In the wake of the initial blast, nuclear physicists feared a second explosion caused by melting corium coming into contact with groundwater.
In episode two, Khomyuk informs the USSR that a follow-up explosion would carry a force of between 2 and 4 megatons, which would wipe out "the entire population of Kiev and a portion of Minsk." The release of radiation, she adds, would "impact all of Soviet Ukraine, Latvia, Lithuania, Belarusia, Poland, Czechoslovakia, Hungry, Romania, and most of East Germany."
Haverkamp said there are too many hypotheticals considered in this scenario.
"They're not saving the world," he said. "That situation might play out if all of the melting corium hit groundwater," but when corium starts melting, it melts "in a very uneven way."
The claim that a second explosion would carry a force of up to 4 megatons, he said, is "an exaggeration."