Reply To: NIMBY FUD

[asymmetric_implosion]

The PF has a bit of an advantage as it doesn’t require liquid helium. One could recycle the helium in a loop because the thermodynamic efficiency is reasonable as you are trying to cool the helium using ambient air. Taking cold helium and turning it into liquid is a very inefficient process because everything his hotter than the helium. Thermodynamics is not in your favor. I don’t have an idea for the loss rate of helium for a PF. I know some next gen fission technology is built around helium coolants so I have to believe the helium release is monitored because Xe and other gases with radioactive isotopes would mix with a gaseous coolant and get released if coolant is released.

I personally favor liquid metal coolants as they tend to remove heat well at modest flow rates and low pressure. If the atomic number of the coolant has the be less than Be, Li is the only option but you have to worry about the neutron activation and all that goes with it. I remain unconvinced that Be is a viable anode material so other options with sodium exist in my mind. Sodium is a proven coolant material that operates at atmospheric pressure. Water is always an option but the flow rates and pressure (which is also true of He) could be an interesting engineering challenge.