Chernobyl was a nuclear power station in the Soviet Union. On April 26, 1986 technicians at the reactor #4 attempted a poorly designed experiment to test . This explosion was caused when the reactor was put too much stress technologically. The technology was not big enough to handle what the test needed and pushed steam to build up, and later caused the explosion. The result of these multiple mistakes was the explosion in the reactor, causing the lid to blow off which sent large amount of radioactive material into the atmosphere. This created environmental issues around the world.
On April 25th, before a routine shutdown, the technicians at the reactor #4 started preparing for a test to determine how long the turbines would spin and supply power to the main circulating pumps following a loss of main electrical power supply.
However, there was a peculiarity in the design of the control rods which caused a huge power surge in the reactor.
The power increase caused the fuel to become very hot. The combination of the hot fuel with the cooling water caused rapid steam production and an increase in pressure.
The pressure caused the 1000 ton cover plate to detach, which ruptured fuel channels and jammed control rods.
The severe steam generation then spread throughout the whole core which resulted in a massive steam explosion.
Thus the explosion released harmful fission products into the atmosphere.
The nuclear power station could have prevented this by maintaining up-to-date technology. The workers set all the emergency systems off, which they should not have, and started their new test. The caused the system to get hot and they did not have the proper technology to help cool the system. Also, the workers were careless. A nuclear power plant needs workers who care, the experiment should not have been conducted in the first place because, they were unprepared and did not have the proper training needed. Power plants need workers to have knowledge on what they are doing, and to be trained on what to do in emergency situations like Chernobyl.