Can't afford the steam turbine.
It's astonishing how much the engineering literature is like a stopped clock. All the time you hear that a new power source could be "competitive with coal" but coal is not competitive with natural gas used to fire an open-cycle gas turbine.
The capital cost of the steam turbine (and associated heat exchangers) at a coal plant or nuclear plant is as humongous as the hardware itself.
A supercritical CO2 closed-cycle gas turbine would fit in the employee break room of the turbine house at a nuclear plant.
Without some transition to a higher-temperature reactor (liquid metal, gas cooled, or molten salt) nuclear power can't possibly compete economically against other power sources.
