Japan's Nuclear and Industrial Safety Agency has revised its rating on the International Nuclear Event Scale of the fatal steam burst that killed five people at the Mihama nuclear plant in Fukui Prefecture.
The agency changed the rating from level 0 plus, a classification indicating ''no safety significance,'' to level 1, a classification indicating an ''anomaly beyond authorised operating regime.''
The revision followed an investigation into owners Kansai Electric and maintenance contractors Mitsubishi Heavy Industries. The agency had originally rated the accident level 0 plus because no radioactivity had been released and the reactor had automatically stopped.
