1in the early morning of March 28th, 978, the refrigeration system of Unit 2 of Three Mile Island PWR Nuclear Power Plant in the United States broke down, resulting in partial melting of the nuclear reactor, which eventually led to the most serious nuclear accident in American history.
The accident was caused by the accident cooling system of the secondary circuit automatically put into operation after the water pump of the secondary circuit failed. However, because workers failed to open the valve of the emergency cooling system after overhaul a few days ago, the water in the secondary circuit was still cut off after the system was put into operation automatically. In this case, when the temperature and pressure in the reactor rise, the reactor will automatically stop and the pressure relief valve will automatically open, releasing part of the steam-water mixture in the core. At the same time, when the pressure in the reactor drops to the normal value, the pressure relief valve fails to return automatically due to the fault, so that the core coolant continues to flow out and the pressure drops below the normal value, so the emergency core cooling system is automatically put into operation. However, the operator did not judge that the pressure relief valve did not return to its position, but closed the emergency core cooling system and stopped injecting water into the core.
This series of management and operation errors are intertwined with equipment failures, which greatly expands a small failure and causes a serious accident of core melting.
Chernobyl nuclear leak
1On April 26th, 986, a serious leakage and explosion accident occurred at the Chernobyl nuclear power plant in the former Soviet Union and Ukraine.
At the time of the accident, an exercise was being conducted to test whether the reactor could be shut down by using the power generated by the rotating kinetic energy of the generator turbine under the condition of complete shutdown. During the test, the operator shut down the safety system of many reactors, which is prohibited by the Technical Guidelines unless the safety system fails.
An important factor contributing to the accident was that the staff did not receive the report of the reactor problem. The designer knew that the reactor would be dangerous in some cases, but he deliberately concealed it. In addition, the chief engineer of this exercise is engaged in electrical engineering, and he lacks knowledge about reactors, so he failed to find and deal with abnormal situations in time.
The rough rules of the exercise, coupled with engineers' lack of knowledge about reactors, led to the tragedy of Chernobyl nuclear leakage.
Japan nuclear accident
20 1 1 March11Up to now, a nuclear accident occurred at the Fukushima Daiichi nuclear power plant in Japan.
There are objective reasons for the nuclear accident in Japan, which are caused by the "combination boxing" of the earthquake and tsunami. After the devastating earthquake in Japan's nuclear power plant, the external power grid was cut off first, then the engine group failed and the valves also failed.
However, the nuclear accident in Japan has reached an uncontrollable level, but it has an important relationship with human factors. Due to the relatively large amount of radiation over the nuclear power plant, the Japanese Self-Defense Force abandoned the operation of injecting water and cooling the Fukushima nuclear power plant by helicopter in the air. Wang Yi proudly said that the possibility of a Japanese nuclear accident in China is almost zero, because we have the People's Liberation Army (PLA) in China.
So in the absence of man-made accidents, nuclear power is safe, more efficient and cleaner than coal-fired power stations, but people are not safe!
There have been several nuclear leaks in the history of the world and several nuclear accidents in the world. Nuclear energy is one of the energy sources with little pollution. However, when an accident occurs in a nuclear facility, a large amount of radioactive materials will leak into the environment, causing pollution to air, rivers, oceans, groundwater and soil. And then endanger animals, plants and people. This is called nuclear pollution or radioactive material pollution. There have been several nuclear accidents or radioactive pollution in the world, which are briefly introduced as follows:
1 and 1957, the most serious accident in the history of the western nuclear industry occurred in the Winskell (now known as Selafield) nuclear complex in Britain. The fire destroyed the core of one of the two plutonium production reactors and released radioactive cloud dust into the atmosphere. A few years later, the leaked radiation caused dozens of people to die of cancer.
2. 1957- 1958 A serious accident happened in the former Soviet Union near the city of Keshtum in the Ural Mountains. Jules Maidevijeff, the geneticist of the former Soviet Union who first reported the disaster, estimated that after an explosion, hundreds of people became sick and died from nuclear radiation.
