Can fusion power be proven impossible?

[repoman]

I have been reading about fusion for a while and I am really not even close to positive about it.

At the energies and densities needed to make it work the dissipative forces that occur seem so large as to break out against the confinement methods and to waste energy through current losses and Bremsstrahlung and so on.

For anyone with more knowledge about this is there a way to quantify even in a rough way all of tge above problems?

The sun confines through gravity and its huge size which keeps the heat in. What we have seems very shaky by comparison. Can that shakiness be quantifed? And can a lower limit to it be drawn? I think that level of stability they say can happen for confinement is so ridiculous it can't happen. Almost like a mass delusion.

It seems that fusion research I have been reading is all based on assuming that confinement will be much less shaky and the losses much less. Also that for example lasers will firing like mad.

Anyway, can fusion power be proven impossible on general principle?

I think dissipative forces occuring in the plasma can be quantified (within a range) for a particular design. Kind of like a wind tunnel can measure drag force for different car designs. If you said, yeah I can drop the drag force by a factor of 10 "somehow" I would tell you to get fucked.

 

[bilby]

Generating power from fusion is easy.

Drill a deep hole. Drop an H-bomb in. Set it off. Drop some pipes down, pump down water, get back steam. When the hole gets cold, drop another bomb in.

Technically very easy. The first part was done often enough in the '60s and '70s. Extracting power from hot rocks is a mature technology in NZ and Iceland.

Politically impossible; contravenes any number of test-ban treaties, and Greenpeace would have a conniption.

 

[Loren Pechtel]

Generating power from fusion is easy.

Drill a deep hole. Drop an H-bomb in. Set it off. Drop some pipes down, pump down water, get back steam. When the hole gets cold, drop another bomb in.

Technically very easy. The first part was done often enough in the '60s and '70s. Extracting power from hot rocks is a mature technology in NZ and Iceland.

Politically impossible; contravenes any number of test-ban treaties, and Greenpeace would have a conniption.

It wouldn't be a good idea, either--you still get venting even from an underground detonation.

However, the basic point that you don't need to confine the fusion reaction is valid. We can do in the lab the same thing the h-bomb does: inertial confinement. Get the temperature and pressure high enough, you'll get fusion before it blows itself apart. We can do that now--it takes a bunch of big-ass lasers but the target pellets do go boom. The issue is getting the yield up--at that point you can switch from a test rig that fires one pellet to a system that fires pellets one after another in rapid succession.

 

[skepticalbip]

Generating power from fusion is easy.

Drill a deep hole. Drop an H-bomb in. Set it off. Drop some pipes down, pump down water, get back steam. When the hole gets cold, drop another bomb in.

Technically very easy. The first part was done often enough in the '60s and '70s. Extracting power from hot rocks is a mature technology in NZ and Iceland.

Politically impossible; contravenes any number of test-ban treaties, and Greenpeace would have a conniption.

It wouldn't be a good idea, either--you still get venting even from an underground detonation.

However, the basic point that you don't need to confine the fusion reaction is valid. We can do in the lab the same thing the h-bomb does: inertial confinement. Get the temperature and pressure high enough, you'll get fusion before it blows itself apart. We can do that now--it takes a bunch of big-ass lasers but the target pellets do go boom. The issue is getting the yield up--at that point you can switch from a test rig that fires one pellet to a system that fires pellets one after another in rapid succession.

That is only one end of the problem. Another end is the amount of energy we have to put into the lasers. Then there is the problem of capturing the energy release in usable form. The goal is to reach a point where the usable energy out of the system exceeds the energy input on a sustained basis. We are a long, long way from that goal even though controlled fusion is relatively common.

The question raised by the OP is a real concern. The research should certainly continue but our energy planning should not have any reliance on us reaching this goal. Fusion power has been only ten years away for quite a few decades now.
.

 

[thebeave]

It wouldn't be a good idea, either--you still get venting even from an underground detonation.

