It is important to remember that the SFP is not in primary containment for a reason. The purpose of primary containment is to contain the energy and materials likely to be released in the design-basis accident. Typically, for LWRs, this involves sudden loss of coolant (like a double guillotine-break in the primary coolant piping) while the reactor is at power and near the end of a fuel cycle, so the fission product inventory is maximum. The primary containment must withstand the initial energy release from steam flashing and coolant blowdown from depressurization of the primary coolant system, and the release of any core material from large-scale pressure vessel failure.
Obviously, the accident scenarios for the SFP are different. There is no operating core. The fission product inventory is lower. So there is less material available, and less stored energy to drive those materials out into the environment. It all comes down to decay heat management, which as we have seen with Fukushima is exactly the cause of the problems they face.
So I expect here we'll see added emphasis on assuring availability of emergency AC power and systems to supplement the cooling of both reactor cores and the SFP. Fukushima is a classic example of a common-mode failure. One event (earthquake-tsunami) took out multiple redundant systems (offsite power and emergency generators). That is the real lesson to be learned here. I hope cooler heads prevail and we learn the right lesson.
I will pit my Rensselaer Nuclear Engineering degree to anything you have to offer, which cannot be much. The GE Mark I Containment is part of the Reactor Building adjoining the Auxiliary Building and then the Turbine Building. This is a GE design that the NRC has audited and reviewed giving the utilities technical specifications that limit how the plant is to be used and managed. The spent fuel pool is next to the drywell to simplify the process of replacing fuel bundles in the reactor. You have no practical solution to relocate the spent fuel pool at plants around the world. Mark I containments within the reactor building have been in place since the 1960s.