It greatly exaggerated the potential enviro damage.
The reactor damage descriptions and sequence in the last episode were much better than i expected.
Some people have said it was exaggerated and others said it was pretty spot on. Sure the redness from exposure (instantly) probably was more dramatic then it was, but it was made for TV and had to speed it up for the timeline.
The reactor damage and sequence was pretty much spot on by the reports of events at the time.
I have to say, most of these “base on real events” tv series, usually are awful and 98% of it was made up to make it interesting for TV, I would have to say it was about 90% true, with some exceptions including Ulan’s (The lady Scientist) character was made up, and of course some the dialogue was made up or made more interesting.