20 Novembre 2013
November 20, 2013
November 19, 2013
Tokyo Electric Power Co. has offered the first glimpse of the operation to remove fuel rods at the Fukushima No. 1 nuclear plant, the most dangerous job since the runaway reactors were brought under control two years ago.
Video footage supplied by Tepco on Tuesday showed workers with protective suits inside reactor building 4 as a crane lowered a huge metal cask into the cooling pool filled with uranium and plutonium rods.
The fuel rods are bundled together in assemblies that must be pulled out of the pool where they were being kept when the March 11, 2011, tsunami smashed into the Tohoku region. There are more than 1,500 assemblies in the pool.
Removal of the fuel rods is a tricky but essential step in decommissioning the complex, which is expected to take decades.
On Monday, the utility said it expects to remove 22 assemblies over two days, with the entire operation scheduled to run for more than a year.
The huge crane’s remote-controlled grabber hooks onto the assemblies one by one and places them in the fully immersed cask.
The 91-ton cask will then be lowered to a trailer and taken to a different storage pool about 100 meters away
Tepco said the work was on schedule with 22 assemblies expected to be placed inside the cask by Tuesday evening.
The No. 4 reactor was not in operation when the crisis started in 2011.
But the pool was heavily damaged and left at the mercy of subsequent earthquakes, storms or tsunami.
The fuel assemblies need to be kept in a more stable facility, but experts have warned that mistakes in the removal operation could trigger a rapid deterioration in the situation.
Tepco’s efforts to contain the crisis have faced a string of setbacks and mechanical glitches, stoking widespread criticism of its handling of the worst nuclear accident in a generation.
The work that began Monday pales in comparison with the much more complex task that awaits engineers, who will have to remove the misshapen cores of the three reactors that went into meltdown.