How many nuclear power plant accidents have there been in history? What's the reason?

17 times.

1. The Three Mile Island Nuclear Power Plant accident on March 28, 1979.

The radioactive material release accident at Reactor No. 2 of the Three Mile Island Nuclear Power Plant was the most serious nuclear power plant accident in U.S. history, although the accident did not cause any casualties.

2. The Palimares hydrogen bomb accident on January 17, 1966.

While refueling over the coast of Spain, a U.S. B-52 bomber collided with a KC-135 tanker aircraft. After the impact, the tanker was completely destroyed, the B-52 bomber was disintegrated, and the four hydrogen bombs it carried "escaped" from the cracked fuselage.

Two of the "non-nuclear weapons" hydrogen bombs exploded when they hit the ground, contaminating an area of ??490 acres (approximately 2 square kilometers) with radioactive plutonium. Searchers found one of the devices in the Mediterranean.

3. The Chernobyl nuclear accident on April 26, 1986.

The Chernobyl nuclear accident is called the worst nuclear power plant disaster in history. In the early morning of April 26, 1986, Reactor No. 4 of the Chernobyl Nuclear Power Plant, located 130 kilometers north of Kiev, the capital of the Soviet Union of Ukraine, exploded. More explosions occurred immediately and triggered a fire, causing radioactive fallout. Fallout enters the air.

It is reported that the amount of radioactive fallout produced by this accident was 400 times that of the atomic bomb dropped on Hiroshima.

4. Thule Nuclear Accident on January 21, 1968.

Due to a fire in the cabin, the crew of a US B-52 bomber was forced to make the decision to abandon the aircraft. Before that, they could have made an emergency landing. The B-52 bomber finally hit the sea ice near Thule Air Force Base in Greenland, causing the nuclear weapon it carried to rupture, causing radioactive contaminants to spread over a large area.

5. The Winskell Fire on October 10, 1957.

A graphite core fire at a British nuclear reactor near Cumberland caused a nuclear disaster. The fire caused the release of large amounts of radioactive contaminants. The nuclear disaster was the most serious reactor accident before the Three Mile Island nuclear power plant accident.

6. The Goiania nuclear accident on September 13, 1987.

Disaster struck Goiania, Brazil, when a junkyard worker pried open an abandoned radiotherapy machine and removed a small piece of highly radioactive cesium chloride. , more than 240 people in Japan were exposed to nuclear radiation at that time. Deceived by the bright green color of the radioactive material, children touched it with their hands and smeared it on their skin, contaminating several blocks and having to be demolished.

7. The Tomsk-7 nuclear explosion on April 6, 1993.

The nuclear accident that occurred in Tomsk, Siberia was caused by an explosion while cleaning a container with nitric acid. The explosion caused the Tomsk-7 recovery and processing facility to release a cloud of radioactive gas.

8. The K-431 nuclear submarine accident on August 10, 1985.

During the refueling process of Vladivostok (K-431 nuclear submarine), the E-2 class K-431 nuclear submarine exploded and radioactive gas clouds entered the air. Ten sailors died in the nuclear accident, and 49 others suffered radioactive injuries.

9. The Donghai Village nuclear accident on September 30, 1999.

The nuclear accident that occurred at the Tokaimura uranium recycling and processing facility northeast of Tokyo was the most serious nuclear disaster in Japanese history. Workers were mixing liquid uranium when the accident occurred.

10. The Jaka Flat Nuclear Accident on December 18, 1970.

During the Barnaberry nuclear experiment, a 10,000-ton nuclear device exploded underground in Gacca Flat, Nevada, USA. After the experiment, the plug that closed the surface shaft failed, causing radioactive debris to leak into the in the air. Six workers at the site were exposed to nuclear radiation.

11. On January 6, 1988, a nuclear power plant in Oklahoma, USA, exploded due to improper heating of the nuclear material barrel, killing one worker and injuring 100 people.

In November 1992, the most serious nuclear accident occurred in France: three workers were contaminated after entering a nuclear particle accelerator without wearing protective clothing.

13. From 1998 to 2002, India had six nuclear leakage accidents at nuclear power plants in four years.

14. On December 29, 2003, a nuclear leak occurred in Unit 5 of South Korea’s Young Kwang Nuclear Power Plant.

15. On August 9, 2004, another steam leakage accident occurred at the Mihama Nuclear Power Plant in Fukui Prefecture, central Japan, resulting in 4 deaths and 7 injuries.

16. In May 2005, the thermal oxygen reprocessing power plant of the Sellafield Nuclear Power Station in the UK was forced to shut down due to a leak of radioactive liquid.

17. On March 12, 2011, a magnitude 9 earthquake in Japan resulted in safety accidents at the Daiichi and Daiichi nuclear power plants in Fukushima Prefecture, Japan.

Extended information:

Nuclear accident:

Generally speaking, an accident occurs in a nuclear facility (such as a nuclear power plant), resulting in the release of radioactive materials , causing workers and the public to be exposed to exposure exceeding or equivalent to the prescribed limit, it is called a nuclear accident. Obviously, the severity of nuclear accidents can have a wide range. In order to have a unified standard of understanding, incidents with safety significance in nuclear facilities are internationally divided into seven levels.

As can be seen from the table, only levels 4-7 are called "accidents". Accidents above Level 5 require the implementation of an off-site emergency plan. This type of accident has occurred only four times in the world, namely the Chernobyl accident in the Soviet Union, the Windskel accident in the United Kingdom, the Three Mile Island accident in the United States, and the Fukushima Nuclear Power Plant in Japan. ACCIDENT.

On April 26, 1986, the No. 4 reactor of the Chernobyl nuclear power plant built by the former Soviet Union caught fire and caused a chemical explosion (not a nuclear explosion). The amount released by the explosion is equivalent to about 3 to 4 percent of the nuclear fuel in the reactor.

Two people were killed at the time of the accident, and one died of a heart attack. 29 people suffered radiation injuries during the firefighting, and 28 of them died from acute radiation sickness. After the accident, 210,000 residents were evacuated within a 30-kilometer radius.

In fact, this was a serious human-caused accident. At that time, the researchers were conducting a safety experiment and cut off all the safety measures of the reactor, but then started the reactor. This experimental plan seriously violated the safety regulations. , which is the human cause of the accident.

The technical reason for the accident was that the graphite water-cooled reactor developed by the former Soviet Union had major flaws. It had a positive feedback working area with a positive temperature coefficient, which was not allowed in the reactor design. In addition, the Chernobyl Nuclear Power Plant does not have a containment vessel that most nuclear power plants have.

In the early morning of March 38, 1979, a serious water loss accident occurred in the No. 2 reactor of the Three Mile Island Nuclear Power Plant built in the United States, 16 kilometers southeast of Harrisburg, Pennsylvania. The core part of the reactor Meltdown, most of the fuel elements were damaged or melted, radioactive fission products leaked into the containment, but did not escape, causing minor environmental impact.

Because the incident occurred in the United States, the accident caused an extremely strong response, but the harm itself was not great. None of the 118 employees in the nuclear power plant were injured or killed, and only three people suffered injuries slightly higher than the quarter. The allowable dose of exposure is within the occupational control dose.

Leaking radioactive materials is also less. Among the 2 million residents within a radius of 80 kilometers, the average radioactive dose received by each person is not as good as the dose received by wearing a luminous watch or watching color TV for a year. The Three Mile Island nuclear accident is the most serious accident to date at a pressurized water reactor nuclear power plant.

Reference: Baidu Encyclopedia-Nuclear Accident