"Ukraine and the whole world will never forget a terrible event of April 26, 1986. Chornobyl will forever remain an unhealed wound in the heart of the country, in the hearts of millions of people," Poroshenko wrote.
According to him, every effort should be made to ensure that this tragedy never happens again.
"We must learn a lesson from those events. The current Chornobyl zone should become a place for new advanced technologies, a territory of change," Poroshenko said.
On April 26, 1986, at 1:23 a.m., a powerful chemical explosion occurred at the fourth nuclear reactor of the Chornobyl Nuclear Power Plant, which caused the destruction of part of the reactor and the turbine hall.
The explosion caused fire, which spread to the roof of the third nuclear reactor. Firemen arrived at the scene almost immediately. The fire was extinguished until 5 a.m. However, inside the fourth reactor it was extinguished only on May 10, when most of the graphite burned down.
The explosion and the fire formed a radioactive cloud, which covered not only the territory of modern Ukraine, Belarus and Russia, but also the territories of many European countries - Sweden, Austria, Norway, Germany, Finland, Greece, Romania, Slovenia, Lithuania, and Latvia. According to the International Nuclear and Radiological Event Scale (INES), this accident was classified at the highest, seventh level of danger.
From the very beginning, Moscow and the leadership of the Ukrainian SSR concealed the fact of the accident and the consequences of the environmental disaster.