Recovery time from a nuclear disaster

August 1945 will forever be remembered as one of the most dramatic months in the history of mankind, when nuclear weapons were used in warfare for the first and last time to date. Tragically, this powerful weapon was aimed at civilian targets: on August 6 the "Enola Gay" dropped the bomb dubbed the "Little Boy" and it blew up over the city of Hiroshima in Japan. The explosion, which amazed the world, instantly killed nearly seventy thousand people and a similar number again died later from injuries and radiation damage.

Three days later, the "Bockscar" dropped the "Fat Man" bomb on Nagasaki. Because of the mountainous topography of the city, the damage was smaller, even though the bomb was stronger than the previous one - forty thousand died from the explosion itself and another twenty five thousand people died later from their wounds. Six days after that the Emperor of Japan, Hirohito, announced to his people that the government of Japan unconditionally surrendered and World War II ended.

But these cities were not completely wiped off the face of the Earth. In Hiroshima, within a two kilometer radius to ground zero, the "Little boy" destroyed all buildings, but within a three kilometer radius or more, most of the buildings remained intact, including public facilities such as the railway station. The restoration process took approximately two years and the city's population, which had dwindled to about eighty thousand after the bombing, doubled in a short time.

Until March 1946 the ruins were cleared, and the buildings that were damaged but still standing underwent controlled demolition. Already by 1947 most of the streets and the shops were restored, and the survivors began to repopulate even the heart of ground zero. The fact that water and sanitation infrastructures were not affected also assisted the restoration process. Photographer Shunkichi Kikuchi impressively documented the reconstruction process of the city and created panoramas of its restoration two years after the bombing.

The restoration of Nagasaki was slower due to financial difficulties and did not start until 1946. The city changed dramatically following the explosion and new buildings were constructed, including civilian factories that replaced the military industrial buildings that were destroyed. Eventually, by the mid-1950s the two cities returned to the same size they were in August 1945.

What about radiation? Surprisingly, radiation damage in Hiroshima and Nagasaki were only short-term, unlike the more recent nuclear reactor disasters that took place in Chernobyl, Ukraine and Fukushima, Japan.

What could be the possible reasons for this? First, the bombs were exploded in the air to achieve maximum damage due to huge shock waves, so the products of the explosion were mainly pushed up into the atomic mushroom cloud. Second, the amount of radioactive material loaded onto the bombs was relatively small - seventy kilograms of uranium on the "Little Boy" and seven kilograms of plutonium on the "Fat Man". By comparison, nuclear reactors contain several tons of radioactive material.

In addition, the products of a nuclear detonation are not particularly radioactive and don’t contain harmful isotopes like cesium-137, which is still polluting Fukushima and Chernobyl in great quantities. Finally, nuclear bombs are a one-time source of radiation, while the melting reactors continue to release large amounts of radiation even today, years after the disaster. Therefore, although we cannot compare the loss of life and property during disasters themselves, Hiroshima and Nagasaki were easy to rehabilitate and rebuild, while the Chernobyl and Fukushima areas will remain abandoned and dangerous to live in for many years to come.