The damaged unit 4 is protected by a sarcophagus cement fence to prevent radiation from spreading, but this is not always safe. The reason is that the sarcophagus built by industrial remote control robot is seriously aging. If the sarcophagus collapses, it may cause the crew to release radioactive dust. The fragility of these sarcophagus may cause their roofs to collapse, even if it is a small earthquake or a strong wind. Therefore, the authorities have formulated several schemes to help the fence.
According to official estimates, after the accident, there is still about 95% fuel in the reactor (180 metric tons), and the total radioactivity of this fuel is about180,000 Ci(670 PBq). At present, the radioactive substance remaining in it has hardened into a ceramic-like substance. They are mainly in the early stage of the accident, and the core fragments of the reactor can wander around in the reactor, consisting of other dust and lava-like "fuel-containing substances" (FCM). It is uncertain when these ceramic-like substances will delay the release of radioactive materials.
According to secret estimates, there are at least 4 metric tons of radioactive dust in the nuclear power plant. However, the latest estimate has investigated the amount of fuel and kept it in the reactor. Some estimates show that the total amount of fuel placed in the fuel reactor is only about 70% of the original fuel. Because of the explosion, the International Atomic Energy Agency lost 5% of the fuel. Moreover, some liquidators estimated that 5 V 10% of the original fuel was only contained in this sarcophagus.
As for other aspects, water continues to leak into the reactor. Throughout the reactor building, the flooded environment is spreading radioactive materials. The basement of the reactor building is also slowly filled with substances contaminated by nuclear fuel, and radioactive wastewater is released. Although the hole formed in the roof has been repaired, in this case, the hole can only continue to deteriorate.
When the sarcophagus is sealed, heating is easier than cooling, which increases the humidity level in the nuclear power plant. At the same time, it continues to corrode the concrete and steel bars in this sarcophagus in the high humidity of the reactor.
The damaged reactor roof was built by this reactor building. These two so-called "giant beams" not only support the roof of the reactor, but also support the walls of other reactor buildings that rely on this structure. If the walls of the reactor building and the roof of the reactor collapse, an amazing amount of radioactive dust and particles will be released directly into the air, causing radioactive substances to destroy the surrounding environment.
A further threat to the reactor is that the position of the sarcophagus itself is very unsafe, because the rubble supports it almost vertically. If the sarcophagus collapses, it will further increase the pressure on the nuclear power plant and spread radioactive materials.
This sarcophagus not only covers the damaged reactor, but also contains the residual radioactive materials from the No.4 reactor. When a new sarcophagus design is put forward, the life can only be predicted as 100 years at most. Therefore, the construction of the permanent sarcophagus will undoubtedly be a challenging project for the next few contract engineers.
According to the Russian news agency 201214 February, the European Bank for Reconstruction and Development promised to provide Ukraine with extra funds of1900 million euros to help Ukraine complete the construction of a new protective cover for the Chernobyl nuclear power plant. The construction of the new protective cover of Chernobyl nuclear power plant needs 740 million euros. 20 1 1 In April, at the international donation conference held in Kiev, more than 40 countries pledged to provide 550 million euros.
The new protective cover of Chernobyl nuclear power plant will further reduce radiation pollution. Ukrainian First Deputy Prime Minister Valery Holosko said: "After the completion of the new barrier, a series of economic and social problems related to the Chernobyl nuclear accident will also be solved." The new shield with a weight of 29,000 tons will be completed in 20 15 years. By then, this wall with a height of 100 meter will surround Chernobyl No.4 nuclear reactor and turn it into a safe and environmental protection system.
A few days ago, the abandoned Chernobyl nuclear power plant in Ukraine collapsed. According to Agence France-Presse, a French company working there evacuated 80 workers. 1986, a major nuclear leak occurred in the nuclear power plant, and then the reactor was covered with a thick sarcophagus. French companies are carrying out reinforcement works. On June 5438+02, the roof partially collapsed, and the authorities said that there would be no nuclear leakage. Blocking pollution sources is an arduous task, and removing nuclear radiation dust is another arduous task. A year later, the first batch of nuclear power plant workers and firefighters killed in the Chernobyl nuclear accident were transferred to a cemetery in Moscow and buried in special lead coffins! Because their bodies have become radioactive sources that can pollute normal people.
