Mark II-5 Reactor
http://www.talonfiremage.pwp.b…pynwflp2gxwnyysd4l215rv9c
Total EU: 24.000.000 EU
Output: 120 EU/t
Effectivity: 2 of 2
Its pretty expensive but wont explode on you IF you stick to the 5 cycles. Go beyond that and it will (6th continued cycle its a Mark III and will blow up after approx 80mins). Allow it to cool down a little (5mins) between cycles and its 100% stable. Plug the Uranium cells in and forget about it 
Cost:
Copper =377
Tin =155
Iron =129
Bronze =229
Cobblestone =8
Rubber =169
Redstone =170
Glowstone Dust =56
Lapis Lazuli =56
Refined uranium (pr cycle) =6