I always said that if they stuck to their old ways of doing seismic analysis then no new nuclear plants will be built. Now, it looks that way. The bizarre physics assumptions that 'pass' the Japan-style BWR, now fail the AP1000. Didn't they learn from Japan that it is all crap? I go on being amused.
This old-style analysis will pass a floppy jello nuclear vault, like the BWR, and fail a stiff shield building on solid rock. It's all to do with response spectrum analysis, and using peak acceleration. I don't expect this to resolve itself until another disaster.