Heat Pipes and Nuclear Reactor not updating temperature

[Foolsirony]

Hello, I encountered a bug with the temperature not updating on the UI or for circuits while building a nuclear reactor. I took some screenshots and put them together to show the issue. The reactor is powered down but is 'stuck' a bit above 500 degrees. All the connected heat pipes are 'stuck' as well and stay that way until broken and replaced, which updates the connecting pipes to the correct temperature. It seems like it's just the UI based on fiddling with it. However it does also effect circuit conditions. In the screenshot I labeled the first two heat exchangers and the last one, then show the connected heat pipe display. Restarting the game did not fix the bug (nor did the update to 2.0.11 while I was writing this up, the log files are from 30 minutes before 2.0.11 was available) and I attached my save file to hopefully help with resolving it. I also was able to take a quick video of when a heat pipe is broken. Thank you for making a wonderful game, I hope this report is helpful.

[Muche]

Heat exchangers have minimum operating temperature of 500 C.
Each tile of heat pipe operates with a 1 C gradient. A pipe right next to an exchanger will have temperature 501 C, the next one 502 C, etc.
So without fuel, the build will finally settle to: all exchangers with 500 C, pipes next to them with 501 C or 502 C, and pipes leading to the reactor 501 C, 502 C, 503 C, 504 C, 505 C, reactor having 506 C.
This seems consistent with shown pictures (taking into account some rounding happening).

[Foolsirony]

If I'm understanding heat exchangers correctly, they operate when the heat pipe next to them is over 500c right? As you can see in the screenshot, that isn't happening. All the pipes are reading the same temperature but all heat exchangers after the first one in the stack aren't working due to "low temperature" even though the UI lists the connected pipe as over 500c.

[Muche]

Exchangers operate, when they themselves are hotter than 500C. That happens when the pipe next to them is hotter than 501 C.
Exchanger 1 is shown as working despite being 500 C due to rounding. I'd guess its temperature is something like 500.001 C and is generating 0.001 steam/s.

[Foolsirony]

So maybe I was misunderstanding something, are you saying that if you power a reactor once to above 506c and the surrounding pipes to over 500c, they stay that "hot" in the temperature display regardless of how long the reactor has been without fuel and not be that hot enough operate exchangers? If that's intended behavior then there's still a UI bug because the first exchanger shouldn't say "working" when it clearly isn't (attached another screenshot with the 'working' exchanger not working along with the connected turbine), plus it's confusing when the whole line of heat pipes list the temperature as a working temperature 501c - 502c but aren't working. Again, I could be wrong, but I'm pretty sure exchangers don't have a "warm up" time. As long as they have the correct inputs (water and heat), they should produce the maximum amount of steam. Which means if the connected heat pipe says 500c then the exchanger should be working.

[Muche]

Yes, unfueled reactor in the depicted setup will stay at 506 C and exchangers won't work.
If you make another setup with 150 tiles long heat pipe between reactor and first exchanger, the unfueled reactor will settle at 651 C, pipes between 650 C and 501 C, exchanger at 500 C and still no steam will be generated after that.
The gradient of 1 C per tile is unavoidable.

I agree having exchanger saying it's working with almost 0 steam output and connected turbine getting that almost 0 steam and saying it's not enough can be confusing.

Also it's possible for exchangers to not work at full power, if the amount of available heat is not sufficient, even though the temperature is acceptable.
Here is an example of power curve of one exchanger plus two turbines at the end of a 150 tile long heat pipe as the reactor is (very) slowly cooling down:

HeatExchanger-cooldown.png (17.45 KiB) Viewed 2029 times

[Foolsirony]

I see, I see. Thank you, your explanation helped me understand the mechanics even if visually it's counterintuitive. What I'm understanding is that heat and temperature are separate even if they are connected and that's where my confusion was coming from. This does lead me to another question about it being counterintuitive, do the heat pipes work the same on Aquilo (where the temperature still reads 500c even if not powered)? Since temperature and heat are separate, that would certainly look odd and possibly confuse people.

[Muche]

I haven't reached Aquilo yet, but I'd expect heat pipes work there the same as on Nauvis.
That said, on Aquilo, heat pipes without a working source of heat and near other entities would not stay at 500 C. The entities would eat up the heat to stay unfrozen, gradually lowering the pipes' temperature; I don't know how low yet.