I think the balance between Nuclear and Fusion power is a bit off.

A DT-fuel cell Produces only 10 GJ compared to the 50 of a Uranium Fuel cell. I would argue that producing a Uranium cell is a lot easier than 5 DT-Fuel cells. DT requires a lot more space and energy (lots of electrolysers) and is way more complex. DT even requires MORE U-235 (its the same amount in the recipe, but you can use 40% productivity in the assembler as opposed to the 20% in the centrifuge).

If you take into account that nuclear reactors have neighborhood bonus and the fusion reactor itself requires lots of energy, the efficiency is even more in nuclear reactor's favor.

Fusion should be better since it's more advanced tech right? Am I missing something?

Read FAQ page, #6.

Ah sorry, didn't see that.

Though i've got to say, I disagree with the " DT-fuel is cheaper." part and don't quite understand what the reactor being an assembler instead of a furnace has to do with the production ratios.

But if the mod devs don't want to discuss this, thats fine.

I mean, it's 1 U-235, 5 rare metals, and 30 lithium for 5 tritium, or 50 GJ (since the other material is water and a reusable casing). compared to nuclear fuel which is 2 u-235 and 10 u-238 and a steel plate for a single 50 GJ. This makes D-T cheaper by far in the uranium category.

Using my process, fission is actually cheaper than fusion.

Using fusion, one tritium costs (using 1.2 productivity module factor):
25 lithium, 0.83 U235, 4.16 rare metals and yields 47.5GJ (5s * 500MW draw) net power.

Using fission, one uranium fuel cell costs (using 1.4 productivity module factor + reprocessing):
1.43 U235, 1.14 U238, 0.71 steel plate, and yields 4 stone, 0.125 tritium, and 87.5GJ (with 1.75 neighbor factor).

On a per U235 basis:

Fusion -> 57.2 GJ per U235
Fission -> 61.2 GJ per U235 or 66.2 GJ if tritium byproduct is burned

U235 isn't too big of a concern after enrichment is researched. The current advantage of fusion is that the capital cost is slightly less when all of the heat exchange hardware is accounted for, but I am on my first playthrough and after crunching the numbers I don't plan to upgrade my reactor until I can't stretch my current setup to meet my power demand. The logistics of moving just uranium ore and steel plates is easier for me at this point in the game.

For me is the logistical setup to get fusion setup for not that much more gain in power. Normally, I'd already have nuclear setup, so it's much easier to scale that and just skip fusion until antimatter.

IMHO Fusion is just a lot simpler to build and require way less space. I usually use something like this https://www.factorio.school/view/-LbgGSB0UaoCww6EOycF for nuclear. Possibly requires less UPS as well.

I don't use fusion as power generator, I don't think it's worse it. But it's perfect for equipment power generation cause it have the advantage to not kill you... :p