According to Japanese media reports, the Japanese government intends to discharge the 1.23 million tons of nuclear waste water from the Fukushima nuclear leak into the Pacific, and it will be finalized at the cabinet meeting in October this year at the earliest . In the face of condemnation from countries around the world, especially neighboring countries, Japanese Prime Minister Yoshihide Suga said: "The (Japanese) government will take the responsibility as soon as possible to finalize the disposal policy."
The reason why it wants to discharge nuclear waste water into the Pacific Ocean is that Japan said it was a "forced and helpless" choice. After the "3.11 Great Earthquake" leak at the Fukushima Nuclear Power Plant, the nuclear reactors were damaged and melted down. In order to cool them down, Japan adopted a water cooling method, which resulted in a large amount of nuclear waste water.
▲ A large amount of nuclear waste water is packed in special water storage tanks and placed in the offshore Fukushima nuclear power plant
At present, the nuclear waste water in the water storage tanks near the nuclear power plant has exceeded 1.23 million tons, which can almost fill 578 standard swimming pools. Moreover, the nuclear waste water is still increasing rapidly at a rate of 170 tons per day. The currently manufactured water storage tanks are only enough. Use until the summer of 2022.
The former Japanese Minister of the Environment Yoshiaki Harada said in an interview that the Japanese government has studied five methods for treating nuclear waste water, including discharge into the sea, evaporation treatment, discharge to a depth of 2500 meters underground, electrolytic treatment, and burying of nuclear waste water into cement blocks. , And finally found that " except for the determination to dilute the polluted water into the (Pacific), there are few other options. "
▲ Former Japanese Minister of Environment Yoshiaki Harada
The Fukushima nuclear leak has developed to the point where "one country pays the bill for the whole world," and we have to start with the 3.11 earthquake in Japan.
After a magnitude 9 earthquake, the Fukushima nuclear power plant leaked
On March 11, 2011, an earthquake with a magnitude of 9 on the Richter scale occurred in the waters of northeastern Japan and triggered a tsunami. According to the statistics of the Japanese National Police Agency, the earthquake directly and indirectly caused about 19,000 deaths and more than 2,500 people were unaccounted for.
After the disaster, almost everyone focused on the disaster situation in the coastal areas. What never expected was that a disaster that was more difficult to face and deal with had already occurred, and that was the nuclear leak- located in Fukushima Industrial, Japan. The nuclear power plants in the district were affected by the earthquake and tsunami. The hydrogen leaked into the reactor reacted with air to cause an explosion, causing radioactive materials to leak outside the nuclear power plant .
▲ After the Fukushima nuclear power plant leaked, it exploded many times
According to the severity of the nuclear leakage, the International Atomic Energy Agency (IAEA) classifies nuclear power plant accidents into 7 levels, the lowest level is level 1 nuclear accident, the highest level is level 7 nuclear accident, and the Fukushima nuclear power plant leak is classified as level 7 nuclear accident .
After the accident, radioactive materials leaked into the sea, and the volatilized radioactive materials spread rapidly with the north wind, causing strong protests from the people of the surrounding countries.
According to media reports in many countries, Tokyo Electric Power Company , the superior management company of the Fukushima Nuclear Power Plant, started processing work about 20 hours later and tried to conceal some facts . The Japanese government was also criticized by the international community for being questioned for inefficiency in its rescue work. China triggered a panic buying incident that "the whole family bought hundreds of kilograms of salt overnight."
What happened after the nuclear leak
For more than nine years, the rescue work at the Fukushima Nuclear Power Plant has not yet been completely completed. Even the radiation in the containment vessel of the Fukushima Daiichi Nuclear Power Plant Unit 2 reactor was as high as 530 sievert per hour. Japanese research and development robots entered the highest radiation area to work. , The support is completely damaged in less than 2 hours.
▲ The situation inside the containment of Fukushima Nuclear Power Plant Unit 3
▲ Robots can't resist strong nuclear radiation
After the accident, Tokyo Electric Power Company (hereinafter referred to as "Tepco") and the Japanese government filed a lawsuit. Tepco believes that the tsunami caused by the earthquake can be warned. The Japanese government did not give a timely warning to cause the nuclear leak. The Japanese government believed that it was Tepco Caused by poor management. After years of "tug-of-war" in lawsuits, according to BBC reports, three TEPCO executives were recently acquitted.
▲ TEPCO 3 executives were acquitted
According to a report from South Korea's SBS, Japan detected in 2011 that spinach and other agricultural products produced in Fukushima exceeded nuclear radiation standards. A few years later, in order to prove that Fukushima Prefecture's agricultural and sideline products are safe, Japanese TV presenters have repeatedly eaten Fukushima Prefecture's vegetables publicly.
