Guide to the Hypertorus Fusion Reactor

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The revision reason is: "HFR gas production was overhauled quite a lot, with different fuels producing different gas mixes. The new crystallizer is required for metal hydrogen, as the open-turf reaction was removed, and the crystallizer does not currently require fusion level temperatures for metal hydrogen production."

The Gas Powered Fusion Donut


The Hypertorus Fusion Reactor (HFR) is a complex, late-round project, added to Atmospherics as part of Fusion's seventh major revision.

Words of Warning

Maintaining the HFR is hard. Maintaining the HFR is really hard. Maintaining the HFR makes managing the Supermatter Engine look like a breeze. Expect to spend half an hour just on building supporting infrastructure, then 15-20 minutes running it, depending on what your goals are.

Getting the HFR operational requires knowledge of how to create uncommon gases. This typically means setting up the Incinerator to produce Hydrogen and Tritium.

Going all the way to Metal Hydrogen requires knowledge of the rarer atmospherics interactions, as well as memorizing many effects unique to the HFR.

Oh God Shit's Fucked What Do Halp

  • Is integrity over ~56%? Is there someone that knows what they're doing around? Do you see Healium around, either in the moderator mix interface or in a nearby canister? If at least two out of three of those were true, leave them to it, unless they're asking for help.
  • Is power offline?
    • Run for the APC with an Inducer to charge it fast.
    • Once power is back, run for the interface and fix the settings. Power disappearing forces the settings to bad values, and your old values don't come back when power does. Iron content goes up by ten percentage points PER SECOND while power is offline, every second counts. Continue down the list, everything will be very badly screwed even if you manage to restore power.
    • If this wasn't a passing problem that the Inducer could fix (Beg the AI to help with whichever of these they can):
      • Maximize SMES output.
      • Turn on the Incinerator if available (the AI can do this immediately on Delta). It was usually set up for Tritium/H2 production earlier, can make a modest amount of energy by default, and can make more energy than most SM configurations, albiet not sustainably, if fully upgraded.
      • If things still aren't fixed, proceed to If all else fails
  • Maximize the Current Dampener. This almost always changes the reaction from exothermic (heating things up) to endothermic (cooling things down).
  • Check: Does Heat Output's value start with a minus sign? If not:
    • Immediately minimize the Heating Conductor.
    • Minimize the Fuel Injection Rate.
    • Try changing magnetic constrictor values to see if you can find values that do make heat output negative. Minimizing is a good start. Give up after five attempts. If you can't make heat output negative, proceed to Strategy: Slowdown
  • Strategy: Starvation. Good if heat output is negative, very good if the fusion mix is very small.
    • Maximize the Heating Conductor.
    • Maximize the Fuel Injection Rate. Make sure that no fresh fuel is being piped in.
    • Add more gas to the Moderator Mix. Room temperature is about as good as frozen relative to meltdown temperatures, and coolant cooling needs to go through the moderator mix anyway.
    • If the Fusion Mix is very unbalanced, AND one of Hydrogen or Tritium is below 25 moles, CAREFULLY add whichever of the fuel components was missing at a VERY LOW RATE to help process what's left, and ultimately further reduce the fuel mix volume.
    • Double check the coolant system. Add more Freezers to the coolant network until the system either stabilizes or melts down.
    • Rationale: Fusion is almost always the hottest mix, and a smaller volume is easier to cool than a larger volume. The HFR restores integrity once the Fusion Mix drops below 800 moles, and lower is better. Many bad effects stop happening if there isn't enough fuel to run the fusion reaction.
  • Strategy: Slowdown
    • Minimize the Heating Conductor.
    • Minimize the Fuel Injection Rate. Make sure that no fresh fuel is being piped in.
    • Add more gas to the Moderator Mix. Room temperature is about as good as frozen relative to meltdown temperatures, and coolant cooling needs to go through the moderator mix anyway.
    • Double check the coolant system. Add more Freezers to the coolant network until the system either stabilizes or melts down.
    • Rationale: If you can't make the reaction endothermic, the most you can do is minimize the rate of change and hope your coolant does the job.
  • If all else fails:
    • Call the shuttle.
    • Consider bombing the HFR before it gets any worse (decide whether or not you want to be in the room at the time to avoid lynching to restore your honor).

So how does this all work, anyway?

The HFR consists of three special gas mixes, plus a simple output port:

  • The Fusion Mix
  • The Moderator Mix
  • Coolant

Temperature transfer

Temperature is exchanged:

  • Slowly between the Fusion Mix and the Moderator Mix.
  • Rapidly between the Moderator Mix and Coolant.

Gases added to or removed from Fusion, Moderator, or Coolant retain whichever quantities and temperatures they had previously. Directly adding large quantities of room temperature gases is a very effective way of rapidly reducing temperature. They could be frozen, but when distributing billions of joules of energy, it doesn't matter too much whether the gas you're adding to dilute the heat comes with a few hundred or a few thousand joules. You could also add pre-heated gases if, for whatever reason, you don't want to burn the small amount of fuel required to get through the first few fusion levels.

The entire volume of the Fusion Mix is heated by the capped heat output, and is itself capped at a maximum temperature of 1e8. A smaller Fusion Mix will heat the Moderator Mix more slowly than a large Fusion Mix while providing the same level of production, and will ultimately require less cooling.

Gases produced directly in the output take a temperature equal to 95% of the Moderator Mix's temperature.

Viewable metrics

The HFR's interface provides a lot of useful information.

The exact contents and composition of the internal Fusion Mix and Moderator Mix are displayed prominently at the top. Very straightforward, keep an eye on these whenever adding more fuel or moderator gas.

