Extreme Disasters - What Really Happened at Chernobyl in 1986?
- 6 years ago
So far, fewer than 50 deaths have been attributed to the Chernobyl disaster, but the final toll may be many thousands.
"April 26, 1986 is a date that will be forever etched into the minds of nuclear and radiation specialists across the globe,” wrote the National Radiation Laboratory’s Murray Matthews in 2006.
On this date, unit 4 of the Chernobyl nuclear power plant, about 100km north of Kiev (then part of the Soviet Union), exploded. In an accident during a safety test, an uncontrolled power surge turned the reactor’s cooling water to steam in a massive explosion. With no coolant, the fuel reached such high temperatures that it didn’t just melt down, it vaporised. A second explosion blew apart the reactor core, which had no containment vessel. The series of explosions, and a reactor fire that burnt for 10 days, released huge amounts of radioactive isotopes – including iodine-131, caesium-137, strontium-90 and plutonium isotopes – into the atmosphere and over large areas of what is now Belarus, Ukraine and Russia. Most of the strontium and plutonium isotopes were deposited within 100km of Chernobyl, but winds carried other radioactive isotopes far over parts of northern Europe, including Germany, Scandinavia and the UK, creating radioactive hotspots where rain washed the isotopes out of the atmosphere.
In the West, the first reports of the accident came from satellite photographs and radiation detectors in Sweden. The Soviet Government’s slowness to release information, along with public mistrust of anything it did say, led to wild speculation about the effect of the accident: some Western newspapers reported that thousands of people, or even tens of thousands, were dead.
Only recently has an international consensus been reached over the health and environmental effects of the Chernobyl disaster. In 2003, the United Nations-led Chernobyl Forum was established to make some “authoritative consensual statements” about what happened. An international conference in 2005 summarised nearly 20 years of research following the accident and attributed fewer than 50 deaths – so far – to the Chernobyl accident.
The highest radiation doses were received by workers onsite when the accident happened, and by emergency and recovery workers: 134 people got acute radiation sickness and 28 of them died within a year of the accident.
Most of the other deaths are attributed to thyroid cancers caused by childhood exposure to iodine-131, a radioactive isotope with a half-life of eight days. Iodine concentrates in the thyroid gland, with iodine-131 emitting beta and gamma radiation that can reach up to 2mm into surrounding tissue. Around Chernobyl, people ingested iodine-131 by drinking milk from cows that had fed on contaminated grass, and by eating green vegetables from affected areas. More than 5000 cases of thyroid cancer have been re
corded from children living in the contaminated area, but thyroid cancer is treatable and fewer than 20 people have died.
"April 26, 1986 is a date that will be forever etched into the minds of nuclear and radiation specialists across the globe,” wrote the National Radiation Laboratory’s Murray Matthews in 2006.
On this date, unit 4 of the Chernobyl nuclear power plant, about 100km north of Kiev (then part of the Soviet Union), exploded. In an accident during a safety test, an uncontrolled power surge turned the reactor’s cooling water to steam in a massive explosion. With no coolant, the fuel reached such high temperatures that it didn’t just melt down, it vaporised. A second explosion blew apart the reactor core, which had no containment vessel. The series of explosions, and a reactor fire that burnt for 10 days, released huge amounts of radioactive isotopes – including iodine-131, caesium-137, strontium-90 and plutonium isotopes – into the atmosphere and over large areas of what is now Belarus, Ukraine and Russia. Most of the strontium and plutonium isotopes were deposited within 100km of Chernobyl, but winds carried other radioactive isotopes far over parts of northern Europe, including Germany, Scandinavia and the UK, creating radioactive hotspots where rain washed the isotopes out of the atmosphere.
In the West, the first reports of the accident came from satellite photographs and radiation detectors in Sweden. The Soviet Government’s slowness to release information, along with public mistrust of anything it did say, led to wild speculation about the effect of the accident: some Western newspapers reported that thousands of people, or even tens of thousands, were dead.
Only recently has an international consensus been reached over the health and environmental effects of the Chernobyl disaster. In 2003, the United Nations-led Chernobyl Forum was established to make some “authoritative consensual statements” about what happened. An international conference in 2005 summarised nearly 20 years of research following the accident and attributed fewer than 50 deaths – so far – to the Chernobyl accident.
The highest radiation doses were received by workers onsite when the accident happened, and by emergency and recovery workers: 134 people got acute radiation sickness and 28 of them died within a year of the accident.
Most of the other deaths are attributed to thyroid cancers caused by childhood exposure to iodine-131, a radioactive isotope with a half-life of eight days. Iodine concentrates in the thyroid gland, with iodine-131 emitting beta and gamma radiation that can reach up to 2mm into surrounding tissue. Around Chernobyl, people ingested iodine-131 by drinking milk from cows that had fed on contaminated grass, and by eating green vegetables from affected areas. More than 5000 cases of thyroid cancer have been re
corded from children living in the contaminated area, but thyroid cancer is treatable and fewer than 20 people have died.