Radiation Hotspots Revealed in Chernobyl's Red Forest—One of the Most Radioactive Sites on Earth

Scientists who loaded radiation detectors onto drones have found previously undetected radiation hot-spots in the Red Forest, which surrounds the site of the Chernobyl nuclear disaster. The team also found parts of the Kopachi village in southwest Ukraine, where radiation rained down after the Chernobyl accident, were more contaminated than previously thought, with a dose rate of 1 millisievert (mSv) per hour. As a comparison, the average person experiences 2.4 mSv per year of background radiation. The Chernobyl power plant exploded in 1986, triggering what is generally regarded as the worst nuclear disaster in history. As a result, residents fled an area spanning 2,600 square km (1,000 square miles) north of Kiev, which became the 1000-miles-square Exclusion Zone. Over three decades on, the area attracts at least 60,000 tourists last year, who seek out eerie abandoned buildings during special tours. The Red Forest is subsequently one of the most radioactive sites in the world: an area where radioactive particles landed on a 400-hectare section of pine forest, killing the trees and turning them a rusty coloor. Last month, experts spent two weeks surveying the Red Forest and its surrounds, using fixed-wing and multi-rotor drones fitted with specially designed radiation detectors. Over a period of 10 days, 50 drone sorties were deployed to scan an area stretching 15km², which saw the equipment spend a total of 24 hours in the air. They used the resulting data to create 3D maps and pinpoint radiation hotspots. Before mapping the Red Forest, the team assessed the village of Buriakivka: 13km away from the Chernobyl power plant and therefore a relatively lower risk than those nearer the heart of the disaster zone. Next, the abandoned settlement of Kopachi was surveyed, then the Red Forest itself. A team at the National Centre for Nuclear Robotics in the U.K. collaborated with Ukraine's SSE Eco Center organization in charge of collecting data on the Exclusion Zone for the research. They flew fixed-wing drones at 45m to 60m above the ground in the area, at around 40mph, in what is believed to be a world first. This enabled the team to reach closer than manned aircraft, and prevented researchers from being exposed to radiation. Rotary drones attached with radiation sensors were sent in to gather more detail.

The team will continue their survey in more trips planned over the next 12 months. Professor Tom Scott of the National Center for Nuclear Robotics, who led the survey, commented: "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. "The same technology has applications in other sectors too. For example, it could be used to identify rare earth, 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." Scott told Newsweek: "The mapping also shows how the majority of the areas mapped, excluding the Red Forest, have remarkably low levels of radiation due to the natural decay that has occurred over the last 33 years and also because the materials have leached into the subsurface, meaning that the emitted radiation is blocked by the soil and sediment overburden." Earlier this year, a separate team of scientists looked at the area in Ukraine from a different perspective: the animals who live in the area abandoned by humans. The study published in the journal Food Webs showed a variety of animals, including eagles and otters, live in the Exclusion Zone. This article has been updated with comment from Professor Tom Scott.