On April 26, 1986, the fourth power unit exploded at the Chernobyl nuclear power plant, which led to the release of a huge amount of radioactive substances into the atmosphere. The Chernobyl disaster claimed the lives of hundreds of thousands of people, and there is still debate about its causes. The events of that fateful night were recovered literally in seconds.
Instructions
Step 1
On April 25, 1986, the fourth unit of the Chernobyl nuclear power plant was to be forcibly stopped due to scheduled preventive maintenance. The specialists, among other procedures, had to perform the so-called "run-out of the turbine generator rotor", which was part of the additional power supply system in case of emergencies. This mode was not worked out, the tests were carried out only for the fourth time.
Step 2
By about 3:37 am on April 25, the reactor power was reduced by 50 percent. The emergency cooling system was turned off. The dispatcher of Kyivenergo forbade to reduce the capacity, but at 23:10 the ban was lifted. The reactor power was reduced to 700 MW thermal, and then to 500 MW.
Step 3
On April 26, at 0:28 am, the switch to an automatic total power regulator was made. The operator could not cope with the control, the reactor power dropped to critical values. It was decided to remove the reactor's absorbing rods and restore its power. The inclusion of additional circulation pumps led to an increase in the load of the turbine generator, a decrease in steam generation. At low power, the temperature of the coolant approached the boiling point.
Step 4
At 1:23:39 am, the emergency protection light came on on the operator panel button. The absorbing rods moved, but for a number of reasons the reactor was not shut down. After a few seconds, several emergency signals appeared, and then the systems sending them refused to work.
Step 5
Most of the witnesses to the accident claim that there were two high-power explosions. According to some reports, there were more explosions. By 1:23:50 am, the fourth reactor of the Chernobyl nuclear power plant was completely destroyed.
Step 6
During the explosion, only one worker of the power plant was killed. Another was seriously injured and died in the morning. Within six months, 28 of the 134 Chernobyl NPP employees and members of the rescue teams, who developed radiation sickness after the explosion, died.
Step 7
On April 26, at 1:24 am, the duty officer of the paramilitary fire brigade # 2 received a signal about a fire in the fourth reactor of the Chernobyl nuclear power plant. By about 4:00, the fire masters managed to prevent the spread of the fire and localize it on the roof of the turbine hall, and by 6:00 they had completely extinguished it. The fact that near the reactor a gigantic level of radiation became known only at 3:30. 69 firefighters worked without special protective equipment. They were wearing only helmets, mittens and combat jackets (canvas robes).
Step 8
Several firefighters were already feeling unwell by two o'clock in the morning. Doctors recorded vomiting, weakness and the so-called nuclear sunburn. The victims received emergency assistance. On April 27, 28 firefighters were sent to Moscow for treatment at the radiological hospital No. 6.
Step 9
35 hours after the accident, information about the temporary evacuation of city residents was broadcast on the radio of Pripyat. The country learned about the disaster that happened only on April 28 at 21:00 from a TASS news report.
