If you take all operational nuclear reactors safety records into account from all countries in the world, including all meltdowns and near meltdown disasters, it's still by far safer and has resulted in less deaths and long term illness than any fossil fuel, on every single metric.
True that newer style reactors are far safer, but that's the point. If we had started to transition in the 70's into nuclear power, we would have made a massive dent in climate change and set the stage to transition into full clean renewable energy sources and along the way improved regulations and engineering standards for existing nuclear plants.