Description

The Fission Reactor is a component that produces heat from the nuclear fission of uranium rods.

Usage

General Operation

The reactor heats water (H₂O) using the energy generated by nuclear fission.

Water has a dual role:

• Cooling the reactor core.
• Producing steam for turbines.

Required Resources

The reactor requires:

• A continuous low-voltage power supply of 1000 W.
• A supply of cold water.
• Uranium rods placed in all 4 internal zones of the reactor.

It is highly recommended to have at least one uranium rod per zone.
A reactor with empty zones will operate very poorly or not at all.

Inventory and Zones

The reactor has 40 slots, divided into 4 independent zones.

Each zone influences its local power and temperature based on the number and type of uranium rods placed.

Control Rods

Each zone has an adjustable Control Rod:

• 0% retracted (fully inserted) → Reaction stopped.
• 100% retracted → Maximum reaction.

Reaction Startup

A manual neutron injection is required via the data port.

Up to 1000 neutrons per second can be sent during startup (up to 250 neutrons per second per zone).

• Even with uranium at 100% U235, an initial neutron supply is necessary.
• With low-enriched uranium (10% U235), startup may require a few minutes of continuous neutron injection.

Chain Reaction Behavior

Although each zone of the reactor has its own uranium rods, temperature, and neutron population, the reactor is designed to simulate a realistic chain reaction across the entire core.

• Zones are not completely isolated.
• Neutrons produced in one zone can partially spread to neighboring zones.
• This behavior improves the stability of the reaction and helps weaker zones sustain fission.

A highly active zone can support a less active one, but having all zones properly fueled remains essential for maximum efficiency.

Cooling and Steam Production

When used with Steam Turbines, the ideal water output temperature is 650 K.

• Below → Reduced energy production.
• Above → Loss of efficiency (no additional gain).

An excessively high water flow can overcool the reactor and limit the power output.

Reactor States

Safety and Meltdown

• Above 1200 K → Enters CRITICAL state - meltdown imminent.

In MELTDOWN:

• Steam flow stops - no energy can be produced.
• The reactor becomes unusable until manually reset.

Reset Meltdown

Via the reset button in the reactor interface (key V).

• In creative mode, this button is always available.
• In adventure mode, it's only available when the reactor has entered meltdown.

Uranium Rod Wear

Uranium rods degrade slowly over time as they participate in the nuclear reaction.

Isotope Consumption

• U235 is gradually consumed to sustain fission.
• U238 can also partially transform into plutonium.

Fission Products

During operation, rods automatically accumulate fission products:

• Xenon (Xe)
• Plutonium (Pu)

These elements directly appear in the rod's composition as it ages.

It is important to note that these fission products currently have no use in the game. To obtain plutonium for crafting the RTG, you must use the plutonium manufacturing process described on the RTG page RTG.

Depleted Rod

When a uranium rod's U235 concentration drops below 4.45%, it becomes depleted.

A depleted rod can no longer sustain a chain reaction, even with an external neutron supply.

Wear Factors

The lifespan of uranium rods depends entirely on:

• Their initial U235 enrichment rate.
• The actual power produced by the reactor (thus the neutron flux).

→ The lower the enrichment and the higher the power extraction, the faster the rod will wear out.
→ Conversely, a highly enriched uranium rod operating at moderate power can last for an extremely long time.

List of inputs

List of outputs

Uranium Rod Manufacturing

Low Enriched Uranium (LEU)

Highly Enriched Uranium (HEU)

UF₆ (Gas) Production

* The production of Hydrogen Fluoride (HF) triggers a highly exothermic reaction. In this specific case, the resulting temperature, even if the chemical furnace displays values around 3000K, does not affect the chemical reaction. However, in subsequent processes, you will need to cool down HF before it can be used, typically with an Active Radiator or a similar cooling device.

Enrichment Centrifuge Usage

Operation:

• The first centrifuge receives uranium hexafluoride (UF₆) from the top.
• The heavy output (bottom) can be discarded as it will only contain U238.
• The lighter output can be sent to another centrifuge for further processing.

Typically, achieving a high U235 concentration requires a chain of 8 to 10 centrifuges.

Back to Solid State and Uranium Rod HEU Assembly