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Water supply for nuclear reactors

Posted: Fri Nov 29, 2019 3:09 pm
by Amarula
How do you set up a reactor to get enough water to keep producing steam?

According to the wiki https://wiki.factorio.com/Power_product ... lear_power, the 'simple ratio' is 1 off-shore pump to 12 heat exchangers to 20 steam turbines. That is the ratio I have for my reactors. Also according to the wiki https://wiki.factorio.com/Fluid_system, water flow capacity drops to 1200/sec at 17 pipes. I have pumps after 5 underground pipes, equivalent to 10 pipes, which I thought should be more than enough to keep the water flowing.
In theory, there is no difference between theory and practice. In practice, there is. Yogi Berra
I ran low on power yesterday, and threw in another reactor complex to compensate. And hey I was still low. So I spent some time watching one of my reactors operating, and observed the following:
-To start, the water pipes and heat exchangers are full of water; the heat pipes are cool and the exchangers are not operating 'no fuel'.
-As the reactor produces heat, the heat pipes and heat exchangers increase in temperature and one by one, from closest to the reactor to furthest away, the heat exchangers start producing steam. For a few seconds after the 12th exchanger starts operating, steam production is in full swing (103/103 steam output).
-As water is consumed to produce steam, the water supply drops until the heat exchangers one by one stop producing the full amount of steam because they are out of water. One by one, they drop to 66/103 steam per second.
-Once the nuclear fuel cell is consumed, the heat pipes slowly cool down (I have delay on refueling until steam drops to a certain level). One by one, from furthest away to closest, the heat exchangers top working 'no fuel'. Slowly the pipes and heat exchangers refill with water.
And then the cycle repeats.

So even though I have a total of 1700 steam turbines, for a theoretical max output of 9.89GW, in practice it only produces 66/103 of that, so I start running out of power for my base around 6.3GW.

I am going to experiment with a few options today and I will report on the results:
-adding a second off-shore pump to start off with twice as much water (in theory);
-putting in more pumps, say one pump for every underground pipe;
-putting in a complete second line from off-shore pump to heat exchangers with a pump every 5 underground pipes.

Any experiences/suggestions/comments are welcome.

Re: Water supply for nuclear reactors

Posted: Fri Nov 29, 2019 4:19 pm
by azesmbog
“A theory without practice is dead, practice without a theory is blind”, this quote is attributed to commander Alexander Suvorov.
theory of wiki.factorio:
2x4 core, 8 reactors, 112 Exchangers, 193 Turbines, 1120MW
In practice, I have this:
2x4 core, 8 reactors, 136 Exchangers, 204 Turbines

You can add another 12 turbines to the current design, but there is no sense anymore, then even at full 60/60 load there is not enough steam. And for this amount - enough.
Offshore pump -14, there are no additional pumps for water, only for steam

Re: Water supply for nuclear reactors

Posted: Fri Nov 29, 2019 4:41 pm
by mrvn
Heat exchangers are pipes too. So you have 10 + 12 = 22 pipes. Or so. Heat exchangers have different dynamics to actual pipes. The flow between pipes and heat exchangers is also different to pump to heat exchangers.

Same goes for steam and steam turbines. It sounds like you have reactors, heat exchangers, steam turbines and only then water pipes. Why not put the water pipes between the reactor and heat exchangers. Or heat exchangers and steam turbines. No underground pipes for water used at all, athough the later needs some for steam. You can even do both, offshore pumps on both sides of the heat exchangers.

If recommend having a pump for the steam at the end of the heat exchangers. You have a lot of pipes to collect al the steam and you want to maximise the height differential in that pipe. With offshore pumps between the heat exchangers and steam turbines (and therefore underground pipes for steam I recommend one on each side of the underground pipe.

Re: Water supply for nuclear reactors

Posted: Fri Nov 29, 2019 4:43 pm
by eradicator
Amarula wrote:
Fri Nov 29, 2019 3:09 pm
Also according to the wiki https://wiki.factorio.com/Fluid_system, water flow capacity drops to 1200/sec at 17 pipes.
Fluid pressure drops on every transfer. Pipes are just the worst, but boilers-to-boiler etc doesn't preserve full pressure.

Re: Water supply for nuclear reactors

Posted: Fri Nov 29, 2019 9:15 pm
by disentius
can you post a screenshot/blueprint? makes troubleshooting easier.
Recent reactor discussion with examples:
viewtopic.php?f=5&t=78025

Re: Water supply for nuclear reactors

Posted: Mon Dec 02, 2019 4:29 am
by leitk
Build the reactor over a lake, with careful placement of landfill you can have pumps directly feeding each end of the heat exchanger line.

