Factorio Kovarex Enrichment Setup: Build a Stable Loop
A reliable Factorio Kovarex enrichment setup separates catalyst stock from new uranium. Start with the full recipe inputs, return the catalysts, and let only net surplus leave the loop. This guide covers startup, a compact belt layout, useful controls, and fixes for stalled centrifuges.
Last updated: November 4, 2026. Recipe figures are separated into total inputs and net changes so catalyst stock is not mistaken for ongoing consumption.
Quick Answer: How Do You Set Up Kovarex?
Research Kovarex, power a centrifuge, and provide 40 U-235 plus 5 U-238 for the first craft. It returns 41 U-235 and 2 U-238: net +1 U-235 and -3 U-238. Return the catalyst, replenish U-238, and route only surplus to storage or fuel production.
- Protect 40 U-235 as catalyst stock; it is not consumed every cycle.
- Start with 5 U-238, then replenish the net 3 used per craft.
- Return catalyst U-235 and divert only the net surplus.
- Keep both output paths clear and test one centrifuge first.
Separate the Loop from Its Surplus
Keep a reliable catalyst reserve inside the loop and give excess U-235 a separate destination. This is an editorial concept illustration, not an in-game screenshot or tested blueprint.
Kovarex Recipe Inputs vs. Net Output
Kovarex returns most of the same items it uses. A base craft takes 40 U-235 and 5 U-238, then produces 41 U-235 and 2 U-238. Compare both sides before setting inserters or belts.
| Item | Recipe input | Recipe output | Net change per craft |
|---|---|---|---|
| Uranium-235 | 40 | 41 | +1 |
| Uranium-238 | 5 | 2 | -3 |
| Craft time | 60 seconds at base recipe time | One completed recipe | Rate changes with machine speed and bonuses |
What You Need Before a Kovarex Craft
A Factorio Kovarex enrichment setup is a later uranium-processing step. Unlock it, power a centrifuge, and prepare both isotopes. Ore processing yields mostly U-238 and only a small amount of U-235, so collecting the first catalyst reserve can take time.
Research and machine
Unlock Kovarex and provide a powered centrifuge with open output capacity. More input cannot fix missing research or power.
Startup stock
Keep 40 U-235 and 5 U-238 ready for the first craft. Protect the U-235 in a marked chest, belt lane, or controlled buffer.
Ongoing feed
Once the catalyst circulates, replenish 3 net U-238 per craft and prevent the output path from taking the U-235 reserve.
Start a Kovarex Enrichment Loop Step by Step
The first craft is hardest because the line has no surplus yet. Treat startup separately, then verify both outputs before switching to normal circulation.
Collect the initial isotopes
Process uranium ore until you have 40 U-235 and enough U-238. Early U-235 output is random, so avoid spending this reserve before startup.
Load one centrifuge deliberately
Supply 40 U-235 and 5 U-238. Keep general belts and requesters from consuming the reserved U-235 before the recipe starts.
Wait for the full recipe
The base recipe takes 60 seconds. Leave room for both outputs; if the machine pauses, check output slots and power before changing inputs.
Return the catalyst and divert one net unit
Return catalyst stock to the centrifuge. Only the net U-235 can grow your reserve or move to production; inspect counts before automating unloads.
Build a Self-Feeding Kovarex Belt Layout
For a Factorio Kovarex enrichment setup, use one centrifuge, a U-238 input, a U-235 return path, and a separate surplus route. A belt loop or controlled chest works if the catalyst returns before storage takes it.
Keep the two isotopes distinguishable
Use filtered inserters, separate lanes, or buffers so U-235 and U-238 stay sorted. Check filter names and belt direction.
Return U-235 to the input
Return enough U-235 for every machine. Give the loop priority over storage so a full chest cannot starve the recipe.
Feed U-238 and remove its excess carefully
Replenish the net 3 U-238 per craft and clear returned U-238 so it cannot block the next recipe.
Test the loop before adding more machines
Watch one cycle: both outputs clear, U-235 returns, and only surplus leaves. Pause the output to confirm the reserve stays safe.
Use Buffers and Circuits Only Where They Help
One machine often needs only filtered inserters and a small buffer. Circuits help when machines share stock or storage must leave the catalyst reserve untouched.
Protect the minimum reserve
Reserve enough U-235 for active machines and any startup margin. Let the output inserter move only stock above that minimum.
Make overflow visible
Use a dedicated destination for net U-235. If output stops, inspect the reserve signal and buffer before adding more circuit conditions.
Handle U-238 returned by the recipe
Reuse returned U-238 but cover its net cost. Leave room for the next craft and route excess away from a full input buffer.
Estimate Output and Scale the Setup
At the base 60-second recipe time, one continuously running centrifuge makes one craft per minute: nominally +1 U-235 and -3 U-238 per minute. Use net figures for feed planning; each craft still handles the full catalyst quantities.
| Running centrifuges | Nominal crafts per minute | Net U-235 per minute | Net U-238 needed per minute |
|---|---|---|---|
| 1 | 1 | 1 | 3 |
| 4 | 4 | 4 | 12 |
| 10 | 10 | 10 | 30 |
Troubleshoot a Stalled Kovarex Setup
Check recipe status and item counts first. Common causes are missing startup stock, a filter error, or a blocked output.
| Symptom | Likely cause | What to check |
|---|---|---|
| It never starts | Research, power, or inputs are missing. | Confirm the recipe, power, and startup stock. |
| It stops after one craft | Catalyst left the loop or U-238 feed stopped. | Trace both outputs and restore the reserve. |
| U-235 disappears | Output takes catalyst before the return path. | Prioritize return and check the reserve threshold. |
| U-238 backs up | Returned material or input buffer has no room. | Clear both outputs and route excess deliberately. |
| It pauses with inputs present | An output slot, belt, inserter, or power supply is blocked. | Inspect output clearance and power. |
| A larger array stalls | Shared feed and inserter throughput do not scale. | Test a small group and check U-238 feed per minute. |
Plan the Uranium Feed Around Your Factory
Plan production inputs and machine counts around your factory, while keeping Kovarex catalyst stock out of general demand.
Factorio Kovarex Enrichment FAQ
How much uranium-235 does Kovarex consume per cycle?
It uses 40 and returns 41, so net production is 1 U-235 per base craft. The 40 are catalysts, not an ongoing cost.
How much U-238 does one Kovarex craft need?
It takes 5 and returns 2, for a net cost of 3 U-238. The first craft needs all 5 available.
How many U-235 do I need to start one centrifuge?
Prepare 40 U-235 and 5 U-238. Return the catalyst, then route the net U-235 elsewhere.
How long does the Kovarex recipe take?
The base recipe time is 60 seconds; speed bonuses and interruptions change the actual interval.
Can productivity modules increase Kovarex output?
Yes. It affects net production, not catalyst quantities. Check the current recipe preview before scaling.
Why does my Kovarex centrifuge stop after one cycle?
Check for catalyst diverted to storage, missing U-238 feed, blocked output, or a wrong inserter filter before adding machines.
Sources and Further Reading
Recipe totals are checked against the Factorio Wiki. Test community-inspired layouts with your own modules and belt tiers.