system
Given the following post, respond as if you're commenting on Reddit:
human
Why don't nuclear power plants use direct air cycle turbines?

DACT were successfully spun up during the nuclear propulsion program but nuclear aircraft were not viable for obvious reasons.

However they seem to make a lot of sense, why heat steam and run a turbine when you can run the turbine directly off the heat of the core? Wouldn't this be more efficient?
gpt
No, so far we haven’t find anything is better than steam. You can look at the PV or TS diagram, steam give you the best result. Coal fired power plant do exactly that. But natural gas turbine will burn fuel at the turbine to generate power and send the exhaust to generate steam for more power, heat recovery steam generator (HRSG). If you use heat to do one task it will ended up losing too much heat (energy).