In a survey toward the decommissioning of the Fukushima Daiichi Nuclear Power Station, TEPCO announced the analysis status of deposits that may be "fuel debris" confirmed inside Unit 1.
As the condition is gradually becoming clear, such as the inclination and the presence of cavities, we will consider how to conduct a detailed investigation such as future sampling.
At Unit 1 of the Fukushima Daiichi Nuclear Power Plant, which caused the accident, deposits were confirmed in the water inside the containment vessel by TEPCO's investigation, and it is highly likely that fuel debris is a mixture of melted nuclear fuel and structures. ..
In June, an underwater robot capable of ultrasonic exploration was introduced to clarify the condition such as the thickness of sediments, and data was measured at 13 locations inside the containment vessel.
As a result, the thickness of the sediment was about 1 meter to 30 cm, and there was an inclination that seemed to flow out from the part directly below the reactor.
Also, by comparing the data with the image, it became clear that there were cavities and parts that seemed to collapse.
TEPCO has decided to consider detailed investigation methods such as sampling using another robot, as the complicated situation has gradually become clear.