According to NHK, Tokyo Electric Power Company recently released the internal picture of Fukushima nuclear power plant, saying that its robots detected neutrons at multiple points inside unit 1, and the detection values in some areas were very high. Therefore, it is inferred that a large number of deposits previously found inside unit 1 may be fuel fragments.
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Internal picture of Fukushima nuclear power plant. Image source: NHK video screenshot
The report points out that how to take out fuel fragments has always been considered as the biggest difficulty for the spent furnace of Fukushima Daiichi nuclear power plant. TEPCO plans to conduct detailed analysis of fuel fragments through robot sampling in the future.
On march11,2011, a 9.0 magnitude earthquake occurred in the northeastern waters of Japan and triggered a tsunami, resulting in heavy casualties and the Fukushima nuclear accident.