When can I (safely) start with nuclear power?

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Laie
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When can I (safely) start with nuclear power?

Post by Laie »

I'm currently at the point where I connected the first external mining sites. For the time being, it feels like I have more than enough iron copper & steel.

Power consumption currently is about 20MW. I have 20 furnaces set up, which ought to be good for 36MW, and I will now have to pay attention not to outrun supply. My demand for coal has already increased noticeably. I'm loath to plant more furnaces and string more coal belts to feed them, I would much prefer if I could just switch to nuclear power and, again, not worry about power demands for a long time to come.

However. My small uranium patch can only satisfy four centrifuges and hasn't been running for very long yet. As I write this, I have a whole 12 items of U-235. I wonder how risky it will be to switch to nuclear right away. With some dumb luck, I might run out of fissionable material. Common lore says that, long-term, one centrifuge will suffice to provide for one reactor. Well, I've got four of them... and, due to the current glut of raw materials, I've already got all the buildings for a 2x2 nuclear power plant fabricated and sitting in boxes.

With a 4x reactor bonus, and a power demand that's much lower than the power plant's output, I think it wouldn't be very risky for me to switch to nuclear power right away. Is that so or have I missed something?

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Re: When can I (safely) start with nuclear power?

Post by cbhj1 »

Each 235 is good for 80GJ of power, more if you have a bigger reactor core, 1x2 - 160GJ, 2x2 - 240GJ. This can go a long time at your current use (more than an hour at minimum reactor size)

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Re: When can I (safely) start with nuclear power?

Post by bormand »

If you plan to build smart reactor with steam storage, you're totally safe.

If you plan to use simple reactor, I suggest to start from 2 cores, 120MW would be enough for a while and you will have some U-235 for enrichment later.

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Re: When can I (safely) start with nuclear power?

Post by astroshak »

I tend to switch from coal to solid fuel for my boilers, and I’m not afraid to have a pair of 1/20/40 arrays on either side of a belt of solid fuel (can actually fuel five 1/20/40 arrays with a single belt of solid fuel).

I don’t go nuclear until I’ve had Kovarex up and running for a while, guaranteeing a plentiful supply of nuclear fuel cells. At that point, conservation of uranium is a non-issue, akin to conserving the water going through your refineries.

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Re: When can I (safely) start with nuclear power?

Post by adamwong246 »

What are afraid of? Running out of fuel for your reactor? Meeting the electrical needs of your factory?

You should build your reactor somewhere out of danger- it will meltdown if it takes damage, so that is something you should be afraid of.

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Re: When can I (safely) start with nuclear power?

Post by Serenity »

Laie wrote:
Mon Feb 01, 2021 8:23 pm
I'm loath to plant more furnaces and string more coal belts to feed them
If you have the coal it's not a problem. Doesn't even more belts. Just upgrade to red belt and you can feed 67 boilers.

I tend to build 4 x 20 boilers for 144 MW eventually

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Re: When can I (safely) start with nuclear power?

Post by foamy »

I build out to 6:120:240, myself. Takes a hair under two red belts of coal, but it can be jammed into a fairly compact space via daisy-chain insertion, and it'll generate ~216MW no prob. Slam on some tanks and convert to turbines later and you have a pretty beefy backup/bridging plant, as well. See here for details.

OP's point of concern appears to be if they're mining the uranium fast enough, though. And the answer to that is 'yes'.

Four unmoduled/unbeaconed centrifuges worth of U-235 production, assuming you can keep that going, will give you ~0.14 U-235/m. Since you can get 10 fuel cells per U-235, that's 1.4 cells/m (again, assuming no modules). That works out to 4.6 reactor-seconds created per second of processing, which means you can run a 480MW nuclear reactor continuously, with a bit of surplus to cover bad luck in the processing.

Using productivity modules will substantially increase that, up to 7.84 reactor-seconds per second, which would almost let you run 8 reactors continuously just from basic processing alone.

If you do a smart-reactor setup of some sort, that U-235 consumption will be drastically cut, as well, as you say you're only drawing ~20MW on average. I would say you're in a position where you *could* build a small smart 480MW plant without issue, especially if you slot in productivity modules into (in order) the fuel cell assembler and then the basic centrifuges. The excess U-235 you can stockpile until you hit the 40 needed to kick-start a Kovarex centrifuge, at which point your uranium supply problems end forever.

