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TL;DR

Basically the current nuclear reactor neighbour bonus system is boring and feels superfluous because it doesn't allow for more than 2*n setups anyways... That's why I suggest making the bonus system depend on dynamic Neutron Emission, meaning each Reactor outputs a certain amount of Neutrons/second which stack up with the Neutrons/second output from other reactors nearby at exponential rate, offering more reactor layout flexibility.

Introduction

Well, like most others I have been playing around with the Nuclear Power stuff a lot in the past week since 0.15 has been on the experimental branch.

And after a lot of different setups I tried I came to the first feedback conclusion. So the way Nuclear Power is currently implemented has ups and downs in my opinion... and I'll try to explain why:

Ups:

• The Heat Pipes, Heat Exchangers and Steam Turbines mechanics are well done and allow for a lot of customization and different layout approaches. Puzzle factor 9000.
• The Uranium Processing mechanics are also cool and also allows for a lot of different approaches on how to implement it, especially the Kovarex Enrichment. Puzzle factor 9000.

Downs:

• The Reactor mechanic itself is a bit boring though... The problem is mainly the neighbouring bonus being too static leaving no room for experiments. It allows only for 2*n builds to be efficient which means all reactor layouts of all people will always be the same... a boring Rectangle of 2*n reactors. Anything else is just not worth going for. So giving each Reactor 160 MW by default and removing the neighbour system entirely would achieve exactly the same as the current system does.
• The control system of reactors is also lacking a bit. While do-able in various ways I really miss being able to take some risks (which may result in a completely uncontrolled exponential fuel consumption or even a melt-down).

So now to my suggestion... What I want to suggest is a fundamental change to how the neighbouring system works from a static to a dynamic system to make it a more worthwhile experience on longterm:

Neighbour Bonus through Neutron Emission

1. The Neutron Cloud
   
   Each reactor should output a certain amount of Neutrons/second (= Emission) it adds to a shared cloud. It would work similar to how the pollution cloud spreading mechanic is working, but on smaller scale (tile level instead of chunk level) and faster decay (meaning it doesn't spread as far and there would be no huge delay to react on changes in the cloud).
   
   That means... each reactor starts building up a neutron flow around itself from the center of the reactor outwards... and that neutron cloud drops off in an 1/r² scheme. The amount of neutrons added to the cloud per second should depend on the current value of the neutron cloud at the center of the reactor. So it would output more and more neutrons over time... growing at an exponential rate. (Read further below on how to control that so it doesn't spiral out of hand). The exponential growth would be accomplished by having graphite moderated reactors.
2. Neutrons/Second influences the heat production (MW/second)
   
   The Neutrons/second value would obviously directly influence how much heat is generated and therefore how much MWs/second are transfered to the Heat Pipes. So higher Neutron flow means more Power can be drawn.
3. How other reactors influence one another
   
   Well as you can imagine if Reactors are placed within a certain distance from one another they will start adding up to the same neutron cloud, especially if the reactor is located within the other reactor's cloud, which means they start boosting one another... which means each reactor will output even more Neutrons/sec... thus becoming hotter and allowing more MW/s to be transfered to the Heat Pipes. And that's the desired neighbour effect.
4. How Fuel consumption is affected
   
   Well the Fuel consumption would then obviously depend on the neutrons/sec output rate at the center of the reactor. The higher the output rate (due to boosting effects) the faster the consumption and the more Fuel will be consumed. With an exponential growth rate of Neutron/Sec output you will obviously face a consumption problem which you need to get under control.
5. How to control the Neutron Flow/Cloud with graphite moderated control rods
   
   There could be 2 ways:
   
   • The default automatic and safe one... That's what the reactor runs in when it is plopped down. This mode puts an upper limit to the other wise exponential growth of the neutron flow and caused heat by automatically adjusting the Control Rods... with the downside that it isn't that efficient because well... the Neutron/second flow & Heat flow isn't allowed to go above the hard cap or the system starts throttling itself automatically. Like said it tries to play it safe. It is what beginners would be using or people who are not into pushing above and beyond.
   • The manual and unsafe one... which removes the cap and lets the neutron flow start to grow exponentially, especially with the boosting effect of other reactors. That is where the player comes in to use the circuit network or other contraptions to take control.
   The controlling would be done using Control rods using graphite moderators. So basically if they are inserted into the reactors they will cause the neutron/sec flow to increase exponentially due to trapping the neutrons, which in turn will heat up the reactor, and if they are retracted the neutron/sec flow will decrease, and thus the heat will drop as well.
   
