If you wanna go make a stable reactor or at least know what you're messing with in Nuclear Playground (v1.0), you could go take a look at this guide i've made in the discussions section.
We'll start with the equipment you'll be using to measure & analyze things. All items in Nuclear Playground will be located in the Machinery section (in v1.0).

Geiger Counter - Shows the dosage of radiation you're recieving (per second?).
Dosimeter - Shows the total radiation recieved per second (sums it up?).
Isotope Tester - Identifies the isotope that it is touching.
Decay Meter - Shows the life of any nuclear fuel rod.
Thermometer - Shows more than the vanilla thermometer can, important when checking fuel rod temp
Power Meter - Measures more than the vanilla electric gauge can.
Super Heavy Isotope Container - Contains exclusively short-lived superheavy isotopes.

If you're starting from 'scratch' instead of spawning 'endgame' fuel rods, this is how it will work.
You can spawn either a thorium or a uranium ore and put it in a Fuel Reprocessor. You'll get U-238 and a chance of the desired U-235. With these two materials, you can take a look at the mod's description on what kind of fuel rods you can craft with the Fuel Maker. They must be in order. You can either get a low-enriched or a high-enriched fuel rod with the fuel maker.

You will either decide on getting HEU-235 or LEU-235 (If you're going the thorium route, TBU, HEU-233, LEU-233). Now, its time to split the atom. Moderators in this mod will kick start a nuclear reaction in your fuel rod.

HE = Highly-Enriched
LE = Low-Enriched

Graphite Moderator - The simplest moderator, average moderation
Heavy Water Moderator - The strongest one, but reduced lifetime by 5%
Boron Control Rod - Reduces nuclear reaction when in proximity
Lead Shielding - Reduces radiation exposure to life near the reaction by 5%
DU Shielding: Reduces radiation exposure to life greatly by 99%

You do NOT have to make or design an advanced reactor, you can in fact pile moderators up and throw the fuel rod at it, though that's not really clean and its too messy. I suggest designing a reactor for it, its fun and you can harvest the heat better. The mod most likely uses a proximity system and detects if the fuel rod is in range of any moderator, lead shielding, etc.

When the fuel rod glows blue, it means the fission reaction is going. If it is not producing heat, you'll need more moderators. This might be a representation of the Cherenkov Radiation phenomenon, where the charged particles are going faster than the speed of light in the matter. (The speed of light is different according to what matter it is travelling in.)

You must find a object that can contain & conduct the heat from the fuel rods, and send it to a turbine for electricity. If the fuel produces too much heat, you can send some of the other heat to a cooling tower. You may implement a heat sensor & heat valve system for further control.

If the fuel rod explodes, nearby fuel rods will also now be dead including the one that blew up. You can reprocess it to get Sr-90 (Strontium-90) and Pm-147 (Promethium-147).


When the fuel rod is under 30% life, it can be put into a fuel reprocessor which will usually allow you to progress. You will need to try reprocessing low-enriched and high-enriched fuel rods and you will be able to get new isotopes you will need to progress. Use the Isotope tester to identify what you're getting.

When dealing with Californium fuels, these ones are hard to safely handle. They will undergo a fission reaction without a moderator (if they're next to eachother) and require lots of cooling. You will get Cf-253 (Californium-253) from Hecf-249 which is an extremely dangerous isotope that can kill all forms of life when in contact with another of its own, or a moderator, though you can get a pretty good power output.

When you want to make a superheavy isotope, you'll need a particle source and a target. In order to properly check the energy, you'll need any object connecting to the source with a red signal wire and upon activation, it will measure the energy in KeV (Kilo-ElectronVolts). You will need 10 MeV (Mega-ElectronVolts). 1000 KeV will make 1 MeV. The description of the target will specify how many MeV it needs. You will not get the material first try and you must fire at the target multiple times. Make sure you have a superheavy isotope container right under the target, the material will inevitably explode soon. AT THE MOMENT, The superheavy isotopes serve no purpose at all and act as a trophy/souvenir.

Fusion reactors are now present in Nuclear Playground, which require a neutron source from the particle source. The more energy, the better. They are a work-in-progress.


You are now able to toggle multiple particles with the particle source by using blue signal wire. It can toggle between Ca-48, Protons, Antiprotons, and Positrons. Ca-48 is currently used just to synthesize superheavy isotopes by colliding them with a target.
Positrons + Antiproton collisions at 10 MeV can make Antimatter, which must enter a bin made of Antimatter walls, the sole way to contain them.

There is an irradiation system for Cobalt-59, Gold-197,Thorium-232, and Bismuth. When exposed to enough radiation for some time (whilst in an active reactor), Thorium-232 can turn into U-233, Gold can turn into Gold-198 (Au-198), Cobalt can turn into Co-60 (Cobalt-60), and Bismuth can turn into Polonium-210.

When you want to protect your humans, you can use an Iodine Syringe which will grant temporary immunity to radiation.

That pretty much does it, but these features might change in the future.

If you want an example on some reactors, you can try some of these, though Kubull has included a tutorial reactor which also functions in the mod description.

https://steamcommunity.com/sharedfiles/filedetails/?id=2508464627
https://steamcommunity.com/sharedfiles/filedetails/?id=2508465609
https://steamcommunity.com/sharedfiles/filedetails/?id=2491060736 (Radioisotope Thermoelectric Generator)

If you have any other questions, I can try to answer them.
I'm not a developer of this mod, I am just an active user & suggestor of this mod. I love this mod.