As a result of ultrasonic exploration, TEPCO's state of deposits that may be "fuel debris", which is a mixture of melted nuclear fuel and structures, confirmed inside the containment vessel of Fukushima Daiichi Nuclear Power Station Unit 1 is different. Announced that it has newly confirmed that it is deposited in two layers, and will continue to analyze it in detail.
At Fukushima Daiichi Nuclear Power Station Unit 1, TEPCO's research confirmed deposits over a wide area around the structure "pedestal" that supports the reactor inside the containment vessel, and fuel debris was a mixture of melted nuclear fuel and the structure. It has become clear that there is a high possibility of.
Earlier this month, TEPCO introduced an underwater robot capable of ultrasonic exploration and measured the thickness of sediments at 13 locations inside the containment vessel.
In one of these, it was found that the thickness of the sediment was about 80 cm to 1 m, and the thickness increased as it approached the opening of the "pedestal".
It was also confirmed that the deposits near the bottom of the containment vessel were dense and lumpy, while the deposits a few centimeters near the surface were muddy and divided into two layers. That is.
TEPCO wants to analyze the data measured at another location in the containment vessel for the removal of fuel debris, which is considered to be the biggest difficulty in decommissioning, and to advance the overall picture of the sediment.