Skip to main content

Documentation Index

Fetch the complete documentation index at: https://mintlify.com/hbmmods/hbm-s-nuclear-tech-git/llms.txt

Use this file to discover all available pages before exploring further.

Metallurgy in NTM goes far beyond vanilla smelting. The mod introduces a full thermal processing system built around TU (Thermal Units) — a dedicated heat energy type distinct from HE electricity. TU is transferred via copper contacts on the undersides of machines and cannot be carried by cables or pipes; heat sources must be physically placed beneath or adjacent to the machines they supply. This system connects the Blast Furnace, Rotary Furnace, Steel Furnace, Combination Oven, and Boiler into a unified thermal hierarchy where fuel quality, stacking arrangements, and heat routing all matter. Understanding the TU system and its heat source options is a prerequisite for advanced alloy production and efficient bulk ore processing.
TU-based machines are identified by a copper contact on their underside. Place a heat source directly beneath the consumer, or chain multiple heat sources together. TU cannot be transported through pipes or wires — physical proximity is mandatory.

​
The TU System: External Heat Sources

NTM’s thermal network is defined by a clear hierarchy of heat source machines. Every TU-consuming machine — including boilers, furnaces, and the Stirling Engine — requires one of the following heat sources placed immediately below it. Heat sources and their consumers at a glance:
Heat SourceOutputNotes
FireboxLow TUCheapest; coal, coke, or Solid Fuel
Heating Oven5× Firebox TU8× fuel consumption; less efficient
Fluid Burner (Oil Burner)VariableBurns flammable fluids (oil derivatives)
Electric HeaterConfigurableConverts HE electricity to TU
Heat Exchanging HeaterHigh TUUses hot coolant fluids from reactors

