[Dmitri wakes Ulana up at her lab, 7 hours after the explosion]
DDmitri
You work too hard.
Ulana Khomyuk
Where is everyone?
DDmitri
Oh, they refused to come in.
Ulana
Why?
Ulana
Why did you come in?
DDmitri
I work too hard. It's boiling in here. [opens a window. A radiation alarm goes off. Dmitri immediately closes the window and then checks the alarm's reading.] Eight millirontgen. Leak?
Ulana
No, it would've gone off before. It's coming from outside.
[Ulana grabs a swab, opens a window, gathers a sample of dust from the window's outside, then closes the window and takes the swab sample to a machine to get a reading. Returns with the reading]
Ulana
Iodine-131. It's not military, it's uranium decay: U-235.
DDmitri
Reactor fuel? [Ulana goes to a phone] Ignalina, maybe? 240 km away?
Ulana
[calls the Ignalina power station] Yes, this is Ulana Khomyuk, with the Institute of Nuclear En...looking for...[listens to the person on the phone] Alright, stay calm- [gets interrupted by the other person on the line before getting hung up on] They're at 4. It's not them. Who's the next closest?
DDmitri
Chernobyl, but that's not possible. They're 400 km away.
Ulana
Well, then that's too far for 8 millirontgen. They'd have to be split open. Maybe they know something. [Calls Chernobyl, and takes a pill, passing the bottle to Dmitri] Iodine.
DDmitri
Could it be a waste dump?
Ulana
We'd be seeing other isotopes.
DDmitri
Nuclear test? Uh, a new kind of bomb?
Ulana
We'd have heard. That's what half of our people work on here.
DDmitri
Something with the space program, like a satellite, or...
Ulana
[looks up] No one's answering the phone.
[The Kremlin, Moscow: Legasov and Ulana Khomyuk explain the consequences of a nuclear meltdown with full water tanks]
Ulana Khomyuk
When the lava enters these tanks, it will instantly superheat and vaporize approximately 7,000 cubic meters of water, causing a significant thermal explosion.
GGorbachev
How significant?
Khomyuk
We estimate between two and four megatons. Everything within a thirty-kilometer radius will be completely destroyed, including the three remaining reactors at Chernobyl. The entirety of the radioactive material in all of the cores will be ejected at force and dispersed by a massive shock wave, which will extend approximately two hundred kilometers and likely be fatal to the entire population of Kiev, as well as a portion of Minsk. The release of radiation will be severe, and will impact all of Soviet Ukraine, Latvia, Lithuania, Byelorussia, as well as Poland, Czechoslovakia, Hungary, Romania, and most of East Germany.
GGorbachev
What do you mean, "impact"?
For much of the area, a nearly permanent disruption of the food and water supply, a steep increase in the rates of cancer and birth defects. I don't know how many deaths there will be, but many. For Byelorussia and the Ukraine, "impact" means completely uninhabitable for a minimum of one hundred years.
GGorbachev
[visibly shaken] There are more than fifty million people living in Byelorussia and Ukraine.
GGorbachev
And how long before this happens?
Approximately 48 to 72 hours. But we may have a solution. We can pump the water from the tanks. Unfortunately, the tanks are sealed shut by a sluice gate, and the gate can only be opened manually from within the duct system itself. So we need to find three plant workers who know the facility well enough to enter the basement here, find their way through all these duct ways, get to the sluice gate valve here, and give us the access we need to pump out the tanks. Of course, we will need your permission.
GGorbachev
My permission for what?
Um, the water in these tanks... the level of radioactive contamination --
Khomyuk
They'll likely be dead in a week.
We're asking for your permission to... kill three men.
[Tense silence.]
GGorbachev
Well, Comrade Legasov... all victories inevitably come at a cost.
Khomyuk
They didn't hurt me. They let a pregnant woman in with -- oh, it doesn't matter. They were stupid. I was stupid. Dyatlov won't talk to me. Akimov, yes, Toptunov, yes, but... Valery, Akimov... his face was gone.
Khomyuk
Is that a choice I even have?
Do you think the fuel will actually melt through the concrete pad?
Khomyuk
I don't know. A forty-percent chance, maybe.
I said fifty. [chuckles] Either way, the numbers mean the same thing: "Maybe". Maybe the core will melt through to the groundwater. Maybe the miners I've told to dig under the reactor will save millions of lives. Maybe I'm killing them for nothing. I don't want to do this anymore. I want to stop. But I can't. I don't think you have a choice any more than I do. I think, despite the stupidity, the lies, even this, you are compelled. The problem has been assigned, and you will stop at nothing until you find an answer. Because that is who you are.
Khomyuk
A lunatic, then.