[Androgeos Exeunt]

http://www.bbc.co.uk/news/science-environment-24429621

I remember asking my Physics teacher about fusion as a source of energy back in middle school, and he was optimistic that it could be a viable source of energy in the near-future. That was in 2006. Now that the NIF have managed to generate more energy from the fusion of two atoms than the amount of energy required to trigger the fusion, the hope that I will be able to see fusion power plants before the century is out has returned.

Fusion is still nuclear energy, though. How much safer is it than nuclear fission? From the little I know, nuclear fission seems to one-up nuclear fusion in terms of radioactive risk.

[Kopachris]

Fusion is still nuclear energy, though. How much safer is it than nuclear fission? From the little I know, nuclear fission seems to one-up nuclear fusion in terms of radioactive risk.

Fusion requires extremely precise conditions.  Any change in those conditions and the reaction will simply stop.  There's virtually no chance of a runaway reaction.  As for radioactivity, the only risk is from pieces of whatever's containing the reaction which may have become mildly radioactive from neutron bombardment (risk is low enough that many hobbyists do that on purpose, for fun).  Also, tritium fuel is mildly radioactive, but safe enough that you don't have to worry unless you actually ingest a bunch of it.

I'm personally rooting for ITER.  I like the idea of tokamak reactors--it's what I usually imagine when some sci-fi show says "The reactor's been hit!"

[Colonol Dekker]

Tritium is so safe it's been used in small arms optics for decades.

[perihelion]

@ Dekker, what use does tritium have in optics???

@ Androgeos Exeunt, fusion should be relatively safe in the sense that a run-away reaction is exceedingly unlikely.  Virtually every fusion reactor that works even a little relies on "pulsed" fusion.  Reaction duration is usually measured in microseconds.  It takes extraordinary effort to even get the reaction to last that long.  I took a course on plasma engineering about 13 years ago, and the basic problem with fusion reactions is that the closer you get to conditions where a fusion reaction is "sustainable," the more efficient all of the various mechanisms for cooling the plasma become.

As for radiation, charged radiation (alpha and beta) are fairly easily dealt with.  Your main problem is neutron radiation.  It is eventually going to make your reactor materials radioactive as all get out.  It is possible to shield against neutron radiation, but not for the materials that are part of the reactor itself.  That results in a kind of "corrosion" as materials in the reactor transmute / decay into other elements.  I suppose this isn't a new problem.  Fission reactors have to deal with this as well, but they usually are filled with a neutron moderating fluid.  That won't be possible in a fusion reactor.

It may be possible to make a useful fusion reactor (in the sense of power generation) at some point, but I wonder if it is going to be more trouble than it is worth.  At least planet-side.  The only place where I can see it really being worth the extreme pain is in space, where the mass of your fuel becomes such a bottleneck to operational range.

[The E]

Same use it has in wristwatches. Small illumination strips, which are used in gunsights to provide reference points in the dark. Think about the targeting dots on your average pistol, for example.

[FlamingCobra]

Fusion is still nuclear energy, though. How much safer is it than nuclear fission? From the little I know, nuclear fission seems to one-up nuclear fusion in terms of radioactive risk.

-snip-

I'm personally rooting for ITER.  I like the idea of tokamak reactors--it's what I usually imagine when some sci-fi show says "The reactor's been hit!"

I personally think stellarators are better. The currents in the plasmas of stellarators are supposed to be more stable than those in tokamaks.

Thomas Klinger, the the Scientific Director of Wendelstein 7-X (a stellarator the size of pre-JET fusion devices) was the guest speaker at the Inside ITER presentation [on April 7, 2011]. His talk and subsequent interview provided some fascinating insights into the W 7-X project and, more generally, on the future of the stellarator—the bright kid who is now getting a second chance.

Asked how stellarators are different from tokamaks, Klinger uses this image: "In a stellarator, confining the plasma is like holding a broomstick firmly in your fist; in a tokamak, it's like trying to balance the same broomstick on your finger."

Stellarators produce intrinsically stable plasmas with no or only modest electrical currents flowing through them; tokamaks, with very strong plasma currents, must devise complex ways of maintaining their equilibrium. "Both are terrible beasts," smiles the Scientific Director of W 7-X. "Ours is a beast to build; yours is a beast to operate."

sauce

[Black Wolf]

I'm personally rooting for ITER.  I like the idea of tokamak reactors--it's what I usually imagine when some sci-fi show says "The reactor's been hit!"

I'm hoping Lockheed Martin get their High Beta working at their proposed timeframe. Partly because it's a brilliant little device if it lives up to spec - small, modular, easy to transport etc., but mostly becaus eI'd love to see the heads of all the modern day hippies explode if the American military-industrial complex saves the world from global warming.

[Aesaar]

Fusion is still nuclear energy, though. How much safer is it than nuclear fission? From the little I know, nuclear fission seems to one-up nuclear fusion in terms of radioactive risk.

On top of what Kopachris said, it's worth mentioning that nuclear fission power is still very safe, in spite of what anti-nuclear activists would have you believe.

[Nuke]

Fusion is still nuclear energy, though. How much safer is it than nuclear fission? From the little I know, nuclear fission seems to one-up nuclear fusion in terms of radioactive risk.

