The man who crawls into the dangerous heart of the Chernobyl reactor

The shattered remains of Chernobyl reactor 4 are one of the most inhospitable places on Earth. The ruins are not only physically dangerous, they are highly irradiated, pitch black, and shrouded in a crumbling concrete sarcophagus, which is in turn covered by the structure of the New Secure Prison.

But it’s important for scientists to understand what’s going on inside. And this task falls Anatoly Doroshenkoa young scientist from the Institute for Safety Problems of Nuclear Power Plants (ISPNPP). He has what could be considered the most dangerous job on the planet: crawling deep into reactor debris to collect data and samples, getting within 8 meters of the core, sometimes once a month.

“It’s not scary,” Doroshenko tells me, standing next to a scale model of Chernobyl in the institute’s laboratory in the closed zone around the plant. “I’ve been preparing for this for a long time. You just have to be in this moral state to accept it and the need to do it.”

“It’s a really special feeling. I think it can be compared to the feeling of conquering Everest, flying into space or exploring the bottom of the ocean. A certain adrenaline rush is always there.”

He has a list of tasks to complete with each dive into the reactor, but he has limited time to complete them, so he needs to balance haste and care. “You should gain knowledge about what you will do, where you will go. You should control yourself,” says Doroshenko. He repeats that second part twice, almost as a reminder to himself.

“You should realize that everything is contaminated. And if you’re touching something, you have to know what you’re touching because you don’t want to contaminate your clothes or yourself,” he says. “The main thing is that you should be aware of your plans because there is not so much time to be there safely. You want to do work and you also want to see something.” [interesting]but it is not an excursion. You work there, so you should be aware of everything you have to do and keep it in your head.’

If Doroshenko visits less dangerous parts of the reactor, she will wear a cap, protective gloves and a respirator. For places with worse pollution, add a full-body suit against dust, or even a third layer of polyethylene suit. It also has lead aprons that can be fitted on top, but the weight and bulk make it difficult to negotiate the tight spaces inside.

As a junior scientist, a senior employee took him to the main circulation pumps that normally cooled Reactor 4 and were part of a safety test that led to the disaster in 1986. “It’s a very important place to see and it’s very well known. We were looking at all the devastation caused by the explosion.”

“The main protection for us is knowledge, not suits,” says the researcher Olena Pareniuk on ISPNPP. “Anatoly is one of our key employees and he looks tired and a little depressed like all of us, but he does a great job. We don’t have that many young people who are dosimetric measurements.”

Doroshenko’s boss, Viktor Krasnovacting director of science at ISPNPP, says generations of scientists have been going to the reactor since 1986 to take measurements and install sensors. There they will encounter confined spaces, pipes full of radioactive water and large swathes of coria – a mixture of molten fuel, concrete and metal formed in the 2,500°C heat of the disaster, which has dripped and seeped through the ruins, forming unusual shapes.

“The very first people who actually got there created these slang names for all these objects: elephant’s leg, cat’s house, dog’s house, octopus ray, mammoth ray,” says Krasnov. “Everything inside is destroyed, so all the paths are quite difficult.

The risks are almost endless. One is the 2,200-ton Upper Biological Shield that once sat atop Reactor 4 and is now nicknamed Elena. It fit like a coin in the explosion, and today it sits at a 15-degree angle, resting on rubble. If it were to collapse, it could release precarious ruins and stir up huge amounts of radioactive dust.

The long-term risk and part of the need for regular and accurate readings comes from occasional spikes in nuclear activity. No one knows exactly where all the fuel material is inside the reactor, and it occasionally activates.

When uranium or plutonium fuel decays radioactively, it emits neutrons that can fuel a fission reaction if the neutrons are captured by another radioactive nucleus. However, large amounts of water slow down these neutrons and prevent them from being captured. Immediately after the disaster, the sarcophagus inside the reactor created dry conditions, which caused a neutron spike.

Later, there was more water, partly because the concrete shelter was riddled with holes that let birds and weather in, so the humidity rose and the neutron flux dropped. “Right now, when the new safety cover is installed, the humidity is lower, so we expect that there could be some accidents and we need to know that in advance,” says Krasnov. Therefore, it is vital that Doroshenko continues to climb inside to better understand the conditions.

Despite the strict safety processes at Chernobyl, it will never be safe to crawl through the exploded reactor. “I know about the risks,” says Doroshenko. “And so I’m worried about my health, because if I don’t take care of it, I can make mistakes. I don’t know if I will have health problems in the future, but I know that if I follow radiation safety standards, I can minimize those risks.”

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