Nations agree to build fusion reactor

dragon · Post by **dragon** » 2006-05-24 11:17pm

fgalkin wrote:
Darth Wong wrote: No they don't. Most of them assume that "natural" means "endless and harmless", when neither of those beliefs is valid. That's why there's such a push for things like biodiesel and ethanol; it is perceived to come from "natural" sources and should therefore be completely ecologically harmless according to their mindset.
We should point out to them that fusion power is "natural" because the Sun does it

Have a very nice day.
-fgalkin

Knowing these fundies they'll start complaining about the sun then.

Post by **Darth Wong** » 2006-05-24 11:22pm

fgalkin wrote:
Darth Wong wrote: No they don't. Most of them assume that "natural" means "endless and harmless", when neither of those beliefs is valid. That's why there's such a push for things like biodiesel and ethanol; it is perceived to come from "natural" sources and should therefore be completely ecologically harmless according to their mindset.
We should point out to them that fusion power is "natural" because the Sun does it

Have a very nice day.
-fgalkin

Unfortunately, I can already predict their response: "It's natural when it happens in the Sun, but it's not supposed to happen here on Earth."

Covenant · Post by **Covenant** » 2006-05-25 12:23am

I say we force them to live as nature intended, being chased by leopards and living in caves, nekkid, and sucking the marrow out of rotting zebra carcasses.

defanatic · Post by **defanatic** » 2006-05-25 05:03am

Dennis Toy wrote:WOW! i hope i am still alive when this is produced. I will actually be 61 years of age when this happens.

One question.

Will this take a lot of energy to start the reaction, confine the reaction using a magnetic containment field and to keep the reaction going? From what i heard, you will still need to use fossil fuel energy to get this thing started.

Does it really matter? It's either a large number of coal fired power plants for a long time, or this thing. Unless the amount of power to get it started is equal to the power produced by that large number of coal power plants over many, many years, it's worth it.

kheegster · Post by **kheegster** » 2006-05-25 08:12am

Dennis Toy wrote:
Will this take a lot of energy to start the reaction, confine the reaction using a magnetic containment field and to keep the reaction going? From what i heard, you will still need to use fossil fuel energy to get this thing started.

IIRC it does take several MW of power to heat the plasma and confine it, and the energy does indeed have to come from somewhere else. However, in a working fusion reactor, the energy produced from fusion would vastly outstrip the initial energy input, and in continuous operation I'd expect that the containment fields be powered from the energy of the tokamak itself.

Think of it as jumpstarting a car with a battery.

Post by **Darth Wong** » 2006-05-25 10:04am

The fact that they have to get their "kick start" power from somewhere else doesn't mean it has to be from fossil fuels anyway.

drachefly · Post by **drachefly** » 2006-05-25 12:37pm

Darth Wong wrote:The interior of the reacting will contain a lining which is slowly eaten away by the neutron and ion flux from the plasmoid even under normal operations. I'll have to look up the heat content of the plasmoid, but I recall it was surprisingly small.

A trickle of stray ions or neutrons are little compared to having a significant fraction of the entire plasmoid hurled into a small region of the wall all at once, as could happen in certain failure scenarios.

When I was describing this damage, I was thinking of it as a worst case, but spoke of it as if it were certain. My apologies for being unclear.

Post by **Darth Wong** » 2006-05-25 12:45pm

drachefly wrote:
Darth Wong wrote:The interior of the reacting will contain a lining which is slowly eaten away by the neutron and ion flux from the plasmoid even under normal operations. I'll have to look up the heat content of the plasmoid, but I recall it was surprisingly small.
A trickle of stray ions or neutrons are little compared to having a significant fraction of the entire plasmoid hurled into a small region of the wall all at once, as could happen in certain failure scenarios.

When I was describing this damage, I was thinking of it as a worst case, but spoke of it as if it were certain. My apologies for being unclear.

