[i have slightly more than zero knowledge on the matter, what i say might be completely wrong]
There are fast nuclear reactors which use lead-bismuth for the coolant ( the Soviet Alfa class submarine used them to mixed success, but that was in the 80s), so maybe there are alloys with fitting temperature characteristics?
There are fast nuclear reactors which use lead-bismuth for the coolant ( the Soviet Alfa class submarine used them to mixed success, but that was in the 80s), so maybe there are alloys with fitting temperature characteristics?