More than half of the fuel assemblies from Fukushima-Daiichi-4 have been transferred to a central storage pool with the remainder scheduled to be removed by the end of the year, operator Tokyo Electric Power Company (Tepco) said.
In an operation that began in November 2013, Tepco has so far removed 792 used fuel assemblies and 22 unused ones from the unit’s fuel pool. The remaining 539 used and 180 unused assemblies should be moved before the end of the year, the company said.
Unit 4 at Fukushima-Daiichi was already shut down for a regular inspection when the station was hit by an earthquake and tsunami in March 2011 and all spent fuel assemblies had been transferred to the spent fuel pool. The unused assemblies were being prepared to be inserted into the reactor when the disaster happened.
Removing fuel assemblies from a fuel pool is “a normal operation”, Tepco said, but because of damage caused by a hydrogen explosion at Unit 4 after the tsunami and earthquake, the job entails a risk that is “clearly different from normal operations in terms of working environment”.