  • Power Level. The Fusion Power Level is a simple number, from 0 to 6. This determines which effects are active. See the table in The Moderator Mix below for moderator effects by gas and Fusion Power Level, and the lists under Safety/Healing for how integrity is lost and restored. The Fusion Power Level is solely based on the temperature of the Fusion Mix:
    • The Fusion Power Level is 0 between 0 and 500 Kelvin. Very little happens here, but you can burn fuel to add heat.
    • The Fusion Power Level is 1 between 500 and 1,000 Kelvin. Not many useful reactions occur here.
    • The Fusion Power Level is 2 between 1,000 and 10,000 Kelvin. There aren't many useful reactions that occur here, either.
    • The Fusion Power Level is 3 between 10,000 and 100,000 Kelvin. This is the first very useful Fusion Power Level, and most effects here are shared with Fusion Power Level 4, while being much friendlier to work with in terms of heat output and inherent gases created.
    • The Fusion Power Level is 4 between 100,000 and 1,000,000 Kelvin. The effects aren't very different from Fusion Power Level 3, but you can get much, much higher rates of production here, if you're willing to take the risk that comes with being much closer to dangerous power levels. Note that because the temperature scale (used to determine the rate of production from current heat output) is also shared between Fusion Power Levels 3 and 4, you can reach a maximum rate of production of 10 with Fusion Power Level 4, while only being able to reach a maximum rate of production of 1 with Fusion Power Level 3, or a maximum rate of production of 5 with other Fusion Power Levels.
    • The Fusion Power Level is 5 between 1,000,000 and 10,000,000 Kelvin. This is the first dangerous Fusion Power Level. Damage is taken based on the volume and temperature of the Fusion Mix, and the steady increase of Iron Content makes it hard to stay on for long. While there are better consumed-to-produced ratios for high tier moderator reactions here than on lower Fusion Power Levels, the maximum rate of production is half that of the maximum rate of production of Fusion Power Level 4, so generally isn't worth it. You could consider briefly staying on this level if you have at least 100 moles of BZ, and want to either quickly add at least 15 moles of PN to the Moderator Mix to kick start level 3-4 PN production, or quickly accumulate 50 moles of Freon to gain its cooling bonus at level 3-4.
    • The Fusion Power Level is 6 over 10,000,000 Kelvin. The maximum temperature the Fusion Mix can achieve from HFR processes is 100,000,000.
  • Integrity. The current health of the HFR. If this reaches 0% for 30 seconds, you get a third of the station EMPed, an impressive hole in Atmospherics, and probably lynched. Cannot fall faster than 1 percentage point per second, though there is are fewer limits to how far the cause of integrity loss can get out of hand.
  • Iron Content. Integrity is constantly lost based on this value. Worsens or recovers based on Fusion Power Level:
    • At Fusion Power Level 0, there is a 25% chance to recover 1 percentage point of iron content each second each update.
    • At Fusion Power Level 1, there is a 12.5% chance to recover 1 percentage point of iron content per second each update.
    • At Fusion Power Level 2, there is a 8.33% chance to recover 1 percentage point of iron content per second each update.
    • At Fusion Power Level 3, there is a 6.25% chance to recover 1 percentage point of iron content per second each update.
    • At Fusion Power Level 4, there is a 5% chance to recover 1 percentage point of iron content per second each update.
    • At Fusion Power Level 5, there is a 85% chance to add 0.5 percentage points of iron content per second each update.
    • At Fusion Power Level 6, 0.5 percentage points of iron content are added per second.
    • When power is lost (no APC providing power to equipment), 10 percentage points of iron content are added each second (!).
  • Energy Levels. E=MC^2. Matter (using the sum of values listed in Energy modifier for the quantity of each gas in the Gas Effects table below) times the speed of light squared. Amplified by the Fusion Mix temperature and heat modifier (using the sum of values listed in Heat modifier for the quantity of each gas in the Gas Effects table below). Fairly technical, it's faster to compare Heat Limiter Modifier to Heat Output instead.
  • Heat Limiter Modifier. 1e[Fusion Power Level - 1] * [Heating Conductor Value]. This is the maximum amount the temperature of the Fusion Mix can incrase in one update from the fusion process. The maximum amount the temperature of Fusion Mix can decrease in one update from the fusion process is one tenth of this.
  • Heat Output. This is the amount that the temperature of the Fusion Mix changes in one update. If this isn't equal to the Heat Limiter Modifier, or to negative one tenth of the Heat Limiter Modifier, your reaction doesn't have enough energy. Check the Magnetic Constrictor was minimized. Add more fuel, and remove moderator gases that kill energy or heat. There are three exceptions as moderator gas effects that bypass this cap, fixed multipliers that alter the heat output after the cap from the Heat Limiter Modifier was applied, after being used to determine the rate of production, but before the heat is applied to the Fusion Mix: N2O (FL2: +5.5% Heat), PN (FL3-5: +25% Heat; FL6: +125% Heat), Freon (FL3-4: -10% Heat; FL5: -50% Heat).

The current temperature of all mixes, the output pipenet, and coolant are also all immediately visible from the interface as well.

Tunable parameters

Besides choosing which gases to add to the HFR, there are a few tunable parameters:

  • Heat conductor. Sets the maximum internal rate of change in the Fusion Mix's temperature, in either direction (though the Endothermic cap is one tenth the size). Along with the Fuel injection rate, one of the two values that will see the most tuning:
    • Maximize when attempting to increase fusion power levels.
    • Minimize if you need to leave the HFR unattended for a minute.
    • Set to the highest rate your cooling setup can stably handle when attempting to maximize production.
    • Maximize when attempting to reduce fusion power levels, if you successfully flipped the reaction to be Endothermic (cooling).
    • Minimize when attempting to reduce fusion power levels, if you could not flip the reaction to be Endothermic.
  • Magnetic constrictor. Should almost always be minimized, at 50. If your mix has an extremely large volume, constricting it to the smallest space can destabilize the reaction, flipping it to become endothermic. When this isn't a concern, higher values reduce the magnitude of the reaction and the scale of gas effects, which can be situationally useful if you need to leave the HFR unattended for a minute. The Heat conductor is generally a more effective means of control. Maximize when attempting to reduce power levels, if you could not flip the reaction to be Endothermic.
  • Fuel injection rate. This serves two purposes: It sets the rate at which gas is pulled from the fuel port into the Fusion Mix, and it also sets the scale at which gas is consumed - one of two key factors for how much gas is produced. There is no way to separate these two purposes. The HFR will always try to pull more gas in than it consumes, so be sure to have a gas pump or gas mixer keep fuel input at low pressures in order to avoid overfeeding. Along with the Heat conductor, this is the value that will see the most tuning:
    • When initially fueling the HFR, this should have a high value, to bring the Fusion Mix up to a functional volume quickly. 250 to 500 is fine. You could also have this maxed out if you want to exclusively manage the external fuel input rate with a gas pump or gas mixer, although this risks consuming gas at a far higher rate than necessary.
    • During stable production, this should have a value paired with the heat conductor value to optimize the production rate while avoiding gas waste. See the table in "Key Parameters" below for details.
    • When trying to process output gas, this should be set to the minimum value, at 5, while Waste Remove is also set to Off. This mostly minimizes (hot) gases being added to the output port, without wasting fuel, giving any freezers or space cooling time to cool existing output that was already removed. The reaction can be flipped Endothermic to completely stop output gases from being added, but this will burn fuel for no production, and setting the FIR to 5 is almost always sufficient.
    • While trying to return to a safe temperature, without attempting to starve the Fusion Mix, this should be set to the minimum value, at 5. Gas is not produced while the reaction is Endothermic, so there shouldn't be a need to burn more fuel than necessary.
    • While trying to return to a safe temperature, with attempting to starve the Fusion Mix, this should be set to the maximum value, at 1500, in order to burn away the Fusion Mix as quickly as possible. Note that this can also burn through any reserve of Healium extremely quickly!
  • Moderator injection rate. Sets the rate at which gas is pulled from the moderator port into the Moderator Mix. If the moderator port is directly linked to a connector, and supplied with canisters, it's generally safe to leave this maxed out at 1500. Leaving it maxed out also means one less setting to change when you want to rapidly add room-temperature gas to the Moderator Mix to cool it down, and every second often counts.
  • Current dampener. Increases the instability of the reaction. A sufficiently unstable reaction will flip the reaction from being Exothermic (heating) to Endothermic (cooling), albeit with a negative heat change cap one tenth of the magnitude of the positive heat change cap. A mix increasing at 5x10^6K will decrease at 5x10^5K instead! This works even at unsafe fusion power levels, and is the main way of correcting reactions about to get out of hand. Given that this flip is all-or-nothing, this should be set to 0W (nothing) or 1000W (maximum) at all times.
  • Waste removal. If enabled, 50% of each of the Byproducts created by the selected recipe per second, 5% of the Fusion Mix's Anti-Noblium per second, and any user-provided Moderator filter gas are moved from their mix to the output. Forcibly disabled at fusion power level 6. Note that any gases created by the reaction directly in the output bypass this - see the table describing moderator gas effects in "The Moderator Mix" below.
  • Moderator filter. If Waste removal is enabled, this removes up to 20 moles per second of a gas of your choice from the moderator mix, placing it into output.


