Chernobyl accident

The Chernobyl disaster was a catastrophic nuclear accident that occurred on 26 April 1986 at the Chernobyl Nuclear Power Plant in the city of Pripyat, in the Ukrainian Soviet Socialist Republic of the Soviet Union. It is considered the worst nuclear disaster in history both in terms of cost and casualties.

Background

The Chernobyl Nuclear Power Plant consisted of four reactors of the RBMK-1000 design, a type of graphite-moderated nuclear power reactor. The plant was located near the town of Pripyat, which was built to house the workers of the plant and their families.

The Accident

On the night of 25–26 April 1986, a safety test was scheduled to be conducted on Reactor 4. The test was intended to simulate a power outage to help create a safety procedure for maintaining reactor cooling water circulation until the backup generators could provide power. However, due to a combination of reactor design flaws and operator errors, the test led to an uncontrolled reaction.

At 01:23 AM, a sudden power surge occurred, and attempts to shut down the reactor completely failed. The reactor core exploded, releasing a large amount of radioactive particles into the atmosphere. The explosion and subsequent fire released about 5% of the radioactive reactor core into the environment.

Immediate Response

Firefighters were called to the scene to extinguish the fires on the roof of the reactor building. Many of these first responders were exposed to high levels of radiation and suffered from acute radiation sickness.

Evacuation and Containment

The nearby town of Pripyat was not immediately evacuated. It was not until 36 hours after the explosion that the order was given to evacuate the town. Eventually, a 30-kilometer exclusion zone was established around the plant, and over 350,000 people were evacuated from the most contaminated areas.

Health and Environmental Impact

The Chernobyl disaster released large quantities of radioactive isotopes into the atmosphere, which spread over much of Europe. The most significant isotopes released were iodine-131, cesium-137, and strontium-90. The radioactive contamination led to increased rates of cancer and other health issues in the affected regions.

Long-term Consequences

The Chernobyl disaster had profound effects on the environment, health, and politics. The disaster highlighted the potential dangers of nuclear power and led to changes in safety culture and regulations worldwide. The Chernobyl Exclusion Zone remains one of the most radioactive areas on Earth.

Also see

• Nuclear power
• Nuclear safety
• Fukushima Daiichi nuclear disaster
• Three Mile Island accident
• Radioactive contamination