Going Nuclear: spent fuel, reprocessing, MOX and repositories
Handbook · RBMK · Next: Troubleshooting
Spent Fuel Solution contains radioactive products and generates decay heat. Complete its collection system before your first reactor startup.
Spent Fuel Pool
Pipe the Waste nozzle to a Spent Fuel Pool and supply water separately. The checked block stores 16,000 mB waste and 8,000 mB water. A decorative pool of ordinary water does not replace the machine block.
Water cools and shields the contents. Monitor water, heat and free waste capacity with Engineer's Goggles. The pool can boil dry and overheat; maintain feedwater and reserve even after reactor shutdown. Cooling time depends on activity and the time model, so no fixed number of wall-clock minutes applies to every batch.
Option A: Dry Cask
A Dry Cask directly beside the pool accepts sufficiently cooled waste. Its checked capacity is 8,000 mB. This is shielded long-term storage, not a void or a reprocessor. Its shielding reduces radiation rather than providing the permanent seal of a repository.
Provide more storage or another destination before a full pool blocks further waste extraction. Do not dismantle filled waste equipment as though it were empty decoration: spills and radiation are part of the system.
Option B: reprocessing
Put a Reprocessing Plant beside the pool. It receives cooled spent fuel, needs Nitric Acid and requires at least 64 RPM. At a standstill, check machine status, cooling, speed and all three output tanks.
| Share of processed fuel | Product | Destination |
|---|---|---|
| 80% | Uranyl Nitrate | Back to centrifuges |
| 6% | Plutonium Nitrate | MOX production |
| 14% | High-level Waste | Vitrification and repository |
Nominal acid demand is 0.5 mB per mB processed fuel, rounded per batch. Outputs also round to whole mB; these percentages do not promise identical absolute yields from every tiny batch.
Use Smart Fluid Pipe filters and separate tanks for all products. A full output can stop the entire process. Higher speed cannot fix an output blockage or fuel that has not cooled sufficiently.
MOX fuel
Use a Mechanical Mixer:
| Inputs | Output |
|---|---|
| 70 mB Plutonium Nitrate + 930 mB Depleted Uranyl Nitrate | 1,000 mB MOX Solution |
The supplied recipe does not require heating. Reactors accept MOX as fuel, but its lower delayed-neutron fraction makes changes more sensitive. Recalculate and start gently instead of reusing a previous rod setting unchanged.
A closed fuel cycle recovers usable materials. It does not create unlimited fuel without losses or eliminate high-level waste.
Vitrify high-level waste
Use a heated Mechanical Press with Basin, through Compacting:
| Inputs | Output |
|---|---|
| 250 mB High-level Waste + 1 Sand + 1 Iron Ingot | 1 Vitrified Waste Canister |
Ponder refers generally to a steel can, but this version's recipe requires an iron ingot. Unsealed canisters still radiate; loose waste can leak.
Build and seal a repository
- Dig a closed chamber deep underground. Default
repositoryMaxYis −32. - Line the floor, ceiling and walls completely with Bentonite.
- Place Vitrified Waste Canisters inside; do not leave an unsecured stockpile outside.
- Put a Repository Vault in the wall with its back facing the interior.
- Close the chamber and right-click the vault.
- Read the validation result for depth, closure, lining and contents.
Only the successful seal message confirms how many canisters were enclosed. The mod describes the seal as permanent: sealed canisters no longer emit. Do not treat it as an ordinary chest to reopen and retrieve later.
For “no room”, check vault orientation; for “lining”, repair the reported position; for “too shallow”, check depth; for “empty”, check canisters. A bentonite surround with an open entrance is not a sealed repository.