The HFR consumes two fuels from the fusion mix from a fixed list of recipes. Only one recipe can be selected at a time. The Primary fuel is consumed slightly faster than the secondary fuel - 0.95F to 0.85F, using the variables described later. There is always one main fusion byproduct, which affect gas effects. Other Fusion byproducts do not directly affect gas effects, but do take up space.

Be careful not to oversupply Oxygen recipes, as only byproducts from the selected recipe are removed. Anti-Noblium is always slowly removed, and Helium is removed in most recipes, but Nitrogen, Pluoxium, CO2, and H2O can only be removed from the fusion mix through the associated recipe.

Note that at Fusion Level 2 specifically with the Tier 3 Gas, the Tier 3 Gas is only produced when more than 50 moles of Plasma is present. All other combinations of Fusion Levels and Recipe Output Gases are produced unconditionally, though in varying amounts.

Primary Fuel Secondary Fuel Main Fusion byproduct Other Fusion byproducts Tier 1 output (FL1,2) Tier 2 output (FL1,2,3) Tier 3 output (FL2,3,4) Tier 4 output (FL4,5) Tier 5 output (FL5,6) Tier 6 output (FL5,6) Cooling Heating Energy Fuel consumption Gas production Maximum temperature
Plasma Oxygen CO2 H2O CO2 H2O Freon NO2 Pluoxium Halon x2.5 x0.1 x10 x3.3 x1.4 x0.6
Hydrogen Oxygen Helium Nitrogen Helium Plasma Oxygen Nitrogen BZ Hyper-Noblium x2 x0.6 x3 x1.1 x0.9 x0.75
Tritium Oxygen Helium Pluoxium Helium Plasma Oxygen Nitrogen BZ Hyper-Noblium x2.1 x0.5 x2 x1.2 x0.8 x0.8
Hydrogen Tritium Helium Helium Plasma Oxygen Nitrogen BZ Hyper-Noblium x1 x1 x1 x1 x1 x0.85
Hyper-Noblium Hydrogen Anti-Noblium Anti-Noblium Helium Proto-Nitrate Zauker Healium Miasma x0.2 x2.2 x0.2 x0.55 x1.4 x0.9
Hyper-Noblium Tritium Anti-Noblium Anti-Noblium Helium Proto-Nitrate Zauker Healium Miasma x0.1 x2.5 x0.1 x0.45 x1.7 x0.95
Hyper-Noblium Anti-Noblium Helium Plasma Oxygen Nitrogen Proto-Nitrate Nitrium Miasma x0.01 x3.5 x2 x0.01 x3 x1

Gas effects

All effects are relative to the space permitted by the Magnetic Constrictor, and the amount of moles of gas in excess of 25 moles. The volume of the Fusion Mix is 25L per m^3/B (or 1250L per 50 m^3/B) permitted by the Magnetic Constrictor, and the factor for scaling gas effects is one half of this. When the Magnetic Constrictor is set to 50 m^3/B, as it usually should be, this makes the scaling factor 1/625.

Gas Location Energy modifier Power modifier Heat modifier Radiation modifier Fusion power
Primary Fuel Fusion Mix 1 0 1.15 0 2
Secondary Fuel Fusion Mix 1 1.05 0 0 5
Main byproduct Fusion Mix -1 -0.55 1.05 0.55 7
Nitrogen Moderator Mix 0.35 0 -0.75 -0.45 0
CO2 Moderator Mix 0.55 0.95 0 0 0
N2O Moderator Mix 0.95 -0.05 -1.45 0 10
Zauker Moderator Mix 1.55 5.55 0 0 0
Anti-Noblium Moderator Mix 20 0 0 10 20
Hyper-noblium Moderator Mix -10 0 0 0 10
H2O Moderator Mix -0.75 0 0 0 8
NO2 Moderator Mix -0.15 1.45 0 0 0
Healium Moderator Mix -0.45 0 0 0 0
Freon Moderator Mix -1.15 -0.75 -0.95 -1.15 -5
O2 Moderator Mix 0 0.55 0 0 0
Plasma Moderator Mix 0 0.05 1.25 -0.95 0
BZ Moderator Mix 0 0 0 1.9 8
Proto-Nitrate Moderator Mix 0 0 0 0.1 0
Nitrium Moderator Mix 0 0 0 0 7
Pluoxium Moderator Mix 0 0 0 0 -10

Key parameters

Effects within Fusion reference either Fuel Consumed (F) or the Scaled rate of Production (P).

The effects we want to maximize reference P, so we try to maximize P, then set F so no excess fuel is wasted.

F = fuel injection rate / 1000 * 5 * power_level

P is clamped between 0 and F, based on heat output. Heat output tends to be either non positive or the maximum, limited by the Heating Constrictor. Once we've found a stable Heating Constrictor value for the current mix and cooling infrastructure, we can work out the ideal fuel injection rate which sets P=F, so that no excess fuel is burned.

