National

Key debris operation at Fukushima clears way for removal of still-simmering fuel rods

by Reiji Yoshida

Staff Writer

Tokyo Electric Power Co. succeeded Sunday in safely removing a massive piece of debris weighing roughly 20 tons from the fuel pool of the Fukushima No. 1 nuclear power plant’s damaged reactor 3 building, the utility said.

The operation was considered a major step toward removing the 566 fuel rod assemblies that have remained in the pool since the triple meltdown at the Fukushima plant in March 2011.

Tepco is aiming to remove all of the still-hot fuel assemblies in the No. 3 pool by the end of March 2018.

The debris, originally a piece of equipment used to remove and insert fuel rod assemblies, fell into the pool after a hydrogen explosion ripped through the reactor building on March 14, 2011.

More than four years after the crisis, radiation still remains dangerously high in the area around the pool.

In Sunday’s removal operation, which took just over an hour, workers used two huge remote-controlled cranes to lift the 14-meter-long piece of debris out of the pool.

The risk surrounding the removal effort — given the huge number of fuel assemblies in the pool — meant Tepco halted all other outdoor decommissioning work.

No significant uptick in radiation levels was observed at the plant during the operation, the utility said.

The gigantic tsunami that hit the Fukushima plant on March 11, 2011, knocked out critical cooling functions and led to meltdowns of three of the six reactors, triggering hydrogen explosions that blew up the upper floors of the reactor 1, 3 and 4 buildings.

Tepco has already moved fuel rod assemblies from the pool of the reactor 4 building — considered the most fragile among the damaged structures — to a safer building within the plant’s compound.