Mr. Mine Wiki
General Info: MaterialsChestsQuestsMilestonesUpgradesBlueprints
Depth Progression: Super MinersCavesScientistsGemsWeaponsCore/Book Of SecretsReactor[Guide]
More: RelicsShortcutsFAQAbbreviations

The reactor is a milestone found at 1133-1134km (W2-101 - W2-102km). The Buff Lab is found at 1135km (W2-103km). This is where you finally learn why you don't sell isotopes. Its shortcut is "R".

The reactor is used to generate Nuclear Energy that is stored in batteries and used for creating bombardments. The bombardments are burned to create late moon isotopes Einsteinium and Fermium.

The Reactor is a puzzle/management minigame into itself, and a quite entertaining one at that. As such, this page has been designed to keep as spoiler-free as possible until the "Strategy" heading. 8th classical guide (careful, as that guide is not spoiler-free) is also linked from there.

For the really helpful Reactor Planner made by Adversarius#2964 click here.

Historical note
  • Before v0.40, the Reactor was located at 1313km, W2-301 and W2-302. The Buff Lab was found at W2-303.
  • When the Reactor was first added all the components were known from the first level.

Basic concepts[]


Once you're near the Reactor, stock up on Oil. It will be your second-most-needed resource.

As now the reactor is unlocked just before unlocking magnesium, at the start there is really not much to do. Without magnesium you cannot craft batteries, and without batteries you cannot store Energy, and thus you cannot use buffs or upgrade the reactor. You can, however, start crafting the other components. Patience. Magnesium used to be the most limiting resource even when the Reactor was unlocked 200 km deeper.


There are six types of components:

  • Rods: Generate energy and heat
  • Fans: Cool/Dissipate heat.
  • Batteries: Store the energy into Nuclear Energy
  • Heat Ducts: Connect Rods to Fans and other Heat Ducts
  • Bombardments: Consume energy to create new isotopes, generate heat
  • Buffs: Enhance the effects of the Rods/Fans/Batteries they are placed next to (cannot buff buffs). Unlocked at Reactor lv. 3

You craft components and put them on a "layout". The components you can craft and the size of your possible layouts will depend on your Reactor level. Your objectives are:

  • First, enough cooling. If not enough cooling, the Reactor will stop.
  • Second, generate enough energy
  • Third, use up that energy.

There are nuances to how fans and ducts connect to rods so if you don't want to read the full strategy it's best to ask questions in the Discord General chat channel if you get stuck.

Shift + Click[]

The most useful shortcut here is Shift+Click.

  • If used on the Inventory (left column), it places that component into the first available slot of the reactor (left to right, up to down).
  • If used on the Reactor, it places that component back into the Inventory. There are subtleties to this, which are explained below, at the start of the Strategy section. The spoiler-free version is: Better not to use it on Fuel Rods OR Bombardments unless you're very sure they've completely burned (finished timer).

Reactor and Buff Lab Level Cost[]

(Very minor spoilers: If you want to discover all by yourself, stop here. The only surprises are the sizes and shapes of the Reactor at each level)

Reactor and buff lab Level costs
level Reactor cost grid space Buff lab cost Buff Discount
level 1 free Reactor level 1 (9 slots) free 0%
level 2 25 Bm

20k power

10 e1

Reactor level 2 Grid (15 slots) 50 Bm

400,000 power

level 3 50 Bm

200,000 power

100 e1

Reactor level 3 grid (25 slots) 100 Bm

3,000,000 power

level 4 100 Bm

750,000 power

50 e2

Reactor level 4 grid (45 slots) 250 Bm

5,000,000 power

level 5 500 Bm

1,500,000 power

30 e3

Reactor level 5 grid (81 slots) 400 Bm

8,000,000 power


Reactor Components[]

(Mild spoilers: If you want to discover by yourself all components and when are they unlocked, stop here. Otherwise, it's nothing the game won't eventually tell you, right on the user interface).

