The risk of a dangerous nuclear accident probably began as the first atomic bomb was assembled at Los Altos, NM in 1945. Since that point, there has been a chance that an accident could occur at a reactor, or due to the unplanned explosion of a bomb.

To find the world’s worst nuclear accident, 24/7 Wall St. reviewed several online sources to list accidents rated Level 4 or higher, according to the International Nuclear and Radiological Event Scale, or INES. Nuclear accidents are assigned a level ranging from zero to 10 by a scale developed in 1990 by the International Atomic Energy Agency and the Nuclear Energy Agency of the Organization for Economic Co-operation and Development. Our list does not include military-related accidents and is in chronological order.

According to the U.S. Energy Information Association, there are 31 countries with nuclear power reactors that generate 10.3% of the world’s electricity. In the U.S., there are 94 reactors operating in 30 states that produce almost 20% of total annual electricity generation. Though nuclear power does not produce carbon dioxide, it does generate nuclear waste, and these materials can remain radioactive and dangerous to people for thousands of years.

There have been very few serious nuclear incidents in the U.S. The most concerning was the accident at Three Mile Island in Pennsylvania in 1979, an incident that eerily followed the release of the nuclear-accident film “The China Syndrome” several weeks earlier.

Nuclear accidents have occurred for a variety of reasons such as miscalculations involving experiments or tests, human error, or a flawed design at some of the facilities. In one case, an old radiotherapy device stolen by scavengers from a Brazilian hospital was mishandled by many people, killing four of them. In Japan, an earthquake and tsunami severely damaged three of the reactor buildings, and fuel in three of the reactor cores melted.

The worst nuclear accident in history was at the Fukushima Daiichi Nuclear Power Plant. Here are the details:

> Location: Fukushima, Japan
> Date: 11 March 2011
> INES level: Level 7

Nature, not humankind, had a hand in the Fukushima Daiichi nuclear power plant accident, one of two Level-7 incidents on the list. On March 11, 2011, an earthquake and tsunami slammed eastern Japan, where the nuclear power plant is located, cutting off external power to the reactors. The ensuing tsunami reached heights more than twice as high as the plant was designed to withstand. That disabled the backup diesel generators and shut down the reactor cooling systems. The overheating fuel in the operating reactor cores led to hydrogen explosions that severely damaged three of the reactor buildings. Fuel in three of the reactor cores melted. Radiation emitted from the damaged reactors contaminated the area around the plant and caused the evacuation of about 500,000 people.

Click here to read The World’s Worst Nuclear Accidents

Get Our Free Investment Newsletter

I have read, and agree to the Terms of Use

Thank you for reading! Have some feedback for us?
Contact the 24/7 Wall St. editorial team.