Fuel, fusion and refining

[captainjack23]

So, I'm hoping to leech off of someone else's knowlege here.....

I'm doing some "conceptual modeling" on travellers powerplants (doing handwave warmup excercises, in other words), and I have come across an interesting issue which may actually be clarified by Real World information (tm).

Here's the deal. I'm puttering around with my idea that the main difference between processed fuel and unprocessed fuel is simply the concentration of heavy hydrogen atoms (deuterium/tritium) - the extra stuff scooped up like ammonia is either discarded or cracked for H2 (and then the extra stuff is discarded) as part of the scooping proccess; the refining process , if used, concentrates the D &T in the portion of the fuel to be fused for the power plant....and the cleaned protium (?) H is for the jump bubble (see my obsessive speculations on jumpspace mechanics for why).

Now here's the question. I know that fusion reactions are easier with the heavy H atoms, as compared to protium-protium fusion. The issue is, given the low percentage of H2/H3 relative to H1, will there be enough to even matter ?

Heres some numbers. Assuming that the Jump/Power ratio is about 10:1, the relative enrichment of the power plant fuel is 10x but the relative concentration only increases from 0.015% to 0.15%. Anyone know enough about fusion reactions to tell me if that level of enrichment has any usefullness whatsoever ?

 

[GypsyComet]

I seem to recall "some other edition" of Traveller reducing powerplant needs by two orders of magnitude from CT/MT levels because fusion is quite efficient.

So you may be on to something.

 

[MrUkpyr]

"Starship Operator's Manual" is the book that you want to look at for some truly detailed information about engines and fuel and purification and all sorts of other stuff.

-MrUkpyr

 

[Jeff Hopper]

Great paper on fusion reactors located at the Missouri Archive. Link is below.

http://traveller.mu.org/house/fusion.html

 

[EDG]

I posted this on the SFRPG boards, but it's probably useful here:

I'd guess that this is the process that goes on in refinement:

1) raw material (water, hydrocarbons, GG atmosphere) is mined/scooped.
2) the raw material is preprocessed to extract hydrogen, deuterium and helium-3 - this is "unrefined fuel". Unrefined fuel contains some hydrogen, tritium, and helium-4 impurities. This can be piped into the reactor but could lead to less stable and less efficient reactions. Unrefined fuel in the jump grid contains elements other than pure hydrogen, which makes the bubble less stable and could lead to misjumps. Note that pre-processors are built into every reactor.
3) If a fuel refiner is present, this can refine the fuel to separate out the deuterium and helium-3 and extract everything else. Refined fuel contains exactly the elements that the fusion reactor needs - deuterium and helium-3 - so when that's piped into the reactor. Refinement also separates out the pure hydrogen, which leads to a stable jump bubble.

 

[captainjack23]

I posted this on the SFRPG boards, but it's probably useful here:

I'd guess that this is the process that goes on in refinement:

1) raw material (water, hydrocarbons, GG atmosphere) is mined/scooped.
2) the raw material is preprocessed to extract hydrogen, deuterium and helium-3 - this is "unrefined fuel". Unrefined fuel contains some hydrogen, tritium, and helium-4 impurities. This can be piped into the reactor but could lead to less stable and less efficient reactions. Unrefined fuel in the jump grid contains elements other than pure hydrogen, which makes the bubble less stable and could lead to misjumps. Note that pre-processors are built into every reactor.
3) If a fuel refiner is present, this can refine the fuel to separate out the deuterium and helium-3 and extract everything else. Refined fuel contains exactly the elements that the fusion reactor needs - deuterium and helium-3 - so when that's piped into the reactor. Refinement also separates out the pure hydrogen, which leads to a stable jump bubble.

Cool, sounds like someone and I are thinking along the same lines. where from originally? Theres a few extra details I'd like to look at, as this seems to be part of a bigger post/article/site.

 

[EDG]

It's from the Science Labs board there, the fusion power: fuel use thread.
http://www.sfrpg.org.uk/phpBB3/viewtopic.php?f=41&t=251

Course the other point is that realistically the amount of hydrogen fuel that a ship carries in Traveller should run the fusion reactor for *centuries* (if not longer), not a couple of weeks.

