Japan suffered one of its worst disasters in modern in history in 2011 when a 9.0 powerful earthquake hit the country, followed by tsunami. The disaster left 18,000 people dead and destroyed more than a million buildings. It also led to the meltdown of the Fukushima nuclear plant.
The Fukushima nuclear calamity was Japan's worst since Chernobyl in 1986.
About 100,000 people were forced to leave their homes, with an estimate of 600 tonnes of toxic fuel may have leaked from the reactor during the meltdown.
Radiation levels on the site have been estimated to be beyond any limits of human survival. So Japanese engineers have been using purpose-built robots to be sent to the site to study the damage. Cameras have been attached to the robots.
Now findings show that even the purpose-built robots have been having serious problems with radiation. A recent trip failed when a Toshiba-designed robot died five times faster than was expected.
The robot stopped 10 feet away from the target and as a result was exposed to far higher levels of radiation than experts earlier predicted. The radiation may have affected the robot's electronics.
The Japanese robot is built to deal with 73 sieverts of radiation, while the recorded level in the reactor of one robot was seen at 530 sieverts. One sievert alone can cause radiation, five sieverts can kill half of those exposed within a month, while 10 sieverts can kill in mere weeks.
The levels in Fukushima's unit two reactor are so dangerous that they can kill a person in just two minutes.
This was the result of an earlier investigation when Tokyo Electric Power carried out a robotic survey of the area around the center that had a meltdown in 2011, triggered by the earthquake and tsunami. The scorpion robot sent got stuck inside the reactor after its crawling functions failed while it was trying to climb over highly radioactive debris. The robot had to be left inside the reactor. It recorded radiation measures in the area of 210 sieverts per hour, and that is how the experts found out that so lethal are the radiation levels inside the reactor that they can kill a human in just two minutes.