[TheThirdRuffian]

“radiation from just about every nuclear reactor in the affected area going into meltdown”

I believe all (or at least most) reactors in the USA are of the sort that simply cease production if left unattended.

[Renderofveils]

I believe all (or at least most) reactors in the USA are of the sort that simply cease production if left unattended.

For most Boiling Water Reactors, SCRAM procedures will effectively shut them down (for the most part an automated process.) For PWRs, control rods drop into place assuming the power is cut, or the heat reaches a certain level. This assumes everything works as intended (and given that we're talking about a zombie apocalypse I'm willing to give a certain level of doubt as to things working as intended.)