[ori_prior]

60% is feasible for e.g. nuclear and gas, if you use more than one turbine and there is a big constant temperature differential. This typically isn't the case for gas plants which are intentionally variable and often intended to be cheap to build. While at peak temperature, they might run at peak efficiency around the theoretical maximum of 60% (thermal to electric) with a multi-turbine assembly, typically efficiency is far lower because gas plants usually don't run at peak efficiency and only have one turbine.

[philipkglass]

I don't think that any nuclear reactor has achieved 60% thermal-to-electricity efficiency. In a water cooled reactor the hot side starts with cooler steam than a combustion-fired plant can generate so it's hard to reach really high efficiency. Reactors cooled with helium, molten salts, or liquid metal could theoretically do better but I don't think that any actually-built power reactors have reached 60%.

The brand new EPR achieves only 37% thermal efficiency and that is considered a good number for a power reactor:

https://www.world-nuclear.org/information-library/nuclear-fu...

[ori_prior]

No, you are right, 60% is a theoretical maximum achievable maybe with supercritical reactor coolant. The actual maximum for existing reactors is somewhere just below 40%.