Workers at the damaged Fukushima nuclear power plant have started removing fuel rods from the plant’s reactor 4, the only one that didn't melt down after the 2011 earthquake.
The highly dangerous procedure is the first step towards full decommissioning and clean-up of the plant, operated by Tokyo Electric Power Company (TEPCO), which is foreseen to take decades.
Unit 4 was the only reactor that was off-line during the tragic 2011 earthquake and subsequent tsunami, as it was undergoing maintenance. Its fuel rods were, at the time of the incident, stored in a storage pool inside the building.
Thanks to this coincidence, the core of the Unit 4 reactor didn’t melt, unlike the other three reactors. However, hydrogen explosions damaged the roof of the reactor building and weakened the structure, making it prone to collapse in case of another earthquake.
Experts have agreed the fuel rods – four metre long tubes containing pellets of uranium fuel, which have remained inside the building ever since the disaster – pose a major safety risk.
TEPCO said it will require more than two days to remove the first 22 fuel rod assemblies. More than 1,500 fuel rod assemblies are inside the pool waiting to be removed. The whole operation, according to some sources, could take up to a year.
Operators will remove the rod assemblies in batches of 22 using a crane. During the operation, the rods will be placed in water-filled casks, preventing them from having any contact with surrounding air.
It is expected it will take 7 to 10 days to remove each batch before it could be placed into a new cooling pool.
At this stage, the operators are unsure, whether the rods or casks were damaged during the earthquake, which would make them prone to leak radioactive material.