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Re: When can I (safely) start with nuclear power?

Post by Laie »

bormand wrote:
Mon Feb 01, 2021 8:43 pm
If you plan to build smart reactor with steam storage, you're totally safe.
I never even considered a non-smart reactor. I figured that this is not done...
cbhj1 wrote:
Mon Feb 01, 2021 8:34 pm
Each 235 is good for 80GJ of power, more if you have a bigger reactor core, 1x2 - 160GJ, 2x2 - 240GJ. This can go a long time at your current use (more than an hour at minimum reactor size)
I think you got the numbers wrong (shoudln't it be 480GJ for 2x2?), but I get the idea -- even if I quadruple my demands over the next hour, I will get so much runtime out of each U-235 that I needn't really worry. I've got like 40 times as many centrifuges as I'd need on average. I'm too lazy to calculate probabilities, but the likelyhood of me running out of material is ridiculously low. Non-zero, of course, but as my grandma used to say: you can also break your finger in your nose.

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Re: When can I (safely) start with nuclear power?

Post by cbhj1 »

The neighbor bonus is 100% per adjacent active reactor. 2x2 - 2 neighbors each for 300% efficiency.

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Re: When can I (safely) start with nuclear power?

Post by pichutarius »

Laie wrote:
Tue Feb 02, 2021 11:59 pm
I never even considered a non-smart reactor. I figured that this is not done...
do kovarex, the process is slow but growth is exponential.

eventually you have more U235 than you ever need, even with nukes.

so imo just ignore the "smart" part, i dont think its worth the hassle. before you have ≥500 u235, stick with solid fuel/rocket fuel.

non-smart is more compact. example:


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Re: When can I (safely) start with nuclear power?

Post by cbhj1 »

I disagree on the hassle level of the smart reactor, it is 2 inserters, power storage for the trigger, and a handful of wire

spent cell remover - enabled on accumulator or steam tank level, read hand
fresh cell inserter - enabled on spent cell > 0, hand size 1

wire them to the storage and each other and they will feed only what is needed to keep the power on

inserter sets can be copy/pasted for multiple reactors, just wire them all together.

edit: if using accumulators, you'll want enough of them in the power grid to support use for a couple seconds as the heat from new cells takes a moment to propagate to the exchangers

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Re: When can I (safely) start with nuclear power?

Post by Laie »

cbhj1 wrote:
Wed Feb 03, 2021 1:09 am
edit: if using accumulators, you'll want enough of them in the power grid to support use for a couple seconds as the heat from new cells takes a moment to propagate to the exchangers
I wondered about the accumulators... every screenshot I see has both solar panels and accumulators for emergency power. Personally, I think that shouldn't be necessary: if you lack fuel cells for insertion, a few seconds of power will not do you any good. And if you have fuel at hand but fail to insert it in time, isn't that a sign that your setup is flawed?

And while I'm thinking about technical details, will I need to worry about steam flow? I guess it's possible to get into a situation when you have considerable amounts of steam in storage but "pressure" is too low to still run all turbines. Is that a valid concern? Or would I need to line up all turbines in single file in order to run into that problem?
Last edited by Laie on Wed Feb 03, 2021 4:13 am, edited 1 time in total.

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Re: When can I (safely) start with nuclear power?

Post by astroshak »

If you look at the cheat sheet (https://factoriocheatsheet.com/), a 1x2 reactor core takes 14 Storage Tanks to hold all the Steam. Every 1x2 you tack on to that adds 26 more Storage Tanks for the Steam. In comparison, a 1x2 reactor core takes 28 Steam Turbines to use all the Steam, and you add approx 55 Turbines per 1x2 you tack onto the reactor core.

There is no reason to have more Storage Tanks than that; the idea behind using Steam Storage Tanks is that the power plant produces one round of Steam (every reactor gets one fuel cell inserted, it heats up and starts making Steam, until 200 seconds after insertion the fuel cell is depleted) which gets almost entirely used up before the process repeats itself. Extra Storage Tanks just take up extra space but should never be used if you have your refueling set up correctly. You want a low amount of Steam left in the tanks, but at least enough to cover the lag between inserting the fuel cell and actually generating Steam again.

