The plant after multiple meltdowns. (Photo: Digital Globe/CC-BY-SA-3.0)

Not even robots can survive a nuclear disaster, it seems.

Five years after a 30-foot tsunami wave crashed into the Fukushima Daiichi nuclear power plant, authorities are still working to decommission the plant after multiple meltdowns.

Part of the decommissioning effort has involved specially-built robots that were sent in to the plant to recover, or at least locate, radioactive fuel rods.

But all five of those robots, Reuters ominously notes, “have failed to return.”

The problem is radiation, which melts robots’ wiring. The plant’s owner, Tokyo Electric Power Company, had spent at least two years building each robot, giving them, among other abilities, the capability to swim underwater.

The company probably doesn’t have any other option than to keep trying; radiation at the plant’s site remains far too dangerous for humans. The decommissioning of the plant, company officials have said, could take up to four decades.