Home » Chernobyl » Glossary

Chernobyl Nuclear Accident


Glossary over the Chernobyl Nuclear Accident

Acute radiation effects

Effects that are caused by (usually short-term) exposure to radiation and that occur immediately after the exposure. (Source: GreenFacts)


Acute radiation syndrome (ARS)

Serious illness that occurs when the body receives a high dose of penetrating radiation (that is, able to reach internal organs) over a short period of time (usually minutes).



Americium is a silvery metal and a completely man-made element whose 6 known isotopes are all radioactive.

Americium-241, the most common isotope, is formed spontaneously by the decay of plutonium-241 and has a half-life of 430 years.


Belgian Science Policy

"The Belgian Federal Science Policy Office has the following mission:

  • preparation, execution and evaluation of science policy and its extensions
  • in particular, on Belgian Government instructions, implementation of scientific and technical means in support of Federal Authority competences
  • development of a permanent knowledge resource within scientific and technical spheres at the service of the Federal Authority.
  • in addition, the Prime Minister and the Minister for Science policy agreed in January 2002 to charge the Belgian Federal Science Policy Office with the question of the cultural goods of the Jewish Community plundered during the war."

Bioaccumulation is used to describe the increase in concentration of a substance in an organism over time.

Bioaccumulative substances tend to be fat soluble and not to be broken down by the organism. (Source: GreenFacts )



Biodiversity is a contraction of biological diversity. Biodiversity reflects the number, variety and variability of living organisms.

It includes diversity within species (genetic diversity), between species (species diversity), and between ecosystems (ecosystem diversity). (Source: GreenFacts)



Caesium is one of the radioactive fission products created within a nuclear reactor during its operation.


Canadian Centre for Occupational Health and Safety

"The Canadian Centre for Occupational Health and Safety (CCOHS) is a Canadian federal government agency based in Hamilton, Ontario, which serves to support the vision of eliminating all Canadian work-related illnesses and injuries."

"The mandate of CCOHS is to promote improvements in occupational health and safety by providing practical information to answer workplace concerns." (Source: CCOHS website )


Any one of a group of diseases that occur when cells in the body become abnormal and have the potential to spread and establish growth in nearby tissues and other parts of the body (malignancy). (Source: GreenFacts )



A clouding of the natural lens of the eye most frequently caused by ageing that can severely blur vision. (Source: GreenFacts)

Circulatory system

The system that contains the heart and the blood vessels and moves blood throughout the body. This system helps tissues get enough oxygen and nutrients, and it helps them get rid of waste products. The lymph system, which connects with the blood system, is often considered part of the circulatory system. (Source: NCI Dictionary of cancer terms  )


Development Gateway Foundation

"The Development Gateway Foundation is an enabler of development. We help improve people’s lives in developing countries by building partnerships and information systems that provide access to knowledge for development. We exploit powerful and affordable information and communication technologies (ICT) that were previously unavailable to:

Increase knowledge sharing;The Development Gateway is an independent not-for-profit organization. It was conceived by World Bank President James Wolfensohn and initially developed in the World Bank. Operations began in July 2001." Enhance development effectiveness; Improve public sector transparency; and Build local capacity to empower communities.

The Development Gateway is an independent not-for-profit organization. It was conceived by World Bank President James Wolfensohn and initially developed in the World Bank. Operations began in July 2001." (Source: DGF website )


The complex system of plant, animal, fungal, and microorganism communities and their associated non-living environment interacting as an ecological unit.

Ecosystems have no fixed boundaries; instead their parameters are set to the scientific, management, or policy question being examined. Depending upon the purpose of analysis, a single lake, a watershed, or an entire region could be considered an ecosystem. (Source: US EPA Glossary of Climate Change Terms   )

Environmentalists For Nuclear Energy

"Environmentalists For Nuclear Energy (EFN) is an independent environmental, non-profit organization which aims at :

  • providing complete and straightforward information to the public on energy and the environment
  • promoting the benefits of nuclear energy for a cleaner world
  • uniting people in favor of clean nuclear energy"
Epidemiological studies

Studies on human populations, which attempt to link human health effects (e.g. cancer) to a cause (e.g. exposure to a specific chemical). (Source: GreenFacts)


EurActiv is the leading internet portal fully dedicated to European public affairs. It brings together daily EU news, weekly "Update" e-mails, in-depth analysis of selected policy topics, and a directory of 10,000 names of names of people and organizations acting on the EU level, the "Guide". All content is free of charge.