​
Machines

The Blast Furnace is the essential early-game furnace for producing Steel, Red Copper (Minecraft Grade Copper), and other basic alloys. It combines two item inputs into one alloy output, often with an optional byproduct.Unlike a vanilla furnace, the Blast Furnace is selective about fuel: it only accepts hot-burning fuels — coal, coke, or Solid Fuel. Wood, sticks, and other low-temperature fuels will not work.Hot Air Blast: Supplying the Blast Furnace with a hot air blast (via dedicated duct blocks) accelerates processing speed up to 3× the base recipe speed, making it essential for high-throughput steel production.Flue Gas: The Blast Furnace produces flue gas as a byproduct. This gas can be burned for energy using appropriate equipment, or simply flared off.Power requirement: Solid fuel (self-contained combustion; no external heat source or HE electricity required).Key recipes:
  • Steel (iron + coal/coke)
  • Red Copper / Minecraft Grade Copper (copper + tin)
  • Advanced Alloy (early game)
  • Various other binary alloys
The Blast Furnace is your first and most important alloy machine. You cannot make Steel any other way in early NTM. Steel is required to build the Steel Furnace, the Boiler, and many other machines — prioritize getting the Blast Furnace running early.
The Rotary Furnace is an advanced alloying furnace that accepts multiple solid item inputs plus one fluid input, producing output as liquid metal that must subsequently be cast. It is the primary source of Weapon Steel and Saturnite, and offers alternate recipes for Gunmetal and Steel.Inputs and connections:
  • Solid items: inserted through color-coded access ports on the back
  • Fluid input: connected to one of the two grey ports on the output side
  • Steam (input): connected to the steam engine duct on the left side
  • Low-Pressure Steam (output): exits through the same steam port
  • Solid fuel: inserted through the iron-bar grate at the front
The Rotary Furnace requires both solid fuel and Steam to operate. It consumes steam during operation and outputs Low-Pressure Steam as a byproduct, which must be condensed or vented.Exhaust: The furnace emits smoke from the opening at the top. Connect a smokestack to manage the exhaust; without one, a smoke plume will billow freely.Power requirement: Solid fuel (coal, coke, Solid Fuel) + Steam fluid input.Key recipes:
  • Weapon Steel (required for high-tier tools and armor)
  • Saturnite (required for late-game weapon components and high-temperature parts)
  • Gunmetal (alternate recipe)
  • Steel (alternate recipe, more material-efficient than Blast Furnace in bulk)
The Steel Furnace is a general-purpose furnace powered by an External Heat Source (TU). It runs three smelting recipes in parallel, making it significantly more productive than a vanilla furnace at the same fuel cost.Certain recipes — particularly ore smelting and log carbonization — include a bonus output indicated by a small secondary progress meter below the main progress bar. Capturing this bonus output is worth setting up a proper item collection system.The Steel Furnace is not the fastest furnace in NTM due to thermal transfer rate limitations, but its versatility and triple-recipe capability make it a long-term staple throughout the playthrough.Power requirement: TU from any External Heat Source placed below.Key recipes: All standard furnace recipes (ore smelting, metal ingots), bonus charcoal from logs, specialty alloy smelting, glass production.
The Heating Oven is an advanced version of the Firebox, serving as an External Heat Source that burns 5× hotter. However, it consumes fuel 8× faster, making it less fuel-efficient overall. It is best used when heat output volume matters more than fuel economy.The Heating Oven has a copper contact at the bottom, allowing multiple Heating Ovens to be stacked vertically. A stacked Heating Oven receiving heat from below operates at 50% efficiency from the lower source. This stacking capability makes it useful for supplying high-demand heat consumers.Placing an Ashpit beneath the Heating Oven captures the produced ash, which can be re-burned or recycled into other materials.Power requirement: Solid fuel (coal, coke, Solid Fuel — same restrictions as Firebox).Best used for: Boilers requiring more heat than a Firebox can supply, Steel Furnaces running at maximum throughput, or Rotary Furnace auxiliary heating.
The Firebox is the cheapest External Heat Source available. It burns coal, coke, or Solid Fuel to generate TU output. Higher-quality fuels increase both TU output and combustion efficiency.The Firebox’s simplicity makes it the default choice for most early TU setups. A single Firebox under a Boiler produces enough heat to supply a basic Steam Engine chain.Placing an Ashpit beneath the Firebox captures ashes for recycling or secondary combustion.Power requirement: Solid fuel.Best used for: Boilers, Steam Engines, early Steel Furnaces, Stirling Engines.
The Electric Heater is an External Heat Source powered by HE electricity. It must be configured with a screwdriver before use. This makes it the bridge between the HE power grid and TU-based machines, useful in late-game setups where electricity is abundant but combustion fuels are inconvenient.
Due to the first law of thermodynamics, using an Electric Heater to boil water for a Steam Engine will always produce less electricity than it consumes. Do not use the Electric Heater in a water-boiling loop expecting to gain power — you will only lose it. Use the Electric Heater for non-steam TU applications where direct combustion is impractical.
Power requirement: HE electricity (input), outputs TU.Best used for: Supplying TU to machines in locations where running fuel pipes is impractical, late-game base automation.
