I would certainly agree that nobody should actually try to put a year's generation of dangerous nuclear waste in 3 shipping containers. It'd be hazardous and the shipping containers couldn't be moved without breaking (probably do some damage to them even without moving them). The point is more that we're dealing with a volume of material that is - for an industrial society - tiny. There is a reason that in practice it is ignored it despite the braying crowd of people insisting that it is an unsolved problem that we can't ignore. It is an extremely ignoreable problem on the scale of benefits that nuclear power provides.