New scanner tackles hazardous nuclear debris at Fukushima meltdown site

Scientists led by Haruo Miyadera have developed a prototype muon scattering tomography scanner to analyze hazardous nuclear fuel debris at the Fukushima Daiichi meltdown site. This technology leverages cosmic ray muons, subatomic particles naturally occurring, to create images based on how they scatter when passing through materials with high atomic numbers like uranium. The scanner, designed to operate in the high-radiation environment of Fukushima, features radiation-resistant muon trackers with a 1.2 × 1.2 m² detection area and advanced FPGA electronics to detect muon events amid intense gamma radiation. The team also devised an analytical method combining muon scattering angles, stopping rates, and debris weight to estimate uranium dioxide content without relying on complex AI, achieving reasonable accuracy within a few hours of measurement. The development is timely as large-scale retrieval of approximately 880 tons of fuel debris from Fukushima Units 1, 2, and 3 is planned to start in 2024. The debris management process involves classifying material