Fusion Level 1 Fusion Level 2 Fusion Level 3 Fusion Level 4 Fusion Level 5 Fusion Level 6
Temperature scale: heat / 100 heat / 1000 heat / 50000 heat / 1000000 heat / 10000000
Max P: 5 5 1 10 5 30
FIR for F=P given max P: 1000 500 67 500 200 1000
Min P: .5 .5 .1 1 .5 .5
FIR for F=P given min P: 100 50 1.34 (min 5, so always burned) 10 20 17

The Fusion mix

Optimal power is when the fusion mix consists of 50% Primary Fuel and 50% Secondary Fuel. Secondary Fuel is consumed at 0.85F, Primary Fuel is consumed at 0.95F. 0.5F of each byproduct gets produced. Counterintuitively, Anti-Noblium doesn't do anything in the fusion mix except take up space and be extremely slow to remove.

The Moderator mix

The fusion mix is always the primary fuel, secondary fuel, and padding. The output gases have departed, and no longer have any effect on the HFR. The moderator mix is where the most interesting effects happen.

Effects tend to reference F or P. So a gas X that gets consumes at 1.1 times the current rate of production, to produce a gas Y directly in the output port at 0.5 times the current rate of production, gets written as "Consumed x1.1P. Adds Y to Output."

Anti-Noblium production (outside of any recipe output) is special, and is based on the amount of scaled main byproduct in the Fusion Mix (so the amount of main byproduct in the Fusion Mix, and the space permitted by the Magnetic Constrictor), and the Fuel Injection Rate. Anti-Noblium production is higher with a lower FIR. This factor, [Main Byproduct - 25] / (12.5 * [Magnetic Constrictor] * [Fuel Injection Rate]) is denoted in the table below as H. For example, given 100 moles of the main byproduct in the Fusion Mix, the Magnetic Constrictor set to 50 (minimized), and the FIR is 5 (minimized), H=0.024.

0.05% of all Moderator Mix gas is lost per second per Fusion Power Level, after all production and consumption. Keep this in mind when attempting to maintain close BZ or Freon thresholds, or hold very large quantities of Healium.

Gas Description Fusion Level 1 Fusion Level 2 Fusion Level 3 Fusion Level 4 Fusion Level 5 Fusion Level 6
Inherent Regardless of the contents of the moderator mix, Fusion Levels have effects of their own.
  • Adds Recipe's T1 Gas x0.95P to Moderator.
  • Adds Recipe's T2 Gas x0.75P to Moderator.
  • Adds Recipe's T1 Gas x1.65P to Moderator.
  • Adds Recipe's T2 Gas x1P to Moderator.
  • Adds Recipe's T2 Gas x0.5P to Moderator.
  • Adds Recipe's T3 Gas x0.45P to Moderator.
  • Adds Recipe's T3 Gas x1.65P to Moderator.
  • Adds Recipe's T4 Gas x1.25P to Moderator.
  • Adds Recipe's T4 Gas x0.65P to Moderator.
  • Adds Recipe's T5 Gas x1P to Moderator.
  • Adds Recipe's T6 Gas x0.75P to Moderator.

If the Moderator Mix temperature is under 1e7, OR if at least 100 moles of Plasma and 50 moles of BZ are present:

  • Adds Anti-Noblium x15.3846...H to Output.
  • Adds Recipe's T5 Gas x0.35P to Moderator.
  • Adds Recipe's T6 Gas x1P to Moderator.
  • Adds Anti-Noblium x1.05263...H to Fusion.
Plasma The first production moderator gas. Your bread and butter.

Plasma adds a decent heat modifier to help the early fusion process, and has a high heat capacity that helps to slow change to moderator heat (and indirectly, fusion heat) in any direction, giving you much more time to react to anything that happens.

Every gas with an interesting Moderator effect can eventually be produced from Plasma.

With at least 100 moles:

  • Consumed x0.85P.
  • Adds N2O x0.5P to Moderator.

With at least 50 moles:

  • Consumed x1.75P.
  • Adds BZ x1.8P to Output.
  • Adds Recipe's T3 Gas x1.15P to Moderator.
With at least 10 moles:
  • Consumed x0.45P.
  • Adds Freon x0.15P to Output.
  • Adds Nitrium x1.05P to Output.

With at least 15 moles:

  • Consumed x1.45P.
  • Adds Freon x0.25P to Output.

With at least 30 moles:

  • Consumed x1.45P.
  • Adds BZ x1.15P to Moderator.
BZ The second production moderator gas after Plasma. Your stepping stone to Proto-Nitrate. Produces the Healium necessary to run dangerous Fusion Levels for extended periods of time, for those wanting to risk it.

While Fusion Level 1 will burn through BZ rapidly with little gain, Fusion Levels 3 and above treat BZ as a catalyst, only consuming BZ at the base rate common to all gases present in the moderator mix.

Massively increases radiation output. Your ability to handle Hydrogen without radiation turning it into Tritium will be very limited after this.

Causes hallucinations to anyone not wearing mesons at Fusion Levels 3 and above. At Fusion Level 6, Mesons will no longer protect you from hallucinations.

With at least 150 moles:

  • Consumed x0.95P.
  • Adds Halon x0.55P to Output.
No effect With at least 100 moles:
  • Adds Proto-Nitrate x1.5P to Output.
  • Adds Healium x1.5P to Output.
With at least 100 moles:
  • Adds Healium x1P to Output.
  • Adds Proto-Nitrate x1.25P to Moderator.
  • Adds Freon x1.15P to Moderator.
If present:
  • Adds Anti-Noblium x222.22...H, but no more than 10 moles per second, to Moderator.
Proto-Nitrate The final production Moderator gas. Produces the rarest gases.

Massively increases radiation and heat, without increasing the rate of production. This means that when an active level of Proto-Nitrate is present, you will need to provide more cooling for the same level of production.

Since you cannot remove moderator gases at Fusion Level 6, Proto-Nitrate's direct Output production is the only way to extract Fusion Level 6 heat. Being able to transfer Fusion Level 6 heat is necessary for Metal Hydrogen production.

No effect With at least 20 moles:
  • Consumed x1.35P.
  • Increases Radiation by 55%.
  • Increases Heat output by 2.5%, without increasing the rate of production.
  • Adds Nitrium x1.05P to Output.
With at least 15 moles:
  • Consumed x1.55P.
  • Increases Radiation by 95%.
  • Increases Heat output by 25%, without increasing the rate of production.
  • Adds Nitrium x1.25P to Output.
  • Adds Halon x1.15P to Output.
With at least 50 moles:
  • Consumed x1.35P.
  • Increases Radiation by 95%.
  • Increases Heat output by 25%, without increasing the rate of production.
  • Adds Nitrium x1.95P to Output.
  • Adds Pluoxium x1P to Output.
If present:
  • Consumed x3.35P.
  • Increases Radiation by 100%.
  • Increases Heat output by 125%, without increasing the rate of production.
  • Adds Nitrium x2.15P to Output.
  • Adds Zauker x5.35P to Output.
Freon A safety moderator gas which quickly reduces fusion energy, and reduces the amount of cooling necessary.

