It comes more than four years after Russia launched a large-scale invasion that put the plant back in danger and raised the risk of another radioactive disaster.
AFP news agency looks at five things to know about the disaster and the plant today.
Explosion
On April 26, 1986 at 1 a.m. 23 minutes local (and Lithuanian) time, due to human error during a safety test, an explosion occurred in the fourth reactor of the Chernobyl nuclear power plant in the north of Ukraine. Ukraine at that time belonged to the Soviet Union.
The explosion destroyed the interior of the building, sent a cloud of radioactive smoke into the atmosphere, and left the nuclear fuel burning for more than 10 days.
Thousands of tons of sand, clay and lead ingots were dropped by helicopter to stop the radioactive leak.
The International Atomic Energy Agency (IAEA) determined that the main cause of the disaster was “major design flaws in the reactor and shutdown system” along with violations of operating procedures.
Radioactive cloud
In the days that followed, the radioactive cloud heavily contaminated Ukraine, Belarus, and Russia, and then spread across Europe.
The first public warning came just two days later, on April 28, when Sweden recorded a spike in radiation levels on its territory.
The IAEA was officially informed of the accident on April 30, but then Soviet leader Mikhail Gorbachev publicly acknowledged it only on May 14.
Thousands of people are believed to have died as a result of radiation exposure, although estimates of the exact number of victims vary.
A 2005 United Nations (UN) report indicates that the number of confirmed and predicted deaths in the three most affected countries reaches 4,000. In 2006, the Greenpeace organization estimated that the disaster killed almost 100,000 people. lives.
According to the United Nations, about 600 thousand the people involved in the clean-up operation, the so-called liquidators, received a high dose of radiation.
The disaster sparked public fear of nuclear power and sparked a wave of anti-nuclear movements across Europe.
Russian occupation
Russian forces occupied the power plant on the first day of Moscow’s invasion of Ukraine in February 2022.
The Russians seized the power plant without a fight, sending tens of thousands of troops and hundreds of tanks into Ukraine from Belarus, a close ally of Moscow.
Russian soldiers dug trenches and set up camps in areas like the so-called Red Forest, named after the color the trees turned after the radiation blast.
The occupation of the defunct power plant has raised huge concerns that a military incident could lead to a catastrophic nuclear disaster at the site.
Russian troops withdrew from the power plant about a month after the start of the war. It was part of the withdrawal operations after fierce Ukrainian resistance failed to encircle and capture the capital, Kyiv.
New threats
The remains of the power plant are covered by an inner steel and concrete structure called a sarcophagus, hastily built after the 1986 disaster.
A newer high-tech outer enclosure called the New Protective Enclosure (NAG) was installed in 2016-2017. It must eventually replace the old sarcophagus, which was not intended as a permanent solution.
The massive metal outer structure was breached by a Russian drone in February 2025, causing it to lose its ability to contain radiation.
In a report published in April, Greenpeace said the outer casing “is not currently repairable and therefore unable to function as designed, and therefore has the potential for release of radioactive material”.
The repairs are expected to take about three to four years.
Another Russian strike could lead to the collapse of the radiation shield, the director of the plant told AFP in December 2025.
Prohibited zone
The area around the power plant was evacuated and became a no-go zone with abandoned cities, fields and forests.
In total, more than 2.2 thousand square kilometers in Northern Ukraine and 2.6 thousand square kilometers in South Belarus are practically uninhabited.
People will not be able to live there safely for another 24 thousand. years, says the IAEA.
The city of Pripete, located three kilometers from the power plant, had a population of 48,000 in 1986. population was completely evacuated.
It remains abandoned, and its empty buildings, including a rusting amusement park and Ferris wheel, resemble a post-apocalyptic ghost town.
Before the Russian invasion, it was possible to organize guided tours to this place, but this area has been closed to tourists for almost three years now.
Without human presence, the territory actually became a huge nature reserve, where rare and endangered Przewalski’s horses were reintroduced in 1998.