Ahem ... this "trickle of stray ions and neutrons" represents a significant fraction of the power output of the entire reactor. Nuclear fusion reactions dump a lot (nearly half IIRC) of their energy as neutron radiation. The heat content of the plasmoid, by comparison, is nothing to write home about. Remember that we're probably talking about less than one gram of plasma in total. Even at millions of K, how much damage can that possibly do? Hell, the STARFIRE theoretical reactor model called for 0.2 grams of plasma in total.

drachefly · Post by **drachefly** » 2006-05-25 05:02pm

Upon further examination of the parameters, I was surprised to note that the plasma is being contained through a very LARGE volume of the reactor, not a very SMALL volume.

Thus, there is no way to get all the energy concentrated in a small region, so dumping the plasma would in the end only cause minor damage -- generally shortening the lifetime of the exposed components. Some of these components have lifetimes on the order of months (5 x 10^5 seconds was given).

Incidentally, it also means that the adiabatic cooling would be insignificant; but due to being spread out more, that is irrelevant.

I was thrown off because I thought the reactor geometry would be much more like that of a particle accelerator. Particle accelerators can be severely damaged by extremely small amounts of material (that would make a milligram look enormous) striking wall even before they get up to full speed, because they are kept that much more concentrated.

Post by **Darth Wong** » 2006-05-25 05:04pm

drachefly wrote:I was thrown off because I thought the reactor geometry would be much more like that of a particle accelerator. Particle accelerators can be severely damaged by extremely small amounts of material (that would make a milligram look enormous) striking wall even before they get up to full speed, because they are kept that much more concentrated.

Yeah, that's apples and oranges. A particle accelerator maintains tight control over the movement of the particles, whereas a Tokomak contains a plasmoid: a body of randomly moving particles held in containment. Its density is extremely low.

Chris OFarrell · Post by **Chris OFarrell** » 2006-05-26 12:29am

Dennis Toy wrote:WOW! i hope i am still alive when this is produced. I will actually be 61 years of age when this happens.

One question.

Will this take a lot of energy to start the reaction, confine the reaction using a magnetic containment field and to keep the reaction going? From what i heard, you will still need to use fossil fuel energy to get this thing started.

Not when you get enough reactors up, you'll just take it off the rest of the grid.

For now though, yes you need energy from somewhere else to start it up. But it doesn't necessary to have to be from fossil fuels, it could be from fision or even 'green' systems...

And the reason the enviro wacos are so against fusion is that it represents the ultimate enemy. The fringe has long since stopped being about protecting the enviroment as much as stopping all human development. Fusion as a source of unlimited, relativly clean power scares the bejesus out of them.

Post by **Darth Wong** » 2006-05-26 01:15am

Chris OFarrell wrote:For now though, yes you need energy from somewhere else to start it up. But it doesn't necessary to have to be from fossil fuels, it could be from fision or even 'green' systems...

When I was in Las Vegas we visited this place called the Hoover Dam ...

Zero · Post by **Zero** » 2006-05-26 01:32am

Are hydroelectric dams considered green-friendly, or are they looked down upon for their effects on fish populations and such?

Post by **Darth Wong** » 2006-05-26 01:35am

Zero132132 wrote:Are hydroelectric dams considered green-friendly, or are they looked down upon for their effects on fish populations and such?

It depends on just how much land is flooded by the dam. In the case of the Hoover dam, I can't imagine there was much of a thriving ecosystem where Lake Mead stands now. It's the desert after all.

In the case of our local dam here in Ontario (Niagara Falls), there was no flooding at all, since it only shunts some of the water that was already flowing over a natural drop.

Darth Raptor · Post by **Darth Raptor** » 2006-05-26 01:42am

A fusion reactor uses hydrogen (or isotopes of hydrogen) as fuel and creates helium plus energy, right? So... how fast would a reactor consume hydrogen, and where are we supposed to get significant amounts of deuterium and tritium? Please excuse the ignorance of this question, I haven't had a physics class since high school.

