Work to remove nuclear fuel debris at the Fukushima Daiichi nuclear power plant was scheduled to begin on August 22.

But the task that was set to get underway on a trial basis at the plant's No. 2 unit was postponed due to problems with assembling a device.

Almost 13 and a half years have passed since meltdowns occurred at some of the reactors when tsunami waves hit the plant after a powerful earthquake.

The removal of nuclear fuel debris that have accumulated at the bottom of the reactors was initially scheduled to begin three years ago.

About 880 tons of fuel debris are estimated to be at the plant.

As the radiation levels in the reactors are extremely high, workers are planning to remotely remove the debris using equipment that has a gripper hanging down.

The equipment with the gripper tool was supposed to be inserted using a device made up of five pipes.

But workers noticed on the morning of August 22 that the pipes were not lined up in the correct order.

Plant operator Tokyo Electric Power Company is investigating what caused the error.

TEPCO officials said they do not know yet when the debris removal work will be resumed.