system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: When a nuclear bomb detonates, what stops the self-sustaining chain reaction of fission events? Why isn't the blast infinite?
gpt
The explosion blasts the nuclear material apart which stops the fission reaction. This typically happens after a few percent of the material has fissioned. Even if you were to keep the material together, there's only a finite amount of nuclear material in the bomb that can undergo fission, so it would still stop once enough of the nuclear material had fissioned that a chain reaction could no longer be supported.