I finally signed up here just to add in that I agree with the above. Blutonium's an interesting concept, but I feel like it's a little, overcomplicated right now.
I spent about ten minutes just now scouring the tech tree to see if I could find anything that would let me store the stuff, so I could actually start using some of the blutonium reactors and the like I've started unlocking. Ended up having to Google it, because I was wondering if something was broke on my game. It's not at all clear that what you get in the initial tank is all you can store, and I don't really understand why that's the case, especially since you can refuel - if they were intended as fire-and-forget then that'd make sense, but.
I like it conceptually, but I feel like you could have made things a lot easier by just doing what's been suggested above, bundling in that Community Resource pack that was mentioned and tying your engines and reactors to Uraninite. Boom. Refueling anywhere but on Kerbin requires mining or refining operations, stations get set up for supplying nuclear powered ships, and if someone wants to stock up for a long trip, they can, 'cause there's containers for extra reactor fuel.
Or if you don't want that, then remove the ability to refuel and just make them fire-and-forget and balance around that. As it is, the Manhattan reactor just seems pointless to me - 8k funds for less than 90 minutes of power generation just seems useless to me. Sure, it's high-throughput, but I can't think of a use-case for a reactor that can pull down 52ec/s for an hour and then it's functionally dead weight. If it did 1ec/s for 52 hours it'd be a lot more useful, and I might actually consider using it.