Unclear Nuclear

[1k4r0s]

I have some trouble with my nuclear setup. I've built a 4 reactor setup, checked the ratios here on the wiki and on YouTube 4 reactors, 48 heat exchangers, 83 turbines, 6 water pumps. I have plenty of fuel, its produces around 480MW as it should be. But time to time it dips down under satisfaction, well below 150M, the usage is around 200MW. The weirdest that, it started acting up in the last like 30 minutes of playtime, before that it was stable. I checked around but couldn't figure out what is going on. Did I missed something or anybody has any idea?
Thank you in advance!

[mmmPI]

It is possible that all the steam doesn't reach all the turbines due to the shape of the pipe networks.

This would behave fine in under certain load, but may become instable past a threshold. Supposedly it could happen that the system look stable at 150 MW due to the steam buffer inside turbines being filed up from a previous period of low consumption but then when consumption is a little higher, it would drain buffers and only produce less than 150MW afterward. If consumption oscillate between the value at which the buffer are filling up and the value at which they are emptying it could look like the problem you describe.


Given your pictures, the steam engines the further away from the heat exchangers are those where no steam is escaping it look like a steam throughput or a water throughput. You could hover over individual turbines and/or heat exchanger to confirm where the bottleneck is. My guess is that sometimes heat exchanger are "full" due to the steam accumulating in front of their ouput.

[FuryoftheStars]

To add onto what mmmPi said, I would maybe add a few pumps into the pipeline, and/or stack the turbines in rows that direct connect to each other. By having that long pipe coming off from the heat exchangers and then going down the rows of turbines, you're running into the fluid "pressure" mechanic limits.

https://wiki.factorio.com/Fluid_system#Pipelines

[Loewchen]

Without save file its a guessing game but your pictures show that while you use six Offshore pumps you only use two pipelines for the water, creating a significant bottleneck. My guess is, that your heatexchangers get water starved when the power demand reaches a certain point.

[astroshak]

48 heat exchangers needing 103.something water/second each takes a cumulative less than 5000 water/second. With two water supply pipes, you can feed 6000 water/second, but only if you have no more than two entities between each Pump. Typically these two entities are the paired Pipe-to-Ground pieces (one going down at the earlier Pump, the other coming up for the second Pump). Any additional entities in there reduces the water flow to the point that you cannot supply the over-4800 water/second needed.

I’d suggest, given the proximity to the water supply, using six individual feed lines, each Offshore Pump feeding only 8 Heat Exchangers. You can have a decent amount of pipe pieces and pipe-to-ground pairs without losing too much water flow.

Look up throughput either on the factorio cheat sheet or on the wiki.

[Tertius]

To give the water supply some numbers:
480 MW require 48 heat exchangers, each consume 103.2/s water.
48 * 102.3 = 4953.6 water/s
This is what you need to supply as total water throughput.

One of your water pipes has 2 pumps, that is 2*1200 = 2400/s
The other has 4 pumps, that is 4=1200 = 4800/s.

The one with 4 pumps has 23 pipe pieces between the last pump and the first heat exchanger. According to the wiki, a pipe length of 20 allows a maximum throughput of 1169/s. 23 allows slightly less. That means all these 4 pumps will not supply more than 1169/s. 1 offshore pump would be enough for this pipe.
The other pipe with 2 pumps has 21 pipe pieces between the last pump and the first heat exchanger. 1169/s maximum throughput as well.
1169/s+1169/s = 2338/s. This is 2338/4953.6 = 47% of the required throughput.
47% of the required water input yields 47% of the steam supply, which yields 47% of the possible energy. 480 MW * 47% = 226 MW, which is the maximum power you can get with this water pipe setup. Since the pipes are even longer to reach the rest of the heat exchangers, the actual maximum throughput, so the maximum power, is slightly less. The 179 MW we see on your chart seems not too much off.

[1k4r0s]

So... I reorganized my turbine setup and moved half of them above the reactors, also opened up more ways for the steam to enter the system, which is already seemingly solved the problem, and fixed the production on 480MW. After that, I redid how the water enters the system too, just to be on the safe side. But looks like the problem has gone away!
Thank you for the help guys! I was genuinely surprised by how many of you came to my aid! Appreciate you a lot!