The remnants of Chernobyl’s reactor 4 stand as one of the most perilous locations on Earth. This site is not only physically hazardous but also highly irradiated, engulfed in darkness, and encased by a deteriorating concrete structure now replaced by a secure confinement system.

Understanding the conditions inside is imperative for scientists. One of those scientists is Anatoly Doroshenko, a dedicated researcher at the Institute for Safety Problems in Nuclear Power Plants (ISPNPP), who undertakes one of the most dangerous tasks in the world. This involves venturing deep into the decommissioned nuclear reactors to collect readings and samples, occasionally getting as close as eight meters from the reactor core.

“I have no fear,” Doroshenko shared with me while beside a scale model of Chernobyl in the lab located within the exclusion zone. “I’ve trained extensively for this. One must be mentally prepared to accept the necessity of this work.”

“It’s an unusual experience. Comparable, I’d say, to climbing Mount Everest, flying into space, or exploring the depths of the ocean. There is a constant adrenaline rush.”

Each time Doroshenko investigates the reactor, he follows a strict checklist under significant time constraints. “You must have a thorough understanding of your tasks and environment,” he emphasizes. “Control is key,” he repeats, as if reminding himself.

“Recognizing that everything is contaminated is essential; if you touch anything, you must understand the implications to avoid contaminating your clothes or yourself,” he states. “It’s vital to maintain awareness of your actions due to the limited safe time available. You want results and to witness any findings.” This job isn’t a casual endeavor. You’re there with a purpose, needing to remain focused on your responsibilities.”

During visits to lower-risk areas of the reactor, Doroshenko dons gloves, a respirator, and a hat. For the most heavily radiation-impacted sections, he’s set to wear a full-body suit, with a third layer of protective polyethylene for added dust defense. He also possesses a lead apron for extra protection, though its weight can hinder movement in cramped spaces.

As a newcomer, he once explored the main circulation pump, guided by a seasoned colleague. This pump, which historically cooled reactor 4, was involved in the safety tests leading up to the catastrophic 1986 event. “This is an iconic spot worthwhile of our investigation as we study the devastation post-explosion.”

‘Our primary protection is knowledge, not just gear,’ asserts researcher Olena Paleniuk at ISPNPP. “Anatoly is pivotal to our efforts. While he may appear exhausted and downcast, like many of us, his work is invaluable. There are few young professionals proficient in dosimetry today.”

Doroshenko’s supervisor, Victor Krasnov, noted that since 1986, numerous scientists have entered the reactor for readings and sensor installations. They encounter a confined environment filled with pipes of radioactive water and significant corium remnants—a mixture of molten fuel, concrete, and metal formed in the extreme conditions after the disaster, creating strange formations as it drips through the ruins.

“The initial explorers coined unique phrases for various formations: ‘elephant’s foot,’ ‘cat house,’ ‘dog house,’ and ‘octopus beam,'” Krasnov shared. “Every journey here presents unique challenges given the extensive destruction within.”

The dangers remain extensive. One significant concern is the 2,200-ton bioshield that was originally positioned above Reactor 4, now known as Elena. This massive structure was flipped during the explosion and now rests askew atop the debris. A collapse could trigger a massive reshuffling of hazardous materials and release substantial radioactive dust.

Ongoing risks and the necessity for precise readings stem from sporadic increases in nuclear activity. While the exact location of all fuel materials remains uncertain, the reactor can become active unexpectedly.

As uranium or plutonium fuel decays, it emits neutrons that may initiate a fission reaction upon capturing. However, water can slow down these neutrons, preventing this capture. After the disaster, the sarcophagus created arid conditions in the reactor, which led to a neutron spike.

Subsequently, the concrete shelter deteriorated, allowing water and humidity to enter, diminishing neutron flux. “Currently, new safety confinement is being installed, and due to the low humidity, we anticipate possible accidents which need monitoring,” Krasnov notes. This reinforces the importance of Doroshenko’s continuous investigations to improve situational awareness.

Though stringent safety measures are implemented at Chernobyl, the risk of entering a destroyed reactor remains ever-present. “We understand the dangers,” Doroshenko remarks. “That’s why I consider my health seriously; if I disregard it, I could make errors. I can’t predict future health issues, but adhering to radiation safety standards helps minimize those risks.”