Hmm, trying to get any of two fuel rods next to each other practically forces redesign of the reactor because every OC vent here have to be surrounded by 4 component vents or else it explodes, leaving no room for two fuel rods next to each other except bottom corners. Also, two quads together give too much heat to handle. So, for this I need to make different reactor design.
About the condensers, hmm, I didn't try it to be honest mainly because I prefer vent-only reactors and didn't want bother with items that need to be recharged, I like to turn reactor on and forget, bringing only new fuel rods from time to time. However using UUM for this looks interesting, I wonder if with correct design it could be self-sustaining, UUM cost for lapis isn't that high from what I remember.