TOKYO — Japanese regulators gave final approval on Wednesday for the removal of fuel rods from an uncontained cooling pool at a damaged reactor building considered the highest risk at a crippled nuclear plant.
Removing the fuel rods from the Unit 4 cooling pool is the first major step in a decommissioning process that is expected to last decades at the Fukushima Daiichi plant, where three reactors melted down after the March 2011 earthquake and tsunami.
The Nuclear Regulation Authority said at its weekly meeting that the proposal by the plant’s operator, Tokyo Electric Power Co., is appropriate and that the removal can start in November as planned, following an on-site inspection by regulators.
‘‘It’s a major step toward decommissioning,’’ said Toyoshi Fuketa, one of the authority’s five commissioners.
The Unit 4 reactor was offline when the plant was hit by the disasters, but the building was damaged by hydrogen explosions and fire. Fuel rods in the pool, however, have since been properly cooled and are safe enough to remove, officials said.