After years of discussions, Japan will formally begin next spring a decades-long plan to discharge water from the Fukushima nuclear process.
Under the action of ocean currents, these treated water will enter the waters of Japan, or have long-term effects on the surrounding countries and the waters of wider countries and regions, thus causing strong opposition from neighboring countries such as China and South Korea.
Where does the discharged nuclear treatment water come from?
What should be done?
What risks might there be?
Are there effective third-party agencies involved in monitoring and evaluation?
Will the emission pose a radiation threat to the marine ecology and human body?
"Hong Kong 01" made an exclusive interview with Tokyo Electric Power Company (TEPCO), the operator of the Fukushima nuclear power plant and the implementation of the sea discharge plan, and interviewed Japanese government officials, marine ecology, cancer pathology and nuclear experts, etc., with a series of special reports answer these key questions.
Ten years after the accident at the Fukushima Daiichi nuclear power plant, the Japanese government officially approved in April last year a plan to discharge more than 1.3 million tons of nuclear treated water accumulated in the nuclear power plant into the Pacific Ocean. After being filtered by the removal processing system (ALPS), and then diluted to meet the regulatory standards, it is discharged into the offshore area about one kilometer away from the nuclear power plant through the submarine pipeline, and finally into the Pacific Ocean.
The International Atomic Energy Agency (IAEA), which participated in the assessment, has been monitoring and licensing the scheme: "Although the large amount of wastewater stored at the Fukushima nuclear power plant makes it a unique and complex case, this move is in line with global practice." However, This has not quelled the strong dissatisfaction of neighboring countries and regions such as China and South Korea.
South Korea condemned this "totally intolerable" behavior and summoned the Japanese ambassador to protest; China's foreign ministry expressed serious concern and firm opposition; the plan also sparked strong opposition from Taiwanese people and the fishery, and the Kuomintang criticized Tsai Ing-wen's government for its weak response.
Amid the controversy, in August this year, Tokyo Electric Power Company (hereinafter referred to as TEPCO) still started the construction of the main pipeline of the sea discharge facility and the pipeline connecting the water storage tank, in preparation for the planned discharge next spring.
It has been more than 11 years since the Fukushima nuclear disaster, and the sewage in the Fukushima Daiichi nuclear power plant1.
(Getty)
Controversy to start construction: 400,000 tons into the sea before 2030
Jun Matsumoto, head of the ALPS treatment water countermeasures at Tokyo Electric Power Fukushima Daiichi Nuclear Power Plant, told Hong Kong 01: After the nuclear treatment water is treated, "there will be planned discharges in 20 to 30 years until the nuclear power plant is decommissioned." Outside the period of regular equipment maintenance, "basically plan to continue emissions", starting from a small amount at the beginning, and gradually increasing the amount of emissions in stages.
Matsumoto said the company plans to discharge about 400,000 cubic meters of treated water by 2030 to meet the needs of the waste furnace.
Since the water storage tank for storing nuclear waste water currently occupies most of the available space in the nuclear power plant, with the progress of the waste furnace work, it will be necessary to store the nuclear waste taken out from the furnace for the equipment required for the construction of the waste furnace in the future. Make room.
TEPCO's medium- and long-term roadmap shows that all these facilities will be completed by 2028.
Since the nuclear disaster, the amount of waste generated is huge. As of March 2021, the amount of solid waste in nuclear power plants has reached 480,000 cubic meters, and it is expected to increase to 790,000 cubic meters in the next ten years.
(Hong Kong 01 cartography)
Filter first, then dilute, then drain
Once the discharge begins, the treated water stored in the high-lying water storage area of the nuclear power plant will pass through the pipeline and enter a pool close to the sea, where it will be diluted by seawater and then discharged through a submarine pipeline with a diameter of 2.5 meters. The sea area 1 km from the coast, this is to minimize the impact on local fisheries.
TEPCO pointed out that according to the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), the radiation amount of the nuclear wastewater discharged after treatment is only 0.0000018 to 0.0000207 millisieverts (mSv) in one year, which is only the natural background radiation value ( 2.1 millisieverts per person per year).
However, local fishermen are concerned that this will still cause irreversible effects on the industry; some marine ecologists are even more worried that nuclides will deposit on the seabed and enter the food chain, and the long-term potential impact is difficult to predict.
In August, TEPCO began work on the subsea pipeline immediately after obtaining permission from the local government, and is expected to complete it by next spring or summer at the latest.
However, local fishing groups are still strongly opposed to the plan, and Fukushima Prefecture Governor Masao Uchihori also admitted that the plan to discharge the sea has not received sufficient support from the people in and outside Fukushima Prefecture, so it may not be able to start discharge as scheduled.
It takes decades to fill 500 standard swimming pools
The Fukushima Daiichi Nuclear Power Plant was hit by a tsunami in the March 11 earthquake in 2011. Three of the six reactors had their cores melted. The basement of the reactor building was also damaged and ruptured in the earthquake, and groundwater was suspected to have flowed into it through the cracks. .
Melting nuclear fuel debris requires a long and continuous injection of cold water to cool it down, but that's not the only reason for such a large amount of nuclear-contaminated water.
Since the basement of the reactor is destroyed, in order to prevent groundwater from entering the reactor building and polluting the water source, the water level in the reactor building must be lower than the groundwater level, so that water will continuously flow into the reactor building from the outside, while the water inside the reactor will not flow out. A large amount of polluted water accumulated in the building.
(Hong Kong 01 cartography)
Since the Fukushima nuclear power plant is built in the coastal area and the terrain is relatively low, a large amount of groundwater and rainwater flow down from the mountainside of Mount Abukuma on the inland side every day and pass through the nuclear power plant.
