Four workers suffered internal radiation exposure due to inhalation of a large amount of plutonium during an inspection at a nuclear research facility in Ibaraki Prefecture on Tuesday, the operator of the facility said Wednesday.
In the wake of what appears to be an unprecedented internal radiation exposure accident, the state's nuclear safety regulator and local labor authorities inspected the scene to see if there were any flaws in safety management.
The accident occurred at the fuel research building of the Japan Atomic Energy Agency's Oarai Research & Development Center when a bag covering a container for nuclear fuel materials, including powder samples of plutonium and uranium, tore during inspection on Tuesday.