Chernobyl
He transferred to the capacitor, where again cools, it becomes liquid water and can be used in the new cycle. What happened at Chernobyl? The basic version is (just say that the details of what happened much uncertainty about what the specialists are still arguing, we're talking about process only popular and in general). At the station, had to undergo a routine stop the 4th power for maintenance. This possibility has been chosen to conduct a "little experiment". It consisted in the fact to make use of rotary inertia ("ramp-down") one of the generators (8 th), to see if he can produce electricity sufficient to maintain the functionality of the station in a stop mode and no external power supply (bad language added – "in case of nuclear war.") On the night of April 26, 1986 began preparations for the reactor shutdown and to conduct the experiment.
Under the plan, everything had to happen at reduced to 700 MW thermal reactor power. But – first step in an accident. It is believed that operator error – power has not declined, and downright dropped to 30 MW and below. Then they decided not to wait for lifting up to 700 and limited to experiment of 200 MW. In this case, the second step in the accident – came the so called "xenon poisoning" of the reactor (in other words – "iodine pit"). This accumulation of short-lived isotope iodine-135 and its decay products – the isotope xenon-135. In itself it is not dangerous and always happens at lower power or shut down the reactor, and decreases its performance.