluded the development of our strategy to remove unirradiated nuclear material from Dounreay and consolidate it at Sellafield.
Dounreay has awarded an important waste clean-up contract to Jacobs as the site plans for the future of its deepest historic radioactive waste store. Jacobs and its supporting partners have been awarded a 6-year contract to provide a design management team to produce a fully integrated design for the shaft and silo project.
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.
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).
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.
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.
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.
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.
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.
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.