From a super pro nuclear source:

> Nuclear plants currently being built have about 34-36% thermal efficiency, while one of the new reactor designs boasts 39%. In comparison, new coal-fired plants approach 40% and CCGT plants reach 60%.(4)

https://world-nuclear.org/our-association/publications/techn...

This is the reason for Pressurized Water Reactors (PWR). Then you can increase the temperature and through Carnot's theorem reach higher efficiency. But now you have a pressurized reactor with another host of complications...

Since a coal boiler is much simpler in construction than a reactor, and do not rely on water to slow down the neutrons causing the chain reaction, they can do more fancy stuff and use supercritical steam leading to the higher, but still not good efficiency.

Something I don't get...

Wind turbines are efficient (to convert mechanical wind energy into electric energy) between 20% and 45% (with a theoretical upper limit of 59%).

Solar panels between 15% and 22%.

Both with variable input energy.

So I am not sure how 34-36% thermal efficiency is so bad, especially for a near-continuous production (or at least, with a predictable thermal input)?

Because for a solar panel or wind turbine that efficiency is simply lost energy. Catching more is better but as long as it is economical it is fine.

For thermal power plants you need to spend money taking care of the waste head leading to more costs.

Fascinating, thanks for sharing!