'Unimaginable' high radiation level measured in Fukushima
This is the highest since the triple core meltdown in March 2011, Tokyo Electric Power Co. Holdings (Tepco) said.
At 530 sieverts, a person could die from even brief exposure, highlighting the difficulties ahead as the government and Tepco grope their way toward dismantling all three reactors crippled by the March 2011 disaster.
The searing radiation level, described by some experts as “unimaginable,” far exceeds the previous high of 73 sieverts per hour at the reactor.
Tepco said on Thursday that the blazing radiation reading was taken near the entrance to the space just below the pressure vessel, which contains the reactor core.
The high figure indicates that some of the melted fuel that escaped the pressure vessel is nearby.
Tepco also announced that, based on its analysis of images taken by a remote-controlled camera, that there is a 2-meter hole in the metal grating under the pressure vessel in the reactor’s primary containment vessel. It also thinks part of the grating is warped.
The hole could have been caused when the fuel escaped the pressure vessel after the mega-quake and massive tsunami triggered a station blackout that crippled the plant’s ability to cool the reactors.
Tepco said it calculated the figure by analyzing the electronic noise in the camera images caused by the radiation. This estimation method has a margin of error of plus or minus 30 percent, it said. ■