UK drones identify new radiation hot spots at Chernobyl
16 May 2019
Radiation distribution has been mapped in 3D using both fixed-wing and multi-rotor drones fitted with custom-built radiation detectors – a world first at Chernobyl.
A team of British scientists has completed the most comprehensive survey yet of Chernobyl’s Red Forest – one of the most radioactive sites on Earth. Using fixed-wing and multi-rotor drones fitted with custom-built radiation detectors, researchers created detailed 3D maps that revealed previously undetected radiation ‘hot-spots’.
The two-week expedition, led by Professor Tom Scott of the UK’s National Centre for Nuclear Robotics and University of Bristol, in April 2019, was the first of several survey missions that the National Centre for Nuclear Robotics will undertake in Ukraine over the coming 12 months. 33 years on from the catastrophic accident at the number-4 reactor, and with 70,000 tourists visiting the Chernobyl exclusion zone last year, national authorities urgently require accurate radiation maps to update safety protocols that will inform both future tourism activity and the ongoing construction of solar energy farms in the area.
Cleaning up legacy nuclear waste is not only an issue at Chernobyl; the UK has 4.9 million tonnes of contaminated material requiring safe disposal, some of which dates to the 1950s [source: Nuclear Decommissioning Authority]. The National Centre for Nuclear Robotics was created to accelerate and reduce the cost of Britain’s nuclear clean-up task by developing state of the art robotics, sensing and AI technologies for carrying out work in complex and hazardous environments. That expertise is now being called upon internationally.
Working alongside colleagues from Ukraine’s SSE “Eco Centre”, the body responsible for gathering survey and research data within the 2,600km2 Exclusion Zone, the UK team flew 50 sorties over 10 days, spending 24 hours in the air to map an area of 15km2.
Starting at the lowest risk site first, the village of Buriakivka, located 13km from the accident epicentre, researchers then moved on to the partially-demolished settlement of Kopachi before tackling the Red Forest.
In a world first, fixed-wing drones were used to quickly map radiation over larger areas, flying at a height of 45m-60m at a speed of c. 40mph. Rotary drones were then used for more detailed investigation of key areas. The aircraft featured a unique sensor system developed jointly by Professor Scott’s team and University of Bristol spinout, Imitec Ltd.
With the fixed-wing drone able to fly lower and slower than a manned survey aircraft ever could, and without risk to life, the National Centre for Nuclear Robotics team was able to create the most comprehensive radiation map yet of the Red Forest.
Their survey not only reaffirmed current understanding of the radiation distribution at an unprecedented spatial resolution, it revealed unexpected areas of major contamination in Kopachi. Registering a dose-rate of greater than 1 millisievert per hour (nb. the maximum permissible dose not requiring an individual's classification as a Radiation Worker in the UK is 6 mSv per year), the area is believed to contain material from the original emergency clean-up activities performed over three decades ago.
Professor Scott said, “We have successfully demonstrated that the UK now has the capability to monitor radioactive sites and respond to nuclear incidents without exposing humans to risk – a guiding aim of the National Centre for Nuclear Robotics. We can fly into a contaminated area from a safe zone, perhaps 10km away from the incident site, and gather detailed information – streaming it live during the flight before returning safely to base”.
Professor Scott continued “The same technology has applications in other sectors too. For example, it could be used to identify rare earths, gold or copper mineral deposits, quickly, cheaply and non-invasively. This could be especially useful for developing nations keen to assess the extent and value of mineral resources ahead of, say, signing away mining rights.”