Nuclear Power/Hypothetical : Nuclear Reactor Meltdown
I am considering a society collapse/ future dystopian book idea and one aspect of the idea is what would happen to a nuclear reactor if abandoned. I realize that it is a complicated question and there is no short answer but a general idea of what would happen would be appreciated.
If there was no one to shut down or maintain the reactor how long would it take to have a meltdown and how far would the radiation or other consequences reach; how far around the reactor would be uninhabitable and how far can the radiation carry on the wind.
Thank you for taking the time to read my question,
In general, if the situation warranted abandoning a reactor, it would be SCRAMmed first (emergency shutdown). It would also likely be poisoned, meaning that neutron-absorbent materials would be injected into the cooling water, further stabilizing the reactor below its critical working parameters. These things take seconds to do. Reactor meltdowns happen when a massive and systemic failure of redundant safety features happens (3 Mile Island), a design/operator error (Chernobyl), or a massive natural disaster (Fukushima), no one just walks away from a running nuclear plant.
That said, it is plausible that everyone at a nuclear power plant could be killed in a chemical weapon attack, or something similar to that. In such a case, automated safety features should still shut down the reactor, but failures of systems not in regular use have happened before. In theory, with some kind of worst-case scenario with a containment breach and absolutely no attempt at containment, the material could remain physically hot for months and seriously (you use the word uninhabitable) contaminate areas downwind for dozens or even perhaps a couple of hundred miles for years to come. Chernobyl was an absolutely huge disaster, see here for information on their exclusion zone. https://en.wikipedia.org/wiki/Chernobyl_Exclusion_Zone In a situation with a complete lack of control, one could expect an "uninhabitable" zone several times the size of what you see on the map there in the permanent exclusion zone that would stay a bad place to live for decades. That said, wildlife in the region appears to be making a major comeback due to the lack of hunting, so the definition of "uninhabitable" might be somewhat nebulous.