Who was responsible for chernobyl?

The culpability is shared, really. On the night of the disaster, the plant operators, under the reckless direction of Anatoly Dyatlov, conducted a very poorly managed safety test. However, the fundamental blame lies with the Soviet system. The RBMK reactor had inherent, catastrophic design flaws. These were known to designers but kept secret from the staff. A pervasive culture of secrecy and a complete disregard for safety protocols were the true root causes. So, it was a catastrophic failure of both specific individuals and a deeply flawed system.