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[10ebbor10]

There are no fusion only bombs. (To be fair, there are a few designs for them, but those are theoretical. The so called neutron bombs).

This is what I said. Hydrogen bombs use the energy from the atomic bomb for a fusion reaction, which produce the thermonuclear explosion. I have a bit of doubt about from what reaction comes the most power, because that's not exactly what tells me other sources, nor correspond with the development "booster" and "super" design.

Wikipedia, and other sources tell me that the fission part delivers the largest amount of the power. Modern multimegation thermonuclear warheads use a 3 or more stage reaction. A nuclear warheads sets of a fusion reaction, which then expells neutrons which cause the detonation of second shell of nuclear material. (Bonus for this is that the outer layer doesn't need to be weapongrade)

Now, deuterium-tritium reaction, which is the considered reaction (I've seen nowhere talking about H² He-3 reaction, nor about "catching electron from reaction").
Deuterium : 1 proton, 1 neutron
Tritium : 2 neutron, 1 proton
When combined, they'll form a 2 neutrons, 2 protons (Helium), and a free neutron. The helium is not radioactive. But the neutron (not radioactive in itself), if absorbed by other particles, can often make the said particles radioactive, like the inner plating (which will then be radioactive waste).
Neutrons in itself are not radioactive. Of course, it's dangerous for (as said), organics, as if you become radioactive yourself (do not try this at home), but on other materials, it change them into radioactive waste (most are not very dangerous, but some can be nasty). For more things about radioactive effects of neutrons.

So yeah, the plant produces radiation, but not directly. As for He-3 deuterium fusion. Wikipedia Scientific PDF.

Not dealing with ebbor's huge megapost.

Any governement is not going to let you build a colony without infiltrating it. Especially in a cold war type scenario. Sure, nobody is going to attack it during the war, but it will be forced to take on allegiance before. Especially if there's a chance of humanity nuking themselves into extinction.

Wait, why are you assuming I'm having the base built during the war, or that such people wouldn't be allowed in the colony if there was room and they didn't try to sabotage the base?

I'm not. However, even before the war it's extremely unlikely that any governement is going to allow you to build a base without sneaking some of their agents onto it. It's a giant strategical asset, after all. Mostly as a launching site for unstoppable weapons of mass destruction, but I'm pretty sure other uses can be found as well.

Oh, and by the way: Since this is a thread which the title and OP pretty clearly indicate is to be talking about a future Martian colony and I have to convince other people that we will and have reasons to colonize other worlds--when there's already attempts to do so underway--I see no point in continuing following this thread. If it was a thread titled something like "Should we colonize space?" or with a similar OP, this would be fine, but as it is...nope. Good day. Have fun discussing fusion in a thread about space colonization.

I like the thread this way more. It doesn't break down the discussion, information and ideas are exchanged, and without the spinoff's the thread would have died a long time ago.

Oh, and humans are like friggin' cockroach. We survive on the ice shelf of the arctic and in the desert of gobi, in the jungles of the Amazons and the plains of Africa. And that was before we had all that fancy tech.

More like really well adapting rabbits actually. One might die, but there are always billions left.

[Morrigi]

A weapon of mass destruction of any kind would be infinitely cheaper and more useful on Earth, simply due to distance. On Mars, you have a communication lag time of around 45 minutes due to the speed of light. Now, if the shit hits the fan, do you really want to have to wait that long, or much longer if your weapon doesn't travel at the speed of light? A garden variety nuclear missile can hit a target anywhere in the world in approximately seven minutes. Not to mention getting an intact WMD to Mars is going to take a very large, obvious rocket launch to get the weapon to Mars, and at the very least one more to set up the necessary infrastructure. It would be rather difficult to explain those away, not to mention the suspicious thing that looks like a weapon of mass destruction on the Martian surface.

[PanH]

Wikipedia, and other sources tell me that the fission part delivers the largest amount of the power. Modern multimegation thermonuclear warheads use a 3 or more stage reaction. A nuclear warheads sets of a fusion reaction, which then expells neutrons which cause the detonation of second shell of nuclear material. (Bonus for this is that the outer layer doesn't need to be weapongrade)

It widely depends on the design of the bomb. Some bombs have more than 3 stages (notably URRS ones), and some have fission third stage or fusion third stage. Each reaction also feeds from the others.
Also, do not confuse boosted with H bomb.
An hydrogen bomb is considered "clean" when less 50% of the energy comes from the fission, and "dirty" when more than 50%.

