Fail safe designs have been around for decades, but they never built them. At this point it doesn't matter. We have 400 non-fail-safe reactors out there. Either

Fail safe designs have been around for decades, but they never built them. At this point it doesn't matter. We have 400 non-fail-safe reactors out there. Either shut them down, or replace them with fail safe ones. The fact fail safe designs 'exist' isn't an argument for continuing to operate the ones we have. Or building more of those non-fail-safe designs which is what's currently happening around the world right now.