Power output on Nuclear reactors not decreasing

[greymane]

Hello, I assume this is a bug so reporting here. I was basically following along a Youtube series by KOS.

I set up a 6 reactor plant with heat exchangers/pipes and turbine and let it run a while (it was up to temp and producing ~900 MW) and then decided to double it. I pasted the blueprint down then went back and added extra pumps/pipes/heat exchangers and turbines to make the ratios right for 12 reactors. After got up to temp it was at 1.7ish gigawatts. This is well more than I needed and I realized I needed to adjust my uranium refineing to buff the output to support that, so I went back to the reactors, and removed JUST the inserters on the extra 6 reactors, saw that I really could downsize more and removed 2 more uranium inserters. I now have 4 reactors running on a pipe/exchanges/turbine setup that supports 12. The remaining 8 reactors are sitting there showing needing fuel but are remaining at full temp.

I expected this was too much strain and the 4 reactors wouldn't be able to keep everything up to temp and that power would taper off over time, so I just left it and went back to other things I was working on. About an hour later, I checked the power to see where it landed at and it was still producing 1.7GW on the 4 reactors. I did NOT expect this and expected it should drop over time and some of the remote exchangers and the unpowered reactors would drop in temp. They had not and still have not even more hours later (at least 3 hours after that). Still producing 1.7GW.

Log and save attached.

[Loewchen]

Nothing is producing 1.7GW in your save. You have a demand of less than 300MW which can easily be produced by 3 reactors not to mention the 4 you have actually running.

[FuryoftheStars]

The 1.7 GW is your power production potential, which to be clear, is the turbines, not the reactors themselves.

[greymane]

So is this working as intended? I wouldn't think potential is what should be reported, as that center graph on the power menu is what is being produced I thought.

So shouldn't the potential be reported as what the reactors are able to produce? If I had a factory needing 1GW of power, it will still show 1.7gw potential but then be under due to to few reactors, so how would I be able to identify the problem?

Also shouldn't the reactors and distant exchangers drop in temp?

My apologies for reporting this as a bug if it is working as intended, but this just isn't making sense to me.

[atomizer]

The potential is reported only for those producers that can provide it (for turbines, those that have steam in them). When they get starved of steam due to lack of supply from exchangers, they will no longer be counted in the potential, and you will clearly see the deficiency.

[torne]

The turbines only consume as much steam as they need to satisfy the current power demand. Heat exchangers only consume as much heat as they need to fill up their output with steam.

This will always scale moment to moment according to your factory's current consumption; steam and heat are never wasted or lost, and the only time any energy is wasted is when a reactor is running while already at 1000C (the energy of the fuel just goes nowhere since it can't heat the reactor above that maximum temperature). As long as your factory's consumption is lower then the maximum output of the reactors you are fuelling, the average temperature of the system will keep going up until the reactors are at 1000C.

The reactors that aren't running are still part of the heat network even though they are not adding any additional heat to the system; they just function like large heat batteries.

Once you start consistently consuming more energy than the fuelled reactors can produce, the temperatures throughout the system will start to drop. Once the temperature at the most distant heat exchangers goes down to 500C, they will stop producing steam, the steam that's already been produced will be consumed until it's all gone, and then once the amount of steam in each individual turbine hits zero, it will cease to be considered a power producer and its potential power generation will disappear from the power GUI.

What you currently have is a system with a lot of internal buffer capacity that can support a very high peak load, but the sustainable load is much lower. The game UI shows you what could be being produced this instant if it was actually needed, and does not take into account whether that production is sustainable or not, because it would be very hard or even impossible to account this correctly in complex setups.

[FuryoftheStars]

So is this working as intended? I wouldn't think potential is what should be reported, as that center graph on the power menu is what is being produced I thought.

It is what's being produced out of your potential. Though as atomizer mentioned and reminded me, it's the potential of whatever is currently producing.

So shouldn't the potential be reported as what the reactors are able to produce?

I believe this was not done for a couple different reasons. The primary reason, I believe, is because steam does not need to be used in power production. You can use steam in regular recipes, so rather than reporting power production potential based on the steam creator, they decided to use the steam consumer (for power). The other reason could be said to be because of the complexity of reactors. It would be even more false and misleading to report a reactor's full capacity if you didn't have enough heat exchangers or turbines to fully consume what it was producing. (And this is also true for boilers/steam engines as you need more steam engines than boilers to fully consume their potential.)

If I had a factory needing 1GW of power, it will still show 1.7gw potential but then be under due to to few reactors, so how would I be able to identify the problem?

The left set of numbers for satisfaction. If consumption starts to exceed what you can produce, then this graph will start to show a gap, as it's displaying production vs demand.

Also shouldn't the reactors and distant exchangers drop in temp?

(torne also has a good point above: you may still have a lot of heat and steam buffered.)
Heat will not naturally dissipate. This game assumes perfect insulation on everything. There are also minimum temperatures on reactors and I believe heat exchangers to where if they reach that temp they stop working and thus distributing/consuming the heat. You should be able to find these numbers in the wiki.

Also, as heat moves through the heat pipes very similarly to steam and other fluids through regular pipes (actually, even easier, I believe), and heat exchangers don't actively "suck" the heat out of the pipes, it's very easy for the heat to spread down the whole line. (The same is true for turbines and steam, though as steam doesn't move as easily through the pipes as heat, the effect is less.)

All of this said, you should check out the Energy Production subforum at some point. There are wasteless desgins in there for reactor setups that will consume uranium only as needed, thus eliminating the need to remove inserters to conserve fuel.

[greymane]

Thanks to both of you. This makes more sense to me. I didn't realize the heat/steam was lossless. That would account for it.

Thanks again and sorry to list as a bug instead of my misunderstanding.

[Tertius]

Another explanation for the potential output number: If you have enough turbines to create 1.7 GW of power, 1.7 GW are displayed as potential maximum output. A reactor doesn't create (electric) power, it only creates heat. And the number you see is electricity, not heat. Reactors create heat (not shown in the numbers), heat exchangers create steam from heat (not shown in the numbers) and turbines create electricity from steam (shown in the numbers).

The reactors are independent from the turbines. For example, you can use 1 reactor with a measly 40 MW heat generation and 4 heat exchangers and slowly fill 100 storage tanks with steam until they are full. Then connect your 304 turbines (with their 1760 MW power output) to the storage tanks. The steam will flow through each of them, and if you have a factory that actually consumes 1760 MW, it will be fully powered by this - until the steam runs empty, and since there is only one 40 MW reactor, it will defintely run empty after a few seconds.