Not sure why you are mention Pebble bed reactors. They are just one of many potential reactor types. And there are also a whole lot of different potential desig

Not sure why you are mention Pebble bed reactors. They are just one of many potential reactor types. And there are also a whole lot of different potential designs for a pebble bed reactor. Not building a containment building would never happen, and if you have small high power density reactor, the containment building is not actually the expensive part. This is an example of a modern pebble bed reactor: https://kairospower.com/technology/ https://kairospower.com/technology/ Building containment about a reactor like that isn't expensive. Containment is expensive if you have to build it around a gigantic PWR reactor with steam heat exchangers.