system
Given the following post, respond as if you're commenting on Reddit:
human
Why did the radiation from Hiroshima not last as long as the chernobyl disaster?

Was it the power of the explosion blowing the radiation away or was the bomb designed in such a way as to avoid long lasting fallout?
gpt
in chernobyl you have 180 tons of radioactive material in the core. A nuke contains 0.05 tons of radioactive material.

There are of course differences: a very violent explosion that absolutely vaporized the bomb and a violent explosion that desintegrated the core and vaporized some. One burst in the air, the other on the ground.

Hiroshima was much smaller and the material was much more dispersed. The main factor is just the vastly greater amount of material that you deal with in a reactor.