December 14 According to a report by Kyodo News Agency of Japan, the Japan Atomic Energy Regulatory Commission concluded that there were two instantaneous explosions in the reactor plant of Unit 3 based on the on-site investigation and related video analysis research carried out in September and October.
The investigation pointed out that not only hydrogen explosions, but also other combustible gas explosions.
These will be included in the accident investigation report summarized in March 2021.
At the end of 10 years of the accident, progress has been made in identifying the actual situation of the explosion.
The fire and black smoke on the south side of the factory were filmed by the camera set up by Fukushima Central Television about 17 kilometers southwest of a core.
The regulatory committee improved the resolution of the video and analyzed how the explosion happened.
The first is the hydrogen gas accumulated in the upper part of the reactor plant caught fire and exploded.
The beams and walls of the roof were greatly damaged, and flames bleed out from the cracks in the roof.
Later, in addition to the remaining hydrogen, gas, which is believed to be produced by melted and organic matter, such as cable insulation pipes, also mixed with oxygen and exploded, causing huge black smoke to pour out of the sky.
The investigation found that the scale of the explosion was slightly smaller than that of Unit 1’s hydrogen explosion.
The regulatory committee believes that it is possible that the first stage of hydrogen explosion occurred on the fourth floor of the reactor plant and the second stage explosion occurred on the fifth floor of the top floor.
The Committee intends to continue to investigate the actual situation of the accident after completing the report.