However, the basic point that you don't need to confine the fusion reaction is valid. We can do in the lab the same thing the h-bomb does: inertial confinement. Get the temperature and pressure high enough, you'll get fusion before it blows itself apart. We can do that now--it takes a bunch of big-ass lasers but the target pellets do go boom. The issue is getting the yield up--at that point you can switch from a test rig that fires one pellet to a system that fires pellets one after another in rapid succession.

That is only one end of the problem. Another end is the amount of energy we have to put into the lasers. Then there is the problem of capturing the energy release in usable form. The goal is to reach a point where the usable energy out of the system exceeds the energy input on a sustained basis. We are a long, long way from that goal even though controlled fusion is relatively common.

The question raised by the OP is a real concern. The research should certainly continue but our energy planning should not have any reliance on us reaching this goal. Fusion power has been only ten years away for quite a few decades now.
.

i wrote an English paper in college about fusion energy, back around 1980. I remember citing a source saying that fusion could be viable energy source for our electrical grid as soon as 1985. I should go find my paper and reread it. I could use a few laughs and facepalms.

 

[repoman]

good slideshow:

http://www.scribd.com/doc/34089596/Fusion-Route#scribd

 

[Loren Pechtel]

It wouldn't be a good idea, either--you still get venting even from an underground detonation.

However, the basic point that you don't need to confine the fusion reaction is valid. We can do in the lab the same thing the h-bomb does: inertial confinement. Get the temperature and pressure high enough, you'll get fusion before it blows itself apart. We can do that now--it takes a bunch of big-ass lasers but the target pellets do go boom. The issue is getting the yield up--at that point you can switch from a test rig that fires one pellet to a system that fires pellets one after another in rapid succession.

That is only one end of the problem. Another end is the amount of energy we have to put into the lasers. Then there is the problem of capturing the energy release in usable form. The goal is to reach a point where the usable energy out of the system exceeds the energy input on a sustained basis. We are a long, long way from that goal even though controlled fusion is relatively common.

The question raised by the OP is a real concern. The research should certainly continue but our energy planning should not have any reliance on us reaching this goal. Fusion power has been only ten years away for quite a few decades now.
.

As I said, we need to get the yield up. When it's high enough we will be able to recover enough energy to power those lasers. Even though they outshine the whole country while they are actually operating the pulse is so short that the total energy involved is quite reasonable.

 

[skepticalbip]

That is only one end of the problem. Another end is the amount of energy we have to put into the lasers. Then there is the problem of capturing the energy release in usable form. The goal is to reach a point where the usable energy out of the system exceeds the energy input on a sustained basis. We are a long, long way from that goal even though controlled fusion is relatively common.

The question raised by the OP is a real concern. The research should certainly continue but our energy planning should not have any reliance on us reaching this goal. Fusion power has been only ten years away for quite a few decades now.
.

As I said, we need to get the yield up. When it's high enough we will be able to recover enough energy to power those lasers. Even though they outshine the whole country while they are actually operating the pulse is so short that the total energy involved is quite reasonable.

The energy balance is no where near reasonable at the current time. The laser fusion work at Laurence Livermore Labs currently hits the pellet with two megajoules of energy to produce the fusion reaction. This reaction produces 17 kilojoules at best from the fusion. Considering the efficiency of lasers, just a pull it out my arse figure would be that they are pumping the laser with something on the order of 20 megajoules to achieve that pulse. The energy from this laser fusion process is three orders of magnitude less than the energy required to produce it. We are doing much, much better with the plasma fusion in our Tokomaks and they are no where near close enough to be encouraging. The current work at Lockheed's Skunk Works is a different approach than either of these. Time will tell how this approach will pan out. The last I heard, they haven't finished building their first model yet and they expected that it would only tell them what modifications would be needed to build the second improved one.

 

[repoman]

Too bad muon catalyzed fusion doesn't work for break-even.

I think that finding a new way to get the reactions to happen faster like muons do is the answer. But muons take energy to make.

I think that confinement is not going to get any better on an order of magnitude scale.

 

[Loren Pechtel]

As I said, we need to get the yield up. When it's high enough we will be able to recover enough energy to power those lasers. Even though they outshine the whole country while they are actually operating the pulse is so short that the total energy involved is quite reasonable.

