At 1:23:40 AM, the reactor was in a deeply unstable state. To raise power from 30 MW, the operators had pulled almost all of the 211 control rods out of the core. Only 6 to 8 rods remained inserted—far below the safety minimum of 30. Every rule in the Soviet nuclear handbook had been broken.

Secondly, the International Nuclear Event Scale (INES) rates disasters from 1 to 7. Chernobyl was the first event in history to be rated a 7—a figure that dwarfs the "10" but highlights the magnitude. However, in the specific context of the documentary’s focus on technical breakdown, the power spike just before the explosion was roughly the normal operational power level. This massive surge is what vaporized the cooling water and blew the reactor apart.

By dawn, the glowing cloud of cesium-137, iodine-131, and strontium-90 was drifting westward over Europe. In the control room, Dyatlov, Toptunov, and Chief Engineer Nikolai Fomin were already suffering acute radiation sickness. They vomited. Their skin turned brown. They refused to believe that a Soviet reactor could explode.

The episode begins on , documenting the final hours of normalcy in the model Soviet city. Viewers follow figures like chief architect Maria Protsenko and young nuclear engineer Oleksiy Breus as they prepare for May Day celebrations, unaware of the impending crisis.

💡 The "Utopia" of Pripyat ended in less than 60 seconds of mechanical failure.

The RBMK’s control rods had a design flaw of horrific proportion. Each rod had a graphite tip (which accelerates fission) on the end, followed by a neutron-absorbing boron section. When Toptunov pressed AZ-5, the rods began descending. For the first 4–5 seconds, the graphite tips displaced the cooling water at the bottom of the core, replacing it with a material that increased neutron speed.

(e.g., the role of Valery Legasov, the evacuation of Pripyat, or the "Elephant's Foot")

: At midnight, a new shift led by Aleksandr Akimov and Leonid Toptunov took over under the direction of Chief Engineer Anatoly Dyatlov , despite having no prior knowledge of the test.

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In a cruel twist of irony that defines the Chernobyl story, the "safety" button was the trigger for the destruction. The control rods, designed to dampen the nuclear reaction, possessed graphite tips. As they descended into the core, they momentarily displaced neutron-absorbing water with graphite, briefly increasing the reaction before slowing it.

Part Two of a Four-Part Series on the Rise and Cataclysmic Fall of the Soviet Nuclear Dream

On a stable reactor, this "positive scram" effect was negligible. On a poisoned, unstable reactor with few control rods inserted? It was a death sentence.