I am certainty no expert on nuclear engineering or containment design but it seems odd to me that the spent fuel rods are stored in above ground pools. I wouldn't even let my kids play in one much less store radioactive materiel that requires active cooling in one.
I've read It's an issue with manipulating the fuel: to do so, you unbolt the containment cap on the top of the reactor pressure vessel and fill the entire path from on top of it to the initial spent fuel pool with water. That allows you to safely transfer hot (thermally as well as radiatively) rods and it's pretty hard to get around if you're using this sort of reactor geometry (I understand it holds for both PWRs as well as these BWRs).
