Subnautica Nuclear Reactor — Power Stats, Rods and Charging Guide

The Nuclear Reactor is Subnautica's endgame power plant: a seabase module that generates 250 power per minute and stores 2,500 energy, burning up to four Reactor Rods (20,000 energy each) for over five real-life hours of continuous base power. It's the answer to every "my base keeps blacking out" problem, and it pairs with the Power Cell Charger and Battery Charger to keep your vehicles topped up. This guide covers the reactor itself, the rods, the chargers, and the Ion Power Cell upgrades — the full Subnautica power system in one place.

Here's what you'll learn:

• Nuclear Reactor stats, build recipe and fragment locations
• Reactor Rod crafting and the depleted-rod problem
• Power Cell Charger and Battery Charger stats (with real numbers)
• Ion Batteries and Ion Power Cells, and the charger trick that exploits them
• Which power source is actually best for your base

Official resources: Steam store page · Official Subnautica Wiki — Nuclear Reactor · Official Subnautica Wiki — Power Cell Charger · Official Subnautica Wiki — Ion Power Cell

Nuclear Reactor: Stats, Recipe and Fragments

The Nuclear Reactor is an interior module built with the Habitat Builder, placed in the center of a Multipurpose Room or Large Room. All numbers from the official wiki:

Fragments: scan 3 Nuclear Reactor Fragments. Locations (verified against the wiki and community guides): the Mountains seabed, wrecks in the Dunes, Mountains, Blood Kelp Trench and Sea Treader's Path, plus one inside the Jellyshroom Cave Degasi Seabase.

Reactor Rods are crafted at the Fabricator from 3 Uraninite Crystal + 1 Lead + 1 Titanium + 1 Glass. Uraninite Crystals spawn in the Blood Kelp Zone, Grand Reef Caves, Deep Grand Reef, the Lost River (Tree Cove, Junction, Mountains Corridor) and the Inactive Lava Zone — the Lost River Junction is the most reliable early farm. The Lost River wiki entry even notes there's enough lead in the biome to build a reactor and its rods on site (Lost River guide).

Per the official Nuclear Reactor databank entry: "Renewable energy sources will usually be sufficient for maintaining a small outpost. For everything else there's nuclear power."

The Depleted Rod Problem

Each rod leaves a Depleted Reactor Rod behind when spent. You can't recycle it and you can't put it in a normal Trash Can — it needs a Nuclear Waste Disposal module. Also: if you deconstruct a reactor with partially-expended rods inside, the rods are lost. And despite the databank's warning to wear a Radiation Suit, there is no radiation hazard around the reactor — that line is lore, not mechanics.

Power Cell Charger: Stats and Fragments

The Power Cell Charger is the vehicle companion to the reactor: it charges two Power Cells (or Ion Power Cells) at once, drawing from your base or Cyclops power pool. Stats from the official wiki:

The 80-second trick: if you put a partially-charged Ion Power Cell in one slot, the charger runs at the ion rate for both slots — so a regular Power Cell next to it charges at 150/min and fills in 80 seconds. It's a niche trick (ion cells are better anyway), but it's a documented behavior and great for a pre-expedition top-up.

The Battery Charger is the smaller sibling: up to 4 batteries, charging at 9 energy/min per battery (a 100-energy battery fills in 11 min 5 s; Ion Batteries at 45/min each). Recipe: 1 Wiring Kit + 1 Copper Wire + 1 Titanium. Fragments are common in Grassy Plateaus wrecks — you'll have this long before the Power Cell Charger.

Ion Power Cells and Ion Batteries

The endgame energy upgrade. From the official wiki:

• Ion Power Cell: 1,000 energy (five times a standard 200) — recipe 2 Ion Battery + 1 Silicone Rubber, and it fills the same slots as a normal Power Cell. Six of them take a Cyclops from 1,200 to 6,000 energy.
• Ion Battery: 500 energy (five times a 100 standard) — recipe 1 Ion Cube + 1 Gold + 1 Silver Ore.
• Blueprint source: both unlock from the Orange Data Terminal inside the Alien Thermal Plant (late-game, in the Inactive Lava Zone — the same area that holds the Blue Tablet, see our Sea Emperor guide).

The catch: they take five times longer to charge (hence the charger math above). The other catch is logistics — Ion Cubes are found in Precursor facilities and the Alien Thermal Plant, not in outcrops, so your supply is limited until you've explored the deep alien bases.

Which Power Source Should You Use?

Honest comparison for base power:

The community consensus (from r/subnautica base threads): one Nuclear Reactor is overkill for a normal base but perfect for energy-hungry setups — multiple Water Filtration Machines, a full charging wall, and a Moonpool. Two rods last roughly the entire endgame. For a Lost River or Lava Zone forward base, a Thermal Plant is cheaper and free forever; for the main base, nuclear wins. If you're mid-game and short on Uraninite, the Lost River guide covers where the crystals actually spawn.

FAQ

How do I get the Nuclear Reactor in Subnautica?

Scan 3 Nuclear Reactor Fragments (Mountains seabed, Dunes/Mountains/Blood Kelp Trench/Sea Treader's Path wrecks, Jellyshroom Degasi base), then build it with 1 Plasteel Ingot + 1 Advanced Wiring Kit + 3 Lead in a Multipurpose or Large Room.

How much power does a Nuclear Reactor generate?

250 energy per minute regardless of rod count, with 2,500 internal storage. Each of its 4 Reactor Rods holds 20,000 energy (~80 minutes under full load), so a full reactor runs 5+ hours.

How do I charge batteries and power cells?

The Battery Charger fills 4 batteries at 9 energy/min each. The Power Cell Charger fills 2 power cells at 30 energy/min each (6:40 for a full cell), drawing power from the base or Cyclops. Both can be built inside the Cyclops.

What are Ion Power Cells?

Precursor-tech cells with 1,000 energy (5× normal), crafted from 2 Ion Batteries + 1 Silicone Rubber. Blueprint from the Alien Thermal Plant's Orange Data Terminal. Six Ion Cells give the Cyclops 6,000 energy.

Is the Nuclear Reactor worth building?

For the main base, yes — it's the only set-and-forget power that runs 5+ hours. For deep forward bases, a Thermal Plant near a vent is cheaper. One reactor is plenty; two is for heavy charger/filtration setups.

Related Guides

• Subnautica Lost River — Map, Entrances & Resources
• Subnautica Cyclops Guide — Fragments, Upgrades and Pilot Tips
• Subnautica Sea Emperor — Story, Location & Blue Tablet
• Subnautica Below Zero Map — Biomes, Coordinates & Navigation

Last updated: August 13, 2026.