-snip-

I'm personally rooting for ITER.  I like the idea of tokamak reactors--it's what I usually imagine when some sci-fi show says "The reactor's been hit!"

I personally think stellarators are better. The currents in the plasmas of stellarators are supposed to be more stable than those in tokamaks.

Thomas Klinger, the the Scientific Director of Wendelstein 7-X (a stellarator the size of pre-JET fusion devices) was the guest speaker at the Inside ITER presentation [on April 7, 2011]. His talk and subsequent interview provided some fascinating insights into the W 7-X project and, more generally, on the future of the stellarator—the bright kid who is now getting a second chance.

Asked how stellarators are different from tokamaks, Klinger uses this image: "In a stellarator, confining the plasma is like holding a broomstick firmly in your fist; in a tokamak, it's like trying to balance the same broomstick on your finger."

Stellarators produce intrinsically stable plasmas with no or only modest electrical currents flowing through them; tokamaks, with very strong plasma currents, must devise complex ways of maintaining their equilibrium. "Both are terrible beasts," smiles the Scientific Director of W 7-X. "Ours is a beast to build; yours is a beast to operate."

sauce

stellarators are cool and all but its still a massive reactor. same with laser ignition (which might allow for some miniaturization as laser tech improves). i tend to root for the smaller reactors like polywells and dpf fusion. because these are the kind of reactors that would be used to power battle mechs naval warships and space craft.

[FlamingCobra]

I thought the Polywell was a good concept but I haven't heard anything new about it lately, so I kind of abandoned ship lost hope.

And let's not forget that fabricating data/scientific BS occurs in this field the same as any other. Remember "sonofusion"?

[IronBeer]

Or ....(snicker) .....pfffff..... "cold fusion".

[Colonol Dekker]

Old British army standard issue rifle optics

[The Dagger]

As for radiation, charged radiation (alpha and beta) are fairly easily dealt with.  Your main problem is neutron radiation.  It is eventually going to make your reactor materials radioactive as all get out.  It is possible to shield against neutron radiation, but not for the materials that are part of the reactor itself.  That results in a kind of "corrosion" as materials in the reactor transmute / decay into other elements.  I suppose this isn't a new problem.  Fission reactors have to deal with this as well, but they usually are filled with a neutron moderating fluid.  That won't be possible in a fusion reactor.

I've had a talk with ITER's security director once and he basically told me that this is the biggest issue as of today. The reactor walls are slowly corroded, creating a very fine very radiactive dust which is a nightmare to handle. Secondly, a catastrophic failure of the reactor would blast the power plant (and by doing so, disperse all radioactive material) but it's long term effects would be nothing compared to a fission reactor failure because most products would decompose fairly quickly. Also, tritium is not bad if it's outside you, but tritiated water can be rapidly absorbed through the skin, which may result in death.

[Nuke]

I thought the Polywell was a good concept but I haven't heard anything new about it lately, so I kind of abandoned ship lost hope.

And let's not forget that fabricating data/scientific BS occurs in this field the same as any other. Remember "sonofusion"?

not so much abandoned as classified. as far as i can tell they are still funded, and their results have been good the last few years since bussard kicked the bucket. remember its the navy footing the bill, they want a fusion reactor to power all the ships. it probibly wont be announced until half the fleet has been retrofitted with the thing.

[haloboy100]

Aw, so I can't sneak into one of these reactors and rig it to explode the next time I feel anarchistic?

[FlamingCobra]

I thought the Polywell was a good concept but I haven't heard anything new about it lately, so I kind of abandoned ship lost hope.

And let's not forget that fabricating data/scientific BS occurs in this field the same as any other. Remember "sonofusion"?

not so much abandoned as classified. as far as i can tell they are still funded, and their results have been good the last few years since bussard kicked the bucket. remember its the navy footing the bill, they want a fusion reactor to power all the ships. it probibly wont be announced until half the fleet has been retrofitted with the thing.

have they outfitted the carriers with the magnetic aircraft launchers yet?

[Klaustrophobia]

the Gerald Ford currently under construction and the follow ships will have them.

unless they decide having a 13,000 volt power grid isn't a great idea after all and revert.

also, they definitely won't be retrofitting new reactors into existing ships.  you'd have to pretty much rebuild the propulsion plants from scratch.  and crack the ship into many pieces.

[BloodEagle]

Aw, so I can't sneak into one of these reactors and rig it to explode the next time I feel anarchistic?

And now the forum has been moved up the list. 

[Flaser]

While all this money is thrown at a problem that has been 5 years away from solution for more than 20 years, am I the only one enraged that research into better fission designs, like molten salt reactors have been deadlocked by bureaucracy?

http://www.youtube.com/watch?v=iCdOgDfsM1I&feature=share&list=SPKfir74hxWhPsAXSrCy--ORaxxbXdWnXK

Estimates are, a commercial molten salt reactor could be developed for 1 billion dollars. It'd reduce the amount of nuclear waste created *at least* a 100 fold, could burn up a great portion of our existing nuclear waste, and would be inherently safer than existing pressurized water reactors.

[perihelion]

No, you aren't the only one pissed off by that.