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Dense Lead Plate

Reactor Chamber

Dense Lead Plate

Advanced Circuit

Reactor Chamber


Dense Lead Plate

Reactor Chamber

Dense Lead Plate

Nuclear Reactor

Nuclear Reactor is an advanced generator that produces EU by slowly breaking down refined Uranium Cells. As cells decay inside the reactor they produce heat. If cooling is insufficient, the reactor will gradually overheat and eventually explode, violently. Luckily, heat may be removed by various cooling methods. A nuclear reactor can be expanded by adding up to 6 Reactor Chambers, one per side. Each chamber will expand the nuclear reactors' inventory by 6 slots.


The nuclear reactor produces EU by draining Uranium Cells in its inventory. Each uranium cell produces a base value of 5 EU/tick. When a cell is adjacent to another (on one of its 4 sides), each cell adds to the amount that particular produces. This is because each Uranium Cell also throws off a neutron pulse in each direction. For instance, three cells in a line would produce (10+15+10=35 EU/tick). The total EU a reactor produces per tick can be read by a EU-Reader.

The efficiency of a reactor is measured by the effective number of cells divided by the real number of cells. For example, a line of 3 cells leads to 7 effective cells (2+3+2), and an efficiency of 7/3 or about (2.33).


Heat is produced by Uranium Cells inside the reactor's inventory. Each uranium cell produces a base value of 4 heat/tick. When N cells are adjacent to another, it produces 2N * (1 + N). For instance, three adjacent cells produce (12+24+12=48 heat/tick).

Without any other component, the produced heat goes to the reactor's core, and heats up the reactor. The core temp can be read by a Digital Thermometer.

On the reactor's core, heat exhibits itself in 4 ways according to its value:

  1. A small fire burning in the reactor (4000)
  2. Evaporation of water close to the reactor (5000)
  3. Radiation poison to nearby players (7000)
  4. Meltdown and consequent nuclear explosion (8500)

Expanding core's heat values

The basic component to deal with core heat is plating. Each component inserted in the reactor's inventory increases the total amount of heat a reactor can sustain:

While previous components increase the core heat capacity, they do not remove heat from it nor cool the reactor down. To cool down the reactor's core, different components have to be used.

Controlling components heat

Like mentioned in the introduction, only when there are no components in the reactor's inventory the heat produced by the uranium cells goes to the reactor's core. However, components can be inserted in the inventory in order to remove heat from other components, for instance from an uranium cell.

The fundamental rule is: heat only goes to the reactor core if there is no other way to go. Heat can be transfered from a component to other by adjacency: components exchange heat when are adjacent (4 sides) to each other. The following table gives the values of some of the main components. They were obtained by systematic tests on the planner.


from core (heat/tick)

from adjacent (heat/tick) self coolling (heat/tick) Storage (heat)
Heat Vent 0 ? 6 1000
Reactor Heat Vent 5 ? 5 1000
Overclocked Heat Vent 36 ? 20 1000
Advanced Heat Vent 0 ? 12 1000

So, for example, an Overclocked Heat Vent will cool a total of 20 heat/tick. The heat can be transmitted to him by e.g. placing it close to an uranium cell. Other option is to put it somewhere, and the uranium cell will emit heat to the reactor (4 heat/tick), which the Vent will absorb (36 heat/tick) and cool itself (20 heat/tick).

In order to efficiently exchange heat between components and the reactor's core, the heat exchangers exist. They basically exchange heat between themselves and other components. The values of the heat exchangers are:


from/to core (heat/tick)

from/to adjacent (heat/tick) Storage (heat)
Heat Exchanger 4 16 2500
Reactor Heat Exchanger 72 48 5000
Advanced Heat Exchanger 8 32 10k
Component Heat Exchanger 0 36 5000

Other components include coolant, the uses of which are unknown; condensators, to remove heat one time; and Neutron reflectors, which increase the efficiency and heat output of uranium cells when adjacent to them .


The Nuclear Reactor, and its 6 added Reactor Chamber, act as a single inventory. When a chunk boundary is running through the reactor, the chambers and their contents can disconnect and drop as items. This can disrupt the regulatory system of the reactor, resulting in a meltdown. So it is recommended to place all reactor parts and cooling system at the same chunk, or if you can't, using a Dimensional Anchor is another option. A Redstone current is required for the Reactor to start generating power.

Unregulated Nuclear Reactors can cause extreme explosions. A base you have worked on for days can become a crater with a 50 block diameter. It is highly recommended that appropriate safety measures be taken.

Therefore, consider using this Nuclear Setup Planner (need java to run). This allows you to experiment setting up the inventory of the nuclear reactor and displays helpful info, such as how much power the reactor would generate and how long it would take before exploding. This makes it possible to experiment with Mark V Reactors without destroying the enviornment! 

Click here to see a reactor that is cheap to run, outputs 220 EU/t, and is completely safe. It is also very easy to make automatic. The plating is unnecessary for the layout, but helps fill the slots, so if you use pipes to make the filling of the reactor with uranium, the uranium will go to the right place. And click here to see another safe reactor which outputs 245 EU/t, more efficient, but also more expensive. For a design that outputs 380 EU/t, much better than the previous designs, with a trade-off of being more expensive click here.

You can also build Breeder reactors to re-enrich depleted uranium cells. This type of reactor needs to be heated to work correctly and can be very dangerous if handled incorrectly. Experiment with a safe reactor first ! Click here to see a breeder layout working at T: 33000. You can heat this layout by adding Quad Uranium cells in the two holes on the middle-bottom. Or you can switch the three Simple cells to Quad cells until it's hot, then switch back quickly to Simple cells to stabilize it.

More in-depth information can be found HERE on the nuclear reactor page of the IC2 wiki. 

File:Tekkit, how to build an absolutely safe nuclear reactor