The sarcophagus is a very complex engineering system, consisting of many rooms, walls and ceilings. Interestingly, partly the sarcophagus is the very fourth power unit, which did not "explode" at all, but simply received significant damage to the walls and roof; the supporting beams of the sarcophagus partially lie on the walls of the former nuclear power unit.
According to the author: I read forums about Chernobyl on the Internet and see that many people who are interested in the topic of the Chernobyl accident and the Zone think that the Chernobyl sarcophagus is just such an empty box that was put on the ground in place of the exploded fourth power unit of the nuclear power plant. This, to put it mildly, is not entirely true.
There are many rooms and rooms under the sarcophagus. Some of them were created after the accident to service the sarcophagus and carry out all kinds of measurements and research - as a rule, they are separated from the destroyed reactor hall by thick concrete walls through which radiation does not penetrate. Another part of the rooms is the former premises of the Fourth Power Unit. It was possible to penetrate some of them only in the early nineties, I came across descriptions of these rooms - "rickety ceilings, traces of soot on the walls, furniture moved from the explosion, a thick layer of dust on all objects, radiation background about 2 roentgens per hour." And in the third rooms (especially in those rooms that are located under the reactor hall) it has not been possible to get to this day, no one knows what is happening there now.
The photo shows the location of the sarcophagus relative to the nuclear power plant itself. This building in the center of the picture is the nuclear power plant itself. The long room with a white wall is the turbine hall; in it, hot steam coming from the reactor halls rotates the turbines and generates electricity. To the left of the turbine hall are the reactor halls.
As you can see, the sarcophagus covers the entire reactor hall of Unit 4 and part of the roof of the turbine hall. The title photo in the post shows the premises of the turbine hall of Unit 4, photo taken in 1989. At that time, these premises were already abandoned and were under the sarcophagus.
This picture clearly shows the destruction of the nuclear power plant from the explosion and the subsequent fire - the roof of the reactor hall was completely destroyed, and the roof of the turbine hall was punctured by debris. A little closer from the vent of the reactor to the point of shooting, you can see that there are many rooms left in the Fourth power unit, only slightly affected by the explosion.
Promotional video:
The erection of the sarcophagus. Here you can also see the windows of some rooms or corridors, some of which were knocked out by the explosion, and some of them were completely intact. Now all this is hidden by the walls of the sarcophagus. I wonder if there are NPP employees in these rooms? I have not seen pictures from there anywhere.
Another shot from the construction site. The collapsed wall on the right exposed the floors and ceilings - these rooms were too close to the point of explosion and fire, and it is clearly noticeable that nothing was left inside. But the rooms on the left are in a fairly good condition, nothing even burned there.
And here is a sectional plan of the sarcophagus. It is very clearly visible how many different rooms and corridors are inside.
As far as I know, it is now possible to walk under the roof of the sarcophagus itself from the premises of the Third Power Unit, which operated normally until 2000. This is how the room of the block control room of Unit 4 looks like - it was from here that the operators controlled the reactor, photo of 1989.
And this is how the control panel looks now. As you can see, all the equipment was removed, and the plastic film was also removed - apparently, the radiation levels fell to acceptable levels.
All this is now also hidden behind the walls of the sarcophagus.
Closer to the destroyed reactor hall, the rooms become more and more neglected and scary. These, most likely, are no longer the premises of the former 4th power unit, but the post-accident structures of the sarcophagus.
And the reactor hall itself looks something like this. The photo shows the concrete reactor lid, which was thrown by an explosion in 1986, and it fell back in this position. The tubes protruding from the lid are the so-called fuel assemblies, and the cone-shaped elements on top are sensors-monitors to monitor radiation levels.
If someday the level of radiation in the rooms of the former Unit 4 drops to acceptable levels, you will definitely need to visit them:)