The robots who went into Fukushima's no-man's land have not returned after radiation levels in the power plant proved too strong for their circuit boards to handle.

The clean-up continues almost five years to the day after the Fukushima Daiichi nuclear power station experienced three meltdowns after a tsunami crashed into the coastal power plant in 2011. The deathly high levels of radiation means it’s impossible for humans to go into areas of the plant to dispose of or contain the radioactivite materials. And it turns out, robots don't fare much better either.

TEPCO and Toshiba developed a series of robots that were able to go underwater in the plant’s damaged cooling pools to remove the radioactive nuclear rods.

Five of the custom-built robots have been sent into the plant to work their magic. So far, none of them have returned. As soon as they get close to the reactors, their wiring becomes destroyed by the high levels of radioactivity and they are unable to move.

“It takes two years to develop a single-function robot,” said Naohiro Masuda, Tepco's head of decommissioning, in an interview reported by Reuters .

“It is extremely difficult to access the inside of the nuclear plant," he added. "The biggest obstacle is the radiation.”

Main image: IAEA Imagebank/Flick CC BY-SA 2.0