Also from terrorist attacks? And the fuel stream from proliferation-related theft?
BTW one way in which SMRs may be safer is if they are installed completely underground - which is hard to do with big reactors. Also SMRs for low-temperature heating are stable: they generate only as much as the coolant circuit takes out, because of the negative temperature coefficient. Like (but look at the time line!)
https://www.world-nuclear-news.org/articles/third-finnish-city-considers-smrs-for-district-heating