All applications for reactor designs go through the US Nuclear Regulatory Commission, and their website has an up to date list on current applications for new reactors Here. Currently operating reactors have licenses that require renewal listed Here. Comparing that list to this one you can see that a significant portion of plants are not requesting renewal and will be decommissioned once their license expires. The Diablo Canyon Nuclear Plant has 2 reactors whose license expires in 2024 and 2025, and their renewal is a highly debated topic despite it generating ~8.5% of California's energy. Regarding new technology, NuScale is the first and only approved Small Modular Reactor, which shows great promise due to its changes to the public zoning requirements changing, the lower initial cost to invest, as well as the fact that we might get them in the next decade.