3. 1979, the worst nuclear accident in American history occurred at Three Mile Island Power Plant near Harrisburg, Pennsylvania. After radioactive gas leaked into the atmosphere, part of one of the reactors melted, forcing residents to evacuate the power plant.
4.1On April 26th, 1986, the Chernobyl nuclear power plant of the former Soviet Union in the suburb of Kiev caught fire due to the explosion of reactor No.4, and a large amount of radioactive materials leaked out, resulting in 3/kloc-0 deaths and 237 serious injuries of radioactive materials, forcing130,000 residents to evacuate and polluting some European countries.
5.1On September 28th, 987, the lead storage tank containing the radioactive isotope cesium-137 lost by the Bavarian Institute of Disease in Germany was sold as a waste to a waste purchasing station. As the workers at the collection station broke open the lead storage tank, radioactive materials leaked out, resulting in three deaths, more than 20 people suffering from radiation sickness and more than 200 people injured.
Nuclear leakage in history, nuclear leakage in the former Soviet Union
1On April 26th, 986, the world's worst nuclear accident occurred at the Chernobyl nuclear power plant in the Soviet Union. The catastrophic fire at the Chernobyl nuclear power plant, which is about 0/30 km north of Kiev, Ukraine, led to the leakage of radioactive materials, polluting most parts of Europe. The international community widely criticized the Soviet Union for blocking the news of the nuclear accident and its slow emergency response. The accident was exposed to the world only after Sweden found that the radioactive material content was too high.
Chernobyl nuclear power plant is the largest nuclear power plant in the former Soviet Union, with four units. In April, during the planned shutdown inspection of Unit 4, the personnel of the power station repeatedly violated the operating procedures, resulting in the increase of reactor energy. In the early morning of 26th, the reactor melted and burned, causing an explosion, breaking through the protective shell, and the factory building caught fire, and radioactive materials were continuously released. Water and chemicals were used to put out the fire, and the fire evaporated instantly, and the fireman's boots were trapped in the molten asphalt. 1, 2 and 3 units were shut down, 30 kilometers around the power station was declared as a dangerous area, and residents were evacuated. At the time of the accident, two people died on the spot and 204 people were injured by radiation. On May 8, the reactor stopped burning and the temperature still reached 300℃. The local maximum radiation intensity is 0/5 milliroentgen per hour, Kiev is 0.2 milliroentgen, and the normal allowable value is 0.0 1 milliroentgen. Radioactive dust was detected in Sweden, which was 100 times higher than the normal value. Western countries quickly evacuated expatriates and tourists from Kiev and refused to accept imported food from Belarus and Ukraine. Four months later, the official of the former Soviet Union announced that * * * * died 3 1 person, mainly rescuers, including a major general; 203 people with radiation sickness; 654.38+0.35 million people evacuated from the danger zone. 1992 Ukrainian officials announced that more than 7,000 people had died of nuclear pollution in this accident.
On May 9, at the invitation of the Soviet Union, Blix, Director General of the International Atomic Energy Agency, inspected the nuclear power plant from an altitude of 800 meters by helicopter. He believes that this is by far the most serious nuclear accident in the world.
In the two years after the disaster, 260,000 people took part in the accident treatment, poured layers of concrete for the No.4 nuclear reactor and buried it as a "coffin". 2 1 10,000 square meters of "dirty soil" was cleaned up, and Slautjec town was built for employees of nuclear power plants, and 2 1 10,000 houses were built for evacuated residents. All this, including the loss of power generation reduction, totals 8 billion rubles (about 654.38+0.2 billion US dollars). Ukraine has decided to shut down the power station permanently.
Belarus has lost 20% of its agricultural land, 2.2 million people live on polluted land, and hundreds of villages and towns have lost their houses. The abandoned restricted area in Ukraine has become a paradise for thieves and wild horses, and all precious items have been stolen, thus spreading the pollution outside the area. Pines and spruces within 7 km of the nuclear power plant withered, and 1000 hectares of forest gradually died. The "safe zone" 30 kilometers away is also unsafe, and the number of cancer patients, children with thyroid diseases and deformed livestock has increased sharply; Even on collective farms 80 kilometers away, 20% of piglets were born with abnormal eyes. All these strange symptoms are called "Chernobyl syndrome".
