I think all they want is to use modern, iterative development principles. It's fine to have the final 'yes' take the full lump sum and a 'no' being a real possi

I think all they want is to use modern, iterative development principles. It's fine to have the final 'yes' take the full lump sum and a 'no' being a real possibility. What they want is to be able to get multiple opportunities to fail and get a 'no' earlier in the process, when the stakes are smaller. While your building analogy is nice, I'll propose a different one - pharmaceutical companies face a similar, lengthy, expensive regulatory process, but a new treatment doesn't just go from a single prototype to human trials - there are many steps, costing more and more as you get closer to certification, and each can block the entire thing. We need a similar path for new nuclear designs if we want to be able to live on this planet for long.