The operator of the Fukushima No. 1 nuclear power plant found the radiation level of the building housing the No. 1 reactor stood as high as 700 millisieverts per hour, the government's nuclear agency said Monday, citing the need for radiation shielding to proceed with work to bring an end to the nuclear crisis.
The radiation level, which was around 10 millisieverts per hour at its lowest, was measured as Tokyo Electric Power Co. workers and agency officials entered the No. 1 reactor building early Monday as part of preparations to start full-scale work to create a stable system to cool the damaged fuel inside.
"An area with a double-digit millisievert level, let alone three-digit figures, is quite tough as a working environment. So we have to do the work by using some shielding," Nuclear and Industrial Safety Agency spokesman Hidehiko Nishiyama said.