Re: Water supply for nuclear reactors

Posted: Mon Dec 02, 2019 1:56 pm
by Honktown
9.89 gigawatts is a lot. In a vanilla game that's.... what, 1k science a minute? Someone already mentioned the normal "build on a lake" strategy

If you want to be a cheating bastard about it, I ported a mod from .16:

https://mods.factorio.com/mod/AdvancedNuclear3

I guess experience wise, pipe flow is one of the most aggressive things about nuclear reactors. I could never keep the flow at max, unless I overbuilt and tapped/replenished middles of lines and stuff.

Re: Water supply for nuclear reactors

Posted: Mon Dec 02, 2019 3:51 pm
by Amarula
leitk wrote:
Mon Dec 02, 2019 4:29 am
Build the reactor over a lake, with careful placement of landfill you can have pumps directly feeding each end of the heat exchanger line.
This.

I am... speechless.

Re: Water supply for nuclear reactors

Posted: Sat Dec 07, 2019 1:00 am
by gGeorg
Amarula wrote:
Fri Nov 29, 2019 3:09 pm
12 heat exchangers to 20 steam turbines. That is the ratio I have for my reactors. Also according to the wiki https://wiki.factorio.com/Fluid_system, water flow capacity drops to 1200/sec at 17 pipes. I have pumps after 5 underground pipes, equivalent to 10 pipes, which I thought should be more than enough to keep the water flowing.
With high truthput on the edge of capacity you might see fluctuations. Jittering.
In my design (smaller) four leaf nuclear I am using 3 pipes for each 24 heaters. Althou, by theory 2 would be enough. 3 pipes per 24 heaters allows quite long transfer without further pumping. Pipes begin with 3 offfshore pump, fallow 3 paralel pipes about 16 tiles of pipes (underground) to the heaters. No more pumps there. Close to heaters, 3 pipes goes into one storage tank, then aattached one pump out to the "T" type cross pipe. It is enough to feed water for 2x12 heaters.
It sound a wierd, but flow system is playfull. It accept feeding three pipes into one storage 3 times faster, as fallow up one pump can suck out water from storage by a speed up to 12000. However, only 2500 is needed. So when you split the stream by T cross, it works.

So, as result
4 leaf plant 48 heaters is suported by 6 offshore pump and 2 electric pump and 2 storage tanks. It could be stretched 50 underground pipes far away without need of aditional pumping.

Re: Water supply for nuclear reactors

Posted: Fri Jan 03, 2020 4:45 pm
by Amarula
So far I have built/replaced 3 reactor sectors to be on the lake rather than beside the lake, and I am pretty happy with the results (600 fewer pipes, 800 fewer underground pipes). However you did warn me:
leitk wrote:
Mon Dec 02, 2019 4:29 am
with careful placement of landfill
Oh boy it is hard to get the landfill placed where I need it to be. So far I have (mis)placed such that once I didn't leave enough room for the chests feeding fuel to the reactor (so room for one less heat exchanger), and once for the offshore pumps (one space of water is not enough). It is tricky because you can place landfill around an offshore pump for heat pipes and water pipes and so on, but if you try to use a blueprint to replicate it, you are out of luck because the landfill goes down first and then you can no longer place the pump.

Thank you again to everyone for your suggestions.

Re: Water supply for nuclear reactors

Posted: Fri Jan 03, 2020 4:52 pm
by steinio
Save often and reload if necessary during landfilling.

Re: Water supply for nuclear reactors

Posted: Fri Jan 03, 2020 8:34 pm
by Honktown
Amarula wrote:
Fri Jan 03, 2020 4:45 pm
So far I have built/replaced 3 reactor sectors to be on the lake rather than beside the lake, and I am pretty happy with the results (600 fewer pipes, 800 fewer underground pipes). However you did warn me:
leitk wrote:
Mon Dec 02, 2019 4:29 am
with careful placement of landfill
Oh boy it is hard to get the landfill placed where I need it to be. So far I have (mis)placed such that once I didn't leave enough room for the chests feeding fuel to the reactor (so room for one less heat exchanger), and once for the offshore pumps (one space of water is not enough). It is tricky because you can place landfill around an offshore pump for heat pipes and water pipes and so on, but if you try to use a blueprint to replicate it, you are out of luck because the landfill goes down first and then you can no longer place the pump.

Thank you again to everyone for your suggestions.
steinio wrote:
Fri Jan 03, 2020 4:52 pm
Save often and reload if necessary during landfilling.
There's a mod that'll do it for you with blueprints: https://mods.factorio.com/mod/LandfillEverything

I haven't tried that, so I can't say anything about it.

Re: Water supply for nuclear reactors

Posted: Sat Jan 04, 2020 1:58 am
by astroshak
You don’t need a mod for that.

If you use Landfill and fill in a lake (making sure not to fill in where you want your Offshore Pumps to go) and then build the reactor setup entirely on that Landfill .. you can include the Landfill in your BP. It WILL NOT put Landfill where dry land is, but by including the Landfill in the BP, you can make bots build everything including setting up the Landfill by plopping that BP down twice : once for the Landfill, the second time after the Landfill is placed, for the rest of it.

