Chernobyl: The History of a Nuclear Catastrophe

by Serhii Plokhy

Trehub and his group of engineers tried to come to terms with the situation. By the time he took over the shift, the reactor’s power level had been reduced by half, from its full power output of 3,200 MWt to 1,600 MWt. Trehub was surprised that the safety system had been shut down. “What do you mean, they turned it off?” he asked Kazachkov. “On the basis of the test program, although I objected,” was the response. Kazachkov added that the power grid dispatcher was expected to give his approval for the shutdown of the reactor around 6:00 p.m. Accordingly, the steam turbine experiment that required the safety water supply to be turned off was postponed, not canceled altogether. Given the difficult and laborious process of enabling and then shutting off the safety system again, Trehub decided to leave it as it was and wait for the grid dispatcher’s approval, then begin the shutdown of the reactor.