Glossary of Chernobyl Meltdown Terms

A comprehensive reference guide to terminology related to the 1986 nuclear disaster

A

Acute Radiation Syndrome (ARS)

Illness caused by high exposure to ionizing radiation, characterized by nausea, vomiting, and hair loss.

B

Bioaccumulation

Process in which radioactive materials accumulate in organisms over time.

C

Chernobyl Disaster

Catastrophic nuclear accident on April 26, 1986, at Reactor No. 4 in the Chernobyl Nuclear Power Plant.

Containment Structure

A reinforced concrete building designed to contain radioactive materials; notably missing from Chernobyl's Reactor No. 4.

Control Rods

Rods used to control nuclear reaction rates. A design flaw in Chernobyl's control rods contributed to the disaster.

D

Dosimeter

Device measuring exposure to ionizing radiation.

E

Elephant's Foot

Solidified mass of melted nuclear fuel and materials beneath Reactor 4, extremely radioactive and dangerous.

Exclusion Zone

Area surrounding Chernobyl declared unsafe due to high radiation, approximately a 30-kilometer radius around the plant.

F

Fallout

Radioactive particles dispersed into the atmosphere following a nuclear incident.

Fission

Process of splitting atomic nuclei to release energy; fundamental to nuclear power.

G

Graphite Moderator

Substance used to slow neutrons in Chernobyl's RBMK reactor design; it caught fire during the accident, exacerbating radiation release.

H

Half-Life

Time required for half the atoms of a radioactive substance to decay; vital in understanding long-term radiation hazards.

I

Ionizing Radiation

High-energy radiation capable of removing electrons from atoms, causing cell damage and mutations.

Iodine-131

Radioactive isotope released during the accident, known for causing thyroid cancer.

L

Liquidators

Workers and emergency responders who managed cleanup efforts after the disaster.

M

Meltdown

Severe overheating of a nuclear reactor's core, causing nuclear fuel to melt.

N

Nuclear Reactor

Facility in which controlled nuclear reactions generate electricity.

Nuclear Fallout

Radioactive debris that falls to the ground after a nuclear explosion or severe reactor accident.

P

Pripyat

Abandoned city close to the Chernobyl plant, evacuated shortly after the disaster.

Plutonium

Radioactive element produced in nuclear reactors, highly toxic and carcinogenic.

R

Radiation Sickness

Illness caused by excessive radiation exposure, with varying severity based on exposure levels.

RBMK Reactor

Soviet-designed nuclear reactor used at Chernobyl, known for critical safety flaws.

Remediation

Efforts to clean or manage contaminated areas to reduce radiation risks.

S

Sarcophagus

The original concrete structure hastily built to encase Reactor 4 and contain radiation leakage.

Sievert (Sv)

Unit measuring radiation absorbed by biological tissue, indicating potential damage.

T

Thyroid Cancer

Common health effect from exposure to radioactive iodine released during the Chernobyl disaster.

U

Uranium-235

Radioactive isotope of uranium commonly used as nuclear fuel.

X

Xenon Poisoning

Accumulation of Xenon-135, which interferes with reactor stability; critical factor preceding the Chernobyl accident.

Z

Zone of Alienation

Official term for the contaminated exclusion zone around the Chernobyl Nuclear Power Plant.

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