Four decades after the 1986 nuclear disaster, researchers at Leibniz University Hannover and the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) examined six tiny, highly radioactive fragments that were released from the destroyed reactor in Ukraine in the wake of the incident. Analyses show that these "hot particles" are far more stable than had previously been assumed. The findings could allow for more precise assessments of the health risks posed by such radioactive particles. The paper is published in the Journal of Hazardous Materials.