EurActiv aims to "facilitate efficiency and transparency (...) by providing news monitoring, policy positions, discussion forums and contacts on selected EU affairs topics, complementing the existing institutional websites."

(Source: EurActiv website )

Exclusion Zone (in Chernobyl)

The exclusion Zone refers to the area extending up to 30 km in all directions around the Chernobyl nuclear power plant that was most contaminated by the accident.

After the accident, its population was evacuated and all agricultural and industrial activities were suspended. (Source: GreenFacts, based on the GreenFacts Digest on Chernobyl )



Contact of the cells of an organism with a substance, micro-organism or radiation. In the case of humans, this may involve contact with a substance or agent by swallowing, breathing, or through the skin or eyes. Exposure may be short-term [acute exposure], of intermediate duration, or long-term [chronic exposure].

Exposure can be divided into external and internal.

External exposure refers to the whole dose to which an organism is exposed.

Internal exposure refers only to that fraction of the initial chemical dose that is absorbed and distributed throughout the body via systemic circulation. (Source: GreenFacts)



The ability of people or animals to produce healthy offspring in abundance.

Unlike fecundity, which measures a potential ability, fertility measures the actual number of offspring of an individual, a couple, a group or a population. It is evaluated by the time to achieve pregnancy.

Please note that "fertility" corresponds to "fécondité" in French and "fecundidad" in Spanish whereas the French word "fertilité" and the Spanish word "fertilidad" mean "fecundity". (Source: GreenFacts)

Food web

The interconnected food chains (feeding relationships) in an ecosystem. Plants, herbivores, and carnivores all form parts of the food web. (Source: GreenFacts)



Water that is not salty, for instance water found in lakes, streams, and rivers, but not the ocean. Also used to refer to things living in or related to freshwater (e.g., "freshwater fish"). (Source: GreenFacts)



The functional and physical unit of heredity passed from parent to offspring. Genes are pieces of DNA, and most genes contain the information for making a specific protein. (Source: NHGRI Talking Glossary of Genetic Terms  )


"Greenpeace is the leading independent campaigning organization that uses non-violent direct action and creative communication to expose global environmental problems and to promote solutions that are essential to a green and peaceful future."

Greenpeace currently focusses on eight projects :

  • Stop climate change
  • Protect ancient forests
  • Save the oceans
  • Stop whaling
  • Say no to genetic engineering
  • Stop the nuclear threat
  • Eliminate toxic chemicals
  • Encourage sustainable trade
Half life

The term which is used for the time required for the amount of a particular substance to be reduced to one half of its value when the rate of decay is exponential.

Radioactive half-life refers to the decay of radioactive substances. Iodine-131, for instance, has a half-life of 8 days whereas that of Plutonium-239 is more than 23 000 years.

Biological half-life refers to decay by biological processes. Substances with a long biological half-life will tend to accumulate in the body and are, therefore, particularly to be avoided. Substances with a short biological half-life may accumulate if some becomes tightly bound, even if most is cleared from the body rapidly. There is also the possibility of cumulative effects of chemicals which have a short residence time in the body. (Source: GreenFacts)



"The innovations-report is a modern forum for Science, Industry and Business for the advancement of innovation dynamics as well as the production of new contacts for a more intensive use of the existing innovation and performance potential. [...]

In more than 2,000 reports every year, the innovations-report offers current information on new technologies, highly interesting research and development results, innovative products and services, and lots more." (Source: IR website )

International Atomic Energy Agency

"The IAEA is the world´s center of cooperation in the nuclear field. It was set up as the world´s "Atoms for Peace" organization in 1957 within the United Nations family. The Agency works with its Member States and multiple partners worldwide to promote safe, secure and peaceful nuclear technologies." (Source: IAEA website  )


Iodine is a trace element that is necessary for the body to produce the thyroid hormone.

It is a bluish-black, lustrous nonmetallic solid element that mainly occurs in nature under its stable form, iodine-127. Stable iodine is naturally present for instance in seaweeds, sponges, and shell fish. It is also artificially added to salt.


Iodine tablets

Stable (non-radioactive) iodine tablets are an established countermeasure to accidents at nuclear installations that result in the release of radioactive iodine.

The tablets saturate the thyroid gland with stable iodine in order to prevent it from accumulating radioactive iodine, hence reducing the risk of thyroid cancer.



Atoms of the same element that have the same number of protons (same atomic number) but different numbers of neutrons (different atomic masses).

