Chernobyl happened for a lot of reasons, you’re being reductive. The reactor design, testing procedure, and crew all contributed to that disaster. If I had to

Chernobyl happened for a lot of reasons, you’re being reductive. The reactor design, testing procedure, and crew all contributed to that disaster. If I had to pick one reason, I would blame reactor design. The RBMK reactor had what’s known as a positive void coefficient. When voids (boiling water pockets) formed, these reduced the reactor’s ability to moderate neutrons, thus accelerating the reaction rate. This makes the reactor fundamentally unsafe, and guaranteed that something was going to go wrong. This is a design flaw that has thankfully been fixed in other reactors, including all other RBMK reactors. The flaw was known to the Soviet’s at the time, but the RBMK was designed to produce nuclear weapons, so they swept the flaws under the rug.