It was only a partial meltdown, some cooling systems failed and it was successfully contained! Safety precautions designed to stop a full meltdown and release of radiation succeeded.
I know that's not really the point of your comment but I feel like this particular incident has a lot of misinfo and I wanted to help elucidate what happened.
This isn't true -- radioactive gases were leaked into the surrounding area. The containment vessel remained intact, and NRC concluded that no measurable harm was done, but there was definitely a release and that's why it was such a big deal. They evacuated children and pregnant women from the area in response.
It's not as uncommon as you might expect -- here is a list for the curious. And I don't mean to denegrate nuclear energy as a power source; it is vastly better than fossil fuels and safe when done correctly -- I have participated in the safe generation of nuclear power. But the ramifications of it being done incorrectly are severe to say the least, and everyone should be aware that we do commonly have issues with it, especially in aging facilities. We commonly extend plants decades beyond what their initial construction planned for.
Edited to say I just realized you said meltdowns, not radioactive leaks, which I do agree with. Sorry for confusion
I'd like to add that I think North America needs to invest in making Thorium reactors and/or Fast-Breeder systems portable: Nuclear trains sounds stupid until you realize Thorium exposed by a train crash or maintenance issue cannot emit lethal doses, and Fast Breeder fuel spheres are no more dangerous in a sunken ship at the bottom of the ocean than in the emergency cooling tank of a damaged ship or the reactor of a working one.