Let's say there's a nuclear reactor that is at 999C, and the fuel cell inside it still has 50% left until it's depleted.
The heat pipes connected to it are still heating up, (i.e the first 5 pipes are at 700C, the next 5 at 600C and so on until 20 pipes), so does this mean that the cell is in fact not being voided by the reactor, but is stored in the pipes with 100% efficiency?
Or is there some energy loss while the heat from an active 999C reactor is transferring to heat pipes?
Question about nuclear reactor heat
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jdrexler75
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Re: Question about nuclear reactor heat
When the reactor is at 999°C, the fuel is still consumed at the full rate. The nuclear reaction cannot slow down. Heat is extracted at the rate that your factory draws power, but any excess heat is lost.
The simplest way to avoid wasting fuel cells, is to only insert a single fuel cell when the reactor is empty and cool enough. You can do this without any combinators, just connect it to the fuel cell inserter, and set the reactor to read fuel and temperature. Then set the inserter to hand size 1, set filter blacklist from the circuit (so it can only handle a fuel cell when the reactor has none), and enable when T is low enough:
For more complex setups, look around the forums, there are many threads about this problem.
The simplest way to avoid wasting fuel cells, is to only insert a single fuel cell when the reactor is empty and cool enough. You can do this without any combinators, just connect it to the fuel cell inserter, and set the reactor to read fuel and temperature. Then set the inserter to hand size 1, set filter blacklist from the circuit (so it can only handle a fuel cell when the reactor has none), and enable when T is low enough:
- Screenshot_20250812_105101r.png (118.74 KiB) Viewed 252 times
Re: Question about nuclear reactor heat
It depends on the heat flow into the pipes next to the reactor. If the heat generated by the cell is able to completely flow into the pipes, the reactor will not heat up more. Its temperature would even lower. The amount of heat depends on the temperature difference between the reactor and the pipe pieces connected to it. It will not happen any surplus heat is forced into the pipe just to avoid going up to 1000°C when the temperature difference isn't enough to actually establish that heat flow.
According to the heat pipe article on the wiki, a heat flow of 40 MW (single reactor, no neighbor bonus) is accomplished by a heat difference of 1+(40/15)°C = 3,667°C. If you have multiple heat pipes connected, divide by the amount of heat pipes. So as long as the temperature difference between the reactor and its directly connected heat pipe(s) is equal to or higher than this value, enough heat is flowing away and the reactor isn't heating up more. If the difference is higher the reactor temperature would lower, and if the difference is lower the reactor temperature will raise. For higher power throughput the difference must be higher of course. For 80 MW it's 1+(80/15)°C=6.33°C, for example.
Rule of thumb: It's unlikely your setup will pull exactly the same amount of heat into the pipes as produced to make it stay exactly at 999°C. If temperature difference was enough to pull the whole heat, the reactor temperature would even lower instead of staying at 999°C. You reach a temperature of 999°C because the reactor was heated up and not cooled enough. So if the temperature stays at 999°C, it's usually because the reactor wants to heat up more but cannot, so the surplus heat is voided. The temperature stays between 999°C and 1000°C due to averages being computed internally and rounding errors.
According to the heat pipe article on the wiki, a heat flow of 40 MW (single reactor, no neighbor bonus) is accomplished by a heat difference of 1+(40/15)°C = 3,667°C. If you have multiple heat pipes connected, divide by the amount of heat pipes. So as long as the temperature difference between the reactor and its directly connected heat pipe(s) is equal to or higher than this value, enough heat is flowing away and the reactor isn't heating up more. If the difference is higher the reactor temperature would lower, and if the difference is lower the reactor temperature will raise. For higher power throughput the difference must be higher of course. For 80 MW it's 1+(80/15)°C=6.33°C, for example.
Rule of thumb: It's unlikely your setup will pull exactly the same amount of heat into the pipes as produced to make it stay exactly at 999°C. If temperature difference was enough to pull the whole heat, the reactor temperature would even lower instead of staying at 999°C. You reach a temperature of 999°C because the reactor was heated up and not cooled enough. So if the temperature stays at 999°C, it's usually because the reactor wants to heat up more but cannot, so the surplus heat is voided. The temperature stays between 999°C and 1000°C due to averages being computed internally and rounding errors.