he was dying anyway, but he wanted to expose the rot of the USSR to the world. He did just that and we all see him as the hero he really was. Its just a shame he never lived to know how his bravery impacted the world. Its also widely believed that the failure at Chernobyl is what ultimately caused the disillusion of the USSR

Reactor#4 was put into minimal power 200 MW by 1:00 and was ready for electrical " Rundown of turbine " test. But all initial steps were a failure. At 1:03 additional main circulation pump was started. It added 7,000 m3/h of water flow across reactor to initial 42,000 m3/h. It affected instantly parameters of boiling water on outlet from reactor and added negative reactivity. to reactor. Nominal pressure of boiling water on outlet should be 70 bar with temperature 284 C and content of steam 14-19% on nominal power of 3200 MW heating and 1000 MW electrical. . Inlet temperature should be 270 C with pressure 79 bar. On minimal power of 200 MW ( heating) parameters of water supposed to be the same to keep water reactivity across reactor constant and output power supposed to be regulated by control rods. Water supply to reactor was not reduced back to nominal and instead control rods were taking out to compensate less reactivity of boiling water which had less voids. It was first mistake. On 1:06 second additional pump was started. Again, total water flow was not reduced and more control rods were taking out. It was second mistake. Total water supply to reactor was increased to 56,000 m3/h. As result, water level in separators dropped, because main circulating pumps were taking more water from them. To prevent emergency shutdown of reactor on low water level in separators this safety was deactivated. It was third mistake. Feeding water to separators from turbine condensers was 1.200 m3/h with temperature 165 C. Water temperature on inlet to reactor dropped to 265 C, because less steam was produced by reactor and temperature on separators dropped. Temperature control on separators was deactivated. It was forth mistake. On 1:09 water feeding to separators was reduced to 180 m3/h on northern side and 90m3/h on southern side to increase water temperature on inlet to reactor to keep it running on minimal 200 MW of heating power. It was fifth mistake. Water temperature on inlet to reactor increased to 281C on northern side and to 283 C on southern side. Outlet temperature was 284 C. Temperature gradient across reactor was 1-3 C instead of 14C nominal. Water started to boil once it entered the active zone. On outlet content of steam reached 100% instead of allowed maximum 19% in a few minutes. Reactivity of boiling water sharply increased with extra voids in it all the 7 meters-long way from bottom to the top. But power of reactor stabilized on 200 MW with almost all control rods taken out and positive reactivity maintained by overheated boiling water. At 1:23:04 " Rundown of turbine " test started. Steam supply to turbine TG-8 was closed, bypassing it directly to condenser. At the same time 4 main circulating pumps were switched to generator TG-8.Two additional circulating pumps, that were put into operation on 1:03 and 1:06, were left on back up electrical supply from the grid. At that time reactor supposed to be shut down by switch AZ-5, but it was not done. Dyatlov decided to repeat test twice or three times if it would fail, for some reason test must be completed by any means before reactor will be put out of operation for weeks. Diesel generators started , but with 6 sec delay for some reason. Water supply to reactor started to drop, because 4 pumps were running on electrical supply from generator TG-8 with turbine running on inertia forces. It overheated reactor even more. At 1:23:39 Toptunov pressed switch AZ-5 for one second before diesel generators went into full power that required 40-45 sec. All control rods went down from the top, short rods that should to go from the bottom at that time were not implemented in reactor, despite of recommendations since 1975. Control rods passed 0.4 meters down for one second, displacing water under it. Lower part of control rod was made of graphite , that was left in active zone as moderator, while boron part ( capturer of neutrons) was in the top position out of active zone. Active zone was 7 meters long, graphite part of control rod was shorter, it was 4.5 meters long and was hanging in the middle, leaving column of water 1.25 meters above and 1.25 meters below. On the way down graphite end of control rod displaced water. Water has less reactivity, even when is full with voids, than graphite, so positive reactivity in the bottom 1.25 meters zone increased further. On 1:23:41 Toptunov pressed AZ-5 second time. All control rods moved further down displacing all water in the bottom of active zone in the next 2 seconds. Positive reactivity of reactor reached maximum level on the bottom zone, especially on the southern side. On 1:23:45 US satellite detected flash of green light over Chernobyl Power Plant. Explosion breached 2-meters thick massive concrete protective plate ( scheme " OR " ) on the bottom on south-east corner, destroyed all inlet water communications further down and this plate fell 4 meters down with support concrete base C in the shape of cross. Top plate " E " ( weight of around 1000 T) was blown up. hit crane on 12 meters height and fell down to reactor place. Top and bottom plates were welded to 160 mm fuel tube channels, these connections were torn off along with inlet and outlet water piping. Debris reached altitude of 3 km. On 1:23:47 sec there was a second explosion, about 10 times more powerful. Analysis of air probes. taken thousands km away, found presence of fission products of isotopes of Uranium, Neptunium and Plutonium. Rate of Xenon-135/ isomer m Xenon-135 ( exited state) was found to be 22. During normal critical reaction in reactor this rate is maintained at 35, after nuclear explosion of A-bombs this rate is about 11. Rate proved that reaction in reactor during first explosion was over-critical in supposedly 3-30 fuel tube channels of over 1,600 total. Estimated power in TNT equivalent was about 10 T. Second explosion was Hydrogen/ Air mixture volume explosion with estimated power of 100 T of TNT. During 2 explosions about 95% of nuclear fuel was dispersed in the atmosphere of Earth.

I finally saw the whole miniseries two days ago. I was 10 years old when this happened. So tragic.

I don't understand why people choose to use robotic narrators; but I do wish folks who employ robotic narrators would make them pronounce names correctly.

Actually in the actual show they say fuel caps were 350 kg each. Great review though, keep it up.

Legasov as other people have said, was the ultimate hero in all of this tragedy. He stood alone in front of the court and spoke the truth

The title of this clip rather misleading. You are talking about the tv-show, not the real event. The scientific reasons for the accident are simplified in the HBO series. Legasov and Cherbina were not present duting the real trial.

Great stuff

It was pretty cool how the reactor blew. It's adventures like this that make life fun and interesting. It was a good learning experience.

Pro tip: Background music is too DAMN LOUD AND DISTRACTING!!! FFS!

Well explained!

1:33 Khomyuk is a fictional character. She never existed. The series' ending credits make this clear.

I "unliked" this video for a TTS narration.

It's a nice video, but it would really be nice if you wouldn't butcher the pronunciation of the names of the characters. Even in English dubbing of the series, they never pronounced "Dyatlov" as "[Die] - ut - loff", as you did. That said, thank you for making this.

...And that's why capitalism, despite all their errors... Still the onlys system you can try to prosper...

Soviet Reactors don't explode :)

Its like repeating word for word movie. Just play the movie.

The ai narrator is insufferable.

In Kiev, as god intended.

huhh???? chernobyl is cheap reactor???

All these AI generated channels these days.

soviet corruption --> soviet disaster (chernobyl) western corruption --> western disaster (fukushima) the story is the same, only the actors change. never forget that.

Stop with the AI voice. Just narrate.

69K Views.

Wow, at the reactor had some democrats in control of which always destroys everything they touch 🥺