Thank you. Yes, I think that there is still some ways to go with making these cost efficient vs other tech. I have heard people mention similar issues that you are rightly calling out. I believe the hope is the viability of these designs relies on cost reductions that would come from mass production/ economies of scale. I don't know how realistic that is, but it does tend to happen when things get produced in greater quantities, smart people find many optimisations to reduce cost.
New Uranium mining is incredibly destructive and limited. Dropping the breeding ratio to effectively zero is a non-starter.
Plus noone really know how you might make TRISO pellets not cost $40-600/MWh (or rather it costs well over $600/MWh and they think it might come down maybe) or cost $20/MWh to handle and store at the back end of the cycle (although this one might be solvable by burying the whole reactor I guess?), so it doesn't really matter how cheap the reactor is if it uses that fuel.
