Tokyo Electric Power Company, or TEPCO, has postponed a test to retrieve nuclear fuel debris from one of its crippled reactors at the Fukushima Daiichi plant.
The utility had planned to begin the experimental debris removal on Thursday morning. It was to be the first such attempt in 13 and a half years after an earthquake and tsunami triggered meltdowns in the plant’s reactors in 2011.
It is estimated that there is a total of 880 tons of fuel debris in the No. 1, 2 and 3 reactors. The debris is a mixture of molten nuclear fuel and parts of the reactor structure.
The removal of such debris is said to be the most challenging step in decommissioning the damaged power plant because of extremely high levels of radiation, which hampers the work.
TEPCO workers began preparations for the debris retrieval before 7:30 a.m. on Thursday.
But the company soon decided to postpone the work after an issue was found with the installation of a device designed to take out the debris.
The device looks like a narrow tube and is designed to be pushed into the interior of the reactor containment vessel using other pipes.
TEPCO says workers found the pipes were in the wrong order when the device approached the piping leading to the inside of the vessel. The work was suspended before 9 a.m.
The company says it is looking into the details of the error, and that it has yet to decide the next steps to be taken in the coming days.
The test retrieval was set to begin three years later than originally scheduled.
The Japanese government and TEPCO believe it is an essential step in the decommissioning process, as data on the nature and condition of the debris are indispensable in designing a method to retrieve a large amount of debris in future.