▲ The Japanese host publicly eats Fukushima products in the show
In recent years, Japanese officials and media have repeatedly used practical actions to prove that the agricultural and sideline products in Fukushima and surrounding counties and cities are safe and reliable, and they have been promoted to Japan and abroad . Former Japanese Prime Minister Shinzo Abe once publicly consumed Fukushima agricultural and sideline products, and the news that he drank milk from Fukushima Prefecture also attracted a lot of attention. According to Southern Weekend reports, 27 countries around the world have completely lifted import restrictions, including Canada, Australia, New Zealand, Myanmar, and India.
What is in Japan's nuclear wastewater?
On the official website of Tokyo Electric Power Company, we found the latest data after the secondary treatment of nuclear wastewater, which they call "treated water."
▲ The latest major data of secondary treated water published on the official website of TEPCO
The elements in the leftmost column from top to bottom are: cesium-134, cesium-137, cobalt-60, ruthenium-106, antimony-125, strontium-90, iodine-129, strontium-89, all related to nuclei, It is radioactive, and it is harmful to the human body if the safe dose is exceeded. (Note: Due to translation software issues, there may be some incorrect translations of element names, please correct me)
According to the latest published data, the seven main elements in nuclear wastewater have been reduced to a low level after secondary treatment. However, many people pay more attention to another element in nuclear waste water-tritium (sound chuān), because it is not as easy to handle as the above seven elements.
Is the treated nuclear waste water harmful to the environment?
Most of the radioactive materials in nuclear waste water are usually not evaporative, and nowadays, there are more mature and safe technologies to deal with. Generally, the method of evaporating nuclear waste water to concentrate nuclear waste is adopted, and solid nuclear waste is made solid for storage. But the tritium in nuclear waste water will not work. It exists in a gaseous state in nature.
▲ Schematic diagram of tritium participating in sudden change reaction. Image source: China Net News
"Tritium" is an isotope of hydrogen, also called superheavy hydrogen. Its nucleus is composed of one proton and two neutrons and is mainly used for thermonuclear reactions. In the atmosphere, the natural content of natural tritium may be less than 2 kg. Tritium emits beta rays and decays into helium 3 with a half-life of 12.5 years.
Because the beta decay of tritium will only release high-speed moving electrons and will not penetrate the human body, only a large amount of tritium inhalation will be harmful to the human body. However, it should be noted that biologically active substances labeled with tritium (such as tritium-labeled thymine), due to their biological activity, will be used by human cells for cell metabolism, causing direct internal radiation, which will seriously harm the health of inhalers .
Whether nuclear waste water containing tritium will cause harm to marine life can only be verified and answered by relevant professionals. TEPCO said that tritium is a natural element, so there is no need to make a fuss.
It is stated in a material published on the official website of TEPCO: Some argue that tritium in ALPS-treated water should be handled differently from tritium generated from usual operation of NPPs because the former is generated as the result of the accident. No scientific reason can be found to differentiate the handling of the two.
▲ Source of file picture: Tokyo Electric Power Company's official website
The general meaning of the translation is: Some people believe that the tritium contained in the treated water is different from the tritium in the water generated during the normal operation of the nuclear power plant, only because the former was caused by an accident. (We) cannot find a scientific reason to distinguish the two treatments.
The implication is that there is tritium in the nuclear waste water produced by the normal operation of nuclear power plants and the nuclear waste water produced by the treatment of nuclear leakage. The waste water produced by the former can be discharged after the treatment reaches the standard. The (nuclear waste water/treated water) we have processed also meets the standard, no Should be treated differently.
According to data released by TEPCO in March this year, the total tritium content of nuclear waste water currently stored in water storage tanks is about 860 trillion Bequ. (Note: Beque is the unit of radioactivity. When one atom of a radioactive element decays every second, its radioactivity is 1 beque.)
▲ Source of file picture: Tokyo Electric Power Company's official website
In addition, according to a report from China News Weekly on October 21, Dale Klein, former chairman of the US Nuclear Energy Safety Regulatory Commission, believes that the current concentration of tritium in Fukushima sewage is low enough to safely discharge water into the sea. When the Director General of the International Atomic Energy Agency visited Japan for the first time in February this year, he also stated that the discharge into the sea was in line with international practice and that he would provide support during discharge .
The Japanese Ministry of Foreign Affairs stated in the question and answer session of the press conference that the discharge regulatory standards for nuclear waste water refer to the relevant regulations of the International Commission for Radiation Protection (ICRP). Assuming that radionuclides in the water only contain tritium, the discharge value allowed by the Japanese regulatory standards is 60,000 per liter. Beck.
According to the contents of the WeChat public account of Southern Energy Observation, China’s "Regulations on Environmental Radiation Protection for Nuclear Power Plants (GB 6249-2011)" stipulates that for each 3000MW light water reactor with a thermal power of 3000MW, the total amount of tritium control value in the liquid radioactive effluent per year It is 3.5×10^13 (35 trillion) Beque. From the point of view of concentration, the "Regulations" do not make specific requirements for the tritium concentration at seaside plant sites, and the inland plant site requires that the tritium concentration does not exceed 100 beqs per liter.
