The Chernobyl disaster was a nuclear accident that occurred on April 26, 1986, at Chernobyl nuclear power plant built at the banks of Pripyat river of Ukraine. A nuclear meltdown in one of the reactors caused a fire that sent a plume of radioactive fallout that eventually spread all over Europe. It is the only accident in the history of commercial nuclear power to cause fatalities from radiation.
Two workers died on the spot. One immediately got burnt to ashes after the accident, while the other got expired at a hospital within a few hours of admission.
28 emergency workers and staff were died within 4 months of the accident due to the thermal burns and the radiation effect in their bodies.
This accident created 7,000 cases of thyroid cancer.
Acute radiation syndrome (ARS) was diagnosed in 237 people, who were on-site and involved in cleaning up.
The land, air, and groundwater were all contaminated to a great extent.
The direct and indirect exposure to radiation led to severe health problems such as Downs syndrome, Chromosomal aberrations, Mutations, Leukemia, thyroid cancer, and Congenital malfunctions etc.
Innumerous plants and animals got affected and killed.
The atomic bomb that detonated over Hiroshima used Uranium-235 while the Nagasaki bomb had Plutonium-239. But the Uranium on Hiroshima was only 1% efficient while the 12 pounds of Plutonium on Nagasaki had a bit higher effect. Most of the plume out of these radioactive materials have dissolved in the land, water, and air. The immediate effect of these bombs killed nearly 2,00,000 people but later on, the land and atmosphere turned out to be safe that and the effect got reduced because of the scattering of those particles into the atmosphere.
In the explosion and ensuing fire that took place at Chernobyl, more than 50 tons of radioactive material was released into the atmosphere, where it was carried out by air currents. The explosions took place were from the build-up of hydrogen due to zirconium-steam reactions.
A total of about 14EBq (14 x 108bq) of radioactivity was released during this devastating accident where more than half of it was from biologically-inert noble gases. This was 400 times to the number of radioactive materials released at the time of Hiroshima bombing. Severe and large quantities of radioactive materials were released into the atmosphere for 10 days after the accident.