Or it can be installed underground, as the same website has proposed in other articles on small reactors: https://www.energy.gov/ne/articles/5-key-resilient-fea

Or it can be installed underground, as the same website has proposed in other articles on small reactors: https://www.energy.gov/ne/articles/5-key-resilient-features-small-modular-reactors https://www.energy.gov/ne/articles/5-key-resilient-features-... It's a lot easier to dig a pit than build a giant 5 meter thick dome. Regardless, the point remains: the question that needs to be asked isn't "are these sites vulnerable to attack" it's "can an attacker inflict more damage here than through conventional means?"