First let me say that that is a nice simple reactor design. I like it. (remember imitation is the sincerest form of flattery) That said,.. it took me about 30 mins to build this replica of your model in bryce (would be faster if I was a better modeler) I then applied a dirty chrome like texture to the whole thing then seelected the center core rod and gave it a glowing green beam effect (one of the default preset textures available in bryce) I then changed the core rod to red (just had to change the material color palette) and changed the sky to give the dirty chrom a different color to reflect. As you can see it doesn't take much to make a 'different' variant of the reactor.
Notice that I removed the Black 2D panel I placed behind the model to reveal the selected sky presets that are reflected on the chrome.
Anyway, I like to share tricks of the trade, and hope this little example will help give you ideas for your reactor.
If you have any questions just fire away.
Cheers!