IIRC you are using some Galacticraft thingy for RF->EU conversion? Could you point me to some more details?
Yes, at the moment I'm using Energy Storage Clusters. They can convert RF into approximately 225 eu/t, so you'll need a lot of them for heavy duty work.
Alternately you can try the Pneumaticraft
Flux Compressor->
Pneumatic Generator combo. A single pneumatic generator can output 2048 eu/t given enough compressed air (and in testing that required 3 flux compressors with around 9 speed upgrades each to achieve). I'm building some of these now but they're way more involved in crafting and setup.
The GC version currently provides a better conversion rate. In an upcoming version that may not be the case.
Might go with the Big Reactors then, I've never used them either and I've a ton of graphite/yellorium laying around. Might just do a larger eu buffer for burst HV manufacturing to get me there until I set up. I've never really enjoyed the IC2 reactors, they've always been rather weak considering the resource requirements and were never long lasting. I had a breeder/hybrid in 1.4.7 that was sustainable at 400 eu/t, but was easily surpassed by the 30 ish RC boilers, or 30ish thermal generators, or finally both versions of the GT Fusion reactor I had.
One thing to be aware of is that its one of the very few energy sources in Infitech2 that is completely non-renewable. Just about anything else you can think of (including diesel) can be acquired via non-gathering means.
To offset this, I typically only use my nuclear for times when my industry is running really hot. I lean on my titanium boiler and old RC boilers most of the time.
Also, if you pursue big reactors:
1) you can't get power out of a passive big reactor. This is completely disabled. You can only go the turbine route, and turbines require cyanite. So be sure to SAG mill your yellorite ore with grinding balls to maximize your chance at cyanite, otherwise you'll have to burn fuel in the reactor until you have enough cyanite.
2) you can use a "passive" reactor with other steam consumers, such as the RC turbine or GT turbines, but those output water at a different rate and you won't be able to make a closed loop. It might take dozens of EIO reservoirs to keep it fed.
PS: Props for doing a ReC fusion reactor, that's a huge accomplishment. And great tip about the eio pipes, I'll keep an eye out for that. We use a lot in our base.