Rector components

this is what it would look like if you have all the components

Component Name/

List Priority

Makes/Does Type Heat Cost to make Unlocks in
Fan -12 heat Fan -12 heat

(-1 Fan worth of Heat)

2.5 million aluminum

1,000 oil

Reactor 1
Highly Enriched Uranium Fuel Rod 4,500 u2

750 u3

2,500 Pu1

500 Pu2

36,000 energy

(10 per sec) 1 hour

Fuel Rod 24 heat

(2 fans worth of heat)

8,000 u1

3,000 u2

500 u3

Reactor 1
Dual Highly Enriched Uranium Fuel Rod 9,300 u2

1,550 u3

5,050 Pu1

1,010 Pu2

108,000 energy

(30 per sec) 1 hour

Fuel Rod 66 heat

(5.5 fans worth of heat)

16,000 u1

6,000 u2

1,000 u3

Reactor 2
Quad Highly Enriched Uranium Fuel Rod 19,200 u2

3,200 u3

10,200 Pu1

2,040 Pu2

324000 energy

(90 per sec) 1 hour

Fuel Rod 180 heat

(15 fans worth of heat)

32,000 u1

12,000 u2

2,000 u3

Reactor 3
Enriched Uranium Fuel Rod 23,000u2

17,250 Pu1

144000 energy

(10 per sec) 4 hours

Fuel Rod 18 heat

(1.5 fans worth of heat)

72,000 u1

11,500 u2

Reactor 1
Dual Enriched Uranium Fuel Rod 23,000u2

17,250 Pu1

432,000 energy

(30 per sec) 4 hours

Fuel Rod 48 heat

(4 fans worth of heat)

144,000 u1

23,000 u2

Reactor 2
Quad Enriched Uranium Fuel Rod 23,000u2

17,250 Pu1

1,296,000 energy

(90 per sec) 4 hours

Fuel Rod 126 heat

(10.5 fans worth of heat)

288,000 u1

46,000 u2

Reactor 3
Mixed Oxide Fuel Rod 2,000 u3

1,500 Pu13

288,000 energy

(8 per sec) 10 hours

Fuel Rod 21 heat

(1.75 fans worth of heat)

22,800 u2

2,880 u3

32,700 Po1

3,270 Po2

Reactor 1
Dual Mixed Oxide Fuel Rod 4,040 u3

3,030 Pu3

864,000 energy

(24 per sec) 10 hours

Fuel Rod 54 heat

(4.5 fans worth of heat)

57,600 u2

5,760 u3

65,400 Po1

6,540 Po2

Reactor 2
Quad Mixed Oxide Fuel Rod 8,210 u3

6,160 Pu

2,592,000 energy

(72 per sec) 10 hours

Fuel Rod 144 heat

(12 fans worth of heat)

115,200 u2

11,520 u3

130,800 Po1

13,080 Po2

Reactor 3
Small Battery stores 5,000 energy Battery 0 heat

(0 fans worht of heat)

2 million magnesium Reactor 1
Large Battery stores 50,000 energy Battery 0 heat

(0 fans worth of heat)

2 small batterys

10 million magnesium

25,000 power

Reactor 2
Extra Large Battery stores 250,000 energy Battery 0 heat

(0 fans worth of heat)

2 large batterys

50 million magnesium

400,000 power

Reactor 3
Heat Duct transfers heat duct 0 heat

(0 fans worth of heat)

15 million iron

2,000 power

Reactor 1
Copper Buff buffs the top and bottom by 55% Buff 0 heat

(0 fans worth of heat)

50 milllion copper

200,000 power

Reactor 3
Platinum Buff buffs the left side and bottom by 55% Buff 0 heat

(0 fans worth of heat)

50 milllion platinium

500,000 power

Reactor 4
Silver Buff buffs the top and right side by 55% Buff 0 heat

(0 fans worth of heat)

50 milllion silver

500,000 power

Reactor 4
Gold Buff buffs the corners by 30% Buff 0 heat

(0 fans worth of heat)

50 million gold

1.5 million power

Reactor 5
Californium Bombardment 1 10 e1

-288,000 energy

(-10 per sec)

Bombardment 24 heat

(2 fans worth of heat)

15,000 power

1 million califormium

1,000 h1

Reactor 1
Californium Bombardment 2 10 e2

-864,000 energy

(-30 per sec)

Bombardment 72 heat

(6 fans worth of heat)

150,000 power

1 million califormium

1,000 h2

Reactor 2
Californium Bombardment 3 10 e3

-2,592,000 energy

(-90 per sec)

Bombardment 216 heat

(18 fans worth of heat)

1.5 milllion power

1,000,000 californium

1,000 h3

Reactor 3
Pu/Po Fuel Rod 2,000 Po3

921600 energy

(16 per sec)

Fuel Rod 36 heat

(3 fans worth of heat)

4,000 Pu3

72,500 Po1

7,250 Po2

Reactor 1
Dual Pu/Po Fuel Rod 4,040 Po3

2764800 energy

(48 per sec) 16 hours

Fuel Rod 96 heat

(8 fans worth of heat)

