The operator of the defunct Fukushima Daiichi nuclear plant has flown a balloon inside the No.1 reactor building to check the upper part of the structure.
Tokyo Electric Power Company on Wednesday launched a balloon from the first floor, to about 30 meters up inside the building.
The 2 meter wide balloon was equipped with 4 cameras and a device to monitor radiation.
Photos showed concrete debris from a hydrogen explosion scattered on the upper floors. But the crane for pulling out fuel rods, and a device for exchanging them, remained intact and had not fallen into the pool for spent fuel rods, as had been feared.
Radiation levels registered at 150 millisieverts an hour around the building’s second floor and 54 millisieverts an hour around the topmost fifth floor.