Some say that the response to the disaster was a failure of the Soviet Union’s political system: reluctance of the Communist Party to admit failure, and the tendency of bureaucrats to downplay problems to their superiors. While those were certainly factors in the way the Chernobyl disaster was handled, there are similar tendencies in the US and elsewhere. Up until Fukushima, Japanese officials and safety regulators ignored evidence that reactor sites in Japan were vulnerable to larger earthquakes and tsunamis than they were designed for, assuring the public that reactors were robust and built to exacting standards, with multiple layers of backup safety systems. And in the US, the Nuclear Regulatory Commission has chosen not to require reactor owners to make safety upgrades to address flooding and seismic vulnerabilities that have been identified since Fukushima. NRC required every reactor owner to inspect the reactor to make sure it meets safety standards for flooding and earthquakes, and to re-evaluate whether the potential for flooding and earthquakes has increased since they were originally licensed. The vast majority of reactors identified violations and increased risks. But in January 2019, the NRC decided not to require them to address the new problems, and made doing so optional.