8,000 Pu3

145,000 Po1

14,500 Po2

Reactor 2
Quad Pu/Po Fuel Rod 8,160 Po3

8294400 energy

(144 per sec) 16 hours

Fuel Rod 264 heat

(22 fans worth of heat)

16,000 Pu3

290,000 Po1

29,000 Po2

Reactor 3
Polonium RTG Fuel Rod 1036800 energy

(6 per sec) 48 hours

Fuel Rod 15 heat

(1.25 fans worth of heat)

2,500 Po3 Reactor 1
Einsteinium Bombardment 1 1 F1

-1,152,000 energy

(-20 per sec) 16 hours

Bombardment 30 heat

(2.5 fans worth of heat)

1,000,000 power

1 million n1

10 e1

Reactor 5
Einsteinium Bombardment 2 1 F2

-3,456,000 energy

(-60 per sec) 16 hours

Bombardment 90 heat

(7.5 fans worth of heat)

3 million power

1 million n2

10 e2

Reactor 5
Einsteinium Bombardment 3 1 F3

-10368000 energy

(-180 per sec) 16 hours

Bombardment 270 heat

(22.5 fans worth of heat)

9 million power

1 million n3

10 e3

Reactor 5


Full spoilers ahead. You've been warned. You can also check 8th's guide

Shorhands / notation[]

We'll be using these shorthands in discussion, and in layouts.

There are five types of Fuel Rods. The color names are also used in the Discord and the Guide.

  • HE (red): Highly Enriched Uranium Fuel Rod
  • E (green): Enriched Uranium Fuel Rod
  • MO (purple): Mixed Oxide Fuel Rod
  • PP (gray): Pu/Po Fuel Rod (gray)
  • RTG (RTG): Polonium RTG Fuel Rod

The first four have a Dual and a Quad version, so Dual Highly Enriched will be DHE and Quad Pu/Po will be QPP in this notation.

There are also six types of Bombardments, three Californium Bombardments (generate Einsteinium) and three Einsteinium Bombardments (generate Fermium). Annotated, CB1, CB2, CB3, EB1, EB2, EB3

Batteries are annotated as "B", Heat Ducts as "HD", Copper Buffs as "CB", Silver Buffs as "SB", Platinum Buffs as "PB" and Gold Buffs as "GB"

General mechanics / Burn cascade[]

This has interesting similarities to real life, like how some nuclear fuels can be used to craft others, and how RTG are used for long-term electricity generation. See Nuclear Fuel and RTG on Wikipedia, for starters. Though the game mechanics are, of course, highly stylized.

Each type of rod will take some isotopes to craft, and give some isotopes as a "decay reward", provided you burn it in full (which you should). Decay rewards more than offset some of the isotopes used on creation, so the rods are "net negative" in some isotopes and "net positive" in others. When we say "use up/consume" here, we'll mean "net negative, after full burn".

  • Red Rods/HE use up U-1, generate U-2, U-3, Pu-1, Pu-2
  • Green Rods/E use up U-1, generate U-2, Pu-1
  • Purple Rods/MO use U-2, U-3, Pu-1, Pu-2, generate Pu-3
  • Grey Rods/PP use up Pu-3, Po-1, Po-2, generate Po-3
  • RTG use up Po-3, generate nothing.

At the same time, Red Rods/HE have very short burn time (1h), with 4h for green rods/E, 10h for Purple/MO, 16h for Grey/PP, and 48h for RTG.

Isotope burn cycle[]

Red -> Purple -> Grey -> RTG. Note the absence of Green.

This is because, for each step (single/dual/quad), Green Rods produce the same energy (with less heat), than the corresponding Red Rod, and they last for 4h instead of 1h, so they're better for both babysitting (less rod replacement) and layout (less fans) reasons. However, they use up, each hour, on net, more than double U-1 than the Red Rods (specifically, 225% as much), without producing the corresponding doubled decay rewards (for Pu-1 it's +72%, and for U-2 it's +90% for the basic Green, and down to +66% for the Quad Green, owing to higher "double/quad" bonus in decay rewards for the Red Rods). Plus, Green Rods do not produce U-3 or Pu-2, both needed for the Mixed Oxide (Purple) Rods. And Purple Rods are the only ones producing Pu-3, needed for the Dual Pu-Po (Grey) rods, which in turn is needed by the RTG.

So, in short, if you burn Green for its advantages over Red, you will end up short in resources for Purple and Grey. So you should burn Red, always, unless time management makes this impractical.