Isotopes have the same chemical properties but have different physical and nuclear properties.

Examples of isotopes are plutonium-238, plutonium-239, plutonium-240, and plutonium-241. Each acts chemically like plutonium but they have 144, 145, 146, and 147 neutrons, respectively. (Source: GreenFacts)



Leukaemia is a cancer that starts in blood-forming tissue such as the bone marrow, which makes blood cells (red blood cells that carry oxygen around the body, white blood cells that fight disease and infection, platelets that help to stop bleeding when it starts).

In people with leukaemia, the bone marrow produces large numbers of abnormal white blood cells and not enough normal red blood cells.

Leukaemia cases represent less than 4% of all cancer cases in adults but are the most common form of cancer in children.

There are different types of leukaemia (e.g. acute, chornic, myeloid and lymphoid leukaemia). (Source: GreenFacts )

Life expectancy

The number of years that a person could expect to live on average, based on the mortality rates of the population in a given year.

Life expectancy can change over the lifecycle. For example, at birth a person may be expected to live for 75 years, but if they survive to 75 they may be expected to live for another 10 years. (Source: New Zealand Ministry of Economic Development Population & Sustainable Development, Glossary  )

Medical abortion

The deliberate termination of a human pregnancy through medical intervention. (Source: GreenFacts )


Death. Usually the cause (a specific disease, a condition, or an injury) is stated. (Source: ATSDR Glossary of Terms   )


Plutonium is a heavy, man-made, radioactive metallic element. The most important isotope is Pu-239, which has a half-life of 24 000 years. Pu-239 can be used in reactor fuel and is the primary isotope in nuclear weapons.

In the context of Chernobyl, an important radioisotope of Plutonium is Pu-241, which has a half-life of 14.4 years and decays into americium-241.



A group or number of people living within a specified area or sharing similar characteristics (such as occupation or age). (Source: ATSDR Glossary of Terms  )


Post-traumatic stress

A psychological reaction that occurs after experiencing a highly stressing event (as wartime combat, physical violence, or a natural disaster) outside the range of normal human experience and that is usually characterized by depression, anxiety, flashbacks, recurrent nightmares, and avoidance of reminders of the event. (Source: Merriam-Webster Online  )

Pregnancy outcomes

Results of conception and ensuing pregnancy, such as sex ratio, birth weight, spontaneous abortion, congenital malformations, lower birth weight, preterm delivery or stillbirth. (Source: GreenFacts)


Energy moving in the form of particles or waves. Familiar radiations are heat, light, radio waves, and microwaves. Ionizing radiation is a very high-energy form of electromagnetic radiation. (Source: US Center for Disease Control and Prevention Glossary of Radiological Terms   )


Radioactive decay

The decrease in the [radiation intensity] of any radioactive material with the passage of time due to the spontaneous emission of radiation from an atomic nucleus. (Source: University of Harvard Environmental Health & Safety   )


Radioactive material

Material that contains unstable (radioactive) atoms that give off [ionizing] radiation as they decay. (Source: CDC Glossary of Radiological Terms   )

Radioactive waste

Any waste that emits energy as rays, waves, streams or energetic particles.

Radioactive materials are often mixed with hazardous waste, from nuclear reactors, research institutions, or hospitals. (Source: US EPA Terms of Environment  )



The spontaneous emission of ionizing radiation from the nucleus of an unstable atom. Radioisotopes lose particles and energy through this process. (Source: GreenFacts, based on Energy Information Administration Glossary   )


Solid cancer

Solid cancers are defined as abnormal cellular growths in "solid" organs such as the breast or prostate, as opposed to leukemia, a cancer affecting the blood, which is liquid. (Source: GreenFacts)


Strontium-90 is one of the radioactive fission materials created within a nuclear reactor during its operation. It remains radioactive for a long period of time and can contaminate property, requiring extensive cleanup. Since strontium can be absorbed into the food chain, it also poses a potential cancer-causing risk.