In fact, when Tokyo Electric Power Company was building a nuclear power plant in the 1960s, it leveled the hillside at the site so that groundwater could be pumped to cool the nuclear reactor and transfer the heat generated by the reactor to the so-called "ultimate radiator". in the ocean.
However, this convenience has brought enormous trouble after the disaster.
Because the 64 kinds of radioactive elements contained in these sewage cannot be completely removed (Editorial note: the wastewater discharged from general nuclear power plants has less than 10 kinds of radioactive elements), and the
half-lives of individual radioactive elements*
are as long as several thousand to hundreds of thousands of years. It is only possible to continuously build water storage tanks in the nuclear power plant for storage.
Over the years, the sewage contained in the giant water storage tanks more than 10 meters high has brought a lot of trouble to TEPCO. The water storage tanks made in the early stage were leaking, the space in the site was insufficient, and the "treated water" that was not fully purified caused public doubts. ...Although discussions on treating sewage into the sea started as early as 2013, due to strong opposition from local fishermen and public distrust of TEPCO after the accident, sewage The final disposal work has been pushed and pushed again and again.
Note: Half-life refers to the time required for the radioactivity of a nuclide to decrease to half of its initial radioactivity
The number of blue and gray giant water storage tanks in the Fukushima Daiichi nuclear power plant has also reached more than 1,000.
(Getty)
At the same time, TEPCO has tried various methods to reduce the amount of sewage, including the construction of an ice wall (frozen earth wall) to block water seepage at a cost of 35 billion yen (about 1.85 billion Hong Kong dollars), and the installation of multiple pumps outside the reactor building to extract water. A large amount of groundwater is used to lower the water level, thereby preventing it from flowing into the reactor, etc.
Although the daily new sewage volume has been greatly reduced, over the years, the total amount of this sewage still reaches about 1.32 million tons, enough to fill 500 Olympic-sized swimming pools.
The number of blue and gray giant water storage tanks distributed like a honeycomb has also reached more than 1,000, and the wastewater is still increasing at an average rate of 120-130 cubic meters per day (according to 2021 statistics).
Tepco previously said that the water storage tank will be filled around next spring.
Of course, some foreign experts questioned the so-called "full" claim of the water storage tank. Because there is a large amount of abandoned land around the nuclear power plant that can temporarily store wastewater and solid waste, more radioactive substances should be disposed of after the half-life period. The decision of the sea.
Changes in the number of storage tanks around nuclear power plants from 2013 to 2020:
(Hong Kong 01 cartography)
How are the 64 nuclear elements handled?
Professor Ichiryo Yamamoto, a nuclear energy researcher and professor at Nagoya University, also participated in the ALPS water treatment working group. He explained in an exclusive interview with "Hong Kong 01", "In fact, a normally operating nuclear power plant has not been hit by a disaster like Fukushima. Unleashing so many different elements."
Yamamoto pointed out that due to the "unusual melting" of nuclear fuel, it is difficult for the sewage treatment equipment used in ordinary nuclear power plants to remove all 64 kinds of nuclides.
In addition to some particles in solid form, there are also a large number of substances in the form of ions. Once dissolved in water, it is difficult to filter directly, and special agents need to be added to make them precipitate: "For example, combining ions with iron can make it It becomes salt, which precipitates in the water.” These are substances that can be “simply removed.”
The remaining large amount of ions that cannot be cured needs to be absorbed and removed with different adsorbent materials.
After these steps were completed, the concentration of a nuclide called "tritium" exceeded the regulatory standards set by the Japanese government.
"Tritium is actually one of the isotopes of hydrogen atoms, and hydrogen atoms are also a component of water molecules, so it's difficult to remove it from water with the methods we're talking about," Yamamoto said.
There are 16 adsorption towers in ALPS (multi-nuclear species removal processing system), the principle is like an air purifier:
TEPCO's countermeasure is to further dilute the purified "tritium water" by more than 100 times to 1,500 becquerel (Bq) per liter, which is one-fortieth of the drinking water standard set by the World Health Organization.
Other nuclear power plants around the world also produce nuclear sewage in the process of cooling reactors, but the Fukushima nuclear power plant is more radioactive because it directly injects cooling water into damaged reactors and comes in direct contact with the nuclear fuel.
Lu Binglin, chairman of the Hong Kong Nuclear Society, told reporters that some of the nuclides contained in Fukushima wastewater, such as iodine-129 (Iodine-129), have a physical half-life of 16 million years, Xun-99 (Technetium-99) has a physical half-life of 210,000 years, and tin -126 (Tin-126) is 100,000 years old, "so there will be doubts that this cannot be compared to normal nuclear power plant emissions."
Matsumoto Junichi of Tokyo Electric Power Company added that some of the ALPS treated water being stored has tested 64 radioactive elements including tritium, but the other part has only tested 7 of them, but after confirming the sea discharge time, TEPCO will A comprehensive inspection of 64 elements will be carried out, "TEPCO will not discharge into the ocean treated water that has not been tested for 64 kinds of radioactive substances."
Judging from the numbers alone, TEPCO's plan to expel the sea is impeccable.
However, in the past few years, there have been many controversies about the purification effect of ALPS devices in Japan and abroad, and nearly 70% of the 1.32 million tons of sewage in the nuclear power plant has not been completely purified. According to Dongdian, the purification is below the regulatory standard.
Some Hong Kong experts questioned whether the ALPS processing system, which is the top priority of the entire project, is completely reliable?
Does TEPCO replace the filter element effectively?
These questions will be discussed further in the next part of this article.
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