TOKYO -- The amount of radiation in an 80km radius surrounding the Fukushima Daiichi nuclear plant has decreased significantly since the disaster nearly five years ago, the latest government findings show.
Japan's Nuclear Regulation Authority released a map Wednesday showing that radiation levels fell 65% between November 2011 and September 2015, when the data was gathered. The reactors operated by Tokyo Electric Power Co. suffered meltdowns in March 2011 as the result of an earthquake and tsunami.
The area northwest of the plant showing readings of over 19 microsieverts per hour had shrunk significantly. Microsievert readings between 0.5 and 1.9 per hour, previously recorded in the southwest to the north of the prefecture, had also declined significantly. Radiation had fallen to 0.1 microsieverts per hour or less in increasing parts of southern Miyagi Prefecture, southern Fukushima Prefecture and northern Ibaraki Prefecture.
The Japan Atomic Energy Agency conducted the yearly survey using helicopters, with equipment measuring radiation levels at 1-meter elevations.