The radiation levels in Fukushima’s unit two reactor building are so high they could kill a human in two minutes, according to data collected by a robot.
Tokyo Electric Power, the company which operates the nuclear plant in Fukushima, carried out a robotic survey of the area around the core that melted six years ago, following the earthquake and tsunami that triggered the nuclear accident.
But the scorpion robot Sasori got stuck inside within after its crawling functions failed while climbing over highly radioactive debris. It had to be abandoned inside the reactor ruins.
It recorded radiation levels in the area of 210 sieverts per hour, which is lethal enough to kill a human within two minutes.
This is not the first time a robot has become inoperable after entering one of the three destroyed reactor buildings.
During a previous survey, another robot designed to clean the debris for Sasori’s passage had to return halfway through when two of its cameras failed, after being exposed for two hours to radiation, and reaching its maximum tolerance of 1,000 sieverts. Such an exposure to radiation can kill a human within seconds. The probe was specially developed for surveying the interior of the crippled reactor and collect data that will assist in removing the melted fuel.
Despite the dangerously high levels of radiation, company officials said it was not leaking outside the reactor.
The high radiation and inadequate cleaning of the reactors could also limit the scope of future investigations and the company may have to develop more radiation-resistant cameras and equipment.
But the extreme level of radiation and the presence of debris seem to have brought the decommissioning project to a standstill, at least for the moment.