Post by **Darth Wong** » 2006-05-26 01:46am

Darth Raptor wrote:A fusion reactor uses hydrogen (or isotopes of hydrogen) as fuel and creates helium plus energy, right? So... how fast would a reactor consume hydrogen, and where are we supposed to get significant amounts of deuterium and tritium? Please excuse the ignorance of this question, I haven't had a physics class since high school.

Fusion reactors would require only fractions of a gram of hydrogen at any given time, and we can get D and T by bombarding hydrogen with neutron radiation. CANDU reactors actually make tritium as a natural side-effect of normal operation.

The_Nice_Guy · Post by **The_Nice_Guy** » 2006-05-26 04:38am

Cheap energy...

Extended lifespans with cloning tech...

Is it okay to be optimistic about the future?

TWG

WyrdNyrd · Post by **WyrdNyrd** » 2006-05-26 04:50am

Isn't deuterium also a naturally-occurring element? You could get it by "enriching" water to get heavy water, and then using electrolysis to get the hydrogen out of it.

Breaking up water to get hydrogen to burn hydrogen to get water (i.e. "the hydrogen economy") is obviously a net loss process, but when you use the hydrogen in a fusion reactor, you get a lot more energy than you expended during the electrolysis.

Thinkmarble · Post by **Thinkmarble** » 2006-05-29 05:50am

Yup, deuterium is supposed to be filtered out of seawater, where as tritium is breed using neutrons from the reator and lithium-6.

LaCroix · Post by **LaCroix** » 2006-05-29 07:53am

Correct me if I'm wrong.

One of the things the reactor creates is neutron radiation. A fucking LOT of it...

It uses deuterium and tritium for the reaction.

Water + neutron = Deuterium, right?

Deuterium + neutron = tritium, isn't it?

So wouldn't an ideal fusion reactor run with pure water, "breeding" it to D and T and then let it react with each other?

You could use water as "neutron stopper" and breeding material.

I've read in some scifi-book (don't know where) that they refueled their reactors with distilled water, and now I remembered this and it made sense...

CaptainChewbacca · Post by **CaptainChewbacca** » 2006-05-29 02:38pm

^That doesn't sound right, but I can't find the flaw in the science on this holiday weekend.

Durandal · Post by **Durandal** » 2006-05-29 02:54pm

Darth Wong wrote:Unfortunately, I can already predict their response: "It's natural when it happens in the Sun, but it's not supposed to happen here on Earth."

These are the same people who go out and picket particle accelerator experiments because they might form a black hole that will suck the Earth in and destroy it.

CaptainChewbacca · Post by **CaptainChewbacca** » 2006-05-29 03:30pm

Durandal wrote:
Darth Wong wrote:Unfortunately, I can already predict their response: "It's natural when it happens in the Sun, but it's not supposed to happen here on Earth."
These are the same people who go out and picket particle accelerator experiments because they might form a black hole that will suck the Earth in and destroy it.

In all fairness, I think the SciFi channel is coming out with a movie featuring that particular plot, so it may be confuising people.

Lazarus · Post by **Lazarus** » 2006-05-29 03:36pm

I actually heard about this around a year ago and produced a presentation based around ITER and the viabilities of fusion power as a practical part of the power generation industry within the next 30 years. I'm glad they followed through on their aims, and I can see this leading to the first fully operational, national grade fusion reactor station within the next few decades, tops 2050 maybe. All luck to them.

Hotfoot · Post by **Hotfoot** » 2006-05-29 03:58pm

CaptainChewbacca wrote:In all fairness, I think the SciFi channel is coming out with a movie featuring that particular plot, so it may be confuising people.

Come on, look at the Sci-Fi original movie plots. You'd have to be retarded or braindead to think that they're even remotely possible. I mean, seriously, Alien Invasion? Giant Animal of the Week vs. Giant Animal of last week?