Tokaimura Tragedy - History's Worst Criticality Accident

Overview

On September 30, 1999, the Tokaimura nuclear accident became the worst criticality accident in modern nuclear history. At a uranium processing facility in Japan, workers accidentally triggered a self-sustaining nuclear reaction while preparing fuel for an experimental reactor. One of the technicians, Hisashi Ouchi, received a massive radiation dose and spent 83 days in intensive medical care before his death. Over time, his story spread across the internet with misleading claims about what really happened. This [HALF-LIFE HISTORY] is the true story.