So yeah, the plant produces radiation, but not directly. As for He-3 deuterium fusion. Wikipedia Scientific PDF.

That definitively looks like something that will happens at best at 2nd generation fusion reactors. With current technology, there's no really point, because it requires more energy (higher temperature requirement), which means less outcome, and there's no real useful application of the electrons. The good point would be no radioactive waste (radioactive != radioactive waste, in occurences and effects), which isn't really worrying.
In any case, you don't want to stand in the reactor, because you'll be fried.

(btw, the pdf you sourced is less than reliable, it takes sources from blogs and such. There is definitively some interesting ideas in it, but it is far from scientific)


The main point of mass destruction weapon is intimidation. If you put one on Luna, that'll force others to develop a way to reach that silo. The lag could actually be helpful for retaliation mesures. I personnaly find it useless, because that's just continuing the nuke race.

[10ebbor10]

A weapon of mass destruction of any kind would be infinitely cheaper and more useful on Earth, simply due to distance. On Mars, you have a communication lag time of around 45 minutes due to the speed of light. Now, if the shit hits the fan, do you really want to have to wait that long, or much longer if your weapon doesn't travel at the speed of light? A garden variety nuclear missile can hit a target anywhere in the world in approximately seven minutes. Not to mention getting an intact WMD to Mars is going to take a very large, obvious rocket launch to get the weapon to Mars, and at the very least one more to set up the necessary infrastructure. It would be rather difficult to explain those away, not to mention the suspicious thing that looks like a weapon of mass destruction on the Martian surface.

Be creative with your weapons of mass destruction. Mars is a quasiideal position to mine asteroids, and you're pretty much going to need to do that in order to supply certain materials. While not the most resource efficient method, you can never be sure that the other party won't also try it.

So yeah, the plant produces radiation, but not directly. As for He-3 deuterium fusion. Wikipedia Scientific PDF.

That definitively looks like something that will happens at best at 2nd generation fusion reactors. With current technology, there's no really point, because it requires more energy (higher temperature requirement), which means less outcome, and there's no real useful application of the electrons. The good point would be no radioactive waste (radioactive != radioactive waste, in occurences and effects), which isn't really worrying.
In any case, you don't want to stand in the reactor, because you'll be fried.

(btw, the pdf you sourced is less than reliable, it takes sources from blogs and such. There is definitively some interesting ideas in it, but it is far from scientific)

The main point of mass destruction weapon is intimidation. If you put one on Luna, that'll force others to develop a way to reach that silo. The lag could actually be helpful for retaliation mesures. I personnaly find it useless, because that's just continuing the nuke race.

((Note to self: Read pdf's before posting))

Deuterium-He-3 is pretty much second/third generation fusion. Main problem we currently have is that rather than having a deuterium-He-3 fusion, the deuterium tends to react with itself, forming tritium and then continuing with normal fusion.

[Starver]

There is some civilians [Fusion generator] prototypes running, and an important test plant should be finished in 2020 (including already 3 years late). Lots of prototypes are running since years, even though they're mainly about testing, potential uses, and not much about energy production.
And it's already used since decades in military devices.

Wut?  I've not heard a thing about fusion power, civilian or military, having been "in use" at all.  They've got various machines where, for a few milliseconds or so they can pump in a huge amount of power and momentarily get...  well, I'm not even sure if they've broken even, just yet, but a (not so?) huge amount back for just that moment, straight from the fusion (or from the heat generated, or something)...  But they're a long way from being self-sustaining.

Unless I've been asleep and missed something.

Hydrogen bomb.

Yes, because I'd consider that self-sustaining(!)...  Press button, boom.  And then?  And making use of the energy?  Even though it obviously makes more energy than was used to initiate it, sorry, I'd rather discounted that.  Apologies if I hadn't made that obvious.

For civilians project, there is some reactors, most of them being built in 80s, for testing and application purposes. The ITER, which would technically work the same as a plant (but for thermal tests, mostly) is being built.
For others military projects, there is some lasers that are being built to improve the atomic/nuclear bombs.

