Chernobyl Nuclear Power Plant: from Construction to Accident

The Soviet nuclear power plant construction program began to take shape in the 1950s as part of a broader initiative for industrialization and energy independence.

In 1954, the Obninsk Nuclear Power Plant, the world’s first commercial nuclear power plant, was commissioned, after which the country’s leadership placed its emphasis on the widespread use of civilian nuclear energy to meet the growing needs of industries and households.

In the 1960s and 1970s, the pace of nuclear construction increased dramatically: the Leningrad, Kursk, Smolensk, Ignalina, Chernobyl, and other nuclear power plants came online. Priority was given to large nuclear power plants integrated into a unified energy grid.

Standard reactor designs were developed: first, water-cooled water-moderated power reactors (VVER), then high-power RBMK uranium-graphite pressure-tube reactors.

By the early 1980s, the USSR was among the world leaders in nuclear generation, and nuclear power was perceived as one of the symbols of progress in science and engineering.

In 1970, construction of the Chernobyl Nuclear Power Plant began on the banks of the Pripyat River, 18 kilometers away from Chernobyl.

The site chosen was a good distance from major cities and close to sources of water needed for cooling. Three kilometers from the plant, the fledgling city of Pripyat cropped up, its life entirely dependent on the nuclear facility. By the spring of 1986, it was home to over 40,000 people. The plant itself operated four RBMK reactor units, each rated at 1,000 MW. At the time, the Chernobyl Nuclear Power Plant was one of the largest in the country.

On April 25, 1986, Unit 4 was scheduled for routine maintenance. However, workers decided to conduct an experiment: they wanted to see whether the turbo-generator could sustain the safety systems temporarily by relying on inertia during a power outage.

Due to demands from the power grid, the reactor’s operating mode was altered several times, which resulted in non-standard states that complicated control procedures. During the testing program at Unit 4, the nuclear power plant staff disregarded all established protocols and regulations.

Shortly after midnight on April 26, at 1:24 a.m., with the emergency cooling system turned off, the reactor could not be safely shut down. A large power surge occurred, leading to an explosion that destroyed the unit.

On the day of the accident, a government commission was swiftly convened to oversee the response and mitigate its effects.

With the vital input of leading scientists, critical decisions were made to shut down the remaining units at the Chernobyl Nuclear Power Plant, evacuate Pripyat and the surrounding villages within a 30-kilometer radius, and infuse stabilizing materials into the damaged reactor. Subsequently, republican and ministerial crisis management centers were established, prioritizing the decontamination of the affected area.

By 1986, large-scale research into the accident’s consequences was launched. Specialized centers, including the All-Union Center for Radiation Medicine, were established to coordinate this effort. Soviet scientists faced an unprecedented array of tasks — from tracking radionuclide migration in the environment to developing innovative safety measures for nuclear facilities.

In the summer of 1986, the USSR submitted a report to the IAEA outlining the causes and potential repercussions of the disaster. However, many of its findings remained classified within the country for some time. It was only in 1988, during a conference in Obninsk, that a more open dialogue about the lessons of Chernobyl began. This experience prompted a fundamental overhaul of nuclear safety protocols, leading to the development of a multi-tiered protection and emergency response system. These reforms significantly revised operating standards for nuclear power plants, ensuring that a catastrophe on the scale of Chernobyl would be virtually impossible at other Russian facilities.