TOKYO - Workers at Japan's Fukushima nuclear plant on Monday began moving fuel rods from a reactor building, in their most difficult and dangerous task since a tsunami crippled the facility in 2011.
Operator Tokyo Electric Power (TEPCO) said it had begun the process of removing the uranium and plutonium rods from a storage pool - a tricky but essential step in the complex's decades-long decommissioning plan.
The operation follows months of setbacks and glitches that have stoked widespread criticism of the utility's handling of the crisis, the worst nuclear accident in a generation.
However, the work pales in comparison with the much more complex task that awaits engineers, who will have to remove the misshapen cores of three other reactors that went into meltdown before being brought under control two years ago.
The fuel rods are bundled together in so-called assemblies which must be pulled out of the storage pool where they were being kept when a tsunami smashed into Fukushima in March 2011. There are more than 1,500 such assemblies in the pool.
Over the course of two days, the company said it expects to remove 22 assemblies, with the entire operation scheduled to run for more than a year.
"At 15:18 (0618 GMT), we started to pull up the first fuel assembly with a crane," a company spokesman said Monday.
The huge crane, with a remote-controlled grabber, is being lowered into the pool and then hooked onto the assemblies, placing them inside a fully immersed cask.
The 91-tonne cask will then be hauled from the pool to be loaded onto a trailer and taken to a different storage pool about 100 metres (yards) away.
Experts have warned that slip-ups could trigger a rapid deterioration in the situation.
"We are concerned that TEPCO may not be capable of conducting this risky operation safely," Greenpeace said Monday.
It added that a botched job may mean "workers could be exposed to excessive levels of radiation and in a worst-case scenario there could be a massive new release of radiation to the atmosphere".