First: running costs
This means how much materials that you will need to be added to run a second cycle.
I'm using industrialcraft-2-2.8.111-ex112.
U-235 here means "Tiny pile of Uranium 235", which is the one used to craft fuel rods, not the "big" pile of U-235.
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Uranium rods:
single: 2 U-238, 3 U-235
dual: 4 U-238, 6 U-235
quad: 8 U-238, 12 U-235, 2 copper
MOX rods:
single: 6 U-238
dual: 12 U-238
quad: 24 U-238, 2 copper, 1 iron
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Second: UUM costs (in EU, running without scrap/running completely on scrap)
Copper plate: 781,700/130,283.33
Iron plate: 763,000/127166.67
Uranium fuel: 33,130,000/5521666.67
MOX fuel: 931,100,000/155,183,333.33
U-238: 1,398,000/233,000
U-235: 8,245,000/1374166.67
Plutonium: 307,600,000/51,266,666.67
Uranium ore: 16,070,000/2,678,333.33
Since a uranium ore can be processed into 2 U-235 and 12 U-238, it is obvious that using uranium ore to get U-235 or U-238 is more beneficial.
U-238 from uranium ore: 1,339,166.67/233,194.44
U-235 from uranium ore: 8,035,000/1,339,166.67
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Running costs in EU:
Uranium rods:
single: 1.5*16,070,000=24,105,000 with 16 U-238 left over
dual: 3*16,070,000=48,210,000 with 28 U-238 left over
quad: 6*16,070,000+2*781,700=97,983,400 with 64 U-238 left over
MOX rods:
single: 0.5*16,070,000=8,035,000 with 1 U-235 left over
dual: 1*16,070,000=16,070,000 with 2 U-235 left over
quad: 2*16,070,000+2*781,700+763,000=34,466,400 with 4 U-235 left over
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Output range in EU, whole cycle
The least amount is calculated by putting the rod in a EU reactor with no rod/reflector next to it.
The highest amount is calculated by putting the rod in a fluid reactor (with a hull temp greater than 50%) and surrounding it with reflectors and using 75% efficiency HU-EU generators.
Uranium rods:
single: 2,000,000-36,000,000
dual: 8,000,000-100,800,000
quad: 24,000,000-268,800,000
MOX rods have half the lowest output of Uranium rods and the same highest output.
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Based on the calculations above, I can conclude that using fluid reactors is efficient enough to duplicate rods even with no scrap provided. If uranium reactors and MOX reactors runs at the same time, it will be even more efficient.