Radiation 36,000 times permissible level found in water at Fukushima plant 03 Dec 2013 The operator of the disaster-hit Fukushima No. 1 Nuclear Power Plant said on Dec. 2 that it has detected radioactive materials that topped 36,000 times the permissible level in underground water extracted in the area. According to plant operator Tokyo Electric Power Co. (TEPCO), strontium-90 and other radioactive substances that emit beta rays were detected at a level of 1.1 million becquerels per liter in underground water pumped up from an observatory well on Nov. 28. The well is located at a sea bank east of the No. 2 reactor, about 40 meters from the ocean.