I know about JET, ITER, and of course the National Ignition Facility (for some reason I have doubts about the sanity of the guy who came up with that precise name...).  Not broken-even, though, any of them.  (And certainly not continuously so, which is what I imagined was being originally claimed.)

The + (for electricity plants) :
No radioactivity
Easy to find fuel (²H)

These are not necessarily correct.  [edit - and I've been ninjaed, by both sides of the argument, so you can probably ignore the following]
We'd probably be looking at ²H+³H -> ⁴He+neutron+energy.

First of all, that's why we'd need the tritium.

Secondly, there'd be a load of neutrons flying about.  With a lot of energy.  Which means that even with the radiologically stable helium by-product from the reaction itself, the container/surrounds of the reactor is going to be irradiated by neutrons, making who-knows-what isotopes in the process.  Eventually you'd need to strip the parts and do something with them, much as you have to consider with fusion reactors, albeit there you have fuel waste as well.

If you insist on deuterium-deuterium (-> bog-standard stable helium without any by-product, right?) you're actually going to get both tritium+hydrogen or helium-3 and... ooh look, a neutron.  And I believe this is a trickier process to get working, so perhaps we'll have to get the principles of tritium-deuterium working first, and then improve the situation.  Perhaps eventually we'd be sending in pure deuterium and 'breeding' some tritium for a secondary 'burn', whilst farming the other atoms to 'jacket' the unit in sufficient quantities of gathered helium-3 to soak up the neutrons...  Not sure how we'd do that.  It'd have to be a thick (and/or super-dense[1]) jacket to make it an effective neutron-soaker-upperer...  From which we can recover the energy.

But I'd imagine using some heavy transuranic element (or something that would irradiate up to that level), with the side-effect (whether publicly positive or not) of generating more 'conventional' nuclear fuels[2].  Or perhaps towards the end of almost immediately fissioning into more 'stable' by-products, with more blockable alpha and beta radiation, and a little more farmable energy.

(And magnetic bubbles can't contain neutrons, by the way.  Unless we can somehow persevere with a fine-structure magnetic field that is capable of polarising the distribution of the quark charges within the hadron itself.  Or have some "new physics" process the likes of which we can only imagine.)


[1] But then we're going to have expertise in making stuff dense, by then, I suppose.

[Starver]

As for the brush thingy, how are you going to brush away the dust in the athmosphere. It's not dust accumulation on the pannels that is the main problem(Though that forms a rather large energy and maintenance problem, as the dust is magnetic electrostatic, you mean? and tends to stick) but the fact that the sun is occluded by "fairly" frequent dust storms, which can remain in the atmos for up to half a year.

That's a good point.  A not insurmountable one (maybe distributed power grid with representative stations at different latitudes, along with different longitudes to handle the daily cycle...), but something I hadn't imagined was being talked about.

The stronger you make the structure, the heavier it becomes. It's a sort of balancing act. And seperating the station from it's powersource will make manoevering quite problematic, though still possible.

A balancing act that is soluble, and a manoeuvring problem that is likewise.  The former can be planned in easily, the latter also, but I'd like to see them try several different solutions to see what works best.

I get the idea you have no bloody idea what you're talking about.

I think, perhaps because you're misunderstanding things that I think I understand, but that you're seemingly interpreting quite differently, I'm perfectly entitled to fire that statement back at you.  However, I'm going to restrain from saying that you misunderstand your understanding, because there may still be more confusions at my end, regarding one or more bits of what I've snipped...

It wasn't directed at you.

No, but I thought I had a valid response, regardless.  It went a bit... wavy... but it was what I was thinking.

I think you forgot to account for the fact that Mars atmos is only 0.6% as dense as Earths.

You're right, I did.  Still, the original point was about the fuel not needing increasing, but the 'air' supply.

Iter should have a break even, and I believe they reached one at the National Ignition facility last year. For now, all fusion energy reactors use more energy than can be recovered from the heat they produce.

Since writing what I did, I checked, and it appears nobody has broken even yet.  (That's merely "recoverable energy", of course, and while they're still concentrating on efficiently pumping energy inwards they're probably neglecting the full potential of energy that they could be recovering.)

