The countries that build traditional nuclear well do some advanced nuclear on the side, as a treat.
China now turning on its first High Temperature Gas Reactor.
Like Russia, China is building lots of vanilla Pressurized Water Reactors while exploring a few additional systems.

Both countries have a Sodium Fast Reactor program. Russia's is, by far, the most successful SFR program in history. Now they're helping China construct theirs.
Both countries believe that essentially all their future nuclear electricity will be from normal light water reactors.

In the past, USA, France, Germany, the UK, and Japan have had sodium reactor programs. Japan technically still has one test reactor open.
India is nearing completion of its first SFRs.
Both Canada and the USA have companies exploring new SFR construction.

High Temperature Gas Reactors may provide options for decarbonizing industrial processes that use extremely hot gases to run.
USA, the UK, Germany, and Japan have operated HTGRs of varying sizes and purpose.
China's is closely related to Germany's efforts, using "pebble" fuel.