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Kermanhouse Electric: Nuclear Reactors (Concept Stage)

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Well, I have been thinking for quite a while that there is one thing all mods that I am presently informed of are missing, that is, as stated in this title, a proper model to simulate nuclear reactor operation.


Yes, I am very well aware of the existence of nuclear reactor mods and they have proved quite interesting, thus making them a source of architectural entertainment for me, but one problem persists, a profound lack of both modularity and actual simulation of reactor physics.  Far too often nuclear reactors have proven to be at best blocks that generate power while consuming uranium, generating some waste heat that must be radiated, and taking a few seconds to get up to power.  At worst they simply magically load follow instantaneously and require no waste heat management.  While indeed these are minor gripes with the present paradigm they also tax the realism and exceptional quantities of FUN that could be had with nuclear reactors as a unique power supply.  


Indeed there are several unique things that reactors present that no other power source does, such as the production of waste heat while non operational, the need for criticality testing before startup, the need for shielding, the need for waste disposal routes as well as possible reprocessing and enrichment of nuclear fuels, and possible PR sapping accidents.  Reactors are wonderful and powerful things that can be far better than any other power source when it comes to extraplanetary operations, but they also present unique challenges and complications that could present many FUN engineering problems as well as operating experiences.


Thus I have decided that I would start to move towards actually putting together a comprehensive plan to create such a mod.  So here is the rough draft of the equation set that I intend to use, please critique them:


Fission Rate Multiplication Factor:

Because all reactors will be operating in the prompt sub-critical, delayed critical, regime the reactor core will have a update occur once every tenth of a second while the player is running it.  A fudge value will be included in the event the player ends up somehow pushing the reactor into the prompt critical regime, making the reactor nigh uncontrollable and prone to all kinds of reputation sapping nastiness.

K = ((σF /(σNF+σ))/ (T(Tc)))N+R

Where K is the fission rate multiplication factor, T is the present reactor temperature, Tc is the "temperature coefficient of reactivity" for the core, N is the neutrons generated per fission event, σNF is the neutron absorption cross section of the nonfuel, σF  fission cross section of the fuel material, and R is a random number set between two small numbers that is regenerated every 0.1 seconds.


The Nonfuel Neutron Absorption Cross Section:

σNF = C(Cσ) + Wσ + Sσ

Where σNF is the absorption cross section of the non fuel, C is the control rod insertion percentage, Cσ is the absorption cross section of the control rods, Wσ is the absorption cross section of waste products, and Sσ is the absorption cross section of the structure of the reactor itself.

Also updated every 0.1 seconds for exactly the same reason stated above.


The Waste Absorption Cross Section:

Wσ = SLFσ + Stσ + LLFσ 

Where Wσ is the waste absorption cross section, SLFσ is the short lived fission products cross section, Stσ is the mean stable waste cross section, and LLFσ is the mean long lived waste cross section.

Also updated every 0.1 seconds for exactly the same reason stated above.


Fission event rate:

FF = K(FI)

Where K is the fission rate neutron multiplication factor, FI is the initial event rate, and FF is the updated event rate

Guess what, updated every 0.1 seconds.


Core Energy Value:

E = EF(FF) + (EI - EO) + D

Where E is the core energy value in units of energy, Ef is the energy per fission event, FF is the fission event rate, EI is the energy produced during the last update, E is the energy output by the core in the intervening time, and D is the decay energy generated likewise in that time period.

Again, updated every 0.1 seconds.

Suggestions are welcome and recommended.  I am presently very, very iffy on the concept of two values for short and long lived waste going into Wσ as it reduces realism; however, at the same time it makes the concept a lot, lot easier to deign excepting the next question as I also have yet to format a nuclear waste buildup equation due to the fact that sleep is necessary as well as a general... confusion as to where to start.  I do not know particularly how I would divide short lived waste from long lived waste, how I would realistically model fission product poisoning, how I would write the decay rate equation, nor do I know how I would write a decay heat equation for such a simplified model.

Thus I would really like suggestions in that matter due to my general confusion on that issue, and as I said before, please, give me advice, I am not a nuclear engineer nor a nuclear physicist, and thus am likely to have made several errors in my attempt to make a simplified, easy to use nuclear reactor simulation that is not computationally intensive.  So please, if you know better, do not be afraid to tell me I am wrong.


And yes, I know these look nothing like the proper equations to compute the criticality in a non-homogeneous reactor core.  The goal is a simplified setup, rather than the full complexity of the proper equations.  I also am worried about computational intensity, which I fear might get out of hand with the proper equations being applied across hundreds of separate isotopes, etc. and at a rapid rate.

Edited by NuclearNut
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Intresting, I will look forward to your ideas and results. You obviously must know a lot about nuclear technology to create such a detailed simulation for space based Nuclear reactors. Any background in this? What kind of reactor do you plan to similate, and why types of nuclear fuel? What level of realism are your trying to achieve? I often struggle with grasping finer technical detais of nuclear technology as most information made avialable to the public is not detailed, contradicting  or in format that I don't understand. For KSPI it is made even harder because most nuclear technology only exisit on paper. Therefore I'm often forced to abstractions.

But the problem with creating mods is that most mod, never get finished and only exisit in the mind of the developer. Making plans and ideas is easy, researching and trying to achieve actual result is hard. Have you made any other KSP Mods in the past? if not I would recommend to team up with someone who does or start small and gradualy incorperate more features and your understanding grows..

Edited by FreeThinker
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