They will close the nuclear fuel cycle in the 2040s and use the nuclear waste which is 95% Uranium 238 by mass.

China first commercial scale large-capacity fast neutron reactors, the CFR-600 power unit (Xiapu NPP) in Fujian Province is the only nuclear power plant outside of Russia with a large-capacity fast neutron reactor. It is either started already and grid connected or will be within a couple of months.

The CFR600 demonstration fast reactor (CDFR) is the first major step in China Institute of Atomic Energy's (CIAE's) program.

CIAE projections show fast reactors increasing to at least 200 GWe by 2050 and 1400 GWe by 2100. China will more than double the US nuclear fission power industry (just under 100 Gigawatts) by 2050 and 14 times by 2100.

Closing the fuel cycle means there would be virtually no nuclear waste or unburned fuel. The plan would involve regular reactors, fast reactors and offsite reprocessing (recycling of fuel) facilities. Fast reactors means the designs generates neutrons that are a hundred to a thousand times faster to split the even numbered isotopes of uranium. Unburned nuclear fuel is mainly Uranium 238 by mass. If you hit Uranium 238 with a fast neutron it briefly becomes Plutonium 239 before splitting.

The impact is there if China follows through makes hundreds of reactors based on this technology. They could leverage this to phase out coal power significantly starting around 2040. This would save hundreds of thousands of lives each year from lower air pollution.

For those who are scientifically and technically aware, you will notice that the breeders also make a lot of plutonium. The CFR-600 can make 200 kilograms of weapons-grade plutonium each year, enough for about 50 nuclear warheads. If there were over 300 hundred such reactors then yes China would help the environment by stopping coal air pollution but they could also make 15,000 plutonium bombs per year. China already likely has over 1000 nuclear weapons. The US will have the SpaceX Starship, which can be the best hypersonic bomber in the world.