finally something i can easily copypasta when people say meltdowns are a legitimate concern nowadays
that was more a reference to the possibility of a nuclear reactor
exploding. its physically impossible for a nuclear reactor to cause a nuclear explosion, but a hydrogen explosion is possible under very certain circumstances.
meltdowns only require 2 or 3 events to occur. even after scramming a reactor in the event of a high-power casualty, decay heat will continue to heat the fuel plates as the fission products dissolved in the plates undergo spontaneous fission. if you ever uncover the fuel plates, ie, the plates are not fully submerged in water, the core will melt down due to decay heat. if you lose flow or pressure, the water on the surface of the fuel plates will boil and they will become uncovered and then meltdown. there are safety features and procedures for all the individual casualties that occur and extremely robust systems protected by layers and layers of redundant systems.
nuclear reactors are 100% safe, clean, and have the lowest death per kilowatt of any form of power generation. lessons were learned from 3-mile-island, which did have a total meltdown. that was due to:
1. stuck open relief valve (resulting in rapidly dropping pressure)
2. complete loss of flow (operators misunderstood their indications)
3. high power history prior to scramming (lots of fission products, therefor lots of decay heat generation)