Nuclear dust is almost everywhere. Nuclear radiation has polluted tens of thousands of square kilometers of fertile farmland in Ukraine.
As a result of the Chernobyl accident, more than 2.5 million people in Ukraine suffered from various diseases, including more than 473,000 children.
According to experts' estimation, it will take at least 800 years to completely eliminate the impact of this catastrophe on the natural environment, and the continuous risk of nuclear radiation will last for 654.38 million+years.
Economically, the former Soviet Union lost about 9 billion rubles: more than 4 billion rubles in the aftermath, and more than 4 billion rubles in agriculture and electricity production. Experts estimate that it will cost billions of dollars to clean up only one item except the loss of the nuclear power plant itself. If all of them are added up, it may reach tens of billions of dollars.
The accident area of Chernobyl nuclear power plant in Ukraine will be open to tourists (but protective clothing must be worn). Baloga, Minister of Emergency Situations of Ukraine, announced in February 20 10 that the accident area of Chernobyl nuclear power plant will be open to ordinary tourists on February 201KLOC-0/2, and the Ministry of Emergency Situations of Ukraine plans to organize regular and systematic tourist routes to visit this area.
Ukrainian Emergency Minister Baloga announced that the direction of Chernobyl is limited to extreme tourism, not mass tourism, and it is only open to foreign tourists organized by several private companies. Baloga believes that the territory of Chernobyl area should be open to ordinary tourists, and the Ukrainian Ministry of Emergency Situations is doing a lot of work, and plans to report the results of its work before the end of 20 1 1, so that this kind of visit will become a regular and systematic form of tourism in 20 12+0. Clark, Administrator of the United Nations Development Programme, supports the tourism initiative of the Ministry of Emergency Situations of Ukraine. She said that visiting Chernobyl can help people understand the tragic history and re-recognize the importance of nuclear facility safety. Although this is a very sad history, this tourist attraction also has certain economic potential.
Ukrainian Minister of Emergency Situations Baloga pointed out that the new "bunker" for completely covering Unit 4 will be completed in 20 15. It is an arch-shaped building with a length of150m, a width of 260m and a height of105m, which is used to completely cover Unit 4 and the temporary protective facility "sarcophagus" previously built. The "bunker" project was supported by donations from the international community. Construction funds were raised by the G8 and 28 Council of Europe member countries and managed by the European Bank for Reconstruction and Development. After 10 years of selection and demonstration, the project is now stepping up construction. It should effectively protect the surrounding environment of the accident area and ensure that some faulty and unreliable structures can be installed and removed. It is believed that this comprehensive protection facility can be completed and used in 20 15. Earlier, Ukrainian First Deputy Prime Minister Klyuyev announced that the total cost of the "bunker" project had increased from 505 million euros in 2004 to 870 million euros due to the sharp increase in safety requirements.
Clark, Administrator of the United Nations Development Programme, promised that the United Nations will continue to fully support the construction of the project in the future, and the Ukrainian government should also continue its dialogue with international partners. 2011news, the Ukrainian government recently announced that the area around the ruins of the Chernobyl nuclear power plant, the site of the worst nuclear accident in history, will become a new tourist attraction. It is expected that the area around Chernobyl will be open to tourists from today.
1986 explosion of a nuclear reactor in Chernobyl, Ukraine. The powerful impact of the explosion blew off the cover weighing 2000 tons on the reactor, releasing 400 times more radioactive dust than the Hiroshima atomic bomb.
Yuri Konev, an accident witness and engineer, recalled the scene and said: The sky was colorful and very bright, orange, red and blue, and the sky was as red as a rainbow.
Igo Kostin, photojournalist of RIA Novosti: When we approached fourth area and circled overhead, I had no idea of the danger. When we flew over the fourth area, I opened the window of the helicopter. I didn't know I had made a big mistake. I only managed to take 12 photos. After returning to Kiev, I began to process photos. I see all the negatives are black and have no color. I didn't know that these photos were all exposed to radiation.