   • In automatic mode those control rods would be handled by the reactor's integrated safety protocoll all by itself.
   • In manual mode the Reactor can output the current insertion level (0-100%) of the control rods as a signal on a circuit network channel... and one can set the insertion level by inputting another signal (0-100%) on another circuit network channel. Probably it would also require a way to measure the current heat levels.
   That effectively gives the player the ability to go with the Neutron/sec flow as high as they want and whatever their build supports.
   
   Also a control rod insertion level of 0% means they are fully retracted, which then brings the reactor below critical mass/chain reaction level, meaning it is shut down completely and doesn't consume any Fuel Cells anymore.
6. Graphite Moderator (blocks) as an item
   
   Additionally to the graphite moderators on control rods built into the Reactors there could also be optional static Graphite Moderator Blocks which can be placed in the empty tiles/space between reactors... which would interact with the neutron cloud, in such a way that the neutrons decay more slowly, which increases the reactivity of the entire layout. That would also offer a way to optimize the layout further.
7. Melt downs
   
   As an optional feature there could be melt-downs implemented, which may occur in manual mode (in safe mode it can't due to automatically regulating the control rods).
   
   It would obviously depend on exceeding a certain amount of Heat. After that the reactor would become so hot that the fuel cells start to melt and the reactor destroys itself.
   
   Usually that would only happen if you fail to get the heat away from the reactors fast enough using the Heat Pipes and Heat Exchangers. So if the Steam Consumption suddenly drops the Heat will start to build up... and that's it. Reactor will melt.
   
   It doesn't have to be implemented, it could also be an option to be activated when starting the game. But it would be interesting to have.
8. Lethal radiation levels
   
   As a side effect of creating such a neutron cloud there could also be radiation affecting the player. If you decide to go inside a fully powered up reactor layout it might kill you within seconds. You'd have to power the entire thing off and let the neutron cloud dissipate before going in.
   
   The safe mode could also be there to cover that aspect... as long as it is in safe mode the radiation levels are small enough so that the player has a lot of time to work there before noticing the radiation effects.
   
   In manual mode you would obviously go far beyond that safe level, but we like the risk don't we?
9. Using the Reactors as breeders
   
   Another sideeffect of using such graphite moderated reactors is that they can be used to breed enriched uranium (and other radioactive elements like weapons-grade Plutonium). So what could also happen there is that the empty fuel cells might not always result in U-238 being the output result of the empty fuel cell reprocessing but instead it also creates more U-235. The exact amount would also depend on the Neutron/sec flow where the reactor is located in, higher Neutron flow has a higher chance to result in more U-235. But that's a matter of discussion/balancing.

So what the above concept means is... you can place the reactors more freely in much different designs and the most efficient arrangement will depend on the actual amount of reactors because of how they influence one another depending on the neutron cloud.

What it also means is that they don't have to touch one another, allowing to place heatpipes and other infrastructure more freely between them, so you don't have to build 2*n rectangles anymore just because of the space the Fuel Cell/Empty Fuel Cell inserters have to go somehwere.



Obviously the suggested system would also mean that there is no fixed ratio of how many Exchangers you need to transfer all the heat. It will always depend on how many reactors are effecting each other, meaningly the total Neutron/sec rate of all reactors and the thereby created heat. So the power output balancing might have to be reconsidered, as it actually depends on the Neutron/Sec flow and not on a static effect.



Maybe I'll add some diagrams later, but I'd like to know what some people are thinking of the basic concept before doing additional work.