Technicians at Japan's crippled Fukushima nuclear plant have begun their most dangerous task in decommissioning the complex damaged by the 2011 tsunami.
The process that started Monday is aimed at delicately removing about 1,500 sets of radioactive fuel rods from a storage pool inside a damaged nuclear reactor building. The uranium and plutonium rods from reactor number four will be transferred to another storage pool in a safer structure.
Tokyo Electric Power Company said it expects the operation to last a year. A mistake or accident that damages the fuel rods could release large amounts of radiation.
In day one of the operation, Japanese workers used a crane to remove four sets of fuel rods from a rack inside the storage pool and placed them into a fully-immersed cask. They plan to fill the cask with 22 sets of rods by Tuesday, before lifting the cask out of the pool and driving it to the safer container building.
Fukushima's reactor number four was offline at the time of the earthquake-triggered tsunami. But hydrogen got into the building and caused explosions that blew off the roof and damaged the walls surrounding the fuel rod storage pool, which is more than 18 meters above ground level. Authorities fear another earthquake could topple the pool.
TEPCO has drawn strong criticism for its handling of the Fukushima decommissioning process. In recent months it has reported a series of mishaps including leaks from tanks storing radioactive water.
After completing work on reactor number four, technicians will begin removing radioactive waste from three other reactors that went into meltdown after the tsunami.
TEPCO said decommissioning the entire Fukushima complex could take 30 to 40 years.