Land and water have been seriously polluted and thousands of people have been forced to leave their homes. Chernobyl became a desolate ruin. 10 years later, radioactivity continues to threaten the lives and health of about 8 million people in Belarus, Ukraine and Russia. Experts say that the consequences of the Chernobyl accident will last for a hundred years.
Terrible leak, fortunately, I was not born at that time, but the harm of this accident lasted for one hundred years ... So, gasket, I want to remind you again: safety in production, life is important.
Ten worst nuclear radiation leaks in history and their details 20 1 1 March11day, a strong earthquake occurred in Japan and caused a tsunami, and the Fukushima Daiichi nuclear power plant was also damaged in the earthquake and caused a nuclear accident.
The International Atomic Energy Agency (IAEA) international nuclear safety and radiation event rating (international nuclear accident rating) is divided into seven grades. The following are the top ten most serious nuclear accidents in history, ranked according to the international nuclear accident level, with the severity from small to large, including the Fukushima nuclear accident that just happened.
1. 1986 Chernobyl nuclear disaster in the former Soviet Union (international nuclear accident level 7) Up to now, the steam explosion and reactor meltdown at Chernobyl nuclear power plant are still the only nuclear accidents with international nuclear accident level 7 in history. Chernobyl has become synonymous with nuclear accident. Anti-nuclear activists often use the words "another Chernobyl" to warn the world that Chernobyl has become synonymous with nuclear accidents. Anti-nuclear activists often use the words "another Chernobyl" to warn the world that more than 335,000 people have been forced to evacuate the evacuation area.
The direct death toll from the nuclear accident was 53, and thousands of others suffered from various chronic diseases due to radiation. During the period of 1986, the Chernobyl nuclear disaster in the former Soviet Union was even more serious in Bikkes. If the degree of nuclear radiation diffusion is used as a measure, the severity of this nuclear disaster is four times that of the Keshtam nuclear disaster.
Up to now, the steam explosion and reactor meltdown accident of Chernobyl nuclear power plant is still the only nuclear accident with an international nuclear accident level of 7 in history. The nuclear disaster occurred in1April 26, 1986, when the technicians of the No.4 reactor were conducting a turbine generator test, that is, using turbines to meet the power demand of the nuclear power plant when it was shut down.
Due to human error, a series of unexpected sudden power fluctuations occurred, the containment cracked and caused a fire, and radioactive fission products and radioactive dust were released into the atmosphere. At that time, radiation clouds covered most parts of eastern, western and northern Europe, and more than 335,000 people were forced to evacuate the evacuation area.
The direct death toll from the nuclear accident was 53, and thousands of others suffered from various chronic diseases due to radiation. Today, the area around Chernobyl presents a strange "contrast".
Chernobyl and Puri Piater, two abandoned cities, are slowly declining, but the wild animals in the surrounding woodlands and forest areas are thriving because of the evacuation of human beings. It is reported that the local lynx and bear that have disappeared for centuries have even reappeared. Their appearance shows that nature has amazing resilience and life has the ability to adapt and adjust even in the most terrible environment.
Chernobyl has become synonymous with nuclear accident. Anti-atomic people often warn the world with words like "another Chernobyl", just as anti-war people often shout slogans like "another Vietnam War". The area where the Chernobyl nuclear power plant is located is called the "evacuation zone", and it is difficult for Ukraine to prevent people who call themselves "stalkers" from entering this area for exploration and fun.
For these guys who don't know what danger is, we have to send them a message-invisible things will make you "very hurt". The Chernobyl nuclear disaster in the former Soviet Union is the only nuclear accident with an international nuclear accident level of 7 in history, but no one can guarantee that another nuclear accident with an international nuclear accident level of 7 or even more serious will not happen.
