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.
Så vandkølede reaktorer bygges ind i store, tykke betonbygninger kaldet indeslutningsbygninger, hvis formål er at holde på al den damp, der vil vælte ud af reaktoren, hvis du ved et uheld mister trykket.