I wasn't surprised by finding that out in the podcast. She felt really out of place in the episode, and seemed to know too much based in limited info. Very much came across as a plot element more than a character. I like the actress though, so it wasn't a big issue.
You are talking about Ulana, the Belarussian scientist? From what I can wiki, it seems the full tanks part was true, but was the potential size of the explosion exaggerated for drama?
She claims 2-4 megatons, 30km blast radius, explosion of the remaining 3 reactors, causing a secondary blast radius of 200km, killing everyone in kiev and some of minsk, radiation impacting ukraine, latvia, lithuania, belarussia, poland, czech, hungary, romania, east germany...ruin for 100 years, 60 million people...
is this exaggerated for drama? If not, I gotta say that, even though they might be blamed for the problem, the USSR certainly saved the day, too.