They house all this nuclear material in massive concrete buildings and thick ,thick metal containers for the reactor cores . Spent fuel is handled in much the same way . Kept well away from the human population in insulated containers . Soon as we have a nuclear dissaster it is all change ! No need for alarm , the water is safe , the air is safe , life just goes on. We are sleep walking into a massive dissaster and there is nothing we can do about it . How many times over the years have there been problems with nuclear fuel ? At this rate we will not have a world we can live on soon !