| Property | Details |
|---|---|
| Type | Exterior Facilities |
| Category | Power |
| Description | Produces a steady trickle of power. Intended as a starter power source for new outposts. Unsafe for long term human exposure. |
| Fragments Required | 2 |
The Radiothermal Generator, also known as the Oldfire RTG, is a buildable seabase part in Subnautica 2. It serves as an early-game power solution that does not require fuel or sunlight, making it ideal for initial outpost establishment.
Usage
The Radiothermal Generator provides a constant, low-level power output. Due to its radioactive nature, it is unsafe for human exposure and should be placed outside the habitat, preferably behind shielding. It is best used as a temporary power source until more efficient and safer generators (such as Bioreactors or Thermal Plants) can be constructed.
Recipe
To craft the Radiothermal Generator, you must first unlock its blueprint by scanning 2 fragments. Once unlocked, it can be built using the Habitat Builder with the following materials:
| Ingredient | Quantity |
|---|---|
| Titanium | 2 |
| Copper | 2 |
| Tar Graphene | 3 |
Fragments
Fragments for the Radiothermal Generator can be found in the Tar Flats and surrounding areas. Below are known locations:
| Location Description | Depth | Coordinates |
|---|---|---|
 In the middle of the Tar Flats | 360m | -281314, 383335, 36000 |
 In the Tar Flats | 355m | -261242, 401273, 35500 |
 Tar Flats on an Alterran platform beneath a large Towershroom | 360m | -243646, 395504, 36000 |
 In Tar Flats Wreck 1 | 450m | -264214, 364053, 45000 |
 In an Axum Cargo Container near an Axum structure on the far east side of the Tar Delta | 370m | -219958, 395109, 37000 |
Databank Entry
Radiothermal Generator
Radioisotope thermoelectrical generators have been called "the worst form of power generation, except when they're the only form." Although they are expensive, heavy, dangerous and inefficient, RTGs generate power without any need for fuel or sunlight.
— Radioactive decay generates heat, which produces electric current in a thermocouple
— Very low power output, but very long lifespan
— No actual nuclear chain reaction: operates purely on decay products
— Unsafe for human exposure; place outside habitat behind shielding
The exact materials used in the RTG are selected by the fabricator on the basis of local scans. The Protean variant requires graphene conductors for the heat sink. The strontium-90 power supply, while inadequately shielded, has been cleared for use by colonists with short survival horizons.
RTGs have two ideal use cases: as a long-term power supply for low-draw systems like probes, or as a portable starter supply for newly constructed bases. Once a local power supply is online, the RTG can be disconnected and reused elsewhere.
"The Oldfire RTG: glow on the go."
Changelog: removed "because a half life might save your life" slogan due to mixed messaging in biobed-supported mission architecture.
Trivia
- Despite the databank entry mentioning a strontium-90 power supply, and the fact that Strontium is an in-game item with a description referencing RTG usage, the crafting recipe for the Radiothermal Generator does not currently require Strontium.
