Applied Energistics have breathed new life into Breeders!
Attach an Import and an Export bus onto the breeder in question. The Import Bus pulls out Re-Enriched cells and the Export bus deposits isotope cells into the now vacant slot with lighting speed! Assuming you actually HAVE several hundred isotope cells stored in your applied energistics ME Network (quite feasible, with how it stores items, assuming you actually have acquired that many), they can be seamlessly re-enriched without needing any user input whatsoever!
I am looking into the break-points for the new Plutonium cells to ascertain viability in CRCS systems, however at this time it doesn't look very viable. The additional EU/t generated is nothing compared to the additional heat generated.
Case in point, a 'block' of four quad uranium cells in a square has an Eff 5, with 400 EU/t and generating 960 Heat. A block of quad plutonium cells has an Eff 7, with 560 EU/t and generating 2752 Heat.
For a 40% increase in EU/t, you net 287% increase in heat generation. That's not a cost effective ratio.
If you have a row of 8 quad-uranium cells with Neutron Reflector 'caps' on either end, you have an Eff 6 reactor producing 960 EU/t with a heat of 2688. First, let me point out that this is LESS than Plutonium was generating in return for 560 EU/t, then let's look at what Plutonium does in that same configuration. It has Eff 9, with 1440 EU/t, and generating 8448 heat.
Granted, you are now producing 50% more EU/t with Plutonium, but you're now generating 314% more heat. You will have less than a sixty second microcycle time... with 60k coolant cells. Even with 360k cells, you're only looking at a five minute micro-cycle. And even the best cooling tower I've yet devised, with a 110 cooling, has a cooling cycle time of 55 minutes. Meaning you're now looking at 11-12 cooling towers.
The only advantage to the plutonium is that it produces so much more EU per cycle due to higher efficiency rating. Which just means you'll be chewing through fewer cells.
Unfortunately, Import Buses tend ignore damage values entirely, and simply look at the item ID. This means hooking up import buses to cooling towers to pull out only full cells doesn't work, because it will pull expended ones as readily. I hope the rumors of a 'fuzzy bus' are not mere speculation, because they would revolutionize the CRCS industry.