people use stainless steel, fiberglass, teflon and other common materials. The most notorious problem is that sCO2 dissolves in hydrocarbon oils, even very heavy hydrocarbons so keeping the CO2 from exiting through the turboshaft seals is challenging, but a solved problem.
The one obnoxious thing for nuclear use is that CO2 reacts with liquid sodium! It's not that hard to contain the effects of a CO2/sodium leak because the volume of the 1500 psi section is small, so that if the coolant loop bursts the overpressure in the (still not very big) confinement structure is more like 15 psi.
https://www.twi-global.com/technical-knowledge/published-pap...
people use stainless steel, fiberglass, teflon and other common materials. The most notorious problem is that sCO2 dissolves in hydrocarbon oils, even very heavy hydrocarbons so keeping the CO2 from exiting through the turboshaft seals is challenging, but a solved problem.
The one obnoxious thing for nuclear use is that CO2 reacts with liquid sodium! It's not that hard to contain the effects of a CO2/sodium leak because the volume of the 1500 psi section is small, so that if the coolant loop bursts the overpressure in the (still not very big) confinement structure is more like 15 psi.