LEGASOV
The time is 38 past midnight. The reactor is nearly shut down, but the operators of Reactor 4 are locked on a path that leads directly to disaster. There is no way to turn back. They do not yet know it, but the die is cast.
Legasov picks up a BLUE PLACARD. A second "Xenon Poisoning" (B5) card. He adds it to the board.
LEGASOV
At 30 megawatts, xenon is still being created, but none of it is burning away. The reactor is drowning in poison. To make matters worse—
—he REMOVES the bottom two red placards, "Positive Void Coefficent" (R2) and "Nuclear Fission" (R3).
LEGASOV
--the reactor isn't hot enough to produce sufficient steam.
THE BOARD: One red placard, five large blue ones.
LEGASOV
The only way to safely raise power from this state is to do it very, very slowly over the course of 24 hours. But Dyatlov wants it done now. Akimov and Toptunov have only one course of action. They begin pulling control rods out. Dozens at a time. Halfway out, three quarters of the way out, and the power still does not budge. So they begin to pull them all the way out. (beat)
There were 211 control rods in Reactor 4. Akimov and Toptunov completely withdrew 205.
Legasov REMOVES the first blue placard - "Control Rods" (B1).
LEGASOV
Remember... control rods are the brakes of this car. Of 211 rods, only six now remain in the reactor. As for the fuel--
Legasov REMOVES another blue placard - "Negative Temperature Coefficient" (B3).
LEGASOV
—it's gone cold, so the negative temperature coefficient is no longer weighing down the reactivity. (MORE)
LEGASOV (cont'd)
(beat)
And even still-- the xenon poisoning is so strong, the best they can do is raise the power to 200 megawatts.
Turns back to the room once more.
LEGASOV
The control rods are out. The emergency system is disconnected. The reactor is now a grenade without a pin, and the only thing keeping it in check is water... and xenon. It is 1 in the morning. The test is minutes away.
538 INT. CONTROL ROOM - REACTOR #4 - NIGHT 538
AKIMOV - punches buttons. Flips some switches. Constantly moving his eyes back and forth between the console and the LED POWER OUTPUT display, which holds at 200.
He slumps. Turns back to Dyatlov, who sits at the desk in the center of the room, casually smoking.
AKIMOV
I'm sorry, but this is all we can get. 200 megawatts. We've pulled almost everything out.
Dyatlov exhales slowly. Thinks. Then:
DYATLOV
Well, if that's what we have, that's what we have.
AKIMOV
But the test requires 700--
DYATLOV (ignores Akimov) Stolyarchuk, let's get ready. Switch on pump four.
AKIMOV Wait a second--
DYATLOV
Stolyarchuk! Stolyarchuk hesitates.
AKIMOV
We barely have any steam as it is. The turbine is going too slow for the test to deliver valid--
DYATLOV
It's enough.
AKIMOV
—and if we add more water, there will be even less steam—
DYATLOV
I SAID IT'S ENOUGH. I know what I'm doing. Stolyarchuk.
Stolyarchuk relents, and hits switches while Kirschenbaum watches— utterly confused by this course of action.
STOLYARCHUK Main Pump 4 is connected. We should warn Khodemchuk... the pipes are going to be jumping.
DYATLOV
Never mind him. Kirschenbaum--
But he's cut off by: AN ALARM - bleating from the panel. Dyatlov puts his hands up. What now?
STOLYARCHUK The steam in the separator drum is too low— five atmospheres...
DYATLOV
All right, let's all help him. Get it up as best you can.
Stolyarchuk mutters to himself.
STOLYARCHUK We should stop.
DYATLOV (yells)
And turn that fucking thing off!
Akimov moves to another panel. Flips some override switches. The alarm CEASES. Dyatlov checks the display. Still 200. Now he looks at the clock. 1:07.
DYATLOV You have fifteen minutes.
Akimov, Toptunov, Kirschenbaum and Stolyarchuk work on the panels, trying to get the steam back in balance.
LEGASOV (V.O.) Fifteen minutes.
539 INT. TRIAL ROOM - NOW 539
Legasov stands by the board.
LEGASOV
They might as well have had fifteen days. The problem they were facing was not solvable. The power was too low. The water was too high. The test was already ruined. The results would have been useless. But Dyatlov didn't care. All he wanted to do was report a completed test. (beat)
1:22. Less than two minutes remain.
540 INT. REACTOR #4 FACILITY - VARIOUS - 1:22 AM 540
—OFFICE - YUVCHENKO sits at his desk flipping through a technical manual.
LEGASOV (V.O.) Yuvchenko, mechanical engineer, is in his office.
—REACTOR HALL OBSERVATION ROOM - PEREVOZCHENKO looks out over the HUGE REACTOR LID, 15m in diameter. The lid is made up of 2,000 cubes of individual steel-capped channels.
LEGASOV (V.O.) Perevozchenko, reactor section foreman, is in the refueling hall, high above the 1,000 ton steel reactor cover.
—ROOM 604 - SHASHENOK is inspecting equipment. Taking notes on his clipboard.
LEGASOV (V.O.) Shashenok, automatic systems adjuster, is in room 604.
—THE PUMP ROOM - where VIKTOR (Degtaryenko) stands by a rats' nest of pipes and gauges. They're SHUDDERING.
LEGASOV (V.O.) Degtaryenko...
Viktor looks across the room at:
LEGASOV (V.O.) ...and Khodemchuk, circulation operators, are in the pump room.
Khodemchuk gives Viktor a baffled look. What is this?
LEGASOV (V.O.) None of them have been told about the test. None of them know what is about to happen.
541 INT. CONTROL ROOM - REACTOR #4 - 1:22:30 541
Toptunov stands by a large DOT-MATRIX PRINTER as it slowly ejects a sheet of data.
LEGASOV (V.O.) 1:22 and 30 seconds. Toptunov sees a report from the reactor's SKALA computer system. Based on the absence of sufficient control rods, the computer is recommending the reactor be shut down.
Toptunov hands the printout to Akimov, who reads it, frets, then hands it to Dyatlov. Dyatlov doesn't take it. Just looks at it. Barely.
DYATLOV
Of course it's saying that. It doesn't know we're running a test.
(oddly cheerful) All right boys. Another few minutes, and it will all be over. Kirschenbaum, when you're ready?
Kirschenbaum turns back to his panel. Deep breath. Akimov and Toptunov walk back to their panels. Toptunov looks over at Akimov. Akimov doesn't look back. Just:
AKIMOV We did everything right.
Kirschenbaum reaches for a switch. Then:
KIRSCHENBAUM Oscillograph on. Closing Number 8 throttle valve.
STOLYARCHUK Generator rotor beginning rundown.
542 INT. TRIAL ROOM - NOW 542
Legasov is staring at the room. It's dead quiet.
LEGASOV
1:23 and four seconds. With every decision, they have pulled this reactor back like a slingshot... further than anyone has ever pulled. (beat)
The test begins. The pumps are shut down.
(opens his fist) And they let go.
Legasov moves to the board. On the right, the single red "Nuclear Fission" card (R1). On the left, blue "Water" (B2) and "Xenon Poisoning" (B4, B5). He removes the "Water" (B2) placard.
LEGASOV
The pumps stop moving water through the reactor. The uranium fuel is now unchecked by fresh coolant. Unchecked by control rods. The balance immediately swings in the opposite direction. In less than a second, reactivity increases.
543 INT. CONTROL ROOM - REACTOR #4 - 1:23:05 543