I'm not sure which direction things get taken; this may be the wrong direction for some of this.
I notice the Iridium reflector exists; it is hideously expensive but has a key usefulness beyond the normal reflectors. What about doing something similar with other reactor components?
WHY MAKE a new part?
1. The liquid reactor shell is under-used. It could EASILY handle 4800Hu/t or more in native IC2, but the highest heat I've seen generated by a stable reactor is 1344ish. Higher-level components means more heat can be vented and more use out of the fluid reactor.
2. I've "blown up" fluid reactors twice now. it was underwhelming, because the fluid shell "took" the blast. The core was gone, the entire shell remained. To me, this means once you finally DO get a fluid reactor made, you lose 99% of the danger of nuclear power. I think a higher-heat reactor would mean more uranium and therefore more chance of causing a larger capital hit if it gets out of control.
3. Nuclear heat power is the pinnacle of complexity in native IC2. This would add some additional level to that, allowing someone to gain EU to get to an even higher achievement.
Suggestions for iridium components, pick one or more:
a) nearly infinite heat capacity for iridium components, so they don't melt as fast and allow the rest of the reactor to cool off,
b) additional capability for iridium components, such as an even more effective heat dissipator (because the engine can run even harder without breaking, or maybe iridium is a perfect conductor of heat)
c) larger "combo" items, like a combo "heat vent / heat exchanger". Perhaps the opposite of the overclocked heat exchanger, it moves 12 heat from the core and 5 from each component, then removes 32 heat from itself.
Here is an example recipe, based on the iridium reflector, for an iridium heat vent.