What calamity would befall Southern California if terrorists launched rocket-propelled grenades at San Onofre’s spent fuel storage systems?

Would there be an explosion — releasing dangerous radioactive clouds — if aging canisters filled with nuclear waste cracked, then water seeped inside?

What of sabotage? Security? Fire?

Michael Corradini, a nuclear engineering professor emeritus at the University of Wisconsin, said cracks would likely be plugged by oxidation in stainless steel canisters, or be so small as to prevent water entry.