A road map produced by the Japanese government and plant operator Tokyo Electric Power (TEPCO) envisages engineers will use much of the next 10 years just trying to work out how to get at the fuel, which has partly eaten through its containment vessels.

Underlining the challenges involved in dealing with the disaster, the plan says that as-yet uninvented technology will be key to safely disposing of the waste left behind by the world’s worst nuclear accident since Chernobyl.