At high Fusion levels, decreases heat and radiation output, without (directly) decreasing the rate of production.

Comes with very strong negative energy, power, heat, and radiation modifiers, so if you're planning to use this to reduce the amount of cooling required, you'll need to factor in the need for a larger moderator mix to maintain positive energy.

At Fusion Level 5, has a very high threshold to activate, but has a very strong effect. Might be useful as an emergency moderator addition when you're losing control of a reactor. Probably more useful when combined with BZ to make more Healium.

No effect With at least 50 moles:
  • Decreases Radiation by 20%.
  • Decreases Heat output by 10%, without decreasing the rate of production.
With at least 500 moles:
  • Decreases Radiation by 80%.
  • Decreases Heat output by 50%, without decreasing the rate of production.
No effect
Healium Directly restores integrity of a heavily damaged HFR that is operating at dangerous Fusion Levels.

This is the magical red gas that will allow the daring to run the HFR at dangerous power levels for an extended period of time. However, the mechanics and their implications are quite complicated. See discussion below.

No effect With at least 100 moles, when the HFR has taken over 400 damage (below ~56% integrity):
  • Consumed x20P.
  • Restores 0.11% integrity per hundred moles.


Important gases for fusion:

  • Hydrogen
  • Tritium
  • Proto-Nitrate
  • Healium

Gases to filter and process internally:

  • H2O (for Hydrogen)
  • Freon (for Healium; can be used in moderator if you want)

Gases to at least collect to make sure other things don't clog up:

  • Pluoxium (useful directly, can also be sold for a decent price)
  • Helium (can be sold for a decent price)

Gases to optionally collect to use or sell:

  • Nitrium

Gases to optionally collect to sell:

  • Halon (if you care about fire, you're going to be using the backpack anyway)
  • Antinoblium (doesn't do anything outside of fusion, but makes cashmoney at cargo)
  • Zauker (currently doesn't explode with PN, so oddly safe. Bug? Intentional removal?)


NB: Hydrogen won't stay as Hydrogen around radiation even when stored in a canister, now. Fuel always needs to be mixed and piped in advance now, update your designs accordingly.

The "I have four minutes before the already unrecallable shuttle arrives"

Output gases are generally favorable with desirable effects in the moderator, and can be filtered out of the moderator mix if not, provided the Fusion Level is less than 6. So the simplest HFR setup just hardpipes output gases back into the moderator port, tries to stay within safe parameters at Fusion Level 3, and sprints for the shuttle when you screw up and hit Fusion Level 6. This is extremely simple to set up, and lets one get a feel for HFR operation without risking much.

The Cargonian

Tier 3 canisters functionally tolerate any degree of pressure and temperature, even beyond what Fusion Level 6 can throw at you. So the next simplest setup involves moving sets of tier 3 canisters around, repeatedly whacking them with an analyzer or your PDA, and throwing down ad-hoc filters to extract what is useful and discard what is not.

The Factorio

It doesn't take much to fully automate fuel input and output, and several filters on the output will capture most of the gases you care about, with anything useless being vented to space. You'll need much more than a few Freezers if you want to run long term at Fusion Power Level 4. If you do plan to spend much time at Fusion Power Level 4, it's worth considering at least routing H2O to Electrolysis.

The Atmosia

The next step is to completely integrate output and filtering with the main Atmospherics intake and filter loops. You have plenty of space to cleanly do so on Delta Station, but doing the same on MetaStation or even IceBox takes a little more creativity with piping layers.

Full setup example: Just stare at the pipes until you get it, round 2

Foreword: Usage on non-Delta stations

This uses Delta Station as a template, since the abundance of space makes the layout much clearer to follow. Much the same is possible on MetaStation, but you need to be a bit more creative with finding space:

  • The top left corner in the bottom right area makes a useful spot for Electrolysis.
  • The filter loop can do a 180 and double back on a different piping layer along the bottom part of the filter loop, which allows for two filters for H2O to Electrolysis and Pluoxium at the left, three filters for your choice in the next block, then six filters for the key Freon Loopback, BZ, Healium, and PN extraction, and Trit/H2 routing.
  • The mixing chamber can be used for Metal Hydrogen production. Disconnect the usual unfiltered gases to chamber. Break the plasmaglass with a fireaxe, add a Holobarrier, and construct a full Airlock to prevent thermal leakage. Adding in a Passive Vent to the middle follows the same pattern as on Delta.
  • It's probably best to skip BZ formation and Freon formation, since the time taken to construct regions gets just bad enough for the payoff that it's better to just run the HFR at stable levels for longer. There's enough room in the Atmospherics Foyer if you have multiple people, or if you just want to try anyway. Freon formation can use a T2+ canister instead of a spread pipe network. Be careful to still leave room for extended main intake cooling, in case you get called upon to do things that aren't playing with gases.
  • Having high tier freezers becomes much more important, since you don't have much space for expansive Freezer arrays near the HFR room. Separating waste processing and waste heat transfer is going to be very difficult, and it may be best to just leave Freezers attached directly, and switch each one off once overloading.
  • If you're just after Nitrium, most of the infrastructure can be skipped.

Preparing Incinerator fuel, preparing additional Intake points, and extending the Filter Loop

Preparing Delta Station's main atmospherics room.

Before anything else, disconnect CO2 and N2O lines from the port mixing area by replacing the manifolds in front of their pumps. This allows anyone to later swap out the pump with a layer adapter without having to drain the loop, or mess around with holofan projectors, alt clicks, and portable scrubbers over highly pressurized pipes.

Swapping out the two topmost waste loop corners with 4-way manifolds allows for more intake points, and is best done before the waste loop has a chance to fill up with anything substantial. Placing the Electrolysis scrubber and injector now will save time later.

There is a very good spot by the central room where the filter loop can be split and extended, adding in a filter for H2O to go to Electrolysis, and corners sending the waste loop above to the expansion room.

Adding a plasma pipeline is very important for later steps, since plasma is used for many purposes. The plasma pump will need to be replaced with a layer adapter, but can otherwise be cleanly pulled up to the expansion room through the left entrance, as the purple pipe network shown in the illustration.

Setting the mixer by the plasma output to 92% oxygen and 8% plasma strikes a good balance between not needing to make manual adjustments too urgently after oxygen saturation, and still saturating oxygen quickly. You can adjust this proportion according to personal preference.

Turning on and maximising all of the pumps between oxygen output and the Incinerator room lets the pipe network in the Incinerator quickly fill with the Incinerator burn mix. Leave the pumps inside the Incinerator room off for now. They'll be dealt with soon.

Optional: BZ production

Configuring the lower supplementary mixing chamber on Delta Station for BZ production.

