[p_l]

The reason we don't have fusion is that we keep looking for above break-even (and for proper fusion power plant we need ratios way above 10:1, afaik) in aneutronic fusion.

If we accepted neutron radiation in the process, which is what would lead to radioactive fusion chamber cladding you mention, we could have broken even already - the experiment JET reactor had the design capacity to run at above 1:1, but wasn't equipped for the damage from neutron radiation.

[pfdietz]

Breaking even in fusion puts you where fission was in 1942. And that's just a step. The engineering obstacles to practical fusion are enormous, far greater than those facing any advanced fission reactor scheme. I very seriously doubt fusion will ever be practical.