Radiation rose to an unusually high level in and near Tokyo Electric Power Co.‘s Fukushima No. 1 nuclear plant Saturday following the powerful earthquake that hit northern Japan the previous day, the nuclear safety agency said, making it the first case of an external leak of radioactive material since the disaster.
While the agency denied the radiation amount will pose an immediate threat to the health of nearby residents, the impact of the quake appeared to widen as the agency added the area close to the Fukushima No. 2 nuclear plant as a zone that requires evacuation.
Given the adjacent No. 2 plant also has quake-triggered malfunctions, the operator of the two plants in Fukushima Prefecture released pressure in containers housing their reactors under an unprecedented government order, so as to prevent the plants from sustaining damage and losing their critical containment function.
But the action would involve the release of steam that would likely include radioactive materials.
The amount of radiation reached around 1,000 times the normal level in the control room of the No. 1 reactor of the Fukushima No. 1 plant, the Nuclear and Industrial Safety Agency said.
The agency also said radiation has been measured at more than eight times the normal level near the main gate of the plant.
The authorities expanded the evacuation area for residents in the vicinity of the No. 1 plant from a 3-kilometer radius to 10 km on the orders of Prime Minister Naoto Kan, who visited the facility.
The government also declared that the Fukushima No. 2 plant is under a state of atomic-power emergency, in addition to the No. 1 plant, and expanded the evacuation area to include the vicinity of the No. 2 plant.
The instruction covers residents living in a radius of 3 kilometers of the Fukushima No. 2 plant. Those living in a radius of 3-10 kilometers of the plant have been advised to stay inside.