Strontium-90 has a half-life of over 28 years. (Source: GreenFacts)

Subjective health

Subjective health refers to how individuals evaluate their own health status. People with subjective poor health are those who perceive themselves as ill. (Source: GreenFacts )


Thyroid gland

The thyroid gland consists of two bodies like small walnuts; they are connected by an isthmus beside the larynx (voice box). The thyroid gland produces thyroid hormones T3 and T4 which regulate the metabolism of all cells in the body. Disorders of the thyroid gland are characterized by the inability to produce or release sufficient thyroid hormones (hypothyroidism) or the overactivity of the thyroid gland (hyperthyroidism). (Source: EMCOM Endocrine Disruptors Glossary  )


UN Chernobyl Forum

'Chernobyl Forum' is the name of a group of UN agencies, founded by the IAEA (the International Atomic Energy Agency), that is working to give people in the villages affected by the Chernobyl nuclear power plant accident greater certainty, by issuing factual, authoritative statements on the health effects caused by radiation exposure from the reactor explosion and its environmental consequences.

The UN organizations involved in the Forum include:

  • the IAEA (International Atomic Energy Agency)
  • the FAO (Food and Agriculture Organization)
  • the OCHA (United Nations Office for the Coordination of Humanitarian Affairs)
  • the UNDP (United Nations Development Programme)
  • the UNEP (United Nations Environment Programme)
  • the UNSCEAR (United Nations Scientific Committee on the Effects of Atomic Radiation)
  • the WHO (World Health Organization)
  • the World Bank.

The Forum also comprises the governments of Belarus, Russia and the Ukraine. (Source: Chernobyl Forum website )

United Nations Development Programme

"UNDP is the UN's global development network, an organization advocating for change and connecting countries to knowledge, experience and resources to help people build a better life. We are on the ground in 166 countries, working with them on their own solutions to global and national development challenges. As they develop local capacity, they draw on the people of UNDP and our wide range of partners." (Source: UNDP website  )

United Nations Scientific Committee on the Effects of Atomic Radiation

"UNSCEAR was established by the General Assembly of the United Nations in 1955. Its mandate in the United Nations system is to assess and report levels and effects of exposure to ionizing radiation. Governments and organizations throughout the world rely on the Committee's estimates as the scientific basis for evaluating radiation risk and for establishing protective measures." (Source: UNSCEAR website )

US Environment Protection Agency

The Environment Protection Agency's of the USA was founded in 1970. It's "mission is to protect human health and to safeguard the natural environment — air, water, and land — upon which life depends."

The EPA enforces federal environmental protection laws. It registers and regulates pesticides, enforces laws covering outdoor air and drinking water quality and regulates the disposal of hazardous and solid wastes.

It has now grown into a big and powerful administration: "18,000 people in Headquarters program offices, 10 regional offices, and 17 labs across the country, EPA employs a highly educated, technically trained staff, more than half of whom are engineers, scientists, and environmental protection specialists. A large number of employees are legal, public affairs, financial, and computer specialists."

U.S. EPA's scientific publications are widely recognized as reference materials. (Source: US EPA website  )

Vulnerability (in health science)

The likelihood of being unusually severely affected by a substance either as a result of susceptibility to the effects of these substances or as a result of a greater than average [exposure]. (Source: WHO Europe  Answers to follow-up questions from CAFE )

World Health Organization

"The World Health Organization  (WHO) is the directing and coordinating authority on international health within the United Nations’ system. WHO experts produce health guidelines and standards, and help countries to address public health issues. WHO also supports and promotes health research. Through WHO, governments can jointly tackle global health problems and improve people’s well-being.

193 countries and two associate members are WHO’s membership. They meet every year at the World Health Assembly in Geneva to set policy for the Organization, approve the Organization’s budget, and every five years, to appoint the Director-General. Their work is supported by the 34-member Executive Board, which is elected by the Health Assembly. Six regional committees focus on health matters of a regional nature."

WHO's scientific publications are widely recognized as a reference source.

The WHO has a number of regional offices which address the specific issues of those regions.

WHO World Regional Offices
  WHO African Region  (46 countries)
  WHO European Region  (53 countries)
  WHO Eastern Mediterranean Region  (21 countries)
  WHO Region of the Americas  (35 countries)
  WHO South-East Asia Region  (11 countries)
  WHO Western Pacific Region  (27 countries)

Other articles you might like...
Single-use plastics home
Reusable tableware consistently outperforms single-use tableware in all the studies and across most environmental impact categories
Children & Screens home
What are the potential consequences of screens at a younger age and what should parents do to protect them?
Fukushima Consequences home
What are the causes and consequences accident at the Fukushima Daiichi Nuclear Power Plant?
A-Z List
    Themes covered
    Publications A-Z

    Get involved!

    This summary is free and ad-free, as is all of our content. You can help us remain free and independant as well as to develop new ways to communicate science by becoming a Patron!