Public information shows that the Fukushima nuclear power plant has a total installed capacity of 7965MW, which is a coastal nuclear power plant.
▲Excerpts from Regulations on Environmental Radiation Protection of Nuclear Power Plants (GB 6249-2011). Picture from: Southern Energy Observation WeChat public account
As of the publication of the article, the National Nuclear Safety Administration and other relevant departments have not yet issued an official evaluation on the details of the Japanese government's nuclear wastewater standards, disposal methods, and discharge duration. According to CCTV News, China’s Ministry of Foreign Affairs responded quickly, urging the Japanese government to thoroughly evaluate the possible impact of the Fukushima nuclear sewage treatment plan and make cautious decisions based on full consultation with neighboring countries.
Following ocean currents, nuclear waste water may circulate most of the Pacific Ocean
▲ Fukushima is roughly located at the intersection of the three lines of the Japanese Warm Current, the Kuril Current and the North Pacific Warm Current in the picture above. Picture source: Xueba.com
The impact of nuclear wastewater on the environment has not yet been definitively determined. As ordinary people, we are more concerned about where the nuclear wastewater discharged into the Pacific Ocean will go.
Based on a rough analysis of ocean currents, nuclear wastewater may not only affect Japan, but also countries or regions along the Pacific Ocean .
One very important reason why Japan chose to discharge nuclear waste water into the Pacific Ocean is that there is a Japanese warm current on the east coast of Japan. It will continuously transport the sewage discharged from the east coast of Japan to the North Pacific Ocean and merge into the North Pacific warm current to reach the west coast of North America. .
▲ The red dot is Fukushima, and line 1 represents the Japanese warm current
After arriving on the west coast of North America, the ocean currents mixed with nuclear waste water will follow the Alaska warm current, the California cold current, the northern equatorial warm current, the equatorial countercurrent, the southern equatorial warm current, the Japanese warm current, etc., and circulate throughout the North Pacific, gradually being diluted, along the coast There are more than ten countries and regions, and the total population of these countries and regions is about 1 billion .
Will China be affected?
The coastal areas of mainland China are theoretically not affected much for four reasons.
1. Since the discharge point Fukushima is on the east coast of Japan and at the end of the Japanese warm current, and the Japanese warm current is a strong ocean current from south to north, nuclear waste water will only follow the Japanese warm current to go north to west, first reaching Canada and the United States. , It was impossible to get close to the coastal waters of mainland China for the first time.
2. The nuclear waste water will follow the ocean current and make a circle around the North Pacific before reaching the vicinity of Taiwan, China.
▲ The nuclear waste water has to circulate in the North Pacific before returning to the west side of the Pacific
3. Due to the existence of two levels of submarine steps, especially the steep rise of the submarine steps close to mainland China, and the barrier of Taiwan Island of China, it is difficult for ocean currents to cross this step on a large scale, so the Japanese warm current flows to the east coast of Japan. .
▲ The red line is the seabed steps, the picture source: Mr. Da Lan (knowledge)
4. The Yellow River, the Yangtze River, and the Pearl River are all injecting water resources into the coasts of mainland China all the time. The strong pressure difference forms a natural water barrier. The principle is similar to "clearly distinguished."
▲ The phenomenon of "clearly distinct" at the mouth of the Yellow River. This phenomenon is called "ocean front"
At the same time, China has a "National Nuclear Emergency Plan" and a set of scientific and complete work plans for dealing with nuclear accidents. Judging from previous response experience, the early warning and monitoring response is timely and sufficient, and we need not worry.
Nuclear power safety is more important than Mount Tai
It is reported that Japan may regard the discharge of nuclear waste water as a "continuous" task, and the discharge time may be as long as 30 years, in order to avoid the pollution of nuclear waste water to the environment as much as possible. People in China, Russia, South Korea and Japan have expressed their opposition.
At present, the details of Japan's nuclear waste water discharge method, total amount, and length of time are still being discussed. The attitude of the Japanese government, the opinions of authoritative experts and the voices of people from all over the world are entwined and become a knot that is difficult to untie.
Tracing back to the source, the Fukushima nuclear leak is the singularity of everything. If the safety awareness of the Fukushima nuclear power plant is higher and the Japanese government's tsunami warning is more timely, perhaps this incident that has not been completely concluded for more than 9 years will not happen or the impact will be minimized, or it may not be today. The problem of "difficult nuclear wastewater treatment".
Now, dozens of countries and regions in the world have nuclear power plants. In some countries or regions, nuclear power is still one of the main sources of electrical energy in the region. Nuclear power has long been closely linked with many people on the earth.
The Fukushima 3.11 nuclear leakage accident and the difficult incident of nuclear waste water discharge have broadcasted a sentence to the world in reality:
Nuclear power safety is more important than Mount Tai .
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