According to overseas networks, Japan’s 311 earthquake and the 7th anniversary of the Fukushima nuclear disaster, Tokyo Electric Power Company conducted a survey in the Tamamachi, where the Fukushima Daiichi nuclear power plant is located, and detected radioactive strontium in fish about 4 kilometers offshore. Exceeding Japanese national standards more than 2 times. Dongdian announced the results of the investigation on Saturday (3rd).
According to the Eastern Network, the East China Power Department regularly checks the fish in the sea area and monitors its radioactive content. The results of the sampling on February 2 found that every 1 kg of the red-finned squid contains 358 becquerels, more According to the Japanese national standard of 100 Becquerel. If you eat 200 grams, it is equal to 1/50 of the radiation exposure of X-rays on the chest, about 1 mSv.
It is reported that the experimental fishing was carried out outside the 10 km radius of the Fukushima Daiichi Nuclear Power Plant.
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Japanese Fukushima food to be lifted? Chinese Academy of Sciences nuclear experts: Most worried about Fukushima soil nuclear pollution
It has been seven years since the Fukushima nuclear accident in Japan. Is it time to lift the nuclear pollution food in Fukushima?
In recent years, the Japanese government has been 'requesting' to speed up the import restrictions on Fukushima foods around the world. Kyodo News reported in early January that China proposed to set up a working group to discuss the lifting of food in the nuclear contaminated areas of Fukushima. Japanese scholar Lu Hao said that it is possible to consider lifting the ban if it meets the Chinese agricultural product standards.
How should we treat Fukushima food today? The Science and Technology Daily reporter exclusive interview with Professor Peng Guangxiong of the University of Chinese Academy of Sciences, from the perspective of nuclear science: Is it time to lift the nuclear pollution in Fukushima?
'I am most worried about soil nuclear pollution'
'Compared with the nuclear pollution of air and ocean, I am most worried about soil nuclear pollution. Once the food produced by long-lived radioactive nuclear pollution land spreads through the food chain, the consequences will be very serious.' Peng Guangxiong said, When nuclear pollution enters the human body and remains, it will directly radiate vital organs such as the human liver, stomach and stomach. 'Once it is eaten, it becomes an internal radiation, which is very harmful.'
The radioactive materials produced by nuclear accidents are invisible to the naked eye, and their linearity is very small. '10-9 meters is the nanometer scale, and the scale of the nucleus is Fermi, that is, 10-15 meters.' Professor Peng said that nuclear radiation first polluted. It is the air. After seven years, the impact of airborne nuclear pollution has gradually diminished, but the nuclear radiation in the air will eventually run into the soil and fields with the rain and snow.
Shortly after the nuclear accident, three kinds of iconic radioactive materials were detected, namely iodine-131, cesium-134 and cesium-137, and their half-lives were 8 days, 2 years and 30 years respectively. The half-life of cesium-137 is 30 years, which means that the number of cesium-137 is reduced to half after 30 years. The half-life reflects the average life or existence time of the radioactive nucleus.
'Compared with the above three types of nuclear radiation, the nuclear radiation I am most worried about is 钚 and 锶. ' Peng Guangxiong said that the radioactive materials produced by nuclear reactors are far more than the three mentioned above. '钚-238 is the most common 钚Isotope, half-life of up to 87 years. In addition, there are strontium isotope with half-life of 6,000 years or even 20,000 years. 锶-90 is classified as a type of carcinogen.
Still emitting nuclear pollutants?
'The real situation of the Fukushima nuclear power plant is neither completely certain nor confident.' Peng Guangxiong said that on the one hand, whether the nuclear pollution discharge of the Fukushima nuclear power plant is stopped or is still being continuously discharged, there is no international The agency inspected and disclosed the information. 'The seabed sewage is difficult to detect even if it is a satellite. On the other hand, the integrity of the Tokyo Electric Power Company, which is mainly responsible for operating the Fukushima nuclear power plant, is questionable. Public information shows that in Fukushima Before the nuclear accident, the Fukushima nuclear power plant had been out of service and had several nuclear accidents. The Tokyo Electric Power Company also had a record of falsifying data and records.
Due to the complexity of the procedure, the scrapping work of the Fukushima nuclear power plant in Japan is slowly progressing. The key to the scrapping of nuclear power plants is to dismantle the used nuclear fuel rods for packaging and post-processing. 'The disposal of nuclear waste is a worldwide problem.' Peng Guangxiong said, A common way is to bury the package deep under the mountain. 'The thick soil layer will not leak out when it blocks the nuclear radiation, but even if it is buried deeply, it will not be known if there is an earthquake or geological change. '1986 The Chernobyl nuclear accident occurred by sealing the entire nuclear power plant through the stone shovel. 'It is equivalent to blocking the nuclear radiation with reinforced concrete, but the nucleus decays according to its own law. The decay occurs in the sarcophagus, and the radiation radiates. Time passes, If there is a crack in the stone shovel, the nuclear leak may occur due to damage and poor maintenance. At present, the maintenance of sarcophagus has become a major issue for the Ukrainian government.