The Heat Exchanging Heater is a powerful External Heat Source used primarily by nuclear reactors that employ a coolant fluid (such as Perfluoromethyl / PFM) instead of boiling water directly. It extracts heat from hot coolant fluid, outputs usable TU through its copper contact, and returns the cooled fluid.GUI configuration:
  • Top field: Amount of fluid consumed per cycle
  • Bottom field: Tick delay between cycles (for fine-tuning heat output rate)
Power requirement: Hot fluid input (no HE electricity required).Best used for: PFM-cooled reactor heat extraction, late-game high-TU applications where reactor heat needs to be converted to mechanical heat for furnaces or boilers.
The Solar Tower Boiler converts water into steam using focused sunlight from heliostat mirrors. Setup requires pointing mirrors at the boiler:
  1. Right-click the boiler to save its position.
  2. Right-click each heliostat mirror to point it at the saved boiler position.
Important positioning rules:
  • Mirrors cannot tilt past 45° — the boiler must be elevated above the mirror field.
  • The horizontal distance between a mirror and the boiler cannot exceed the vertical distance.
  • The higher the boiler tower, the larger the mirror field that can serve it.
The boiler has no GUI and cannot receive water directly — water must be supplied via pipes. The resulting steam feeds a Steam Engine for power, producing Low-Pressure Steam that is condensed back into water for a fully renewable loop.The Solar Tower Boiler does not work at night. A minimum of roughly a dozen mirrors is needed to reach boiling temperature.Power requirement: Sunlight (no fuel or electricity).Best used for: Passive renewable power generation, aesthetic builds, supplementary steam supply.
The Automatic Buzzsaw automatically cuts down trees and plants within a 10-block radius. When supplied with fuel (such as Wood Oil), it rotates slowly and extends its blade only when wood or plant blocks are detected. Felled trees are fully harvested and replanted if leaves were present.Positioning: The Buzzsaw should be placed at the same height as the target trees, with the blade striking the second-lowest log block. Sugar cane and cacti can also be harvested if the blade height is set to avoid breaking the lowest block.Harvested items are dropped on the ground at the cut location — unlike the Automatic Thresher, which ejects items from the machine directly. A collection system (fans, hoppers) is recommended.
Touching the spinning sawblade is lethal. Build adequate barriers around the Buzzsaw’s operating area.
Power requirement: Liquid fuel (Wood Oil or similar).
The Automatic Thresher harvests crops and plants in a 7×7 area, cycling every 10–15 seconds when supplied with fuel. Wheat, carrots, and similar crops are replanted automatically after harvest. Sugar cane and cacti are harvested from the top, leaving the base block intact.The Thresher also works on tall double-plants like Hemp and Mustard Willow, removing only the upper block. Mustard Willows are only harvested at maturity. Sunflowers and tall grass yield items at a low rate without being destroyed.Unlike the Buzzsaw, the Thresher collects harvested items internally and ejects them from the back of the machine, making automated output collection straightforward.Hostile mobs struck by the thresher’s reel yield small piles of Nitra on death — a useful secondary resource for explosives.Power requirement: Liquid fuel (Wood Oil or similar).
The Ashpit is placed beneath compatible combustion machines to collect their ash byproducts:
Machine AboveAsh Produced
FireboxAsh (type varies by fuel)
Heating OvenAsh (type varies by fuel)
Standard SmokestackFly Ash
Industrial SmokestackFly Ash + Fine Soot
Fine Soot collected from Industrial Smokestacks is the raw material for crafting Fullerite, a high-value late-game material. This makes the Ashpit + Industrial Smokestack combination worth setting up for any base planning to engage with late-game content.Collected ash can be re-burned for additional energy or recycled in chemical processing.Power requirement: None (passive collection).
The Pyrolysis Oven becomes available after completing the Vacuum Oil Processing chain and plays a role similar to the Coker Unit. Instead of producing Petroleum Coke, it converts oils and residues into the more energy-dense Solid Fuel.The Pyrolysis Oven also handles several Bedrock Ore Processing recipes shared with the Combination Oven, as well as unique recipes for producing Syngas and Fine Soot (the Fullerite precursor).Power requirement: External Heat Source (TU via copper contact).Key recipes:
  • Solid Fuel from oil residues (higher energy density than Petroleum Coke)
  • Syngas production
  • Fine Soot for Fullerite
  • Bedrock ore processing intermediates
The Pyrolysis Oven is only available after completing the Vacuum Oil Processing chain. Do not expect to build it until deep into the mid-to-late game.

​
Heat System Reference

TU Transfer Rules

TU moves only through copper contacts — physical stacking of blocks. No pipes, no cables. Heat sources go below consumers. Multiple consumers can share a stacked heat chain with efficiency penalties.

Alloy Progression

Steel (Blast Furnace) → Red Copper (Blast Furnace) → Weapon Steel (Rotary Furnace) → Saturnite (Rotary Furnace). Each tier requires the previous tier’s products to build.

Renewable Heat

The Solar Tower Boiler + heliostat mirror array provides passive, fuel-free steam generation. Best suited for supplemental power or dedicated renewable setups.

Waste Management

Pair every Firebox or Heating Oven with an Ashpit below. Industrial Smokestacks with Ashpits produce Fine Soot for late-game Fullerite synthesis — a passive resource that would otherwise be wasted.

Build docs developers (and LLMs) love

Get started for freeTalk to us