How to use the fast breeder reactor. Under construction to reflect the changes made in Update 3. The Basics: A fast breeder reactor is the endgame of nuclear power, based on cutting edge nuclear research in the real world. It works on the principle of a breeder reactor, in which atoms of heavy but non-fissile isotopes are exposed to the alpha particles and neutrons emitted from a nuclear reaction to transform them into more useful nuclear fuel isotopes. In the type of fast breeder reactor depicted in the game, the fuels used are mixtures of fissile material in a liquid form alloyed with molten salt, as opposed to conventional solid nuclear fuel rods. "Blanket fuel" and "Core Fuel" are the inputs. "Depleted Core Fuel" and "Enriched Blanket Fuel" the outputs. They are all molten liquids, which can be carried with pipes but cannot be stored in liquid storage or carried by trucks. All the loops for processing must be built close to each other. Keeping the loop going requires a constant input of steel, acid, salt and molten glass (along with yellowcake, nuclear waste and/or depleted uranium), the requisite supply of fresh water and steam reprocessing, as well as a block of steam turbines to make the power. The reactor can self-regulate if it is provided with processing power. If the reactor ever shuts down either due to overheating or because the output loop is blocked, all core fuel will be destroyed and you'll need to make more to restart it. Under construction: The fast breeder reactor has been changed a bit in Update 3. I'm working on updating the guide. The main change is that the research is now locked behind space science, and the reactor itself now requires titanium alloy to construct. There is also a setting to change the ratio of enriched products in the reactor itself, so producing a surplus of enriched blanket fuel is now optional. Establishing the recycling loops There are two output loops that need to be handled. Depleted core fuel is handled in a nuclear reprocessing plant. It requires acid and steel, as well as an input of molten glass. Using a whole blast furnace just for this is a bit overkill, but since molten transports have to be flat the only other option is relocating your glass production to near the reactor. You only need one of these plants, it has the capacity to handle two reactors worth of output and then a bit more, but you'll need a second if you want to reprocess old depleted fuel or MOX casks into blanket fuel, that'll come later. Depleted core fuel is produced one for one when the reactor consumes core fuel. For each ten units of depleted core fuel, the reprocessing facility outputs eight units of core fuel and two units of fission products. So you get four units of core fuel back for consuming five units of depleted core fuel. This means you only need to replace one out of five. The one vital thing that you cannot allow to happen is letting the output for depleted core fuel back up. That will cause a shutdown. If the output of enriched blanket fuel is full there's no consequences, the reactor can still run. If there's no input of blanket fuel, there's no problem, but no new core fuel can be created by the blanket fuel recycling loop, and so you'll eventually run out of core fuel. If you use up the core fuel you can make more using the chemical plant recipes. But if the output of depleted core fuel backs up there's nothing to be done, you can't dump, store or remove that depleted core fuel from the reactor, you have to reprocess it, and that means you need access to the inputs and need to make sure that the core fuel produced has somewhere to go. The second loop (for blanket fuel) is done in an enrichment plant. It takes in enriched blanket fuel in 15 unit batches and outputs three core fuel and 12 blanket fuel. There's no external ingredients required for this and no by-products. The rate at which blanket fuel is converted to enriched blanket fuel is settable by the player to either off, sustaining or surplus. If enriching is off you'll get no blanket fuel but the consumption of core fuel will be cut in half. You'll need to use one of the startup recipes to make up the shortfall. At the normal enriching level you will produce just enough to keep up, creating just enough new core fuel to make up for the loss on the depleted core fuel loop. At high level enrichment you will make a surplus, but in exchange the reactor will produce far less steam: at speed level 4 it will make as much steam as a level 1 on a different setting. Surplus enriched blanket fuel can be used for other processes. It can be used to convert depleted uranium into new blanket fuel (in a Chemical Plant II). In older versions of the game depleted uranium and salt could be converted directly into blanket fuel, but now this process requires enriched blanket fuel. It can also be used to make 20% uranium or plutonium (in an Enrichment Plant). Since these products can be stored and used to make core fuel they are a useful way to stockpile resources to start more reactors or generate plutonium for space probes (or restart your reactor in case of a shutdown error). Remember, 20% uranium can be stored in an ordinary flat storage but plutonium can only be stored in a nuclear waste facility. Creating the starter core fuel The reactor produces its own core fuel