The operator of the Fukushima Daiichi nuclear power plant has launched a trial to retrieve nuclear fuel debris from one of the plant’s crippled reactors, after a delay caused by misaligned pipes.
Tokyo Electric Power Company, or TEPCO, was due to begin the experiment at the No.2 reactor on August 22, only to call it off at the last moment. The work resumed on Tuesday.
This is the first attempt to retrieve fuel debris from the plant’s reactors since they suffered meltdowns 13 and a half years ago after the 2011 earthquake and tsunami.
Nuclear fuel debris consists of molten fuel mixed with parts of the reactor structure. About 880 tons are estimated to be inside reactors No.1, 2 and 3.
Removing the debris is considered the most challenging step in decommissioning the plant, due to extremely high levels of radiation.
TEPCO’s initial attempt had to be called off when it found a mistake in the order of the pipes designed to push the retrieval device into the containment vessel.
After taking steps to prevent similar errors, the utility said it resumed the procedure on Tuesday morning, inserting the retrieval device into a pipe that leads to the interior of the containment vessel.
The retrieval device is shaped like a narrow tube. It is designed to lower a tool via cable from its tip to retrieve several grams of fuel debris from the bottom of the vessel. Most of the work will be handled remotely.
TEPCO says it will carefully monitor the situation as it proceeds with the trial. It estimates that the process will take around two weeks to complete, even if the work goes smoothly.
Debris retrieval is already three years behind schedule. TEPCO was initially due to launch the process in 2021.
The outcome of the experiment is being closely watched. The government and TEPCO say the data regarding the properties and condition of the debris obtained in this trial will be crucial in studying the best method for full-scale removal work.