Fusion/Fission Reactors Question

No. Fusion uses light elements (z = 1, 2, 3; in reality, only 1:(H))

Fission uses heavies (z=92 (U) or z=94 (Pu)).

Totally different. The waste for each are at opposite ends of the spectrum as well.

I like that there is a thread on this. A secret project to develop fusion power is emerging as a sub-plot in my novel.

Ocotilo is mostly correct but leaves out the reasons why this is so.

Fusion can occur with just about any atomic number(s) for the initial materials and heavier atomic numbers for the results. Basically, atomic nuclei get smashed together into heavier ones. Fission is the opposite process, where heavier atoms split into lighter ones. You knew this already.

All elements heavier than helium are created by fusion. Helium is created by fusion; most of it in stars. A lot of the universe's helium was created shortly after the big bang. So why can't you get energy out of fusing heavier elements, or splitting lighter ones? That's where things get interesting.

Fusion is an exothermic process all the way up to iron and nickel: when these "light" elements are created, there's a net release of energy. Beyond that it's endothermic: it requires energy input. This normally happens only in two places: supernovas and atom smashers built by advanced civilizations.

The whole life cycle of a star centers around being able to withstand gravitational collapse by getting heat from fusion. When a star can't get heat that way any more—its core is all iron—it either stops there and turns into a white dwarf or a neutron star or, if it's big enough, goes supernova and further fuses that iron into heavier elements, some of which get blown all over the place. We are stardust.

We can get energy from fusion by colliding H2 with H3 to get He4 + N; we can get energy from splitting heavy things like U and Pu into lighter elements such as Pb (lead) and other crap. There is, unfortunately, no single fission-fusion cycle that is exothermic all the way around. That would get you arrested by the Thermodynamics Police.

*lol* (breaking the LAW)

*ahem* But just feel the need to point out that, no, Ocotillo was totally correct, not mostly correct. Fusion uses lights, fission uses heavies. Just didn't explain. (actually tried to, later, though not as thoroughly as you did, but man, I get tired of fighting the time-outs -- hate writing a post to lose it).

ok, i think i didn't maybe post correctly the intent. Fusion reaction would occur until we get to Fe and then that iron gets transferred into a fission reaction where those atoms are broken back down to hydrogen and rinse and repeat. I understand there is still a need for outside energies to run the reactions, but my question is whether it is remotely possible to undertake without the disability of lack of technology.

i think the issue comes with the fission of Fe down to H, normally we do fission reactions on U, Pu, and possibly other transitional heavy materials.

i understand the thermodynamic laws (equal and opposite, cannot be created or destroyed only transferred, and that other guy), ultimately it's the neutrinos released that im concerned with for the antimatter drive. My intent is to try and make this as plausible as possible, because the suspension of disbelief has to be low.

There is no I in team, but there are four in platitude-quoting idiot.

Procrastinating is like Masturbating, in the end you only screw yourself.

What you are trying to do breaks thermodynamics. Irregardless of the route net energy inflow must match outflow. Hydrogen fuses exothermically until it reaches Iron, but then Iron would undergo fission exothermically, reabsorbing all that energy you just released. If you successfully managed to do this it would be a zero energy change, or even an energy loss as no transfer of heat is 100% efficient so some energy would be lost to the environment.

There’s a whole new universe waiting for you: http://www.vastdistances.wordpress.com

I'm not entirely sure what you meant by being concerned of released neutrinos? Just to point out, neutrinos are different from neutrons. Neutrino is probably something you're not concerned about, since they really don't interact with anything, around 50 trillion neutrinos pass through you body every second.

GREAT POST!!!!

~Jesse James Akins

yeah, ultimately im trying to harness neutrinos, positrons, and antiprotons. Basically the Fusion/Fission would be used to generate those particles to use in an antimatter drive. the power generated from the fusion/fission is not really important. Most of the stuff used works off of very small amounts of energy and are mostly self supporting as technology and humanity exist and work together. Think robots and humans working in a lab to discover the mysteries of the universe. The thing im having trouble with is production of antimatter for an antimatter drive.

Fusion/Fission reactions have been noted to produce antimatter that speeds away at the speed of light. Im "creating" a way to harness them by using cold and electromagnetism. By cold im talking .1 Kelvin. Just need to think of a plausible way to generate the antimatter needed to drive starships at 2.97x10^8 m/s. thanks for the input guys and gals, it's greatly appreciated. didn't even think about the thermodynamic laws when i was envisioning this.

There is no I in team, but there are four in platitude-quoting idiot.

Procrastinating is like Masturbating, in the end you only screw yourself.

and im as genius, i have been meaning antineutrinos. sorry for my stupidity

There is no I in team, but there are four in platitude-quoting idiot.

Procrastinating is like Masturbating, in the end you only screw yourself.

Antineutrinos?

In what system of subatomic particles do those exist?

Anti- means that the electric charge is the opposite. That is, a positron has all the same properties as an electron except that it is positively charged. An anti-proton is a negatively charged proton. Neutrinos ('little neutral ones"), like neutrons, don't have electric charge. There is no antimatter equivalent; they are it.

Oh, and the process by which elements heavier than iron become elements even more heavier than iron is still fusion; the difference is that it is endothermic—energy goes in.

There are antineutrinos. Apparently neutrinos have left-handed helicity and antineutrinos have righ-handed helicity. So they seem to be the same particle, yet they are anti-particles at the same time. Or that's what I gathered from wiki. I'm still not really sure if they'd have enough energy to power a flashlight, but not gonna start calculating that.

Or, alternately, if they're thinking of a fusion/fission cycle that can release net energy all the way around, we could handwave Einstein's famous equation relating matter/energy and say that the cycle's net energy release ultimately causes the matter involved to be consumed. The net energy thus comes from somewhere....

Hard sci-fi? Soft? Should be more like peanut butter -- neither hard, nor soft, and either way you have it a bit nutty.