Delta comes with additional mixing chambers. The south mixing chamber is very attractive for BZ production provided nobody else wants to use it, and it requires very little setup. Open floor tiles come with 2500L capacity each, and so is significantly more efficient than trying to perform the same reaction in the port area with T1 canisters, which have a capacity of 1000L each. Even with T2 canisters, which have a capacity of 3000L each, this nine-space (effectively ten-space, if you make the input pipenet large enough, as shown in the illustration) area will easily outproduce even six T2 canisters monopolizing the ports area. Six T3 canisters in the ports area is barely more efficient, providing 30kL of volume instead of 25kL, but maintaining throughput while taking advantage of the lower potential pressure per 5000L reaction area is much harder than running parallel in the supplementary mixing chamber, along with taking much longer to build and losing easy access to the cooling required to maintain sufficient mass at low pressure.

Replace the inbound connector with a Gas Mixer, and set it to pump 60% Node 1 (plasma) and 40% Node 2 (N2O), as in the illustration. The rate of consumption is closer to 66:34, but being bounded by N2O will cause much of the produced BZ to become oxygen instead, which is an important condition to avoid. The ratio can be changed closer to consumption values once filled with the safer, N2O-heavier buffer, if desired. Setting the output pressure to 40kPa ensures a good set-once rate of production and throughput. You can lower this once the chamber is filled if you like. Space cooling (to about 27K) lets you reach required mass values while being tolerant of proportion divergence even at 5kPa (holding a mass of 54.4 moles in a 2500L volume, where BZ formation requires 10 moles each of plasma and N2O), though this will take longer to replace input, so setting a target pressure below 15kPa or at least 10kPa is not recommended - the actual pressure will tend to be lower than this, anyway.

Grab a hardsuit, drop a holofan projection between the airlocks to stop station air leaking, and press the vent control button to open up the chamber to space. Replace the vent with a pipe into a manifold, add a Passive Vent to the middle of the chamber, and keep extending the pipe network with a heat exchange junction to space. Drop down a few 4-way Heat Exchanger manifolds. 4-way manifolds add 140L, and a straight pipe adds 70L, so using 4-way manifolds adds just as much volume as clever overlapping setups, while being much simpler to build. A few HE 4-way manifolds is enough to provide minimal cooling. Extending to 15 HE 4-way manifolds brings the network volume to 2625L, which means that if the BZ formation reaction is occurring in the open floors, it will also be occurring in the pipe network, functionally adding a tenth open floor space for the formation reaction to occur in.

Scrubber configuration

You can quickly shift click examine the scrubbers to make a record of their ID in the chat panel. Do this for the topmost (to be Metal Hydrogen production) mixing chamber, and if you set up the lower chamber for BZ production, make a note of this one as well.

Set the Operating Mode to Contaminated to quickly set all scrubbers to extract most gases at maximum range. The expansion area's Air Alarm is unlocked, while the main Atmospherics Air Alarm will require unlocking; either will control the main area.

  • If the lower chamber was configured for BZ production: Configure its scrubber to remove everything except Plasma and N2O.
  • If seeking to make Metal Hydrogen later: Configure the upper chamber's scrubber to remove everything except H2 and BZ.
  • Configure the Electrolysis scrubber you added earlier to remove everything except H2O and N2.

The two supplementary mixing chamber scrubbers should be near the top of the list, while the newly added Electrolysis scrubber will be at the very bottom.

Configuring the Incinerator

Configuring the Incinerator room for Tritium and H2O production.

The first thing to do is to add a new scrubber in the burn chamber, immediately below the starting one. Grab a hardsuit, and enter the Incinerator burn chamber. Swap out the inner pumps for straight pipes while you're waiting for the airlock to depressurize, along with installing the new manifold in preparation for the second scrubber. If you have the engineering door remote, hacking tools, or a friendly idle silicon, you can unbolt both doors and place a holofan projection in the middle to move through much faster, while still preventing air leakage.

Once the second scrubber is installed, consult the room's air alarm. Set the operating mode to contaminated to quickly scrub most gases at extended range, then change the individual settings on the two burn chamber scrubbers (these will be the first and last entries on the scrubber list) to not scrub Plasma, and to additionally scrub N2, in order to remove everything except O2 and Plasma from the mixing chamber.

The output filter needs to be replaced with a corner pipe that doesn't lead to space before the burn can be started. Once you're no longer in danger of losing valuable gas, you can fire it up and turn on the volume pump at an appropriate rate. As a crude rule of thumb: 50L/s for each tier of Freezer parts you're about to install, so 150L/s for T3 Freezers. The incinerator will produce gas very quickly, so you can delay ignition until the filter loop has finished being extended if you prefer.

Main filter expansion and auxiliary production

Setting up the expansion room on Delta Station for additional filtering, and optionally Freon and Healium production.

The lines to and from the original filter loop are brought up on the right, and sent back down again on the left. Many filters are added on this line, most of which lead directly into a connecting port with an associated canister, as in the illustration. There are five key filters, on the top right:

  • Hydrogen. Unable to be safely sent directly into a canister ever since canisters stopped blocking radiation, since Hydrogen turns into Tritium when exposed to radiation. This gets sent into a layer adapter - make sure to remove the vent-to-space piping that the room comes with first - and is split to go to HFR fuel mixing and to Metal Hydrogen mixing.
  • Tritium. Excess can be stored in a canister as a buffer. Sent to HFR fuel mixing.
  • Proto-Nitrate. Stored in a canister, ready to be moved to the HFR moderator when needed.
  • Healium. Stored in a canister, ready to be moved to the HFR moderator when needed.
  • BZ. Excess stored in a canister as a buffer, can be moved to the HFR moderator if needed. Used for Metal Hydrogen formation mixing, Freon formation, and Healium formation.

The next two lines below this are specific to Freon formation, and can be skipped (so the upper BZ manifold then leads directly into the Healium formation mixer; a line to Metal Hydrogen creation can still be pulled up) if Freon formation production is skipped.

  • CO2. Used purely for Freon formation. Excess goes through a pressure valve back to the original filter loop, and is stored in the main CO2 holding chamber.

The next two lines below this are specific to Healium formation, and can be skipped (so the only BZ split heads to Metal Hydrogen, and there is no manifold where Healium and excess BZ returns to the filter loop) if Healium formation production is skipped.

Optional: Freon formation

Freon formation is the most complicated part of this area, but is necessary if you want to transform excess BZ into Healium. Follow the illustration closely. Assuming CO2 and Plasma are functionally free, this ultimately transforms 7 parts BZ into 40 parts Healium, which is a massive boost to relevance. Combined with BZ production, this can quickly produce large quantities of Healium outside of the HFR itself.

