Aside from the need to supply input coal (dust) to re-enrich uranium (for the sake of argument, let's assume one has a chest full of coal dust, so no need to produce or macerate it) would it be possible to set up a heat-neutral Mark 1 reactor, extract it's spent fuel (Red Power, presumably), insert new fuel, take the spent fuel, put it in a breeder* (which likewise also maintains its own fueled state), extract the re-enriched cells and put them back into storage used to supply the Mk1 reactor with fuel.
I've been fooling around with this and the only conclusion I've come to so far is that you cannot rely on a CASUC system. The refueling and cooldown systems tend to get in each other's way (so while theoretically possible to maintain, if a uranium cell gets into the slot where a water bucket is supposed to go there will be a catastrophic failure in the future, in the opposite case, the reactor cools down and becomes non-operational).
Which leaves the maximum recator efficiency at 2.33 (for EU) and 1 to 5 breeding (the Mark X Perfect Breeder).
The "Mark 1-2.33E" reactor uses three fuel cells, the perfect breeder one (producing four), so in theory, this should be self-sustaining entirely without player intervention (aside from a supply of coal dust, though with the EU output and a mass fab, it could fabricate enough UU-matter to craft into coal making the device 100% self-sufficient and only use a small fraction of the total EU output: 517,528 EU to create and macerate 20 coal, enough to sustain 3.33 cycles).
The challenge, then, is to create a tube/pipe system capable of performing the proper exchanges without causing widespread devastation.
*Preferably a heat-netural hot-breeder, though not required. The only requirement is that it will re-enrich enough uranium to supply itself AND the main reactor in a 1:1 ratio (1 used-uranium to 1 re-enriched uranium).
