High levels of radiation have been recorded at Fukushima
Tokyo Electric Power (Tepco) said atmospheric readings of up to 530 sieverts an hour had been recorded inside a containment vessel of a reactor that was hit by a huge tsunami in March 2011.
The worryingly high readings show the scale of the task confronting thousands of workers as pressure builds on Tepco to begin the 40-year-process of decommissioning the plant.
The recent reading is far higher than the previous record of 73 sieverts an hour in that part of the reactor and has been described by some experts as “unimaginable”.
A single dose of one sievert is enough to cause radiation sickness and nausea; five sieverts would kill half those exposed to it within a month, and a single dose of 10 sieverts would prove fatal within weeks.
Tepco also said image analysis had revealed a hole in metal grating beneath the same reactor’s pressure vessel.
The one-metre-wide hole was probably created by nuclear fuel that melted and then penetrated the vessel after the tsunami knocked out Fukushima Daiichi’s back-up cooling system.