Regarding Fukushima Daiichi Nuclear Power Station Unit 1, which is undergoing decommissioning work, it was pointed out that the water level inside the containment vessel containing the reactor is high, and some facilities may be overloaded and damaged in the event of a large earthquake. In response, TEPCO decided to lower the water level.
At the Fukushima Daiichi Nuclear Power Plant, Units 1 to 3 melted down, and the containment vessel containing the reactor contained melted-down nuclear fuel, so-called fuel debris, and water injection was continued for cooling.
For this reason, a certain amount of water has accumulated inside the containment vessel, and the water levels of Units 1 and 3 are relatively high.
Regarding this, the Nuclear Regulatory Commission pointed out that a large amount of water could cause a load in the event of a large earthquake and damage the part called the pressure suppression chamber at the bottom of the containment vessel.
In response to this, TEPCO has recently decided to lower the water level of Unit 1.
The water level of Unit 1 dropped due to the impact of the February earthquake, and TEPCO currently maintains a water level of about 1 meter from the bottom of the containment vessel. I plan to gradually lower it while checking.
However, due to the high radiation dose at the site, it will take time to prepare, so it will not be until 2023 or later that it will start to be lowered in earnest.
In addition, it is expected that Unit 3 will be after 2024.