A team led by University of Bristol scientists have tested a new radiation scanning system at the heart of the Chernobyl disaster zone.

The researchers were granted unprecedented access to Chernobyl’s reactor 4, which triggered the worst nuclear disaster the world has seen, to test systems developed to aid the decommissioning process.

It scans fluctuating levels of radiation at nuclear sites to create a 3D map of risk, improving safety over the course of the decommissioning and dismantling process.

Several robotic systems were fitted with the radiation sensors and deployed in reactor 4, and also within the new safe confinement structure that encases it, the University of Bristol said.

The structure was built over “the sarcophagus” – the casing hastily erected over reactor 4 after the 1986 disaster in a bid to limit radioactive contamination of the surrounding area.

The sarcophagus is now so degraded the site has been granted permission to begin dismantling it remotely – a process that relies heavily on robotic technology.

The recovered reactor core debris will be retrieved and packaged to prevent radiation leaks.

Scientists expect radioactivity levels and distribution will change rapidly during the decommissioning process.

The robotically deployed scanning systems develop 3D models of the site to pinpoint and monitor the level of nuclear hazard, helping keep workers safe.

The project was funded by the Engineering and Physical Sciences Research Council (EPSRC) and the Robotics and Artificial Intelligence in Nuclear (Rain) research consortium.

It was developed by the universities of Bristol and Oxford as part of the Rain project.

Lead researcher Professor Tom Scott, from the University of Bristol and co-director of Rain, said: “To actually venture inside the control room of the failed reactor was a tense and yet exhilarating experience.

“The team did a fantastic job of deploying our systems quickly and in challenging conditions.

“It’s a huge reward after months of hard work and planning to know our technology performs well in real nuclear environments.”

He added: “We are now entering a phase of decommissioning here in the UK, at Sellafield and Magnox, therefore we are developing new sensing systems, robotic solutions and special types of detectors because that technology is needed now.

“Robots can make nuclear decommissioning faster, cheaper and more importantly, safer. We would only be able to develop this technology with the guidance and information from our Ukrainian partners.”

The Bristol team’s deployment follows the signing of a memorandum of understanding in early 2021 between the University of Bristol and the Institute for Safety Problems of Nuclear Power Plants (ISPNPP) at the Ukraine National Academy of Science.

Dr Maxim Saveliev, senior researcher at ISPNPP, said: “Importantly, this scientific data will inform future planning for the eventual removal of fuel-containing material from the shelter facility and will ultimately aid Chernobyl’s transformation – and the area surrounding it – into an environmentally safe place.

“This is the second time we have worked with the Bristol team here at the Chernobyl nuclear power plant and the results of this most recent visit provide fresh impetus for continuing and strengthening our cooperation into the future.”