It is understood that Japan's discarded nuclear fuel rods have been taken out and stored in the local area. Nuclear power plants will have various conditions such as 'small fire', such as 'small fires', and nuclear sewage will be discharged into the sea without treatment. The product causes pollution.
Exploring the status quo of Fukushima's import of food
Is Fukushima food safe?
Tencent’s “Yizhen Fengbao” released an article “Can Japanese food still be eaten at the end of 2017? After 10 days of interviews in Fukushima, we have seen this issue of nuclear pollution in Japanese food”.
1. Fukushima Prefecture has established a set of daily and regular inspection mechanisms for agricultural and forestry aquatic products. For example, the rice and cattle are fully tested. The seafood products are sampled and tested in accordance with the standards before they can be sold. From the data point of view, in recent years, Fu The proportion of unqualified samples of agricultural and forestry aquatic products in the island is getting lower and lower, and the safety is getting higher and higher. However, there are some flaws in the whole mechanism. For example, the number and frequency of sampling are somewhat low, and there may be artificial space for fraud.
2, If you are traveling to Japan for a few days, and do not go to Fukushima, then food from the common sense, experience, and into the circulation system can be considered safe. However, it is best to grow vegetables on the mountain (Japan) It is called 'wild vegetable'), wild vegetables (called 'mountain dish' in Japan), wild mushrooms and some river fish have a long heart.
In early January this year, relevant news reports on the lifting of the ban on Fukushima food were overwhelming. Peng Guangxiong believed that after the Fukushima nuclear accident, it was absolutely necessary and very correct for the Chinese government and governments around the world to ban, restrict and strengthen inspection and quarantine. In the past seven years, according to the degree of pollution, the policy should be properly improved and adjusted. According to the current situation, there are steps, plans and stages to carefully discuss the lifting of the ban. 'Can be used as a response and response to Japan's request to lift the Fukushima food.'
Can agricultural and sideline products produced in Fukushima be safe to eat?
Peng Guangxiong said that this issue should not be treated scientifically with subjective color. 'The results of agricultural and sideline products testing have reached no food safety standards, and food nuclear pollution testing countries have their own standards but the difference is not large. Soil sampling The unit mass of radioactivity and radioactivity ratio can be achieved. 'It is reported that some local residents of Fukushima have returned home. 'The nuclear radiation range will decrease with time, mainly depends on the radiation situation of the place where it is going back. rebuild home. '
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'Growing vegetables' is good for cleaning up soil nuclear pollution
How to clean up nuclear pollution?
'Nuclear pollutants with short half-life will naturally dissipate. For example, the half-life of iodine-131 is only 8 days without fear.' Peng Guangxiong said that nuclear pollutants with long half-life want to take too long to dissipate naturally, and take active measures, such as planting. Some green plants absorb nuclear pollutants into plants and then dispose of them, which can minimize the amount of nuclear pollution in the soil. 'But the plants used to remove pollution must not be allowed to eat.'
Multi-country or region still restricts or bans the import of Fukushima food
According to the Global Times, a poll released by the NHK Institute for Cultural Studies in 2016 showed that 60% of respondents were 'uneasy' about nuclear radiation, and only 34% of respondents were 'reliable' on food in the affected areas. .
At the same time, according to the statistics of the Ministry of Agriculture, Forestry and Fisheries of Japan: As of December 2017, China, the United States, Russia, South Korea, Singapore and Taiwan and other countries or regions still maintain import restrictions on food in some parts of Japan or all regions.
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Japan's Dongdian evaluation shows that Fukushima frozen soil wall has limited effect on anti-nuclear sewage
According to Japanese media reports, the results of the assessment by Tokyo Electric Power Co., Ltd. show that the effect of reducing the amount of nuclear sewage generated by the frozen soil wall around the Fukushima Daiichi nuclear power plant is only about 80 tons per day. The reduction in the application of various combinations of countermeasures, including frozen soil walls, is about 380 tons per day. The frozen soil wall was built by the Japanese government for about 35 billion yen. The current doubts about the limited use of frozen soil walls alone. getting bigger.
According to reports, the frozen soil wall is buried in the pipeline about 1.5 km around the No. 1 to No. 4 unit, and the ice wall is built underground by circulating cooling liquid. The purpose is to prevent groundwater from flowing into the plant, thus preventing the groundwater and the underground of the plant from working high. After the mixing of nuclear sewage, the sewage will increase.
At the Fukushima Daiichi nuclear power plant, TEPCO took measures to prevent groundwater from entering the plant. In addition to the frozen soil wall, it also combined the 'groundwater flooding discharge' that drained groundwater from the west side of the plant and then discharged into the sea and the 'shaft' near the plant.
According to the assessment results, about 490 tons of sewage per day due to rainwater and groundwater before the construction of the frozen soil wall, if the above measures are combined, the sewage will be reduced to about 110 tons after the completion of the frozen soil wall, less than the previous quarter. one.
In March 2016, the frozen soil wall began to freeze. At present, almost all temperatures in the underground have dropped below 0. It is said that the maintenance fee needs more than one billion yen per year, and the Atomic Energy Regulatory Commission has questioned the effect from the beginning.