 

[GypsyComet]

Course the other point is that realistically the amount of hydrogen fuel that a ship carries in Traveller should run the fusion reactor for *centuries* (if not longer), not a couple of weeks.

Hence TNE's reduction of powerplant fuel. Puts the consumption of jump fuel into proper perspective...

Megawatts constant for a year out of this 55-gallon drum, or *one* jump to Barnard's Star with the contents of those ten tanker trucks...

 

[captainjack23]

I posted this on the SFRPG boards, but it's probably useful here:

I'd guess that this is the process that goes on in refinement:

1) raw material (water, hydrocarbons, GG atmosphere) is mined/scooped.
2) the raw material is preprocessed to extract hydrogen, deuterium and helium-3 - this is "unrefined fuel". Unrefined fuel contains some hydrogen, tritium, and helium-4 impurities. This can be piped into the reactor but could lead to less stable and less efficient reactions. Unrefined fuel in the jump grid contains elements other than pure hydrogen, which makes the bubble less stable and could lead to misjumps. Note that pre-processors are built into every reactor.
3) If a fuel refiner is present, this can refine the fuel to separate out the deuterium and helium-3 and extract everything else. Refined fuel contains exactly the elements that the fusion reactor needs - deuterium and helium-3 - so when that's piped into the reactor. Refinement also separates out the pure hydrogen, which leads to a stable jump bubble.

Cool, sounds like someone and I are thinking along the same lines. where from originally? Theres a few extra details I'd like to look at, as this seems to be part of a bigger post/article/site.

Oh ! Okay...It's posted by and written by you. And then I followed your link to SJG boards, where it's posted originally, and then on that thread, I found and followed your earlier reference to a thread here, and then I discover that it was the thread where I was first discussing this idea....wow. Perfectly closed ideation and reference loop.

Still, it looks like the answer to my question is there in yur stuff, which is that in fact, the fusion plant should probably be able to be run entirely off of what the processing system I describe would produce just from cleaning out the heavy H isotopes of the jump hydrogen.

Okay, thats interesting. So it seems I have a working explanation for why so much jump fuel, what the dickins is refined fuel, and where does the Power plant get its D &T for fusion (He3 would be an option, also but only when scooping a Gas Giant, I think), BUT now we have those pesky PPlant dTons of fuel to explain.

Hm. Maybe the damn thing uses it for coolant ? Oh yeah, there's a clever idea for a volatile gas...( :roll: )

back to the handwavium generator.....


Hmmm. Perhaps we could use a closed ideation loop to produce limitless power ? But then.....cooling is still aproblem, if it generates flames....
(yeah, okay, this is a bad pun, not a poke at the above discussions or people...)


EDIT: Oh, and before I forget, Thanks !

 

[Infojunky]

"Starship Operator's Manual" is the book that you want to look at for some truly detailed information about engines and fuel and purification and all sorts of other stuff.

Too bad the science in that edition was abysmal..... Ruined a lot of good ideas with really bad science.

 

[captainjack23]

So, to continue, I think I have the whole "Why does the jump drive need refined fuel, and what the heck is refining" thing answered to my satisfaction (for what that's worth), but I'm still looking for some idea about the huge fuel that the power system uses if one assumes it is a straight fusion->power reaction.

Is there a (hypothetical) system that produces power by a combination of some kind of fusion reaction and some kind of use of H for non fusion power generation, or for some secondary but necessary function ?

I'm thinking that with gravitics, one could be creating a fusion reaction simply by compressing a portion of the Hydrogen to the point where a basic solar proton-proton reaction occurs, but controlling it so that the reaction doesn't become self sustaining (the grav compression relaxes at that point). This reaction then creates a mass of plasma out of the rest of the H in that portion, which is the power source. Then, it repeats.

An advantage would be that if the compression was tightly controlled, one need not risk much of a runaway reaction - once fusion occurs, the compression relaxes; and relying on monatomic* hydrogen reactions turns the difficulty of creating PP fusion into a benefit.

