China News Service, April 26. According to Kyodo News Agency of Japan, Tokyo Electric Power Company plans to reduce the amount of nuclear sewage accumulated in the containment vessel of Unit 1 of the Fukushima Daiichi Nuclear Power Plant.

The Atomic Energy Regulatory Commission pointed out that maintaining a high water level will cause a burden on the equipment, and the damage may expand in the event of an earthquake.

TEPCO plans to pump sewage from the pressure control room under the containment after 2023.

The picture shows the nuclear sewage storage tank of the Fukushima Daiichi Nuclear Power Plant in Japan on February 13.

　　According to reports, TEPCO continued to inject water into the containment vessel to cool down the nuclear fuel (fuel fragments) caused by the accident. The sewage of Unit 1 has reached a height of about 2 meters from the bottom.

However, after an earthquake with the largest intensity of 6 (Japanese standards) was observed in Fukushima and Miyagi prefectures on February 13 this year, the water level dropped by about 1 meter.

According to analysis, the damage that originally caused the water leakage was enlarged by the earthquake, and the water level is currently stabilized at a height of about 1 meter lower than the damage.

　　Previous investigations found that almost all of the fuel fragments of Unit 1 were distributed at the bottom, with deposits about 30 cm high around them.

Before pumping out sewage from the control room, the water level needs to be lowered to the root of the pipe connecting the containment and the control room (about 30 cm from the bottom). However, there is a concern that fuel fragments and accumulations will be exposed to the water surface and the temperature will rise, or radioactive materials will be scattered. .

　　In the water injection test conducted by TEPCO in 2020, it was confirmed that the water level dropped below the height of the water level gauge 62 cm from the bottom, and no radioactive material was scattered after two days.

In order to pump water from the control room in the future, equipment that can monitor the water level and temperature at a lower position is required.

　　TEPCO focuses on the method of pumping water through existing pipelines and is currently discussing it.

　　On March 11, 2011, a magnitude 9.0 earthquake occurred in the waters near Fukushima Prefecture, Japan.

Affected by this, the cores of units 1 to 3 of the Fukushima Daiichi Nuclear Power Plant operated by TEPCO melted down.

TEPCO continues to inject water into the containment of Units 1 to 3 to cool the reactor core and recover sewage.

As of March this year, 1.25 million tons of nuclear contaminated water has been produced in the nuclear power plant, and the amount is still increasing.

　　On the 13th of this month, the Japanese government officially decided to discharge the above-mentioned nuclear-contaminated water into the sea after being filtered and diluted.

Emissions will begin in about two years, and the emission period is expected to last 20 to 30 years.