[Immortal]

On the topic of why. I would go if I had the money, and I believe many others would be happy to also (Elon Musk is dreaming about it and trying to get something moving).

Also on the topic of fusion us Canadians are doing some work.
http://www.generalfusion.com/

[PanH]

Yes, because I'd consider that self-sustaining(!)...  Press button, boom.  And then?  And making use of the energy?  Even though it obviously makes more energy than was used to initiate it, sorry, I'd rather discounted that.  Apologies if I hadn't made that obvious.

So you're dismissing it because the use of the fusion power is used for destruction ? Then I guess atomic bombs don't use fission power, but most probably magic.
Also, don't forget that one-hit reaction, when repeated, can form things like gasoline engine.

I know about JET, ITER, and of course the National Ignition Facility (for some reason I have doubts about the sanity of the guy who came up with that precise name...).  Not broken-even, though, any of them.  (And certainly not continuously so, which is what I imagined was being originally claimed.)

JT-60 in 1996 reached the break-even. Their best is something like 1.25, which isn't much admittedly, but that's the point of a test reactor. This is the reason why they don't do continuously : why would you let it run for no benefit, when you can observe the results immediately.


For tritium, there is currently a stock from fission plants. But as said earlier, one of the aim of ITER, is to see the production of tritium, inside the reactor. So it would produce his own fuel, based on the deuterium (not much), and lithium (much likely), with help of the neutrons.

Finally, neutrons are not radioactive. They can modify atoms that then become radioactive (though, more often, it will do nothing). So, it can wear the inner plating into radioactive waste, but not something fast. You could always replace it for maintenance say, each 10yrs (or even more, I think).
In fact, neutrons don't seem to be a concern at all for the ITER, because it is even planned to use lead, which when receive a neutron, will release 2, to increase the likeliness of lithium-neutron reaction.

[Starver]

Yes, because I'd consider that self-sustaining(!)...  Press button, boom.  And then?  And making use of the energy?  Even though it obviously makes more energy than was used to initiate it, sorry, I'd rather discounted that.  Apologies if I hadn't made that obvious.

So you're dismissing it because the use of the fusion power is used for destruction ? Then I guess atomic bombs don't use fission power, but most probably magic.
Also, don't forget that one-hit reaction, when repeated, can form things like gasoline engine.

No, I'm dismissing it because it's not self-sustaining in any way consistent with power-generation.  Which I believe was what was being discussed.  (Not even easily harvested for power on an more occasional basis.)

Inertial Fusion Plants are far from being realised.  As far as I can tell, the stage of realisation that they've reached is identical to that of non-inertial versions of fusion power...  Getting the fusion 'fuel' to be fused in the first place.  The rest of the process (abstracting useful work/energy from the fusion and cycling the process in a repeatable manner) is still a pipe-dream.

(Personally, I'd wonder if something more akin to a turbine method would be better than a "reciprocating engine".  Continuous flow of fusion materials into a 'hotspot', this energy being used to sustain the flow in (against the pressure of 'combustion', of course) while the end-products get exhausted out the other way.  Perhaps with a 2²H method, the ²H+³H and ³He+n products could be processed in an 'afterburner' unit, or two...  But that's at least as speculative...  As is such a unit being, at least partially vented, directly providing reaction thrust, and a much smoother and easier-throttled version than that of either of projects Orion and Daedalus)

JT-60 in 1996 reached the break-even.

"During dueterium plasma experiments in 1998 plasma conditions would, if the D-D fuel were replaced with a 1:1 mix of deuterium and tritium), have exceeded break-even..." "...does not have the facilities to handle tritium..." ",,achieved conditions which in D-T would have provided Q = 1.25..." "A self sustaining nuclear fusion reaction would need a value of Q that is greater than 5"...  Courtesy of Wikipedia.  Selective quoting, for the sake of brevity.  My emphasis on the "would have" bit.  It would have been better than break-even, for fuels it can't handle.  And, even then, this is less than the self-sustaining value.  (Not sure why Q>5 is needed, exactly, but perhaps that can be shaved closer to 1.25 with a better design...)

Finally, neutrons are not radioactive.

I never said they were.  I said that they can convert other materials to radioactive ones, as you also acknowledge.  They're radiative, however, and damned difficult to corral.  Not completely a problem if you can put your reactor far from the people it's supplying energy to (or Propulsion...  c.f. 'Discovery One' in 2001:aSO, although those were apparently fission engines), or behind a sufficient amount of dead-weight mass, but this still has to be considered.

