For the record, I'm not an advocate of small modular reactors if they are of the pebble bed variety, which the majority are. The reason for this is the fuel in such reactors is encased in silicon carbide which is almost impossible to melt down or chemically process for fuel reprocessing so you end up with a lot of very long term waste, with actinides that last millions of years, that you can't recycle and burn. I am very much in favor of molten salt breeders that can burn the actinides leaving only short term fission products for waste. The big challenge with these reactors are materials, you need materials that can withstand a corrosive environment. But they're not significantly pressurized so a failure isn't the end of the world.