The Nuclear Regulatory Commission, which resumed the investigation of the accident at the Fukushima Daiichi Nuclear Power Station, compiled a draft report on the newly discovered pollution of radioactive materials inside the facility, and there are still many unexplained events. He points out that it is important to continue the investigation as much as possible.
In the accident at TEPCO's Fukushima Daiichi nuclear power plant, a meltdown occurred in Units 1 to 3 where nuclear fuel melted down, and hydrogen explosions occurred in Units 1, 3 and 4.
The Nuclear Regulatory Commission has resumed the accident investigation from the beginning due to the decrease in radiation dose at the site, and on the 26th, compiled a draft report of 326 pages, and said that three new facts have been revealed. ..
Of these, at Units 1 and 3, which attempted to "vent" the gas inside, part of the gas flowed back, which may have spread pollution inside the building.
It is possible that this regurgitation also contained hydrogen, and it is necessary to investigate the relationship with the hydrogen explosion in the future.
In addition, in Units 2 and 3, a large amount of radioactive material was found to be attached to the lid directly above the reactor.
The draft report states that the structures under the lid should also be investigated in the future, as the full picture of where the meltdown reactor radioactive material has subsequently leaked or accumulated is unknown.
In addition, video analysis of the hydrogen explosion was also conducted for the first time, and it is highly possible that the explosive combustion of flammable gas occurred continuously at Unit 3 following the first explosion.
On the other hand, it is said that there are still many unexplained events such as the operation of the device that lowers the pressure of the Unit 3 reactor for which the cause is unknown. Is important.