In a way, its kind of a model of an IC engine with a compression phase, ignition and then expansion. And it would require lots more hydrogen than a self sustaining reaction, which is the whole goal here.

Now, the question is, is there a way to use a bunch of decompressing superheated hydrogen plasma to efficiently generate energy ?


*assuming refinement is to clean out all the Deuterium and Tritium so as to increase the predictability of the reaction. WARNING: handwave zone->we don't want the easier D-H reaction, or the He3 reactions -too easy to become self sustaining and run away or occur earlier in the process causing backfires on a Megawatt scale. Which is nice as it also adds a slight penalty for using unrefined fuel -either in terms of power hiccups, and/or icreasing stress on the equipment.

 

[Infojunky]

Now, the question is, is there a way to use a bunch of decompressing superheated hydrogen plasma to efficiently generate energy ?

Depends, what is the overall charge state of said plasma?

Could be taking power off of it directly with the appropriate charge....

Using gravtic ignition the extra mass might be used as a damper for the reaction during the power recovery pulse.

 

[captainjack23]

Now, the question is, is there a way to use a bunch of decompressing superheated hydrogen plasma to efficiently generate energy ?

Depends, what is the overall charge state of said plasma?

Could be taking power off of it directly with the appropriate charge....

Using gravtic ignition the extra mass might be used as a damper for the reaction during the power recovery pulse.

heck, I don't know. What would work ? I like the damper mass idea.

Wasn't there a way to produce electricity direct from plasma floated about somewhere ?

 

[Jeff Hopper]

Great paper on fusion reactors located at the Missouri Archive. Link is below.

http://traveller.mu.org/house/fusion.html

The link is a great resource.

 

[captainjack23]

Great paper on fusion reactors located at the Missouri Archive. Link is below.

http://traveller.mu.org/house/fusion.html

The link is a great resource.

No kidding ! Thanks !

Okay, there's an MHD system for the plasma - cooooool.

Info on a catalyzed PP reaction, if one doesn't want to use a straight PP reaction by squishing it (which will still work, just less....well compression, I guess).

The cold start mechanism is great. That was one problem I was mulling just before I read the article.
Its interesting that as far as I can see, the use of gravitic compression isn;t adressed - the focus is on thermal initiated or magnetic compression reactions. So I wonder if my idea is off base by a big margin......Still, very very helpful. So, taking big chunks from that article (thanks to : J. Duncan Law-Green at http://traveller.mu.org/house/fusion.html[/quote])

So, assuming the gravitic compression model is usable, I see a dual or triple phase start up:
1. a cold start D+D fusion, possibly via standard means -can be stored in a cache after protium filtering;
2. possibly providing power for a catalyzed PP (CNO) reaction to get the grav compression running to levels needed to
3. squish out pulsed PP fusion as described above, probably allowing fusion to occur only on a very small number of H atoms.
4. The pesky extra hydrogen is plasmafied by the fusion pulse and then passed thru an MHD for power, and then thru a heat exchange box to grab the last ergs, the rest is dumped, possibly for reaction jets, or to provide the blue glow.
5. Power is first routed to the Grav system for the next pulse, and then to the ship as a whole.
6. When the reactor goes into overdrive for jump, I'd see the reaction simply allowing the fusion pulses to occur more often; possibly with a catalyst reaction to increase efficiency.

The D for the startup is either from the processing of the jump fuel or provided in very small amounts by the basic power system; alternately they could be completely seperate - the excess D & T from the jump bubble could just be vented in Jumpspace or wherever. (try to be polite and avoid inhabitated areas, obviously)

The CNO for the phase two reaction cycles and can be very easily topped up.

The huge amount powerplant fuel is explained by lowered efficiency of the PP cycle, (but higher safety), and the fact that most of the H is used as plasma, not as a fusion fuel.

Messy Hydrogen (unrefined) in the power plant can cause problems as mentioned above; and this is an even bigger issue in overclock ( along with the posited issues of non-monatomic H in the jump bubble at entry) -thus the minus to jump roll.

Hmmmm. Okay. Science and engineering flames are welcome (but helpful critques or corrections are preferred )