The energy balance is no where near reasonable at the current time. The laser fusion work at Laurence Livermore Labs currently hits the pellet with two megajoules of energy to produce the fusion reaction. This reaction produces 17 kilojoules at best from the fusion. Considering the efficiency of lasers, just a pull it out my arse figure would be that they are pumping the laser with something on the order of 20 megajoules to achieve that pulse. The energy from this laser fusion process is three orders of magnitude less than the energy required to produce it. We are doing much, much better with the plasma fusion in our Tokomaks and they are no where near close enough to be encouraging. The current work at Lockheed's Skunk Works is a different approach than either of these. Time will tell how this approach will pan out. The last I heard, they haven't finished building their first model yet and they expected that it would only tell them what modifications would be needed to build the second improved one.

Yeah, get the yield up!

 

[skepticalbip]

The energy balance is no where near reasonable at the current time. The laser fusion work at Laurence Livermore Labs currently hits the pellet with two megajoules of energy to produce the fusion reaction. This reaction produces 17 kilojoules at best from the fusion. Considering the efficiency of lasers, just a pull it out my arse figure would be that they are pumping the laser with something on the order of 20 megajoules to achieve that pulse. The energy from this laser fusion process is three orders of magnitude less than the energy required to produce it. We are doing much, much better with the plasma fusion in our Tokomaks and they are no where near close enough to be encouraging. The current work at Lockheed's Skunk Works is a different approach than either of these. Time will tell how this approach will pan out. The last I heard, they haven't finished building their first model yet and they expected that it would only tell them what modifications would be needed to build the second improved one.

Yeah, get the yield up!

Just damned. Why didn't I think of that? It's so simple. Or better yet, why hasn't any of the researchers who have been promising every year, ever since the 1950s, that our power grid would be powered by fusion reactors within ten years? You would think that, after almost seventy years of research, at least one of them would have thought of cranking the gain up...

Show

Sorry, but I had to go with sarcasm. You solution is nothing but just a restatement of the problem. Essentially you are saying that all that is required to attain fusion power is to make fusion power work.

 

[Loren Pechtel]

Yeah, get the yield up!

Just damned. Why didn't I think of that? It's so simple. Or better yet, why hasn't any of the researchers who have been promising every year, ever since the 1950s, that our power grid would be powered by fusion reactors within ten years? You would think that, after almost seventy years of research, at least one of them would have thought of cranking the gain up...

Show

Sorry, but I had to go with sarcasm. You solution is nothing but just a restatement of the problem. Essentially you are saying that all that is required to attain fusion power is to make fusion power work.

The point is that yield is a matter of engineering, not something that we can pretty much say is impossible like all the attempts at magnetic confinement of the plasma.

 

[repoman]

I could look and find the answer, but I will test myself on this. I think that it is not just the massive energy (making high temp and pressure) released by the fission that jumpstarts fusion. I mean by that if you could magically have some other way of getting the T and P as quickly as fission it would not ignite the fusion as well. Didn't they use the neutrons from fission (and maybe how they react with the shell) to help with fusion?

If this is the case, then controlled fusion power seems even more illusory.

Ok, I will read about this on wiki now.

 

[barbos]

As I said, we need to get the yield up. When it's high enough we will be able to recover enough energy to power those lasers. Even though they outshine the whole country while they are actually operating the pulse is so short that the total energy involved is quite reasonable.

The energy balance is no where near reasonable at the current time. The laser fusion work at Laurence Livermore Labs currently hits the pellet with two megajoules of energy to produce the fusion reaction. This reaction produces 17 kilojoules at best from the fusion. Considering the efficiency of lasers, just a pull it out my arse figure would be that they are pumping the laser with something on the order of 20 megajoules to achieve that pulse. The energy from this laser fusion process is three orders of magnitude less than the energy required to produce it

You are a bit out touch with current state of the affairs in inertial confinement fusion.
They are getting more energy out than they put in already.

