Although Japanese people are increasingly worried about nuclear power safety after the Noto earthquake, Japan's pace of restarting nuclear power has not stopped, and many nuclear power plants are advancing the restart work. At the same time, the decommissioning of Japan's nuclear power plants is very difficult.

▲ Kashiwazaki Kariwa Nuclear Power Plant.

On March 19, Japanese Minister of Economy, Trade and Industry Ken Saito held a telephone conversation with the governor of Niigata Prefecture, Japan, seeking local understanding of restarting the Kashiwazaki-Kariwa nuclear power plant. It is understood that the Kashiwazaki Kariwa nuclear power plant was previously banned from operating due to security issues. Whether the local government can agree to restart the nuclear power plant is currently receiving widespread attention. In fact, although the Japanese people are increasingly worried about nuclear power safety after the Noto earthquake, Japan's pace of restarting nuclear power has not stopped, and many nuclear power plants are advancing the restart work. At the same time, the decommissioning of Japan's nuclear power plants is very difficult. Take the Fukushima Daiichi nuclear power plant, which has been in the accident for 13 years, as an example. Over the years, not only has the power plant made slow progress in the aftermath of the accident, but its decommissioning plan is also in the foreseeable future.

The total amount of nuclear contaminated water discharged into the sea exceeds 30,000 tons

It is understood that after the accident at the Fukushima Daiichi nuclear power plant, the Japanese government and Tokyo Electric Power Company decided to gradually complete the decommissioning of the nuclear power plant within 30 to 40 years. Specific work includes the treatment of nuclear contaminated water in the nuclear power plant unit, the removal and storage of spent fuel in the unit, and the removal of fuel debris formed by fuel melting. The initial goal of the Japanese government and Tepco was to reduce the production of contaminated water at the Fukushima Daiichi nuclear power plant to zero, but the plant was more damaged than expected and could not stop Rain Water and groundwater from seeping in. as a result, about 90 tons of nuclear contaminated water are produced every day. From August last year to March this year, the Japanese government and Tokyo Electric Power Company carried out four rounds of nuclear contaminated water discharge into the sea, with a total amount of 31200 tons. While the discharge of nuclear contaminated water into the sea has aroused opposition from the international community, treatment facilities have also broken down frequently. In October last year, two workers cleaning contaminated water treatment facilities came into contact with radioactive liquid because the water pipe fell off. In February this year, another worker did not pay attention to the opening of the valve on the pipe, resulting in the leakage of radioactive liquid in the contaminated water treatment facility. Although Tepco claimed that the radioactive material had no external impact, residents of Fukushima Prefecture expressed concern and unease in an interview with local media. According to Tepco's plan, it will take at least 30 years to discharge all the existing nuclear sewage. However, the nuclear contaminated water is formed by the continuous injection of fuel cooling water and the continuous infiltration of Rain Water and groundwater into the unit. In other words, as long as the fuel debris inside the unit is not removed, the Fukushima Daiichi nuclear power plant will continue to produce nuclear contaminated water.

Progress in fuel removal is difficult

Tokyo Electric Power Company is not optimistic about the handling of fuel in the unit. Currently, units 1 and 2 of the Fukushima Nuclear Power Plant contain more than 1000 pieces of spent fuel, which are planned to be taken out and transferred to storage facilities in 2031, 10 years later than the original plan. On the other hand, nuclear fuel fragments in Units 1, 2 and 3 are planned to be removed in 2021. However, due to the slow progress of equipment installation, the planned trial removal work in Unit 2 at the end of this year has been postponed. Unit 3 will How to carry out the removal work has not yet been finalized, and the overall removal work of the nuclear power plant is far away. To make matters worse, according to the Nihon Keizai Shimbun, the currently discussed removal method can only remove a few grams of debris at a time, which is equivalent to "the size of an earspoon." Hiroshi Miyano, chairman of the Fukushima Daiichi Nuclear Power Plant Waste Reactor Research Committee of the Japan Atomic Energy Society, pointed out:"It is estimated that it will take 50 years at the earliest and 100 years at the longest." In March this year, relevant Japanese agencies proposed using a new fuel debris removal method, which is to fill the unit with filler to solidify the nuclear fuel debris inside, and then dig it out from the top. But this method has never been used to remove fuel debris, and details such as filler material, injection location and method are difficult to determine. Tokyo Electric Power Company plans to take one to two years to verify the feasibility of this method, which means that most current projects will have to be reviewed or postponed. The previous decommissioning plan for the Fukushima Daiichi nuclear power plant has been revised five times, and the plan to complete the decommissioning within 40 years is becoming increasingly uncertain.

Concerns about nuclear power restart intensify

On the 13th anniversary of the Fukushima Daiichi nuclear power plant accident, about 300 people held a protest rally in front of the headquarters of Tepco, calling on Japan to shut down all nuclear power plants. Others oppose the restart of the Kashiwazaki Kariwa nuclear power plant, which was lifted this year, and highlighted the dangers of nuclear power restart in Japan, citing the Shiga plant, which was damaged by the earthquake in January. At the beginning of this year, the earthquake in Nengdeng, Japan, caused damage to the Shiga nuclear power plant, which is planned to restart. Northland Electric Power Company, which belongs to the nuclear power plant, concealed the true damage, causing concern among the Japanese public about the restart of nuclear power. Earlier, a group of people from many places in Japan had sued Kansai Electric Power Company, asking it to shut down Unit 3 of the Meibin nuclear power plant in Fukui Prefecture. After the lawsuit was rejected by the local court, the public then filed a lawsuit with the Japanese High Court, which was rejected again in March this year. It is understood that the Meibin nuclear power plant began operation in 1976, has been 48 years of history, a previous accident killed five people. After the restart in 2021, residents worried about the aging facilities of the plant, the lack of seismic capacity, the risk of serious accidents, and the contingency plan did not take into account similar scenarios in which houses collapsed in the Nengdeng earthquake and residents were unable to take refuge indoors.

Wen| Our intern reporter Yang Muyan