A CO2 filter added specifically for Freon formation takes in excess CO2 from the station and incinerator, and tries to combine it to produce Freon. A pressure valve to send excess CO2 forward in the filter loop, set to some high value such as 3500kPa, prevents excess CO2 from blocking the filter loop if unprocessed.

The mix consumed for Freon is 6 parts plasma, 3 parts CO2, and 1 part BZ. The main limiter for mass is 20 moles of BZ, provided all other gases were added in the correct proportions. Given the variance in input gas temperature straight off the filter loop, adding in heat exchangers to the inputs of mixers is important to ensure the mixers send through the correct ratios of gas mass, and not merely gas pressure. To avoid unbalancing the BZ mixer, and to reduce gas volumes to quantities easier to equalize, separate the Plasma input pipe network for Freon from the main Plasma pipeline with a gas pump.

The simplest way to maintain even ratios is to mix 25% BZ with 75% CO2 first, then mix this intermediate mix (yellow pipe network in the illustration) at 40% (final: 10% BZ, 30% CO2) with Plasma at 60%.

Maintaining the high temperatures needed for efficient production, while making sure the process doesn't run into a condition that stops processing, while also making sure the setup can run unattended, takes a bit of work. Conditions to avoid:

  • Pressure at either of the Gas Filter outputs, including the loopback output, exceeding 4500kPa. Will quickly happen if frozen (compressed) gas is pumped in and receives heat.
  • Insufficient mass for processing. Can happen if the temperature is too high.

The first condition will quickly happen if cold (and so highly compressed) gas is pumped in, then receives heat. The simplest approach to avoid this is to split the production pipe network (brown in the illustration) into two: A staging area, where the gas is heated to at least 800K (the temperature gate will require a Multitool to invert the usual "cooler than" operating mode; at least T2 lasers are required in the Heater), and then set to pressurize the main area up to 2500kPa. This leaves room for the temperature to increase 50% to 1200K, while not exceeding 3750kPa.

For the second condition: The sprawling brown manifolds in the illustration creates a sum volume of 1260L, which is enough to operate at full T4 Heater temperature while meeting minimum mass requirements, with a small amount of leeway for input proportion variation. If this is desired, the temperature gate would need to have its minimum temperature increased and run for a while before the main Heater can have its temperature increased, in order to not exceed Gas Filter maximum pressure. It would also need periodic monitoring to make sure the proportions haven't diverged too much.

Optional: Healium formation

Significantly easier to produce than the Freon it consumes, and takes up very little space. Given typical gas input temperatures, the Freezer in this gadget can be skipped if Freon formation is skipped. Takes up a small 2x8 block, most of which is the filtered Freon output line.

Main HFR room

Setting up the main HFR room, and surrounding infrastructure.

When it comes to cooling, there really is no limit for how much cooling is too much. A couple of Freezers are sufficient to sustain Fusion Power Level 3. An order of about five is enough for safety to pull you down from accidental Fusion Power Level 4, and you really want at least nine if you plan on running at Fusion Power Level 4 long term. You theoretically need quite a lot more if you want to recover from accidental Fusion Power Level 5 or 6, but being able to add large quantities of room temperature Plasma directly to the Moderator Mix to dilute the energy and resulting temperature lets you sidestep this somewhat.

Plasma has a very high capacity, so is very useful as coolant. Filling the coolant network up to about 800kPa is safe for both tier 3 and tier 4 freezers. This can be increased if you know you are only ever using tier 3 freezers, but keep in mind that tier 4 freezers can compress four times as much mass into this space at the same pressure, and can risk emptying the entire plasma holding chamber (!) if blindly pumped in by volume pump or similar.

This design uses many devices in parallel to control the flow of coolant to and from the core.

Leaving the HFR without coolant or moderator gas will very, very quickly raise the temperature of the Fusion Mix while starting up. Leaving the HFR for unattended for two updates (2-4 seconds, depending on current space lag) can be enough to go up a Fusion Power Level, so stay absolutely glued to the HFR interface if you do this - even very brief digressions to the next room over can ruin you!

Fuel used by the HFR is consumed at 47.22...% Tritium to 52.77...% Hydrogen. Setting the mixer to 54% H2 to 46% Trit seems to work out better in practice, for reasons unknown (outstanding temperature differences?)

The configuration shown in the illustration ensures that all important controls are located close to the interface, for easy access. The moderator port is also easy to reach. Fuel Input and Waste Output generally do not need to be interacted with much, so were assigned to East and North respectively simply due to being closer to the networks they want to be connected to.

Waste output, despite being called "Waste", is typically the most valuable output, and the reason to run the HFR in the first place. This design uses two outlets, each behind its own manual valve:

  • HFR Heat exchange to Metal Hydrogen. The gases themselves are largely ignored, but the extreme heat from unsafe Fusion Power Levels is used to power Metal Hydrogen formation.
  • HFR Output to output gas cooling and processing. Sends output gases through cooling, and around the filter loop once at easy-to-move-and-also-not-catch-fire temperatures.

Optional: Hydrogen to Tritium conversion

Adding optional H2 to Tritium conversion to the HFR room.

While not a concern during initial setup, a long running HFR can accumulate excess Hydrogen relative to Tritium, especially at Fusion Power Level 4 where large quantities of H2O are produced for Electrolysis conversion.

The HFR gets crowded quickly, but there is still room for adding an area for excess Hydrogen to be converted directly to Tritium. Since canisters are no longer radiation shielded, a canister on a connector works about as well as a passive vent on a floor sealed by windows, while being much easier to set up. Given the importance of Hydrogen in other processes, set a high Pressure Valve output value to make sure this is truly excess Hydrogen being converted.

The concerns for pressure around the Gas Filter are the same as around Freon formation: Pressure cannot exceed 4500kPa on either output, including an output looped back to the input, or the filter will stop moving gas. Setting a low output pressure prevents this. Here, an arbitrary 800kPa is set. There is room for much more, but be wary of tying up too much Hydrogen for Tritium conversion.

Metal Hydrogen production

The pinnacle of atmospherics:

  • Make Golems at a fraction of the rate that science can manage, twenty minutes later!
  • Export for a price laughable compared to what you already produced from the Incinerator alone!
  • Wear pretty-sweet looking armor with resistances a fraction of what the basic hardsuits offer, and die to the inevitable thermal leak which makes every area fewer than five airlocks away uninhabitable!

You do get a lot of kudos just for being able to make Elder Atmosian gear, though.

Competes with Nitrium Formation for hardest reaction to master, except you can't bypass the process to make Metal Hydrogen bars using fusion.

