As far as I know, the second explosion, which is really dangerous, occurs right after the first explosion, as soon as the core meets the air, so the time interval between them is a maximum of five seconds.
The nature of the second explosion is still debated though. But as I understand it.
01:23:39-40 AZ-5 is pressed
01:23:41 Massive neutron spike, runaway starts
A lot of the following events are happening in parallel
01:23:44 Reactor power surges way beyond maximum design spec
01:23:44 Fuel superheated and fragments, cladding fails and the fuel enters into the coolant. Massive increase in steam generation, over pressure recorded.
01:23:44 A number of channels has already ruptured, increase in pressure in reactor space recorded.
01:23:44-45 Upper biological shield dislodges, tears off the zirconium channel to stainless steel pipe welding's.
01:23:45 Rupture of significant number of channels, massive amount of coolant flashes to steam
01:23:45 Backflow valves close due to over pressure
01:23:45 No more coolant enters the core, reactivity surges again, channels are shattered, coolant and fuel dumped on to the graphite stack
01:23:46 Reactor lid is ejected, severing the remaining channel connections (First explosion)
01:23:47 Backflow valve opens as reactor pressure is lost due to the lid being ejected. Large increase in coolant flow recorded, likely the remaining water in the pump header all being dumped into the core
Not sure where you are getting the 1:23:44 numbers from, but the absolute most we can say is that the signs of physical destruction of the reactor space (not the building) were recorded in the interval 1:23:47-49.
Then there is a point of departure, regarding what you think the sequence of destruction was.
Can't say I have noticed any such trend in the sources. Although the data do suggest the reactor surging out of control by 4 seconds, and some kind of explosion by 8 seconds.
Soyuzchernobyl veterans attribute the first double explosion to 1.23.45, the second powerful one after 2.7 seconds. I have read many different analyses on these seismograms, but I consider this study to be the closest to reality, except for the time of the first explosion, because some researchers believe that some data has been adjusted (falsified) still at the investigation stage. However, this does not change the essence of the matter. Ветераны Союзчернобыля относят первый двойной взрыв к 1.23.45, второй мощный через 2,7 секунды. Читал много различных анализов по этим сейсмограммам, но это исследование считаю наиболее близким к реальности, кроме времени первого взрыва, потому что некоторые исследователи считают, что некоторые данные были скорректированы (сфальсифицированны) ещё на этапе следствия. Правда сути дела это не меняет. http://www.souzchernobyl.org/files/History/app_analysis.pdf
Oxygen coming into contact with hot stuff isn't going to cause a destructive explosion. That's an HBO line. Either hydrogen was produced by water coming into contact with hot zirconium, or the explosion had some other cause.
For some reason, many people say that fuel assemblies do not explode, despite the fact that the Americans themselves blew up experimental reactors, and in the USSR in 1985, in Chazhma Bay, the reactor flew away with the lid and all its insides far into the sky after a self-sustaining chain reaction.. Почему-то многие рассказывают, что тепловыделяющие сборки не взрываются, не смотря на то, что американцы сами взрывали экспериментальные реакторы, да и в СССР в 1985 году в бухте Чажма реактор улетел вместе с крышкой и всеми его внутренностями далеко в небеса после возникновения самоподдерживающейся цепной реакции..
What does "oxygen coming into contact with hot stuff" have to do with it? A study of the hot particles of the western trace showed that at the time of their formation (that is, at the time of the second explosion), the fuel was in contact only with the zirconium shell and steel adapters in the absence of not only oxygen from the air, but even water vapor. Причём тут «контакт кислорода с горячим предметом»? Исследование горячих частиц западного следа показали, что в момент их образования (то есть в момент второго взрыва) топливо контактировало только с циркониевой оболочкой и стальными переходниками в отсутствие не только кислорода из воздуха, но даже паров воды.
Pro civil nuclear lobbyists don't like to admit that uncontrolled criticality excursions in reactors can cause explosions.
But the laws of physics are not amenable to negotiation and we have several small reactor explosions as evidence. Those include the 1985 event with K-431 and the SL-1 reactor in the USA.
However, the yields of such accidental explosions will be orders of magnitude below those of carefully designed nuclear weapons.
I think NUREG-1250 provides some good insights into the potential fuel and clad failure modes at Chernobyl. Hot fuel fragments mixing with water would then generate a lot of steam.
Steam would also have been the combustion product of hydrogen and oxygen, if any hydrogen explosions did occur.
In the study of criticality accidents, it is standard practice to evaluate the magnitude of the energy release. The feedback mechanisms that eventually terminate the fission chain reaction are also studied. For Chernobyl my guess is that the ejection of fuel and moderator from the core would be the most obvious termination mechanism.
Sorry man I'm not sure how I missed the notification for this. Those holes are big enough to reach your whole arm through. The centered group of them are where all the fuel and control channel tubes penetrate. The two outer rings are for the reflector region cooling, and shield tank circulation/cooling. The reflector being just a ring of graphite blocks surrounding the "active zone" to route some neutrons back inward.
These are the side cylinders of the reactor filled with water and sand, and the upper and lower reactor lids filled with serpentinite. Designed to protect plant personnel from ionizing radiation from the reactor. Это боковые цилиндры реактора, заполненные водой и песком, и верхняя и нижняя крышка реактора, заполненная серпентинитом. Предназначены для защиты персонала станции от ионизирующих излучений реактора.
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u/New_Car_2304 3d ago
As far as I know, the second explosion, which is really dangerous, occurs right after the first explosion, as soon as the core meets the air, so the time interval between them is a maximum of five seconds.