In fact, neutrons don't seem to be a concern at all for the ITER, because it is even planned to use lead, which when receive a neutron, will release 2, to increase the likeliness of lithium-neutron reaction.

I don't find that unconcerning at all...  Getting two neutrons for the original one (presumably converting lead to thallium in the process) seems a little like increasing the issue.

Of course, the daughter neutrons will probably be randomly flying around (as many back towards the core as were originally flying away from it, and a significant amount diagonally through the shielding, with increased chances of further capture and conversion) and probably with less energy, but I'd need to dig out my old text-books (probably some mathematics ones, as well as those relating to the physics of the issue) before I could fully reassure myself about the wisdom of this idea...  The guys who have suggested it have probably satisfied themselves, sufficiently, but the devil is in the details that you omit...

[PanH]

No, I'm dismissing it because it's not self-sustaining in any way consistent with power-generation.  Which I believe was what was being discussed.  (Not even easily harvested for power on an more occasional basis.)

Then I misunderstood you. You talked about fusion power, and I gave you a fusion power example. I didn't understood it was specifically for electricity generation (because, electricity is still under testing). Though I said it was testing prototypes only for this purpose.

JT-60 : Effectively, it's theoric Q (blame my non-english Wikipedia page). On the other hand, I think they could have done. The requirements for tritium are mainly those of stockage (which is quite difficult). And they probably didn't want to use tritium which is quite expensive as for now. The 5 I think is for the electricity production to be interesting, lower it would be too expensive, but maybe better ways will be discovered until.

Neutrons : The radioactive waste created is not necessarily very dangerous. For example, I doubt that a piece of radioactive concrete is as dangerous as depleted uranium/plutonium, etc. This would also be an effect of long time reaction. In any case, the radioactive effects are considerably lower than a fission one, which drastically reduce hazards.
For example, contrary to popular belief, the big concrete pillars in fission plants are not to protect from radiation, but for cooling down. Some centrals don't even have them.

For lead, I think that the 2 neutrons created are of lesser energy. Though my point was more than, if they are trying to get the more neutrons, it doesn't seem it's a very concerning matter for them, and I think they know way more than me in this field. There's also some testing they will do with ITER, like lithium battery to capture neutrons, etc.

[Starver]

AFAIK, everyone else was talking about (usable, trappable, convertible to electricity) fusion power, is all...

The (en.)wiki page seems to say that JT-60 is at the apex of returns on energy, so I don't dismiss it, although it looks like there's nothing better right now.  As well as storage it may be a matter of packaging the mix.  (Getting a nice homogeneous mix of deuterium for a D-D fusion event might be easier than getting the D-T mixture to present itself for almost entirely a D-T fusion and very little D-D/T-T fusion attempts.)  I don't know, that page was sparse on details and I didn't follow up any citations at all, so I'm just guessing.

Depleted Uranium isn't completely safe, but I think I'd worry more about its toxic effects (or, possibly, that the armoured vehicle I'm in is being shot at by DU rounds) than its radiative qualities, although I'd be avoiding ingestion/inhalation as much as possible in all cases.  It has a half-life of billions of years, rather than the millions of years of the 'useful' U-235, and isn't actually spewing much radiation out when purified enough for its typical civilian and military uses.  Actually, I'd probably be happy holding both isotopes in my (rubber-gloved) hands, unless the latter has been 'activated' as is (or was recently) actively cascading, and now has a substantial amount of shorter half-life isotopes ready to irradiate me.  Concrete with an abundance of silicon (stable with 28-30 nucleons) potentially knocked up to ³²Si for a hundred-odd year half-life would probably give out more radiation, and oxygen-(16..18) becoming oxygen-19 for a matter of seconds, then (IIRC) fluorine-17... which I couldn't quickly find data on, but ISTR fluorine-18 has about 2 hours of half-life.  I'm not immediately sure what calcium (as another common atom in a generic 'concrete' mix) might do, but I could make guesses.  All kinds of other materials might end up in concrete as the 'bulker' for the basic cement mix, probably stuff that's the otherwise unwanted by-product of smelting processes, so could be anything.

