Putting decommissioning on the map
Reactors and robots, paratroopers and planes - the Harwell site in Oxfordshire has seen it all. Soon to be hailed as an international business centre, the area is currently undergoing a thorough liability review. In the second part of the UK Atomic Energy Authority (UKAEA) series, Beverly La Ferla learns how a new computer mapping tool has facilitated a site assessment for chemical and nuclear ground contamination.
Three years ago, the Site Survey Project was born, headed by Clark Colyer, senior project manager at UKAEA. He put together a team that could cover both the historical records aspect and the assessments of land quality, and combine these to provide a comprehensive report on the possible presence of contaminants throughout the site.
Database issues soon took priority: the project had to incorporate a quality-controlled, auditable procedure for collecting, collating, retrieving and interpreting the environmental survey results and cross referencing these with the history of the buildings and the site. UKAEA commissioned ESiT Ltd (Effective Solutions with Information Technology) to develop a data management system called IMAGES (Information Management And Geographical Evaluation System), which comprised a number of database modules and desktop tools.
The database modules were created to record a range of environmental data types, such as groundwater quality monitoring data, ground investigation data, sample analysis results, radiation survey data, and building history in the form of documents and images. The databases that contain information with a geographic component were designed to interface seamlessly with Arcview GIS (Geographic Information Systems), a computer system which enables a pictorial representation of the data to be displayed.
UKAEA were delighted with this tool and the project started to gather pace after February 1999. Malcolm Crook, environmental records manager, was put in charge of the historical side with Grant Baldwin as project operator feeding survey information to Sandra Owsett, GIS operator. This three-man team, headed by Clark Colyer, started to put together an assessment of potential liabilities on the site - a task which they have almost completed.
Malcolm's extensive experience in records management made him the ideal person for his job. "I delve into the archives for records that gives me an idea of what the buildings or areas of land were used for and extract information on potential areas of contamination," he says enthusiastically, "The history of the site goes back to when it was an operational RAF base in 1937, complete with dispersed runways and practice bombing areas."
Bought for just £11,000 by the Ministry of Supply (now the Ministry of Defence), the site was an operational training unit for bomber command. During the second World War, it played a vital part in sending paratroopers and light forces to Normandy on D-Day, an accomplishment it is still proud of today.
"The buildings, originally built for the RAF, have been converted through the years for other uses," Malcolm explains, "For example, one RAF barracks block was turned into laboratories in Harwell's nuclear physics heyday and is now office accommodation."
A total of 627 records on all the buildings ever constructed at Harwell - including general purpose huts, air-raid shelters and toilet blocks - contributed to the historical side of the database, and this information was then used by Grant to select areas that needed to be sampled for possible contamination.
A number of surveys have been done on the site. Geo-physical techniques, which measure the change in electrical conductivity of the soil, have uncovered objects like bullet cartridges and flares, which have been buried for decades. The radiation data was gathered using a Global Positioning System (GPS) to pinpoint areas of interest and chemical surveys have involved digging 'trial pits' down to three metres to collect samples for laboratory testing for contaminants. The pits are also given the once over with radio and metal detectors, a CAT scanner, and a photo-ionisation detector which determines the levels of volatile organic carbons (VOCs) present.
These results, complete with location tags, are then fed back into the database by Sandra. Clark Colyer explains: "Because the historical records and sampling data are held electronically in a way that's retrievable and geographically traceable, we can combine them to make maps showing areas of potential liability. It would be nearly impossible without the program - we'd have to use at least one aircraft hangar to store all the files that we've generated in the last three years!"
After three years of extensive searching, the surveys have brought up nothing unusual, leaving Harwell on course for unanimous approval as an international business centre. The mapping team is two-thirds the way through the Site Survey Project and hopes to finish it next year. After that?
Well, there are plenty more nuclear sites being decommissioned in the UK and
many others who could apply the techniques the Harwell team have pioneered to
return land that has been used for industrial purposes to green field status.