Would it be possible to add a 'Recipe' of sorts that turns a fuel cell, such as a uranium fuel cell, into its spent counterpart?

So you're asking for a recipe to simulate a nuclear reactor, correct?

Yep. (support for modded ones too would be nice, though that sounds like it might be a bit difficult...)

Hm I actually hadn't considered this exact proposal before. People always wanted full power simulation, which is a 'maybe later' topic. This would be interesting though, and much less complicated to do. I guess I could do the same for boilers etc. I'll think about it.

Thanks. It would be very useful (especially for modpacks with complicated reprocessing setups).