I made a Tiny Breeder which is pretty efficent with Cell usagen and Cell Production.
It produces for Each Uranium Cell 16 Reinriched Uranium Cells and you can run it 24/7 with out exploding.
Here is the Reactor Setup: ClickMe
Now an addition to that i made it even better. Normally the Reactor would cool down every Time when you exchange the cells (the Uranium or Neardepleted cells),
now with my setup it is exchanging the Cell so fast that you do not loose any heat at all.
Here a video about that reactor: ClickMe
^^" Sadly this automation setup is as far as i know not possible because i use a custom BuildCraft version for that which does have the require feature for that.
I will release the version soon anyways so not much worry there...