top of page

Nuclear Accident Three Mile Island | Nuclear Disaster Fukushima | Nuclear Disaster of Chernobyl

Updated: Apr 14, 2023

10 WORST NUCLEAR DISASTERS: Details of nuclear disasters in the world, including the nuclear accident three mile island, nuclear disaster Fukushima, and nuclear disaster of Chernobyl.

Radiological Event Scale

When a nuclear disaster occurs, there may be long-term environmental and health hazards. The worst nuclear disaster sites may present danger for thousands of years. Exposure to radiation from a nuclear accident can cause cancer and gene mutation. Radiation and contamination can also change how plants grow and how animals live, affecting the whole ecosystem. This is the case at sites of the worst nuclear accidents, including the nuclear accident three mile island, the nuclear disaster Fukushima, and the nuclear disaster of Chornobyl.

The International Atomic Energy Agency created the International Nuclear and Radiological Event Scale (INES) in 1990. The intention of the scale is to measure the current safety level of all nuclear and radiological events in the world. The INES gives all nuclear events a level from 0 to 7. Level 0 is an anomaly, and level 7 is a major accident.

The INES rates the safety of nuclear sites, level 0 is an anomaly and level 7 is a major nuclear accident.

The INES ranks the safety of nuclear-contaminated sites seven levels. The scale is logarithmic. This means that the severity of an event is ten times greater for each increase in level of the scale. A level-7 site is 10 times the risk of level-6 sites, 100 times the risk of level-5 sites, 1000 times the risk of level-4 sites, and so on.

Events are considered in terms of three things. First in consideration is the impact on people and the environment. Second is impact on radiological barriers and control. Lastly is impact on defense in depth.

Let’s look at the worst nuclear disasters in history.

10 Worst Nuclear Disasters

Chernobyl, Ukraine (Level 7) - Nuclear Disaster of Chernobyl

The accident at the Chernobyl nuclear power plant in Ukraine is the worst nuclear disaster in history. In April 1986, the nuclear reactor blew up due to a combination of design flaws and workers not following safety precautions. Scientists agree that the radioactive fallout from this explosion was 400 times worse than the radioactive fallout from the bombings of Hiroshima and Nagasaki.

Radioactive fallout spread over much of the northern hemisphere. The official death toll directly attributed to explosion is just 31. However, hundreds of thousands of citizens were sent in to put out the reactor fire and to facilitate cleanup. Due to the long-term effects of radiation exposure in the region, the indirect death count is thought to be as high as 830,000.

The Ukrainian government relocated 335,000 people from Pripyat and the area around it. To this day, a no-go zone 19 miles wide is set around the reactor core. The area around Chernobyl may not be safe to live in for another 20,000 years.

Fukushima, Daiichi, Japan (Level 7) - Nuclear Disaster Fukushima

In March 2011, a terrible earthquake measuring 9.1 on the Richter scale hit northeastern Japan. This caused a tsunami with waves over 132 feet high. The government was still reeling from the effects of the tsunami when it discovered that power to three nuclear reactors at the Fukushima Daiichi Nuclear Power Plant had been interrupted. Without power to the cooling towers, three reactor cores largely melted in the first three days.

There were no direct deaths from the nuclear accident, but official figures reveal 2313 disaster-related deaths among evacuees from Fukushima region. Disaster-related deaths are in addition to the about 19,500 that were killed by the earthquake or tsunami. Over 100,000 people were evacuated from their homes as a preventative measure. Government nervousness has delayed the return of many.

Kyshtym, Russia (Level 6)

The third worst nuclear accident happened in Kyshtym, a part of the Soviet Union. After World War II, the Soviets built a nuclear plant in Kyshtym named Mayak. This plant was a nuclear enrichment plant used to make atomic weapons. In 1957, the cooling system for the reactor broke down, which caused an explosion that sent a lot of radioactive materials into the air.

Since the program was highly classified, the authorities didn't tell anyone about the accident and took a long time to tell people to leave. The Soviets didn't admit there was a disaster until 1989 and kept downplaying how bad it was. Because of this, no one knows how many people died because of Kyshtym.

