So water-cooled reactors are built inside of big, thick concrete buildings called containment buildings, which are meant to hold all of the steam that would come out of the reactor if you had an accident where you lost pressure.
Reatores de água são construídos dentro de enormes, largos recipientes de concreto chamados edifícios de contenção, que estão lá pra isolar o vapor que escaparia do reator em caso de acidentes com perda de pressão.