San Onofre is a fission reactor not a Light Water. But there is always a chance of a meltdown that is why U.S. reactors have so much safety standards. One feature is a containment dome. That is why they constantly drill if there is an accident. I was even given a suit just in case.
All commercial nuclear power plants in the entire world are fission reactors. Light Water reactors are a type of fission reactors.
None of those operating in the US are capable of an explosion. Meltdown under extreme situations is possible but a meltdown is not an explosion.
You should be less quick to insult people who are trying to help you understand. Unlike
@Joe Wooten, I didn't work directly in US nuclear industry. I did take nuclear engineering while getting my electrical engineering degree specializing in power systems.