You Liya Madge, a local resident of Chernobyl: I remember that the kindergarten teacher gave us iodine tablets, and then my parents came to pick up the children. Everyone ran around, but they didn't panic. We thought we would be away for three days at most. They let us get on the bus. I clearly remember the toys I had to choose to take away. I have many dolls, but I can't take them all away. We don't even have time to bring warm clothes.
So is there any radiation danger for tourists visiting the Chernobyl nuclear power plant? Why does the Ukrainian government want to develop this tourism project? CCTV reporters Zhang Jianing and Fei Lei and intern reporter Zhang Yajiao interviewed Yu Zusheng, member of the Expert Committee of the State Nuclear Power Corporation and member of the Expert Committee of Nuclear Safety and Environment of the Ministry of Environmental Protection.
Although more than 20 years have passed since the Chernobyl nuclear accident, painful memories are like scars that are still aching and have not been forgotten. Yu Zusheng, a nuclear safety expert, believes that the impact of the accident at the Chernobyl nuclear power plant is far from being eliminated.
Yu Zusheng: This is the first time that mankind has released a large area of radioactive materials into the environment. There was a westerly wind blowing at that time, so a lot of radioactivity reached Europe. After air convection and sedimentation in Europe, after a period of drift, a large number of radioactivity decreased. At that time, East and West Germany had not merged. What did West Germany find? The pasture is polluted by radioactivity, and the milk produced by cows eating the pasture is also radioactive. The milk has been poured out for two weeks, which is the influence in the surrounding area. The impact on the local Chernobyl nuclear power plant is that hundreds of thousands of people have all moved out within 30 kilometers of Fiona Fang with the nuclear power plant as the center. After 20 years, people have not come back, and that area has become equivalent to a dead city. Statistics show that in order to save and eliminate the consequences of this accident, the cost of money, manpower and material resources is about 100 times that of building this nuclear power plant.
Some commentators believe that the Ukrainian government has set Chernobyl as a new tourist attraction to promote economic development. Yu Zusheng believes that as a nuclear safety education base, guided visits are safe.
Yu Zusheng: It should be said that he made this kind of visit under the condition of ensuring safety. The purpose of this visit is to tell people that nuclear energy is a good thing, but nuclear accidents can't happen again. In fact, it is a kind of safety education. In this sense, I think it is of positive significance. In any case, the safety of all passengers is still within the standard range of this country. It should be said that there is no problem, because after 20 years, the real core part can't go, so we can only look around and watch the tragic scenes of these 20 years over and over again. Cities that are not suitable for human habitation have become dead cities, and thatch is taller than houses. It should be possible to visit a specific route while maintaining safety, at least there will be no major security problems.
However, the "radioactive intensity" in different locations varies greatly. From the place with the smallest radiation in the restricted area to the place with the largest radiation, the gap is as high as 1: 1000. Visitors must visit under strict guidance, because in fact, until now, the scientific research on the impact of nuclear accidents on human body has not been completed.
Yu Zusheng: Because radioactive things are invisible and intangible, on the surface, it seems that the ecology has basically recovered. Whether it is animals, plants or lush, then its entire nuclear radiation and nuclear consequences have disappeared. This estimate may be different. Some people say radioactivity, just like saying that this reactor will produce some secondary and long-term radioactive elements. The only way to make all radioactivity harmless is decay. The secondary decay period is very long, although the amount is very small, and human habitation has not been restored within 30 kilometers, so the impact on the surrounding area and beyond 30 kilometers after 2030 should have no impact. The International Atomic Energy Agency (IAEA) and the International Health Organization (WHO) have published many articles, and compared the statistical data of human diseases and cancers, what is the impact? It should be said that childhood leukemia around Chernobyl was obviously on the rise at that time, and there was no contrast among other cancers, and there was no obvious self-increase. It should be said that it is impossible to classify the long-term consequences of the Chernobyl accident on human beings and organisms very strictly.
We walked into the most dangerous no man's land. The red light is on: the radiation we suffered has exceeded the standard.