Windscale, UK (Level 5)

In 1957 was the worst nuclear disaster in the UK. In the late 1940s, the country built two nuclear power plants in Windscale. In 1957, uranium cartridges broke because one reactor overheated. The fire burned for 16 hours and let out radioactive materials dangerous to humans.

The government wouldn't say how much damage was done, but milk sales were banned for many weeks in a 200-square-mile area around the plant. Experts think that this action may well have stopped a lot of serious health problems from happening.

3 Mile Island, Pennsylvania, USA (Level 5) - Nuclear Accident of Three Mile Island

In 1979, a broken safety valve in a nuclear reactor at 3 Mile Island in Pennsylvania sent plant workers into a panic. They made some bad decisions that caused the reactor to melt down partially. They also didn't find out about a radiation leak for more than 24 hours.

Women and young children who lived within five miles of the reactor were told to leave by the governor. People got scared, and more than 100,000 people left town. This accident didn't cause any serious health problems, but it did make many people afraid and made a lot of people against the nuclear program.

First Chalk River, in Canada (Level 5)

In all of Canada's nuclear energy history, there has only been one nuclear accident. It happened in 1952 at the first nuclear research reactor at Chalk River Laboratories. Due to a coolant leak, the reactor's core was damaged and had a partial meltdown.

Thankfully no one died because the problem was found in time. But the cleanup took a long time and a lot of work, and many people had to help. At the time, Jimmy Carter, who would later become president of the US, was a nuclear engineer in the US Navy and also worked on the cleanup crew.

Jaslovskè Bohunice, Czechoslovakia (Level 4)

Czechoslovakia built their first nuclear power plant in Bohunice. The plan was for the reactor to run on uranium mined in the region. The nuclear power plant had several accidents, but the worst one happened in 1977. A worker mistakenly used the wrong cooling rods during a normal fuel change. This caused a huge radioactive leak. The government shut down the plant.

SL-1 Experimental Power Station, Idaho, USA (Level 4)

In 1961, the SL-1 nuclear reactor in Idaho blew up. This was the only reactor accident in US history that killed someone. The SL-1 was one of several nuclear reactors built in Idaho to learn how to make nuclear energy.

After 11 days of being shut down for maintenance, three military personals came to restart the reactor. Unfortunately, something went wrong with a control rod, which caused an instant explosion. All three men died, but no radioactive material left the building, ensuring that nobody outside was exposed to radiation.

Saint-Laurent, France (Level 4)

At the nuclear plant in Saint-Laurent, France, there have been two level 4 nuclear accidents. The first time was in 1969, when some of the uranium in the reactor melted, having caused a partial meltdown. Workers spent a year cleaning and fixing the reactor in a very dangerous environment.

France kept working on making nuclear weapons, but in 1980, another accident happened at Saint-Laurent. The cooling system for the reactor broke, which caused two of its fuels to melt.

Tokaimura, Japan (Level 4)

In 1999, there was a nuclear accident in Japan. Three people were mixing two fuel types in a small plant to make uranyl nitrate for a nuclear reactor. They miscalculated the mix ratios, therefore employing seven times the amount of uranium allowed. This caused them to get sick from the radiation, which killed some of them.

High radiation levels were also found in over 70 other people, mostly plant workers but also a few people from the outside. Authorities told people who lived near the plant to leave their homes while also they checked to make sure the area was safe and clean.

Conclusion and resources

Even though nuclear power could be a source of energy that can be used for a long time, there is no doubt that it tends to come with some problems. Thankfully the knowledge gained from these nuclear disasters had been used to design next-generation nuclear energy technology. The risk of accidents in nuclear power plants is low and declining. Radiological effects on people of any radioactive releases can be avoided.

Further Reading

Nuclear technology is a fascinating and ever-evolving field. Want more? Check out these additional readings and resources.




16 views0 comments
Post: Blog2_Post
bottom of page