Oh, I never thought TVA would ever have a containment problem. The containment portion of nuke plant designs is wildly over-engineered.
Where Fukushima has opened our eyes is the support infrastructure design issue. The tsunami exposed cascading, multiple system failures. Outside power failed, then the gensets failed, then the battery systems failed. With no power, they had no way to vent H2 out of the building containment, which is a large part of what has complicated their situation.
I think that two things come out of Fukushima for those of us who aren’t henny-penny anti-nuke types:
1. We really have to get away from the uranium/plutonium fuel cycle for power reactors. The only reason why we’re actually using u/Pu as fuel is an artifact of the Cold War and the nuclear weapons fuel processing.
2. Nuke plants need to think more about the SHTF scenarios and start modeling some really big crapstorms that include such things as “OK, you’re going to be cut off from the outside world of resupply for 30 days. How do you use what is on-site to get back to a stable state?”
There is no firm evidence at this point that the use of MOX fuel in Unit 3 has complicated or made the overall event worse in any way. Pu production is a natural consequence of the use of LEU and most of the added Pu is burned up fairly early in the fuel cycle because of it's enhanced fission properties. So I don't see any compelling reason to abandon it at this point.
If you're referring to advanced fuel cycles or thorium-based systems then it's going to be a tough go at least initially because of the huge investment in the LEU/LWR infrastructure. Until there is a market-driven reason to move away from that, I don't see much change in the near future.
2. Nuke plants need to think more about the SHTF scenarios and start modeling some really big crapstorms that include such things as “OK, you’re going to be cut off from the outside world of resupply for 30 days. How do you use what is on-site to get back to a stable state?”
I don't have a problem with reasonable thinking-outside-the-box exercises, as long as they don't go hog wild into unreasonable scenarios. I've seen editorials and blog postings faulting the Japanese nuclear program for "ignoring" evidence of tsunamis in the past that reached up to the lower slopes of some of the nearby mountain ranges. Well, cripes, you're talking about events millions of years passed in that case. It is simply unreasonable to single out a particular industry and hold them to standards that are based in data millions of years in the past, when no other industry has to do likewise.