Those plans are to some degree a consequence of a conservative outlook when they were initially approved mixed with local politicians fearing a backlash in a cold winter if there is even a short period with a power shortage. This happened a couple of winters ago in some regions of China and is part of the reason for the coal power plant build spree they went on. Have a search for news on the coal power plant news in 2023. However, these plants turn out to not be really needed and are idle a lot and approvals are plummeting for new coal plants in 2024 already and I would expect to see the same for nuclear soon as renewables continue to prove their reliability and as battery storage continues to grow massively.

That said the growth in renewables will still take some years to make a big dent in coal in China so the nuclear power is welcome!