Fusion … again? Still?

[Elixir]

I don’t even know how to comment on this.

The federal Lawrence Livermore National Laboratory in California, which uses a process called inertial confinement fusion that involves bombarding a tiny pellet of hydrogen plasma with the world’s biggest laser, had achieved net energy gain in a fusion experiment in the past two weeks, the people said.

Someone who knows more than I (almost anyone) please comment!

 

[Worldtraveller]

It's a tiny, but positive, step.

My understanding is that it is a net gain, based on energy (heat) out was greater than heat in. That heat has to be usable though, or it really doesn't mean much.

Technically, as the 2nd law of thermodynamics states, all engines are over unity. It's just that in most cases, the heat is wasted.

 

[Elixir]

It's a tiny, but positive, step.

My understanding is that it is a net gain, based on energy (heat) out was greater than heat in. That heat has to be usable though, or it really doesn't mean much.

Technically, as the 2nd law of thermodynamics states, all engines are over unity. It's just that in most cases, the heat is wasted.

My understanding may be flawed but I gather that only a tiny fraction of the gross heat product needs to be converted to electricity to make this process practical.
What are the barriers to realization? Nobody talks about that when these “breakthroughs“ are announced.

 

[Jimmy Higgins]

There is also the 300 MJ powering of the laser for that period of time that is outside the ignition conversation.

 

[lpetrich]

I'm old enough to remember when cold fusion first came out. I was *very* skeptical. I knew what was involved: getting nuclei close enough to tunnel into each other. That's quantum-mechanical tunneling, and that explains alpha decay. As "pycnonuclear fusion", this is expected to happen in white dwarfs and in the crusts of neutron stars, where the pressures are high enough to make densities much greater than in familiar circumstances. If one needs a WD or NS to do this kind of fusion, then one won't do it in a lab.

I remember going to a talk by someone who tried to replicate this alleged discovery. He failed. No noticeable production of neutrons, what one would expect from nuclear fusion.

 

[Elixir]

There is also the 300 MJ powering of the laser for that period of time that is outside the ignition conversation.

I believe that was included in the accounting.

 

[bilby]

It's a tiny, but positive, step.

My understanding is that it is a net gain, based on energy (heat) out was greater than heat in. That heat has to be usable though, or it really doesn't mean much.

Technically, as the 2nd law of thermodynamics states, all engines are over unity. It's just that in most cases, the heat is wasted.

My understanding may be flawed but I gather that only a tiny fraction of the gross heat product needs to be converted to electricity to make this process practical.
What are the barriers to realization? Nobody talks about that when these “breakthroughs“ are announced.

The biggest barriers are that it has now become clear that fusion will be incredibly expensive, if it can be achieved at all; And that if it were to become (by some miracle) both cheap and effective, it would instantly be demonised by the same vocal group of neo-luddites who have killed fission power.

If we were able to find a technology that could generate electricity at a price competitive with burning coal, but far safer, far less polluting, and fuelled by a material we can extract from the oceans indefinitely in any quantity we could reasonably expect to ever need; A technology whose waste products are tiny in quantity, and easily managed to avoid any risk to people or the environment; A technology that has zero carbon dioxide emissions, and is more reliable than any previous electrical generation technology - then the Greens would steadfastly oppose it, and do their utmost to make it unpopular, unprofitable, and wherever possible, illegal.

We know this to be true, because we have had exactly such a technology since the 1950s, and that's exactly what has happened to it.

 

[lpetrich]

There is also the 300 MJ powering of the laser for that period of time that is outside the ignition conversation.

Source for this? This is likely included in the energy input to this kind of fusion.

 

[Elixir]

if it were to become (by some miracle) both cheap and effective, it would instantly be demonised by the same vocal group of neo-luddites who have killed fission power.

I was afraid you were going to say that.
I have no answer for stupidity. It would be nice to pretend it didn’t exist, but in fact it is the greatest “technical” barrier to making things better in general.

 

[Politesse]

Refusing to recognize that fission technology has any downsides isn't the winning rhetorical strategy that nuclear fanboys seem to think that it is, despite trying and failing to win the public over with exactly this tactic these past seventy years.

If anything, this new technology would be a good opportunity to win people back over to atomic science. All the cheap electricity, but semantically disconnected from Three Mile and Chernobyl. Win win. At least if the scientists involved have the plain common sense to never, ever refer to the resulting machine as a nuclear plant.

As for the main story, I'm glad Livermore is still working on this, and will be interested to discuss the implications of fusion reactors should anything tangible actually come of this. I drive past their field lab every morning, so I will watch and let you know if any mysterious arcane lights or indescribable Voids open up over the annex.

 

[Elixir]

if the scientists involved have the plain common sense to never, ever refer to the resulting machine as a nuclear plant.

Fusion is still a positive buzzword. But if this tech succeeds at all, it won’t be a positive buzzword for long.

 

[steve_bank]

The grid cod not supply the instantaneous power need to initiate the Princeton reactor.

A giant flywheel was spun up at night during off peak hours, then a generator switched in for the ignition.