Natural disasters, human errors and equipment aging are inevitable realities in the nuclear industry. There are nearly 500 nuclear power plants in operation and under construction all over the world. The question we are facing now is not whether there will be another nuclear accident in the future, but when.
2.20 1 1 Fukushima Daiichi accident (international nuclear accident level 4+) The Fukushima Daiichi nuclear power plant is located in the northeast of Tokyo 170 miles (about 270 kilometers) and is one of the largest nuclear power plants in the world. * * * The Fukushima Daiichi nuclear power plant with six nuclear reactors is located at 170 miles (about 270 kilometers) northeast of Tokyo. It is one of the largest nuclear power plants in the world, with six nuclear reactors. * * * Fukushima Daiichi Nuclear Power Plant is located at 0/70 miles (about 270 kilometers) northeast of Tokyo, and it is one of the largest nuclear power plants in the world, with six nuclear reactors, which are responsible for supplying power to Tokyo and Japan power grids. On March 1 1, an earthquake of magnitude 9 occurred in Japan, and Sendai was not spared.
The power failure caused by the earthquake caused the reactor coolant pump to stop working. Backup diesel generators stored in low-lying areas were also seriously damaged in the tsunami caused by the earthquake.
Because the generator in the building where 1 reactor is located can't be started, the core temperature of the reactor keeps rising, and the hydrogen in the containment building keeps accumulating, reaching dangerous levels. The spark generated by the generator may cause hydrogen to explode and overturn the roof of the containment.
The next day, the hydrogen explosion intensity of the building where the No.3 reactor was located was even stronger. 14, the building where the No.2 reactor is located also exploded.
Because the water in the storage tank has completely evaporated, the fuel stored in the building where the No.4 reactor is located may catch fire. The Fukushima Daiichi nuclear power plant accident is still in progress, and the international nuclear accident level is set at level 4, but the French Nuclear Safety Administration believes that the actual severity exceeds level 4.
At the press conference held on June 5438+04, Andrew Claude lacoste, chairman of the Nuclear Safety Administration, pointed out: "Level 4 is already very serious, but we think the severity of this nuclear accident is at least level 5 or even level 6." 3. In 2004, the accident at Japan's Meibang Nuclear Power Station (international nuclear accident level 1) did not lead to nuclear leakage, but the steam explosion still killed five workers and injured dozens.
Although it did not lead to nuclear leakage, the steam explosion still killed five workers and injured dozens. 1990, the international atomic energy agency introduced the international nuclear accident scale, which was graded by logarithm. The magnitude difference of each magnitude is nearly 10 times, which is similar to the Richter scale used to judge the earthquake magnitude.
The list of the world's most serious nuclear accidents on webecoist website began with the steam explosion accident at Meibang nuclear power plant in Japan on August 9, 2004, and the international nuclear accident level is 1. Smith Barney nuclear power plant is located in Fukui Prefecture, about 320 kilometers west of Tokyo. It was put into operation on 1976. From 199 1 to 2003, several nuclear-related accidents occurred.
On August 9, 2004, when the staff were preparing for routine safety inspection, the water pipe connecting the No.3 reactor in the building where the turbine was located suddenly burst. Although not.
The worst nuclear accident occurred in the history of Three Mile Island nuclear power plant in the United States. Please introduce 1979 from Three Mile Island, USA. At 4: 00 am on March 28th, the red light flashed, the siren sounded an alarm, the turbine stopped running, and the core pressure and temperature suddenly increased. Two hours later, a large amount of radioactive material overflowed.
Six days later, the core temperature began to drop and the steam bubble disappeared-the threat of hydrogen explosion was lifted. Although 100 tons of uranium fuel did not melt, 60% of uranium rods were damaged and the reactor was finally paralyzed.
After the accident, the whole country was shocked, and residents near the nuclear power plant were terrified. About 200,000 people were evacuated from this area. People in major cities in the United States and residents in areas where nuclear power plants are under construction held a * * * * *, demanding that nuclear power plants be stopped or closed.
The United States and some western European countries have to re-examine their plans to develop nuclear energy.