Obviously when you turn the neutron source off it you quickly lose the newly created short-lived isotopes (although one can only imagine what this means about the structure of the molecules in the concrete so affected...  again, I'm sure others have researched this, as well as actually analysed the results around the many reactors and other neutron sources that have been actually used).  Also if this is a space (or non-terrestrial 'dirtside') location I can imagine them just sending the unwanted material in a degradable solar orbit if they really wanted to get rid of it without too much more fuss.

It's not really the longer half-lifed materials (which are probably emitting comparable to 'earth-normal' background radiation levels) or the shorter ones (that can be left alone for enough time to decay to stable ones) that would concern me (armchair physicist as I am), but the intermediate ones, and the chains of decay-products that "keep on giving", chucking out a beta particle here or an alpha particle there for a whole stack of radiative goodness.

And although there's more than enough radiation to be bothered about in space (one might argue) when it comes to operating a neutron-spewing power-plant, kicking materials off, that's what I'd be most concerned about.  (That and the 'random' degradation of the materials, crumbling concrete and realligning atoms in alloys.)

(The specs for the steel used in in BNFL's nuclear fuel flasks, I happen to know via family connections, were quite rigorously, and possibly over-, engineered (as well as being used in container walls 14" thick, IIRC).  Although that was for the relatively neutron-poor radiation of 'spent' fuel, mostly.)


But, hey, it's all a lot of theory.  And I might even take my "fusion turbine" idea for some bit of speculative fiction of mine I have in the pipeline.  (Might need some refining, but it'll be no worse than a lot of fictional techs. )

[10ebbor10]

About the fusion turbine. Seems like a typical fictional fusion engine to me. (Which is remarkably similair to a fission based engine, with the only difference that the fuel also counts as the heat source).

Problems are that you will very rapidly loose energy. Even a closed circuit fusion reactor has problems with maintaining the temperatures required, and the problem becomes exponentially worse as you start to dump heat/matter.

It is however technically possible.

[Starver]

Indeed, there's probably something better out there, but I find the Daedalus-style "rear-end shunting" nuclear drive a little... inelegant, and I suppose I have the same prejudice against what might effectively be a nuclear 'two/four-stroke engine' (which would also be less good outside of power generation of actually... driving wheels?  ...but that'd be a strange 'land dreadnought' sort of construct).

Big Dumb Rockets becoming Big Dumb Rocket Only Nuclear Powered also lacks finesse (although it may be the most efficient thing, to concentrate your fusion precursors in at the focal point of a suitably radiation-armoured rocket 'bell'...  Or aerospike/SERN it...

With a whole heap of engineering challenges needing to be worked out (or fudged, in a work of fiction) I just like idea of a turbine-analogue engine which can be tapped for huge amounts of power (for the, possibly equally fictional, other future-tech items equipping ones spaceship, like force-shielding or warp/wormhole generating and maintaining hoojamaflips) as well as perhaps being an ion-drive on steroids.


Which is not to say that fission-powered reciprocating devices might not even start out as analogues to Newcomen-style 'atmospheric' engines, then perhaps through a Watt-style method of enhanced efficiency, before even entering the standard piston (or multi-piston) configuration.  Hey, it makes one wonder if a Wankel-style rotary treatment could ever be applied to the idea of fusioning fuel pellets...  But on this point I acknowledge I've strayed beyond most currently projected engineering goals and hopes...

[10ebbor10]

Well, that last thing could work if you go with the National Ignition's facilities approach, where they just fire a single laser at a pellet.

Oh, and btw, I wasn't referring to the Daedalus drive, but to another type of engine in which hydrogen fuel (Ie, typicall rocket fuel) is simply dumped through an openended reactor in order to heat it up and propel it outward. Kinda like the Nerva engine.(Which was quite efficient, but in effect just a glorified chemical engine.)

[Starver]

Applies to spent (through fissioning) nuclear fuel[1], but that old stalwart of XKCD (its What-If section) has an interesting thing here, that may not be utterly relevant to the discussion topic but still might interest those who have been interested in the nuclear-power diversion we've generally been having recently.




[1] And also refers to a neutron-irradiated bit of scrap, but I'm not intending to make a direct comparison with fusion-reactor externals.