 

[bilby]

Refusing to recognize that fission technology has any downsides isn't the winning rhetorical strategy that nuclear fanboys seem to think that it is, despite trying and failing to win the public over with exactly this tactic these past seventy years.

Yeah, telling people the truth is sucky marketing.

Of course fission technology has downsides; Every technology has downsides. But fission technology is literally unbelievably better on almost any metric you care to name than any other electricity generation technology.

The neo-luddites have neatly and cleverly spun the fact "nuclear power is the safest way to make electricity" into "nuclear power is perfectly safe" - which isn't true of ANYTHING, and is less true of their preferred "alternatives" than it is of nuclear power. Then they claim that this lie is being espoused by those lousy fibbing fanboys.

Fucking charming. Were over here actually doing something to save the planet, while they get accolades for obstructing our efforts.

Because technology is bad, and big technology is worse. Allegedly.

 

[Elixir]

If it is resolved that we are going to increase or at least maintain our level of energy dependence, humans will generate that energy and it will have downsides. Using current energy generation profiles, that will spell certain disaster as surely as swallowing an entire set of scrabble tiles.

So I regard this fusion “breakthrough” hopefully.

 

[Jimmy Higgins]

There is also the 300 MJ powering of the laser for that period of time that is outside the ignition conversation.

Source for this? This is likely included in the energy input to this kind of fusion.

It was in any article I read on the subject. Which also makes it a massive asterisk on the outcome of the experiment.

Before we get to visions of fusion power plants dotting the landscape, however, there's the uncomfortable fact that producing the 2 megajoules of laser power that started the fusion reaction took about 300 megajoules of grid power, so the overall process is nowhere near the break-even point. So, while this was a real sign of progress in getting this form of fusion to work, we're still left with major questions about whether laser-driven fusion can be optimized enough to be useful. At least one DOE employee suggested that separating it from its nuclear-testing-focused roots may be needed to do so.

 

[Jimmy Higgins]

Refusing to recognize that fission technology has any downsides isn't the winning rhetorical strategy that nuclear fanboys seem to think that it is, despite trying and failing to win the public over with exactly this tactic these past seventy years.

Yeah, telling people the truth is sucky marketing.

Of course fission technology has downsides; Every technology has downsides. But fission technology is literally unbelievably better on almost any metric you care to name than any other electricity generation technology.

The neo-luddites have neatly and cleverly spun the fact "nuclear power is the safest way to make electricity" into "nuclear power is perfectly safe" - which isn't true of ANYTHING, and is less true of their preferred "alternatives" than it is of nuclear power. Then they claim that this lie is being espoused by those lousy fibbing fanboys.

Certainly the waste in fusion is less, but the idea that the reaction itself would be remotely safe, especially if containment was lost is outrageous. If anything fission is probably a lot less dangerous of a process than maintaining fusion, because if I'm not mistaken, we aren't forcing fission. We are simply taking advantage that it is happening.

 

[Cheerful Charlie]

 

[steve_bank]

I thought if containment failed the reaction stops. There is no possibility of a runaway condition or explosion.

Am I wrong?

 

[Jimmy Higgins]

I thought if containment failed the reaction stops. There is no possibility of a runaway condition or explosion.

Am I wrong?

Yes.*

* - I may be incorrect.

 

[bilby]

Refusing to recognize that fission technology has any downsides isn't the winning rhetorical strategy that nuclear fanboys seem to think that it is, despite trying and failing to win the public over with exactly this tactic these past seventy years.

Yeah, telling people the truth is sucky marketing.

Of course fission technology has downsides; Every technology has downsides. But fission technology is literally unbelievably better on almost any metric you care to name than any other electricity generation technology.

The neo-luddites have neatly and cleverly spun the fact "nuclear power is the safest way to make electricity" into "nuclear power is perfectly safe" - which isn't true of ANYTHING, and is less true of their preferred "alternatives" than it is of nuclear power. Then they claim that this lie is being espoused by those lousy fibbing fanboys.

Certainly the waste in fusion is less, but the idea that the reaction itself would be remotely safe, especially if containment was lost is outrageous. If anything fission is probably a lot less dangerous of a process than maintaining fusion, because if I'm not mistaken, we aren't forcing fission. We are simply taking advantage that it is happening.

The waste in any technology that doesn't exist is non-existent.

We don't yet know what waste issues will arise from fusion reactors - not so much as a result of the fusion process itself, but as a result of neutron bombardment of the reactor components. Certainly there's likely to be small amounts of radioactive material to dispose of at decommissioning; Possibly there's going to be some radioactive material to dispose of while the reactor is running too - any gas or liquid phase radioactive material that the neutron bombardment causes will need to be managed.

It's unlikely to be a significant problem, as the volumes will be tiny in comparison to the energy produced. But then, that's true of fission reactors too - and the neo-luddites have leveraged it into an unsolvable problem (or rather, a problem they like so much that they reject any and all solutions to it).

Neither fission nor fusion reactors have a credible mechanism for causing nuclear bomb like explosions.

If you could accidentally make a nuclear explosion, the Manhattan project would have been over in a month, and would have cost a few thousand bucks. Sadly for the US taxpayer, and fortunately for humanity, nuclear explosions are very difficult indeed to make happen.