Thirteen years ago, there was a major nuclear accident at the Fukushima Daiichi nuclear power plant in Japan.

As a result of an earthquake and resulting tsunami, the nuclear reactors we unable to be cooled properly, and the electrical grid failure meant that containment was compromised. This led to radioactive substances being released into the environment, the worst nuclear disaster since Chernobyl in 1986.

Though nobody died at the time, one worker died of lung cancer four years later; his death was attributed to the disaster.

In the years since, cleanup of the site has been a major undertaking. The safety concerns are significant, and this is a large site that needs thoroughly decommissioning.

For the scientists, engineers and specialists working on the project, it is important to know the composition of the radioactive waste so that they can understand how best to remove it.

Expected to take at least 30 to 40 years, the project has now had a huge new development. While the team watched on from a safe location, a robot has been used to remove spent nuclear fuel from the site.

In a statement, Tokyo Electric Power Company Holdings, who operate the site, explained that the robot was able to retrieve a small amount of debris from the site in October. The ability to analyse this debris in specialist labs is leading the hope that the company will, in the future, be able to safely and efficiently remove further nuclear waste from the site:

“From the results of primary containment vessel internal investigations, we have deduced that the accumulated debris on the surface of the floor inside the pedestal is solidified molten material that consists of fuel elements and also may contain a lot of metal.

By analyzing the attributes of the sampled fuel debris we will directly ascertain information such as the composition of debris at the sampling location and radioactivity density.”

The retrieval of this waste has taught the researchers that much of the debris consists of molten metal and fuel. By better understanding exactly how radioactive the debris is, and how safe it is to transport for proper disposal, the TEPCO team will be able to make a plan for the further decommissioning of the site.

According to the statement, the next step – after fully understanding the composition of the debris – is to gradually collect larger and larger amounts of debris, all whilst continuing to ensure that retrieval is safe and viable.

This is no small task. The total debris is estimated at 880 tons.

While the robot has only started to make a dent in the retrieval process, it is hoped that by better understanding the waste, much more significant quantities will be able to be removed in the near future.

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