How a man with one of the most dangerous jobs in the world lives — descending beneath the ChNPP reactor

Anatoliy Doroshenko. Photo: old.nas.gov.ua

For 12 years, he has been descending beneath the ruined 4th power unit of the Chernobyl NPP in a special protective suit.

Doroshenko works at the Institute for Safety Problems of Nuclear Power Plants. Part of his duties involves working in a room that is likely one of the most dangerous in the world.

The 'Heart' of Chernobyl

The reactor of the 4th power unit was destroyed after the explosion on April 26, 1986.

The reactor support was located at a height of about 15 m above the ground. Beneath it are technological rooms — rooms and corridors that survived the explosion.

That is where the equipment that scientists check is located. Anatoliy and his colleagues go there regularly. Some monthly, some more often.

The scientist's job is to check the equipment, collect data, and monitor the parameters of the nuclear fuel's state.

Researchers get very close to the destroyed reactor — within 10-12 meters.

Labyrinth of Danger

The labyrinth beneath it is called one of the most dangerous places in the world. Everything there is contaminated with radiation — the floor, equipment, walls, air.

Павялічыць

Some of Anatoliy Doroshenko's colleagues visit the 'shelter' 10-12 times a month. Photo: hero's archive

In some rooms, the radiation level is so high that a scientist can only stay there for a maximum of 4 minutes — to complete all tasks and leave quickly. In others, the radiation level is extreme, and it's generally dangerous to stop there.

“Radiation is uneven. There are places with very high doses — it's better not to even stop there. You pass that place and move on. You need to work where there are cleaner zones. Here, all scientists know where we can work and where we cannot,” the scientist assures.

They compile contamination maps that show where the radioactivity level is highest. These need to be constantly updated.

The scientist's work is critically important, as he must ensure that conditions inside the reactor remain stable after the Chernobyl disaster.

Doroshenko says his work is frightening, but he uses fear as an ally.

“Fear helps you keep yourself in check. It helps you accurately perform actions that will ensure you receive a lower dose of radiation,” he believes.

“The risk is indifference and getting used to this place. You get used to the fear of radiation and seem to no longer pay attention to it. But you cannot ignore radiation in the exclusion zone. A glove, a piece of metal — everything can be contaminated,” says the scientist, who has been working at the Chernobyl NPP since 2014.

Not to get lost under the reactor

The labyrinth Doroshenko walks through consists of dark, in places dimly lit, rooms.

Anatoliy and his colleagues always carry flashlights. The path needs to be lit, because in some places the ceiling is too low and you have to crouch.

The rooms and corridors under the reactor are marked. Nevertheless, scientists must know the route by heart so as not to get lost among the passages. No one ever descends under the reactor alone — someone must always be nearby.

“There were cases when a flashlight ran out. It's good that colleagues had light. There was a time when a colleague got lost under the reactor. But they immediately start searching for the person. The main thing is to find a place in a cleaner zone to wait,” the scientist recounts.

Important Measurements

In 1986, the 'Shelter' object, which eventually became known as the 'Sarcophagus,' was built over the destroyed power unit. It buried hundreds of tons of nuclear fuel, radioactive dust, and everything that remained of the reactor.

Over time, the 'Sarcophagus' developed cracks, allowing radiation to escape again. Therefore, another shelter was built over it — the 'New Safe Confinement' (Arch). Scientists constantly check how well it protects against radiation leaks.

After a Russian drone strike in 2025, the arch lost some of its protective functions — the drone pierced a hole in it.

Doroshenko goes under the arch and into the old 'Sarcophagus' to descend beneath the reactor. There he takes measurements to study the state of the nuclear fuel.

After the 1986 explosion, a significant portion of the fuel is in places inaccessible to scientists. The fourth power unit was covered with a huge amount of concrete to stop radiation leakage.

“If we could take samples of nuclear fuel from the destroyed reactor itself, we could accurately say how nuclearly dangerous it is. But since it is under a huge layer of concrete, human access there is impossible,” the scientist explains.

Therefore, measurements are taken in the surviving rooms under the reactor to understand what processes are occurring inside. For example, scientists measure the neutron flux density using special detectors.

Protective Clothing

To descend under the reactor, Anatoliy puts on several layers of protective clothing in a special room. The basic layer consists of white trousers, a shirt, a jacket, a hat, gloves, shoe covers, and an FFP2 valved respirator.

“If you can get heavily contaminated during work — for example, if you have to crawl through some debris — we put on an additional set of special polyethylene clothing. It is designed to protect against external contamination by radioactive substances,” Anatoliy recounts.

After exiting the labyrinth, there are several control zones. All clothing is removed in the so-called 'dirty zone.' It is then sent to a special laundry or destroyed if radiation cannot be removed. After this, the scientist takes a shower and undergoes dosimetric control.

Doroshenko admits that visiting the fourth unit causes "a kind of euphoria."

“It's like conquering Everest. Anyone can get there, but to do so, you need to get a job, study the material, be useful. Then you will be allowed access to the facility. But not everyone is suited for it,” he says.

Anatoliy urges not to 'demonize' Chernobyl.

“This place is shrouded in myths. But when you get there, you see that it is a man-made building that requires constant control and supervision. You understand: if people stop coming here, some uncontrolled process will begin, and that is dangerous.”

"Isn't it scary in there?"

“There is a certain fear,” the scientist answers. “The main thing is not to panic. Panic leads to mistakes.”

Monitoring Health

The institute's office is located in the Chernobyl Exclusion Zone — Anatoliy lives and works there from Monday to Thursday. Once a month he comes directly to the plant.

The scientist understands the health risks. Once a year, he undergoes mandatory medical examinations, and during his vacation, he tries to go to the sea.

“I will walk into the labyrinths under the reactor as long as I can. I set no limits for myself. If I saw a generation that could replace me, I would gladly already be thinking about retirement,” he says.

It is important that people understand the challenges Chernobyl faces: containing radiation and controlling nuclear facilities.

“Chernobyl is not actually as scary as many try to portray it. Many people here continue to contain radiation. It is worth remembering that this place is less scary precisely because of the people who continue to work there,” the scientist believes.

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