jamesr wrote: I think, for a Brayton cycle you would need the helium temperature to be higher.
This may be eventually achievable with some fancy materials technology to allow the anode surface to run hotter without boiling off.
curiously, 565°C (838K) is the usual upper limit for the Rankine cycle, due to the creep strength of stainless steel.
— http://www.engineersedge.com/material_science/creep.htm
to run the anode surface hotter, creep limit is really the property we want to know. for 90-day service, that would be specified as something like “creep rate of 0.01 in 2000 hours at operating temperature of X”