Shift + Click Subtleties[]

  • For Fans, Batteries, Heat Ducts and Buffs, there is no problem (other than probably stopping the Reactor) with moving them from the Inventory to the Reactor and vice versa.
  • Spent (empty) Fuel Rods automatically collect its decay rewards. Be careful: Decayed fuel rods still serve as connections and removing them can stop your reactor. This applies especially when you are expecting to fill your batteries once one or more bombardments end.
  • Full Fuel Rods (haven't started burning, either because you put them into the Reactor when it was stopped, or because putting them in caused the Reactor to stop), can be recovered freely.
  • Half-spent Fuel Rods are another matter. You can't recover partially-spent Fuel Rods (trying to recover them would delete them instead). The game puts up a confirmation message if you click or shift-click a partially spent Rod.
  • Bombardments: There is not a confirmation message for half-done Bombardments (as you recover them, they count as a Full Fuel Rod), so you can make the mistake of recovering a partially-used Bombardment. This has the effect of losing all of its progress (all the energy spent is wasted), although you can place it again in the Reactor. All in all, the only thing you lose is time. Be careful around them.

He is for Ein[]

After blueprints levels 24, all Helium is used for is Einsteinium. Use it all up, no worries. The problem will be He-3. It always is. See Helium for details.

Ni is for Fm[]

  • After blueprints for level 26, all Nitrogen is used for Fermium.

Layout tips and tricks[]

  • Generally, a layout is something you get to incrementally, instead of designing it from scratch (at least, from level 3)
  • You can always substitute a Duct for a Fuel Rod, in a layout.
  • Try your heat model with a Californium Bombardment, instead of a fuel rod. If it works, you can recover it (there's no commitment)
  • Design first for heat, then for other things.
  • Design a workable prototype first, then substitute components with Buffs, using the +55% twice trick to slowly increase the amounts.
  • Buffs on Fuel Rods help with getting more energy from them, faster, useful sometimes with the long-time RTG, or when waiting to empty reactor


  • If Reactor is generating energy and the rods finish burning, the Reactor will stop (but only when the last fuel rod stops burning), and you will get a notification in news. If it is consuming energy for Bombardments, the Reactor will stop when it doesn't have any energy (and thus, notification). However, it there are batteries and bombardments, the energy will be consumed (and no notification will be sent) until all energy is consumed, even if the rods themselves burn (another way of looking at it, Bombardments are rods too, so until they are consumed, not all rods are burned, thus no notification). So, in short, if you are counting on notifications to change your rods (for example, to maintain your buffs), you cannot do Bombardments at the same time. Or, if you do Bombardments, you have to manually check rod's expiration (either on the Reactor, or having an eye on the energy meter).

Reactor component progression[]

  • At Reactor Level 2, you'll be able to craft Californium Bombardment 2, Large Battery (50k energy each), and Dual versions of all rods except RTG.
  • At Reactor Level 3, you'll unlock Californium Bombardment 2, the Quad versions of the Rods, and the Extra Large Battery (250k energy each).
  • At Reactor Level 4, you'll unlock Platinum Buff and Silver Buff.
  • At Reactor Level 5, you'll unlock Gold Buff and Einsteinium Bombardments 1, 2, and 3.

Reaching Level 4 is quite quick if you don't sell isotopes, because you'll be able to power through a lot of burning with timelapses. You may be able to reach it around depth 1350. However, Level 5 requires Einsteinium 3, which requires Helium 3, which is very, very rare, and only becomes practical to obtain (in the amounts needed for this) around depth 1465, when you'll be mining promethium. Thus you will reach Reactor Level 5 around depth 1500 (or more).

Level 1[]

This is the starter level. At first you'll only be able to craft Fans, Heat Ducts, Small Batteries (5k energy each), the 5 basic Fuel Rods and Californium Bombardment 1. You start with 1 Highly Enriched Uranium fuel rod, 2 Fans and 1 Small Battery.

Your mission is to get 20k energy and 10 e-1 for the next level. For this you have to

  • Craft 2 small batteries. Fill them, along with the starting one, for 15k energy, to create your first Californium Bombardment 1. Use Highly Enriched Fuel Rod (red rod) for this.
  • Burn the CB1 (8 hours), using more Red Rods for energy.
  • Craft an additional battery. Fill up the 4 for 20k energy
  • Upgrade!

Level 2[]

more additional energy save up on on magnesium (pls refine these last four levels if you can

Level 3[]

Level 4[]

250 building materials 1.5 million energy and the 30 einsteinium 3 you probably cant get this till 1430 roughly when production goes up a lot

Level 5[]