Personally, I don’t believe there is a “right” setting for how much Steam is in the tank(s) being monitored. This is because at low power demands, there will be a low Steam demand, and the reverse is also true. As your factory approaches maximum power plant capacity, the greater the amount of saved Steam needed to fully power the factory, thus reducing the time the reactor spends without fuel.

Also, once you get Kovarex up and running, it will provide all your uranium needs very very easily. Beaconed and moduled, I’ve had 6 Kovarex-running machines keep a surplus of fuel cells while keeping more than 200 Reactors fed, without the smart controls set up. For me, I just put down a dumb reactor, on account of the smart reactor not saving anything. I’ve yet to mine one uranium patch dry, and my maps tend to have more than a few of them despite setting frequency (of all resources) to the bare minimum when I start a new game.

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Re: When can I (safely) start with nuclear power?

Post by pichutarius »

cbhj1 wrote:
Wed Feb 03, 2021 1:09 am
...
on megabase, it is possible to have more than 100 reactors, running > 70% all the time. wastage is negligible, ups can be spent on better places. not to say reactors spans multiple chunks, so wire them together is a hassle. at that scale "smart-reactor" = "hassle-reactor".
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Re: When can I (safely) start with nuclear power?

Post by Khagan »

astroshak wrote:
Wed Feb 03, 2021 4:12 am
a 1x2 reactor core takes 14 Storage Tanks to hold all the Steam. Every 1x2 you tack on to that adds 26 more Storage Tanks for the Steam.
You don't need anything like that many tanks to hold all the energy from one nuclear fuel cell, since the heat pipes also store energy, and you will have at least 3 of those per heat exchanger. In fact the heat pipes alone would just about do the job, except that you have to allow for the finite time it takes to reheat the system after it has got 'cold' (i.e. fallen to 500°C); you need stored steam to cover that time. Empirically, I find that 4 steam tanks for each row of 12 exchangers and 20 turbines is enough for the worst case scenario.

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Re: When can I (safely) start with nuclear power?

Post by foamy »

Laie wrote:
Wed Feb 03, 2021 3:55 am
cbhj1 wrote:
Wed Feb 03, 2021 1:09 am
edit: if using accumulators, you'll want enough of them in the power grid to support use for a couple seconds as the heat from new cells takes a moment to propagate to the exchangers
I wondered about the accumulators... every screenshot I see has both solar panels and accumulators for emergency power. Personally, I think that shouldn't be necessary: if you lack fuel cells for insertion, a few seconds of power will not do you any good. And if you have fuel at hand but fail to insert it in time, isn't that a sign that your setup is flawed?

And while I'm thinking about technical details, will I need to worry about steam flow? I guess it's possible to get into a situation when you have considerable amounts of steam in storage but "pressure" is too low to still run all turbines. Is that a valid concern? Or would I need to line up all turbines in single file in order to run into that problem?
In general, the solar panel UPS setup is being used to run circuitry/pumps/inserters, so that you don't brownout spiral if you overstress the nuclear plant. All the stuff required to keep it running is on a separate grid that will never, ever be overloaded. It's not needed if you're well overbuilt, but, you know, power use can creep up on you.

WRT steam (and water) flows, yes, you'll want to pay attention to them. They're by far the most likely reason for a nuclear plant not hitting its rated capacity, particularly in 2xN indefinitely-tileable layout, since the entire infrastructure has to be linear. Smaller, squared-up reactor configurations can use all four sides and so both have more pipe runs and runs of shorter length, both of which improve pipe throughput.

WRT smart reactors: Given your relatively small uranium income and power use ATM, I would recommend using one. That way you can stockpile U-235 to boot up Kovarex, at which point there's no further worries.

The simplest conceptually is to simply hook a steam tank or two at the far end of each turbine row (putting it between the exchangers and the turbines causes flow issues) and wire them all together. Then trip the inserters when the steam in the tanks drops below full, with a timer lockout (doable with one combinator, see here: viewtopic.php?f=208&t=92673) to keep them from overinserting.

