Fukushima Daiichi nuclear disaster on the International Nuclear Event Scale (INES). This scale runs from 0, indicating an abnormal situation with no safety consequences, to 7, indicating an accident causing widespread contamination with serious health and environmental effects. Prior to Fukushima, the Chernobyl disaster was the only level 7 event on record, while the Three Mile Island accident was rated as level 5. A 2012 analysis of the intermediate and long-lived radioactivity released found about 10–20% of that released from the Chernobyl disaster. Approximately 15 PBq of caesium-137 was released, compared with approximately 85 PBq of caesium-137 at Chernobyl, indicating the release of of
Timeline of the Fukushima Daiichi nuclear disaster of a new leak of radioactive water into the sea. The Itabashi Ward Office announces that a concentration of caesium-134 at 2,700 becquerels per kilogram – in excess of the government's provisional limit – was detected in tea processed from leaves picked on 9 May in Tokyo. The water decontamination and water recycling systems are now both functional. 100% recycled water is now used for reactor cooling, and no additional volume of contaminated water is being generated. Radioactive caesium-137 is found in Tokyo's tap water for the first time since April. Radioactive caesium from Fukushima was expected to enter the