If you have any part of the BP you are saving over dry land, the BP will not consider saving Landfill there. It needs to entirely be on Landfill.

Re: Water supply for nuclear reactors

Posted: Mon Jan 06, 2020 6:52 pm
by Honktown
astroshak wrote:
Sat Jan 04, 2020 1:58 am
You don’t need a mod for that.

If you use Landfill and fill in a lake (making sure not to fill in where you want your Offshore Pumps to go) and then build the reactor setup entirely on that Landfill .. you can include the Landfill in your BP. It WILL NOT put Landfill where dry land is, but by including the Landfill in the BP, you can make bots build everything including setting up the Landfill by plopping that BP down twice : once for the Landfill, the second time after the Landfill is placed, for the rest of it.

If you have any part of the BP you are saving over dry land, the BP will not consider saving Landfill there. It needs to entirely be on Landfill.
Thanks for the detail. So you do still have to do it at least once, but it doesn't need mods.

Re: Water supply for nuclear reactors

Posted: Tue Jan 07, 2020 9:36 pm
by disentius
You can sideload water for a 1.1 GW plant. using 3 pumps and a tank, you can feed 28 heat exchangers.
1.1 GW reactor-water sideload.png
1.1 GW reactor-water sideload.png (3.42 MiB) Viewed 14162 times

Re: Water supply for nuclear reactors

Posted: Tue Jan 07, 2020 10:30 pm
by Honktown
disentius wrote:
Tue Jan 07, 2020 9:36 pm
...
Is this another one of those fluidboxes vs pipes things again? In my mind the flow should drop to trash by the end of the first exchanger banks.

Also I was trying it out, and because the pumps feed the water, if you overdraw the reactor it extinguishes itself around 1.3 GW

Re: Water supply for nuclear reactors

Posted: Wed Jan 08, 2020 11:15 am
by astroshak
disentius wrote:
Tue Jan 07, 2020 9:36 pm
You can sideload water for a 1.1 GW plant. using 3 pumps and a tank, you can feed 28 heat exchangers.
Does that single pipe segment between the three Offshore Pumps not restrict the flow too much?

How much more could you get if you had the Offshore Pumps feeding directly into the Storage Tank?

Re: Water supply for nuclear reactors

Posted: Wed Jan 08, 2020 3:04 pm
by Bauer
astroshak wrote:
Wed Jan 08, 2020 11:15 am
disentius wrote:
Tue Jan 07, 2020 9:36 pm
You can sideload water for a 1.1 GW plant. using 3 pumps and a tank, you can feed 28 heat exchangers.
Does that single pipe segment between the three Offshore Pumps not restrict the flow too much?
This setup is limited by the single pump between the offshore pumps and the tank.

astroshak wrote:
Wed Jan 08, 2020 11:15 am
How much more could you get if you had the Offshore Pumps feeding directly into the Storage Tank?
Nothing. You get 1200/s in both cases.

Re: Water supply for nuclear reactors

Posted: Wed Jan 08, 2020 3:42 pm
by mrvn
astroshak wrote:
Sat Jan 04, 2020 1:58 am
You don’t need a mod for that.

If you use Landfill and fill in a lake (making sure not to fill in where you want your Offshore Pumps to go) and then build the reactor setup entirely on that Landfill .. you can include the Landfill in your BP. It WILL NOT put Landfill where dry land is, but by including the Landfill in the BP, you can make bots build everything including setting up the Landfill by plopping that BP down twice : once for the Landfill, the second time after the Landfill is placed, for the rest of it.

If you have any part of the BP you are saving over dry land, the BP will not consider saving Landfill there. It needs to entirely be on Landfill.
But the mod is much better. It takes your blueprint without landfill and adds landfill everywhere needed and only where needed.

If you build your reactor by hand and misplace landfill you can take a blueprint of the whole thing (without landfill) and export it to the library. Then load the last save and place the blueprint with landfill added. Voila. mistake gone.

Also if you later want a second reactor you can just copy&paste it to a new lake without running into problems where the old reactor didn't have lake.

Re: Water supply for nuclear reactors

Posted: Wed Jan 08, 2020 3:45 pm
by mrvn
Honktown wrote:
Tue Jan 07, 2020 10:30 pm
disentius wrote:
Tue Jan 07, 2020 9:36 pm
...
Is this another one of those fluidboxes vs pipes things again? In my mind the flow should drop to trash by the end of the first exchanger banks.

Also I was trying it out, and because the pumps feed the water, if you overdraw the reactor it extinguishes itself around 1.3 GW
You want to pump steam into a separate tank with steam turbine that powers just the pumps and inserters. Disconnected form the rest of the grid.