As of October 7, 2013, this facility is understood to have achieved an important milestone towards commercialization of fusion, namely, for the first time a fuel capsule gave off more energy than was applied to it. This is a major step forward.[2]

 

[Loren Pechtel]

I could look and find the answer, but I will test myself on this. I think that it is not just the massive energy (making high temp and pressure) released by the fission that jumpstarts fusion. I mean by that if you could magically have some other way of getting the T and P as quickly as fission it would not ignite the fusion as well. Didn't they use the neutrons from fission (and maybe how they react with the shell) to help with fusion?

If this is the case, then controlled fusion power seems even more illusory.

Ok, I will read about this on wiki now.

The laser fusion systems work--the target pellet does produce a fusion boom. It's just it doesn't produce a big enough boom.

 

[repoman]

So I read about H-bombs on wiki and read a couple of the external links. It seems that there is enough fusion fuel to act as a self-insulation for loss of energy and mass. Basically, the fusion fuel is igniting more fusion fuel - there is not an opening for the reactants to leak out. Also the design and the fission helps trap all the fusion fuel and the reaction happens too fast for much loss.

The sun is the ultimate for self-insulation with how massive it is. Compare that to the tiny pellets used in these experiments.

 

[skepticalbip]

The energy balance is no where near reasonable at the current time. The laser fusion work at Laurence Livermore Labs currently hits the pellet with two megajoules of energy to produce the fusion reaction. This reaction produces 17 kilojoules at best from the fusion. Considering the efficiency of lasers, just a pull it out my arse figure would be that they are pumping the laser with something on the order of 20 megajoules to achieve that pulse. The energy from this laser fusion process is three orders of magnitude less than the energy required to produce it

You are a bit out touch with current state of the affairs in inertial confinement fusion.
They are getting more energy out than they put in already.

As of October 7, 2013, this facility is understood to have achieved an important milestone towards commercialization of fusion, namely, for the first time a fuel capsule gave off more energy than was applied to it. This is a major step forward.[2]

You had my hopes up. Googling your quote led to a wiki entry citing a 2013 test. I don't know exactly what energy they are referring to in their "...more energy than was applied to it" but I would assume they are talking about the x-ray energy from the gold coating which would be significantly less than the laser energy that is exciting those x-rays or the energy that is required to pump the lasers.

The full paragraph from the wiki entry that I found by googling your quote:

 http://en.wikipedia.org/wiki/Inertial_confinement_fusion

The largest operational ICF experiment is the National Ignition Facility (NIF) in the US, designed using all of the decades-long experience of earlier experiments. Like those earlier experiments, however, NIF has failed to reach ignition and is, as of 2013, generating about 1/3rd of the required energy levels.[1] As of October 7, 2013, this facility is understood to have achieved an important milestone towards commercialization of fusion, namely, for the first time a fuel capsule gave off more energy than was applied to it. This is a major step forward.[2] A similar large-scale device in France, Laser Mégajoule, has not begun operation.

ETA:
I found a little better description of that test:

https://www.llnl.gov/news/laser-fusion-experiment-yields-record-energy-llnls-national-ignition-facility

According to this release from Lawrence Livermore, this particular test yielded 8,000 joules of neutron energy and the laser energy applied to the pellet was 1.7 megajoules.

 

[fromderinside]

this particular test yielded 8,000 joules of neutron energy and the laser energy applied to the pellet was 1.7 megajoules.

Entropy here: Looks like a winner to me.

 

[Loren Pechtel]

So I read about H-bombs on wiki and read a couple of the external links. It seems that there is enough fusion fuel to act as a self-insulation for loss of energy and mass. Basically, the fusion fuel is igniting more fusion fuel - there is not an opening for the reactants to leak out. Also the design and the fission helps trap all the fusion fuel and the reaction happens too fast for much loss.

The sun is the ultimate for self-insulation with how massive it is. Compare that to the tiny pellets used in these experiments.

You're talking about maintaining an ongoing fusion reaction. Inertial confinement is not about a sustained reaction, but rather a series of reactions like how your car works.

 

[barbos]

skepticalbip, "applied" is actual energy which fuel received from compression.
Compression using lasers is inherently inefficient because it's done through heating and evaporating material, most of the energy is taken away by that material flying away.
Nevertheless it's important benchmark and when ignition actually happens there will be a lot more fusion than they are currently getting.