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The well known 2019 show Chernobyl mentions an operator who happened to walk through the reactor hall of Unit 4 seconds before the reactor exploded. He allegedly saw this:

enter image description here

If this story seems implausible, it is supported by an earlier Discovery documentary, Zero Hour: Disaster at Chernobyl

The details are however, noticeably different. This alone rises some doubt about the authenticity of this story. The Zero Hour scene occurs earlier than the Chernobyl one.

And then, we have this paper written by a retired nuclear scientist, which refers to the story, but with an even earlier time. In the introduction it says:

The slower start is derived from a report by the reactor section foreman Valeriy Perevozchenko, who 3 min before the big explosions stood on an open platform some 15 m above the floor of the reactor hall. He then observed how the 350-kg caps atop the fuel channels jumped up and down, and he felt shock waves through the building structure. 2

The source that the author has listed does not provide any citation. And so we have 3 conflicting accounts of the same incident, none of them with evidence. Now I shall introduce the version of Grigoriy Medvedev's The Truth About Chernobyl/Chernobyl Notebook, the earliest account of this particular incident I know of. On page 73-74 he writes:

The time was now 1:23:40. For the 20 seconds remaining before the explosion, we shall leave the control room of No. 4 reactor unit at the Chernobyl nuclear power station.

At that precise moment, the foreman in charge of the reactor section on Akimov's shift, Valery Ivanovich Perevozchenko, entered the central hall, at level +50 (164 feet above the floor of the reactor building, and some 45 feet above the floor of the central hall), on the balcony near the fresh fuel transfer station, on his rounds. He looked at the loading machine, which was standing still near the far wall, and then at the door in the wall behind which Kurguz and Genrikh, the central hall operators, were in a small compartment. He then looked down at the floor of the central hall, checked the spent fuel storage pools, which were heavily loaded, and turned toward the reactor lid, known affectionately as the pyatachok, or "five-kopek piece."

Pyatacbok is the name given to the upper biological shield of the RBMK reactor, a circle 49 feet ( 1 5 m) in diameter, consisting of twothousand cubes. Each of them, weighing 770 pounds (350 kg), sits like a cap on top of a fuel channel containing a fuel bundle. The pyatachok is surrounded by a stainless-steel floor made up of insulating blocks covering the compartments of the steamwater pipelines from the reactor to the drum-separators.

Suddenly Perevozchenko shuddered. Strong and frequent shocks began, and the 770-pound (350-kg) cubes—known by the technical term "assembly eleven"—started to jump up and down on top of the channels, as if one thousand seven hundred people were tossing their hats in the air. The entire surface of the pyatachok came to life, rocking in a wild dance. The insulating panels around the reactor shook and became bent, indicating a mixture of detonating gases beneath them was already exploding.

That's pretty detailed. It's as if Perevozchenko himself sat down with Medvedev and told this story. Except: Valery Perevozchenko was a Chernobyl victim, not a survivor. ​

Keep in mind that all 4 of the sources I have mentioned present their claims as fact. Yet not only do their narratives differ, they also cannot bring up a single direct quote, authentic or otherwise, from a witness.

And in fact, Anatoly Dyatlov, the deputy chief engineer of Chernobyl Power Station, who was present in the control room at the time of the accident, flatly denied this. In chapter 9 of his memoirs, Chernobyl: How It Was he wrote, after quoting the above:

Well, the blocks (assembly 11) are only 50 kg, but that doesn’t matter.

G. Medvedev sets it up beautifully. I made the men jump up and throw their hats. Rich fantasy. Only technically it is unthinkable. He is talking out his ass again. G. Medvedev narrates that this is about hydrogen.

This won’t withstand the test of time.

At 01:23:40, power at 200 MW, stable parameters. There is no fantasy here - just what the control system registered. Nothing can happen.

At 01:23:43 there were alarms for excess power and decreasing reactor period. Still nothing can happen, since total power is only 520 MW. But here there are already ambiguities and we will address them for the beginning of this dance.

At 01:23:47 there was already an explosion. So you cannot make it from the balcony on the 50th mark through the central hall in four seconds in any extreme situation. There is no spiral staircase, the author confused the first line with the second.

Still in prison, when I read the story, I wrote several letters to the witnesses for clarification. Sasha Yuvchenko, a senior mechanical engineer (SME) for the reactor shop, on this topic wrote:

“From the beginning of the shift to practically the very time of the explosion, V.I. Perevozchenko and I were together. At first in the Unit 3 Control Room, then the Unit 3 MCP Room, then in my SME office. From there we were going to go to Khodemchuk in Unit 4 (to room 435). He was suddenly called to the Unit 4 Control Room for an urgent matter and left, telling wait there and not to go alone. After he left (1 to 2 minutes later) the first shock sounded, and then the explosion. So he could not have been able to make it to the hall and observe what G. Medvedev describes. He never mentioned anything about it.”

I also confirm: Perevozchenko arrived in the Unit 4 Control Room just before the start of the rundown.

No one heard such a story from Perevozchenko.

The IAEA report backs Dyatlov's objection that there was insufficient time. Alarms were only set off at 43 seconds, and at 49 seconds there was already alarm for burst fuel channel. So, are there any eyewitness accounts confirming that this story is true?

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    Wikipedia claims that Perevozchenko lived until June 13, so it's not as though there wouldn't have been time for him to make a report. Sep 18 '21 at 5:59
  • Check 16:45 of this lecture youtu.be/Ijst4g5KFN0 (pause and read the screen) -- he is displaying a page where what I can make out is from the URL is "...oedc...org" and it refers to the blocks jumping. This report is probably from here oecd-nea.org/jcms/j_6/home -- but I don't have time to track down the specific authoritative source.
    – Dave
    Sep 20 '21 at 13:58
  • 1
    Actually scratch that -- the timeline is from here chernobylgallery.com/chernobyl-disaster/timeline -- not really authoritative
    – Dave
    Sep 20 '21 at 14:08
  • 3
    The HBO miniseries is a historical drama -- observing differences in detail between this type of entertainment and other accounts is not surprising.
    – Dave
    Sep 20 '21 at 14:16
  • Why the downvote?
    – Abdullah
    Nov 28 '21 at 17:36

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