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[Siquo]

If discussion going forward will discount athropogenic global warming as a reason for adopting one source or the other, I am more than happy to leave the subject.

Who cares? If Armok told you to go green, I'd be more than happy, and wouldn't care about the argument.
And "global warming" is just one scenario. How about anthropogenic we're totally fucking up our only planet to live for an argument?

[PTTG??]

If discussion going forward will discount athropogenic global warming as a reason for adopting one source or the other, I am more than happy to leave the subject.

Shall we also discount the germ theory of disease for our new sewer system design?

EDIT: But, sure, let's roll with that. Geothermal is still cheaper than coal, and Nuclear is still cleaner in terms of toxins and carcinogens. Oil production will peak in the next decade, and from that point on will grow exponentially expensive as demand far outstrips supply. Solar and Fusion, on the other hand, will become less expensive and more feasible, respectively, as new technologies are developed.

[Criptfeind]

Yeah. To be fair I have no idea how fusion works.

You combine atoms into larger atoms, for example, two hydrogen atoms into a helium atom. Due to weird quantum shit, the resulting fusion products have marginally less mass than the stuff that goes in. The difference is converted into preposterous amounts of energy. Fission is the opposite, breaking larger atoms into smaller atoms. All matter in the universe that isn't hydrogen comes from the fusion reactions inside a star that died billions of years ago. All matter heavier than iron comes from supernova explosions.

So, like five hydorgen go to one Beryllium or something and the + turns to energy? Das cool.

[Darvi]

Actually it's 4 H ->1 He.


Somehow. Two of the protons turn into neutrons and emit radiation. I think beta.

[Criptfeind]

Oy, right right, forgot about the fact H has no neutrons. Odd little guys.

[Darvi]

Its isotopes do. In fact I think it was actually along the line of H₁₊H₃->H₄.


Should look that up.


Edit: It's H₃ + H₂ -> H₄ + n

[PTTG??]

We could always use vats of shrimp to produce what might be fusion energy.

(Not serious)

[Nadaka]

Its complicated. But its probably easier and mostly accurate to look it up on wikipedia than it would be for me to explain it.

Simply put: up to iron, the mass of a particle is less than the sum of the mass of its parts up to iron, and that difference is released as energy.

Technically this is also true for a ways past iron, but the boundary layer where fusion occurs in a star only allows similar mass nuclei to come in contact.

The energy released is from the conversion of a proton absorbing an electron and flipping its quarks as well as the difference in binding energy between the two nuclei configurations.

[Il Palazzo]

The problem with nuclear fusion, providing that we're thinking fusion reactors, and not stellar fusion, is that you can't really use the proton-proton reactions there(i.e. can't just use regular hydrogen obtained from simple water electrolysis).
The transmutation of one of the protons into a neutron, to form a deuterium nucleus, is extremaly unlikely, and would be thus unfeasinble for the artificial energy generation. We're talking once-in-billions of years event for any given pair of protons. The only reason why it works in the stellar core, is because there's so many protons out there.
In your reactor, you don't want to have to deal with the weak interaction, which is responsible for just that, and rather have particles like deuterium, tritium and helium-3, lithium-7, or berylium-11 with 'ready-made' neutrons within.
Also, it's by no means a 'clean' energy source. Or at least, not unless you'll settle for fusing only He-3 together, and berylium/lithium+proton as a side reaction - but then you'll have to think of some way of getting your fuel at all, as He-3 is extra rare on Earth, meaning extra expensive. Some people suggested that there might be more He-3 on the far side of the Moon, but getting it from there is another daunting obstacle to surmount.(nota bene, the film "Moon" has such an operation as a setting for it's plot. Great movie, too)

What I mean by fusion not being clean, is that, providing you're extracting deuterium from the water to fuel your reactions(which is not that easy either, I bet), and not flying to the Moon, it produces far more free neutrons than fission does, per unit of energy generated. Neutrons cannot be contained by a magnetic field, so they will inevitably irradiate the reactor, which after some time will have to be stored away in the same way as we're doing it today with nuclear waste. Not to mention that a completely new one will have to be built in it's place.
Also, there's an option of manufacturing He-3 from tritium decay, but is not only uneconomical, but also involves emission of neutrons, causing further problems with the cleanliness of this energy source.

This is not to say that fusion is completely unfeasible as an energy source. It's just that due to those additional dificulties mentioned above, it's way, way more distant than what you might think when you read about some scientist bragging about their working reactors.

tl; dr;
Fusion technology will not let you turn your tap water into energy.

[Fayrik]

I remember reading somewhere that the best setup for a Nuclear Fusion plant would be by the sea, and would pump up sea water, split it (thus desalinating it), taking the ²H₂ out for fuel, then some H₂ and O₂ out for bottling, recombining some for drinkable water, and recombining some to pump back into the sea.
In the same document, I also read we're no where near ready to use ²H₂ as a fuel yet. So that idea's out of reach as of yet. I believe the current designs use Lithium instead, yes?

[olemars]

Current designs use the Deuterium-Tritium fuel cycle, but Lithium is used to produce the Tritium needed (through neutron absobtion).

[PTTG??]

I am unsure of the fuel cycle of my personal favorite, the Polywell.

[olemars]

Deuterium-Deuterium and/or Deuterium-Tritium, according to WP.

My favourite design is the stellarator, mainly solely because of the name.

[Virex]

What I mean by fusion not being clean, is that, providing you're extracting deuterium from the water to fuel your reactions(which is not that easy either, I bet), and not flying to the Moon, it produces far more free neutrons than fission does, per unit of energy generated. Neutrons cannot be contained by a magnetic field, so they will inevitably irradiate the reactor, which after some time will have to be stored away in the same way as we're doing it today with nuclear waste. Not to mention that a completely new one will have to be built in it's place.
Also, there's an option of manufacturing He-3 from tritium decay, but is not only uneconomical, but also involves emission of neutrons, causing further problems with the cleanliness of this energy source.

I think the neutrons are also a pre though. There's just not enough tritium present in water for recovery to be effective and the D-D cycle requires temperatures and pressures too high to be viable soon. So instead, the neutrons from the D-T cycle are captured by lithium, causing fission. The fission products in this case are tritium and helium. The tritium is extracted and fed into the reactor and the helium is either cooled to serve as a coolant to the superconducting magnet coils (or sold at exorbitant rates because once DEMO goes on-line most helium wells will probably have dried up).


Also, while the reactor shielding and some parts of the tubing will become radioactive, proper material choices can push the half-life of the formed radioisotopes down to around a decade or two. At that point it becomes much more manageable.

[PenguinOverlord]

http://www.telegraph.co.uk/finance/comment/ambroseevans_pritchard/8393984/Safe-nuclear-does-exist-and-China-is-leading-the-way-with-thorium.html
China has harnessed the power of Thor from the Scandinavians.