What criteria do you use to determine "best"? Safety, construction cost, fuel efficiency, capacity factor? Pretty much all modern designs are much safer than d

What criteria do you use to determine "best"? Safety, construction cost, fuel efficiency, capacity factor? Pretty much all modern designs are much safer than designs of Fukushima and Chernobyl reactors developed in 60s. One of the most recent designs (classified as generation 3+) with operational reactors is VVER-1200, operational reactors: Leningrad-2, Novovoronezh-2 and soon Astravets (Belarus). Next iteration VVER-TOI is under construction in Kursk-2 and Akkuyu (Turkey). Both of those designs easily satisfy post-Fukushima safety requirements. https://en.wikipedia.org/wiki/VVER https://en.wikipedia.org/wiki/VVER Other reactors can be found here: https://en.wikipedia.org/wiki/Generation_III_reactor#Generation_III+_reactors_currently_operational_or_under_construction https://en.wikipedia.org/wiki/Generation_III_reactor#Generat... Also arguably operational BN-600 and BN-800 can be considered Gen IV reactors (though they currently lack necessary fuel processing lines).