but you will need to make a bit to get started. It is produced in a Chemical Plant II from 20% enriched uranium and salt. You make 20% uranium by processing 4% uranium in an enrichment plant with more Hydrogen Fluoride, you can use a loop back and sorter to accomplish this. Update three adds a second option for producing your starter supply of core fuel: plutonium and salt. So if you plan ahead you can stockpile some plutonium instead of converting it to MOX rods, a smart idea since there is a use for plutonium in space probes now (although it is possible to make plutonium from enriched blanket fuel, I'll cover that in the section on recycling.) Use a pipe balancer to make sure that the core fuel coming back from the two recycling loops is given priority over new core fuel otherwise the loop might back up. Once the system is running you can pause this plant but be ready to use it to start up again. If you run the reactor in non-enriching mode it will consume half as much fuel, but you will need to produce more using these methods. Enriching fuel is more cost effective, so under most circumstances that is what I would recommend. Creating input blanket fuel Blanket fuel recycles through the loops but it diminishes as it's converted to core fuel, so you'll need a constant input of new blanket fuel. There are two machines that can make it, and four possible input products to make it from. Using a Nuclear Reprocessing Facility, you can make blanket fuel from either spent fuel or spent MOX, giving you a way to reuse the wastes from your older reactors. These can be belted in from the waste facilities where they are stored. There's no chance of backup as they're used in the same amounts, so feel free to share a belt for these. As before the byproduct is fission products, and you'll need inputs of salt, acid and molten glass (but surprisingly not steel, I guess since the waste comes in as a barrel the plant is just reusing the same barrel for the fission products). You will want to start out this way to get rid of your hazardous waste. It makes two a minute in a 1 to 1 ratio with either waste input. The second way is in a chemical plant II, which can process either yellowcake or depleted uranium along with salt. Yellowcake requires only salt, but to make blanket fuel from depleted uranium you must provide an input of enriched blanket fuel. You get back four blanket fuel per minute in either case, but with depleted uranium it's only a net of two (as you consumed two enriched fuel to make it). One reactor won't fully load the recycling loops, so only one of these methods is needed at a time, but I recommend first using up your hazardous spent fuel and MOX to free up the storage, then switching to your depleted uranium stockpile and then back to yellowcake. Using up the waste you generated on the earlier reactors might take you a century or more. The depleted uranium method can't make enough new blanket fuel on its own to keep up with the reactor, so you will need to use yellowcake or reprocessed waste to make up the deficit. Superheated steam - power generation and more The FBR generates superheated steam, which has double the energy content of regular high steam. To optimally use the steam, you should build a shaft with two super turbines, two high-pressure II, two low-pressure II, and four large generators all plumbed in series. That will consume 96 superheated steam and give back 96 depleted steam, and completely occupy the 72 MW torque limit of a single shaft, which yields 60 MW of electricity. Four such shafts deliver 240 MW. One large cooling tower can recover the steam from one shaft, so you'll want four of those as well. If you recycle all the steam you'll need 24 new water per level per minute to make it up as the cooling tower can only recover 75%, that is 96 at full speed. If you send the depleted steam to a bank of vacuum desalinators instead of cooling towers you can consume all the steam of a full output power plant and get a net gain of 37.5% extra fresh water, but that will require 16 desalinators, using 64 workers and 6.4 MW of power and a lot of space. If instead you feed 12 superheated steam to two desalinators you'll net all the water you need to make up for the loss plus a surplus of 36 per minute, using only 800 KW and 8 workers. Keep in mind that if you use all your steam for power you'll have none for desalination, so your reactor could run dry if you're at the redline unless you use a pipe balancer to ensure that the desalination gets priority. Most of the groundwater aquifers can support 96 water a minute (that's two pumps) sustainably if you don't use it for anything else, more than that they'll deplete over time. The hydrogen reformer also includes a new method of splitting water using superheated steam to make hydrogen and oxygen that uses less energy than electrolysis. Tapping into your superheated steam for these processes will mean you can't fully use all of it for power generation. It's far more flexible to use power to make superheated steam in electric boilers, but that incurs a small loss. Also, superheated steam isn't compatible with the oil refining process, so if you had been tapping your old reactor for your refinery's steam you'll need to either tap in after the super pressure turbine or use an electric boiler instead.