>>26120
> ionising radiation from the heightened levels of radiation would also ensure that sterile surfaces actually remain sterile
That's assuming the radiation is pervasive. It's not. It doesn't hang in the air like a pall the way Bethesda Fallout depicts it. It's just dust that gives off radiation, and with the core being capped, it's not really flowing out into the environment anymore. What did escape has largely dispersed on the wind, or was washed away by rain. You do end up with concentrated pockets of it that create hotspots, but for the most part the exclusionary zone is back down to normal background levels and has been for decades. They're fairly infrequent, so you can walk around without a Geiger counter and suffer no ill effects, even long term, because your exposure time is so brief. Most people could live there long term with no negative health effects, but it's safer for everybody to just cordon off the area.
Strontium-90 and Caesium-137 have half-lifes of about 30 years, so about half of it has already decayed and is gone. The Iodine-131 only had a half-life of 8 days, so it was pretty much gone within a month of the disaster. Most of the other radioactive materials released have half-lifes so long that they don't really pose much of a danger.