In 1945, the year on two Japanese cities, Hiroshima and Nagasaki were dropped two atomic bombs. Decades later, April 26, 1986, the year of the Chernobyl nuclear power plant in Ukraine exploded fourth reactor.
Today in Hiroshima and Nagasaki safely home to about 1.6 million people, and the so-called Chernobyl exclusion zone with a diameter of about 30 km around the former power remains relatively uninhabited.
Fell on Hiroshima bomb called “Little Boy” was about three feet long, weighed about 4.5 tons and contained about 63 kg of uranium. As planned, a bomb exploded at an altitude of just over 600 meters above Hiroshima, the reaction started, and as a result of the explosion power of 16 kilotons. Since Hiroshima is located on the plain, “The Kid” has caused great damage to 70 thousand people were killed and as many were injured, and nearly 70% of the buildings in the city were destroyed. Still about 1,900 people after some time died of cancer.
The bomb called “Fat Man” dropped on Nagasaki, contained more than six kilograms of plutonium and exploded at an altitude of 500 meters above the city, creating an explosion of power in the 21 kiloton. As the bomb exploded in the valley, most of the city was not damaged by the explosion. However, the 45-thousand to 70-thousand people died on the spot, another 75,000 were injured.
As Chernobyl, it was possible to prevent. The design of the reactor had significant disadvantages. First, when the refrigerant is reduced, the reaction proceeds more rapidly and thus generate more heat: thus, the coolant was getting smaller. Secondly, instead of reinforced concrete in the construction of the reactor was used heavy concrete.
When engineers decided to test for performance, fuel had only six employees of the rods 205. Thus, the cooling water received too little, and the one that was in the reactor was rapidly converted into steam with heat and the remaining graphite rods jammed. As a result of the explosion, and splashed around ten tons of nuclear fuel. Accurate data on the number of people killed as a result of the radioactive release, hard to find.
So, in the 30-kilometer exclusion zone of Chernobyl radioactive contamination appeared isotopes such as cesium-137, strontium-90 and iodine-13, making an unsafe living here people. In Hiroshima and Nagasaki, this is not observed. This difference is due to two factors: the reactor of the Chernobyl nuclear power plant was much more nuclear fuel much more efficiently used in the reaction, and in addition, there was an explosion on the ground, not in the air.