For supplying water, my own personal preference is to glue offshore pumps directly (or nearly so) to the heat exchangers. Doing so requires landfilling everything else bar the pools the offshores pull from, but it is by far the simplest way to build them at any kind of scale. For preference I put them on the end closest to the reactors since it lets you use a narrower lake.

@Khogan: And reactors, of themselves, will buffer 5GJ, which is a pretty big chunk of things even if you're getting the full 32GJ/cell with neighbbour bonuses. Don't want to forget that in your calculations :)

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Re: When can I (safely) start with nuclear power?

Post by gGeorg »

astroshak wrote:
Wed Feb 03, 2021 4:12 am
If you look at the cheat sheet (https://factoriocheatsheet.com/), a 1x2 reactor core takes 14 Storage Tanks to hold all the Steam. Every 1x2 you tack on to that adds 26 more Storage Tanks for the Steam. In comparison, a 1x2 reactor core takes 28 Steam Turbines to use all the Steam, and you add approx 55 Turbines per 1x2 you tack onto the reactor core.

There is no reason to have more Storage Tanks than that;
Misleading information alert. :idea:
Get noticed, there is an info by small letters down there, in the https://factoriocheatsheet.com/ that those numbers of storage tanks are "without the thermal capacity of other parts. " Sounds like something minor, but is not. When you do your homework and count the thermal capacity, you find that for an average 4 core plant you are safe with 5 (Yes, Five) Steam storages. My personal 4 core CloverLeaf design uses 8 Storages becouse of other reasons. For example I suck steam to train and deliver it elswhere.

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Re: When can I (safely) start with nuclear power?

Post by JasonCurnow »

I'm kind of necroing an old topic and it's probably way too late for you, but perhaps not for others..

Steam power will take you a very long ways, especially once you can use blueprints to expand. Find a good spot near water and a big patch of coal and just start cranking out what you need for steam. There's not a big rush to get off of it, as you can just keep expanding it. If you run out of coal... Find a new coal patch and some water and start building more steam generation.

BUT.. Once you find uranium and research Uranium Processing start mining as soon as you reasonably can. It's kind of a hassle, with a need for sulphuric acid, however. I usually make a little dedicated acid production - One refinery doing basic oil processing, one plant doing sulphur and one plant making acid. Daisy chain a bunch of chests behind your centifuge so you can collect a lot of U238 and, more importantly U235. You're going to need a lot of it later.

You're probably want to research Kovarex processing before you build your first nuclear plant. If not, the U235 goes pretty fast. You need ~40 U235 to start doing Kovarex, but once you have it going and outputting U235's you should have plenty available to make nuclear fuel. and start building reactors!

Good luck, and have fun!

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Re: When can I (safely) start with nuclear power?

Post by Laie »

JasonCurnow wrote:
Tue Feb 23, 2021 10:23 pm
I'm kind of necroing an old topic and it's probably way too late for you, but perhaps not for others..
I don't think four weeks is a necro, thanks for the reply!

Perhaps the most important lesson learned from that project was that conventional power does indeed go a long way. I've been seeing my power demand rise, I've seen how many ore patches I needed to exploit to satisfy my needs until that point, and I expected further demand to grow on the same scale, but oddly enough, it didn't.

By the time I launched The Rocket (only one, but in less than 15 hrs, yay!), power demand was on the order of 60-70MW. Getting the nuclear plant working was a nice excercise, but totally unnecessary for what I eventually did in that game. Though, on the other hand, it worked wonders with regards to pollution. I may not have had such a peaceful game if I had stuck with conventional energy.

I dare say that Kovarex isn't strictly necessary if you employ a smart reactor that only inserts fuel when needed. Depends on demand, I guess, I can totally imagine someone expanding their factory much faster than i did, but in my case I needed less than 1 U-235 per hour. I had 12 units when I posted this Q, possibly 16 by the time I got the reactor going, and there was never even the slightest risk of me outpacing my supply.

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Re: When can I (safely) start with nuclear power?

Post by Serenity »

Yeah you don't need much production just to launch a rocket if you just wait and let things produce over time. Where power production goes up drastically is when you use beacons and productivity modules everywhere.

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