I came up with this reactor by just messing with the reactor planner and it has an efficiency of 2 because it uses 6 uranium cells but it has a cool down of 24 minutes and an EU output of 120EU/t, which in my opinion, the extra 2 cells would be worth it, once you gain enough resources 6 cells wouldn't be a problem. It runs for a full cycle and if you really want you can run it through 5 cycles before you need to cool it or you wont have a reactor anymore:p
Here is the link. http://www.talonfiremage.pwp.b…10101001511f21s1r14lflr10
If someone already came up with this design then let me know, I'm sorry if it is someone else's design, I didn't look through all of them and I didn't look at any of them before I made this, it just came to my head after a few hours of using the reactor planner.