Tokyo Electric Power Co. said Thursday that radiation levels of up to 9.4 sieverts per hour have been detected near a reactor containment vessel at the meltdown-hit Fukushima No. 1 nuclear power plant.
Sept. 4-25 checks found the extremely high radiation levels in a small building containing a pipe that is connected to the reactor 2 containment vessel at the plant, which was devastated in the March 2011 earthquake and tsunami, Tepco said.
Exposure to such a dosage for some 45 minutes would result in death. Tepco said it expects decontamination work at the site to take at least one month.
Although details surrounding the high radiation levels remain scarce, the highest contamination was detected near the floor of the building, according to the company.
Tepco had planned to begin checking the inside of the containment vessel in August by using a remote-controlled robot, but high radiation levels have stalled the examination.
Extremely high radiation levels and the inability to grasp the details about melted nuclear fuel make it impossible for the utility to chart the course of its planned decommissioning of the reactors at the plant.
Correction, Nov. 1, 2015:
This article has been edited for clarity.