The process is too random to make a universal prescription, though 97% H2 3% BZ injected with a slow input will cover most cases. Some notes on both direct and emergent behavior:

  • More hydrogen is not necessarily better. Hydrogen and BZ is consumed proportional to the amount of Hydrogen present, though randomly relative to each other, but will still only randomly produce up to one bar per atmos update in ideal conditions.
  • More heat is not necessarily better, as it reduces the odds you will produce usable Metal Hydrogen bars.
  • Meeting mass and temperature conditions without meeting pressure conditions will cause the reaction to fizzle: still rapidly consuming energy as normal, but never being able to produce bars. Either ensure you have enough heat that when you have the mass, the pressure threshold is met, or enough mass that when you have the heat, the pressure threshold is met, since this will quickly deplete your heat supply otherwise.
    • A mass of at least 301 moles per tile will ensure this condition is never met, but will triple the rate of consumption for the same result.
    • or a temperature of at least 28.7 million Kelvin will ensure this condition is never met, but will come with slightly worse than 50/50 odds that hydrogen is consumed without producing anything.

Keep an eye on your hydrogen and heat budgets, as well as how much time you are willing to wait to produce bars, and continually adjust your strategy to suit the circumstances.

Try to make sure the HFR doesn't EMP a third of the station in the process. Reaching over 300% iron content will make it very difficult for the HFR to return to safe operating parameters, regardless of Healium availability. Throwing on the brakes at 280% will keep you safe, but will give you only about four minutes of sustained heat availability.

Optional: Immediate volatile gas filtering

Adding filters before our intake joins the main intake, to capture the most volatile gases.

Because Zauker decomposes almost immediately into common gases upon being exposed to common gases, adding in filters before intake rejoins the main intake is justified.

TODO: This is almost certainly true for Proto-Nitrate as well. Find a way of pulling up Proto-Nitrate to a location convenient for HFR moderator input from a similarly early position? Possibly an earlier position to avoid Tritium response from Incinerator output?

Optional: Additional gas filtering

Adding more filters, after previous filters, to capture additional useful or reactive gases.

The main reactive gases remaining are Halon, Nitrium, and Pluoxium.

  • Nitrium is highly desirable, both for its effects in internals, and for its high price.
  • Pluoxium is almost as desirable, serving as very effective internals, and selling at a decent price in excess.

With all optional components added, the main mixing/unfiltered chamber will fill with Helium and Anti-Noblium. Consider switching off Mix to Waste to avoid clogging the filter loop.

  • Helium serves no purpose other than to clog the Fusion Mix and to be sold at Cargo for a decent price, at a rate slightly better than than of Tritium.
  • Anti-Noblium has no reactions available, but can be useful in the Moderator Mix to make changing Fusion Power Levels happen much faster, or to enable running with a smaller Fusion Mix.


When you first activate the HFR, a paper titled "How to safely operate the HFR" will appear above the interface. This serves two important purposes. First, you can alt-click it to fold it into a paper plane. Second, you can throw it into the SM, slightly offseting the amount of power you're about to consume, and making a strong symbolic gesture.


A pair of mid tier Freezers on coolant is more than enough to stably run Fusion Power Level 3 at modest production rates. Three will let you run at higher rates, and recover faster from a small accident. Every Fusion Power Level comes with an order of magnitude more heat produced, and so an order of magnitude more cooling required. Expect to need at least half a dozen high tier freezers to run Fusion Power Level 4, and more if you want to be able to recover from more serious accidents (or intentional overcharging). You get to diminishing returns at a Dozen high tier Freezers, since running at low Fusion and Moderator Mix mass allows you to efficiently add in room temperature Moderator Gas directly, at the expense of the HFR needing much more micromanagement.

It's difficult to run much lower than 500 total moles of Fusion Mix without depowering your reaction, but Fusion Power Level 4's heat output at high rates of production with this small of a fusion mass can be effectively managed with nine Freezers and cycling in fresh room-temperature fuel and moderator gas. Keep in mind that raising the heat limiter to increase production also reduces the window you have to respond to anything getting out of hand!


Losing power is extremely bad. The settings are forcibly set to values that are not helpful for a meltdown:

  • magnetic constrictor to 100
  • heating conductor to 500
  • current dampener to 0
  • fuel injection rate to 200
  • moderator injection rate to 500
  • no waste removal

Your previous settings are not restored when power is restored!

Most significantly, iron content increases by 10 percentage points every second that the HFR goes without power (!).


The HFR takes damage and provides healing based on fusion volume and temperature. Examples of damage/healing at various values are provided for a sense of scale.

If the power level is 5 or more:

  • Takes damage equal to ((((fusion_mix_moles) * 1e5 + fusion_temp) / 1e5) - 2500) / 200 per atmos tick
    • Temperature of 1e8: Take 0.5 points of damage per 100 moles over 1500 moles per atmos tick
    • Temperature of 5e7: Take 0.5 points of damage per 100 moles over 2000 moles per atmos tick -- point at which metal hydrogen's efficiency maxes out
    • Temperature of 2e7: Take 0.5 points of damage per 100 moles over 2300 moles per atmos tick
    • Temperature of 1e7: Take 0.5 points of damage per 100 moles over 2400 moles per atmos tick
    • Temperature of 2e6: Take 0.5 points of damage per 100 moles over 2480 moles per atmos tick
    • Temperature of 1e6: Take 0.5 points of damage per 100 moles over 2490 moles per atmos tick
  • Takes damage equal to log(10, fusion_temp) - 5
    • 2.7 damage per atmos tick at 5e7
    • 2 damage per atmos tick at 1e7
    • 1 damage per atmos tick at 1e6

If the amount of moles in the fusion mix is less than 1200, or the power level is 4 or less:

  • Heals (800 - fusion moles) / 150 each atmos tick
    • Heals .6 damage per atmos tick when total fusion moles are 700
    • Heals 2 damage per atmos tick when total fusion moles are 500
    • Heals 2.7 damage per atmos tick when total fusion moles are 394
    • Heals 4.5 damage per atmos tick when total fusion moles are 125

If fusion is active, the fusion temperature is below 5e5, and the power level is 4 or less:

  • Heals log(10, temperature) - 5.5 each atmos tick
    • Heals .5 damage per atmos tick when fusion temperature is 1e5
    • Heals 1.5 damage per atmos tick when fusion temperature is 1e4
    • Heals 2.5 damage per atmos tick when fusion temperature is 1000
    • Heals 3.5 damage per atmos tick when fusion temperature is 100
    • Heals 4 damage per atmos tick when fusion temperature is 30

Takes damage equal to ((iron content rounded to nearest 100%) - 1) every atmos tick

The final sum from all of the above effects is capped to losing at most 0.5% integrity (taking 4.5 points of damage) every atmos tick.

In short: run with a starved fusion mix to avoid damage and start healing, and work on reducing temperature if you can.

Full power: How I learned to stop worrying and love Chernobyl