Nuclear accident: what is it, consequences, Chernobyl

Definition: what is a nuclear accident?

A nuclear accident is an event that can lead to an abnormal release of radioactive elements into the environment.. This type of accident is characterized by a significant release of toxic elements (especially radioactive) and/or by a strong irradiation likely to harm public health. A nuclear accident is called anuclear incident if its seriousness and its consequences on populations and the environment are judged to be very low.

Nuclear accidents can occur:

• in nuclear power plant
• in facilities producing, conditioning, storing or reprocessing nuclear fuel and in nuclear research laboratories
• in one establishment carrying out a nuclear activity (military site, hospital, research laboratory etc)
• during the transport of radioactive substances (in particular for medical use, but also nuclear fuel, radioactive waste or nuclear weapons) by rail, road, plane or boat.
• during a unintentional or malicious release of radioactive substances into the environment.

The nuclear accident in Chernobyl, a small town in Ukraineoccurred on April 26, 1986. the Reactor No. 4 of the plant, in service since 1983, accidentally explodes during a technical test : handling errors and reactor weaknesses lead to disaster. At 1:23 a.m., the reactor spirals out of control and a steam explosion occurs in the building, the deflagration raises the upper slab of the reactor (2000 tons). The core of the reactor is in the open air, the graphite catches fire, several hearths light up. The firefighters put out the fire with great difficulty (some died on the spot). This accident released radioactive materials into the atmosphere which seriously contaminated the area and whose effects were recorded throughout Europe. The Chernobyl power plant had no containment building that could have prevented radioactive products from escaping beyond the reactor area. The lightest particles created a radioactive cloud.

What is the list of nuclear accidents?

The list of nuclear accidents

• Tokaimura: Japan1999.
• Goiânia (State of Goiás): Brazil1987.
• Chernobyl disaster: Ukraine1986.
• Saint-Laurent nuclear power plant (Loir-et-Cher): France1980. This is the most serious nuclear accident ever recorded for a reactor in France.
• Three Mile Island: United States1979.
• Lucens nuclear power plant: Swiss1969.
• Mayak Nuclear Complex (Kyshtym): USSR1957.
• Windscale: Britain1957.

What is the list of nuclear accidents in France?

The only nuclear accident in France occurred in February 1980 at the Saint-Laurent-des-Eaux nuclear power plant (Loir-et-Cher) : a technical failure led to the local ignition of the fuel. The accident seriously damaged the installation.

What is a nuclear risk?

Nuclear risk arises from the possibility of a nuclear accident, leading to a release of radioactive elements outside the containers and enclosures provided to contain them. The two main nuclear risks are:

• Irradiation : the body is exposed to radiation from a radioactive source. It is said to be external if the radiation source is external to the human body. It is internal if the radiation source is inside the human body.
• Contamination : the contamination is external when we have a deposit on the skin of a radioactive substance. It is internal when the radioactive source is inside the human body (via the respiratory, digestive and cutaneous (via wounds) tracts).

What are the consequences of a nuclear accident?

A nuclear accident causes multiple consequences, in particular on the environment and human health. The consequences listed by the Institute for Radiation Protection and Nuclear Safety (IRSN) for exposed populations (civilians and workers) are:

• the thyroid cancer : “To date, thyroid cancer in people exposed during childhood and adolescence is the main demonstrated health effect associated with radioactive fallout from the Chernobyl accident, due to iodine-131. The thyroid gland is an organ particularly sensitive to ionizing radiation, especially after exposure in childhood“according to the IRSN.
• One acute radiation syndrome (ARS)
• A skin degeneration secondary to radiological burns
• From cataracts : “Exposure to ionizing radiation of the lens is a known risk factor for the appearance of cataracts in humans“ indicates the IRSN.
• Increased risk of leukemia “including for chronic lymphocytic leukemia generally considered as not radiation-induced”
• Increased incidence of multiple myeloma and myelodysplastic syndrome
• Increased incidence of solid cancers
• The pathologies of the circulatory system : “Ischemic heart disease and cerebrovascular disease mainly caused by atherosclerosis. Eventually, these plaques can cause damage to the arterial wall (sclerosis), lead to vessel obstruction or even rupture, with consequences such as acute myocardial infarction or stroke”.
• Effects on neurological development and cognitive functions (Ongoing studies).

What to do in the event of a nuclear accident?

In the event of a nuclear accident, the government recommends:

• Take shelter in a solid building, close doors and windows and turn off the ventilation. If you are in a vehicle, get to shelter (building, accommodation, etc.) as quickly as possible.
• Do not touch objects (to his vehicle in particular), to food, to water.
• If it’s raining, leave anything outside that might have gotten wet from the rain. (umbrella, shoes, coat, raincoat…).
• Stay informed to comply with the protection instructions of the public authorities (on taking iodine in particular) disseminated by the media, the website and the accounts of your prefecture on social networks.
• Do not pick up your children from school.
• Do not seek to reunite with family if members are outside.
• Do not call to avoid saturating communications and preventing the emergency services from acting.
• Take iodine only on instruction of the prefect.
• Prepare for an evacuation and follow traffic instructions.

What is the impact of a nuclear accident on the environment?

In the event of an accident in a nuclear power plant, radioactive substances are released into the environment. We then speak of “radioactive plume“. This plume will disperse and cause a air and environmental contamination. This contamination is higher in the zone closest to the plant and it decreases as one moves away. Radioactive substances carried in the air are gradually deposited on ground surfaces, on plants, inhabited areas (roads, walls, roofs, etc.) : these are the radioactive fallout from the accident. “The fallout on the surface waters (rivers, lakes, open reservoirs) lead to immediate water contamination, at least temporarily. We observe a leaf contamination and, therefore, plant production for human food and that of livestock. leafy vegetables (salads, spinach, leeks, etc.) are the most immediately affected by this contamination. The grass is immediately contaminated by radioactive fallout and the animals that feed on them are in turn contaminated. Among animal foodstuffs, milk (cows, sheep, goats) is most quickly affected by this transfer of contamination. Meat becomes contaminated more slowly but more permanently if the animal continues to eat grass or contaminated fodder” develops the IRSN.

What is the biggest nuclear disaster?

As of March 9, 2022, it is Chernobyl nuclear power plant accident which is the biggest nuclear disaster in the world.

Sources:

Risks – prevention of major risks, Nuclear accident, government site

Definition of nuclear risk, 2012, Prefect of Seine-Maritime, government.

Environmental consequences of an accident, IRSN

State of knowledge on the health consequences of a nuclear accident, IRSN