Hot stuff: Lab hits milestone on long road to fusion power

[StringJunky]

Quote

With 192 lasers and temperatures more than three times hotter than the center of the sun, scientists hit — at least for a fraction of a second — a key milestone on the long road toward nearly pollution-free fusion energy.

Researchers at the National Ignition Facility at the Lawrence Livermore National Lab in California were able to spark a fusion reaction that briefly sustained itself — a major feat because fusion requires such high temperatures and pressures that it easily fizzles out.

The ultimate goal, still years away, is to generate power the way the sun generates heat, by smooshing hydrogen atoms so close to each other that they combine into helium, which releases torrents of energy.

A team of more than 100 scientists published the results of four experiments that achieved what is known as a burning plasma in Wednesday’s journal Nature. With those results, along with preliminary results announced last August from follow-up experiments, scientists say they are on the threshold of an even bigger advance: ignition. That’s when the fuel can continue to “burn” on its own and produce more energy than what’s needed to spark the initial reaction. 

Read more:  https://apnews.com/article/science-fusion-energy-lawrence-livermore-a3c1ecbb738640b0a2e384dc80b8dd07

 

[beecee]

51 minutes ago, StringJunky said:

With 192 lasers and temperatures more than three times hotter than the center of the sun, scientists hit — at least for a fraction of a second — a key milestone on the long road toward nearly pollution-free fusion energy.

Researchers at the National Ignition Facility at the Lawrence Livermore National Lab in California were able to spark a fusion reaction that briefly sustained itself — a major feat because fusion requires such high temperatures and pressures that it easily fizzles out.

 

[StringJunky]

2 minutes ago, beecee said:

 

The ITER milestone is not about 'how hot' but 'how long'.

[beecee]

2 minutes ago, StringJunky said:

The ITER milestone is not about 'how hot' but 'how long'.

Understood, but in reality both.

https://www.sciencefocus.com/future-technology/fusion-power-future/

"In June 2021, China’s Experimental Advanced Superconducting Tokamak (EAST) reactor maintained a plasma for 101 seconds at 120,000,000°C. Before that, the record was 20 seconds. Ultimately, a fusion reactor would need to sustain the plasma indefinitely – or at least for eight-hour ‘pulses’ during periods of peak electricity demand.

A real game-changer for tokamaks has been the magnets used to produce the magnetic field. “We know how to make magnets that generate a very high magnetic field from copper or other kinds of metal, but you would pay a fortune for the electricity. It wouldn’t be a net energy gain from the plant,” says Luce".

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It would be great if finally after so long, success was finally imminent.

[mistermack]

I have to admit that I know very little about inertial confinement fusion, but the temperature thing is a bit misleading. Fusion takes place when you get a combination of two factors, temperature and pressure. In the laser inertial confinement approach, they generate phenomenal pressures, so they don't need the same sort of temperatures that the Tokamaks use. 

In the centre of  the Sun, you get high temeratures and enormous pressures, that's how you get constant fusion. A Tokamak can't get anywhere near the pressures of the Sun, so it needs much higher temperatures for fusion to happen.

Inside the fuel pellet of an inertial confinement reaction, the hydrogen is squeezed so hard, it's density can touch 300 times that of lead. So you don't need for it to get as hot as a Tokamak.

One thing I haven't seen, is what mechanism they are planning to use, to achieve a constant burn. Will they keep firing the laser constantly, in a running power plant? Or do they hope to achieve a constant burn without external power input, once fusion is running? If they need the lasers to achieve the required pressure, then it looks like they need a continuous laser for a generating plant.

[exchemist]

13 hours ago, mistermack said:

I have to admit that I know very little about inertial confinement fusion, but the temperature thing is a bit misleading. Fusion takes place when you get a combination of two factors, temperature and pressure. In the laser inertial confinement approach, they generate phenomenal pressures, so they don't need the same sort of temperatures that the Tokamaks use. 

In the centre of  the Sun, you get high temeratures and enormous pressures, that's how you get constant fusion. A Tokamak can't get anywhere near the pressures of the Sun, so it needs much higher temperatures for fusion to happen.

Inside the fuel pellet of an inertial confinement reaction, the hydrogen is squeezed so hard, it's density can touch 300 times that of lead. So you don't need for it to get as hot as a Tokamak.

One thing I haven't seen, is what mechanism they are planning to use, to achieve a constant burn. Will they keep firing the laser constantly, in a running power plant? Or do they hope to achieve a constant burn without external power input, once fusion is running? If they need the lasers to achieve the required pressure, then it looks like they need a continuous laser for a generating plant.

My understanding is they envisage a stream of fuel pellets, each "ignited" in turn by a laser. As in our previous discussion about tokamaks, there's some way to go before the energy output exceeds the input enough to run the laser. Also I don't know how they extract the energy. I presume it would be by some kind of intercepting shield that gets hot and raises steam. 

[mistermack]

I'm sure that they will be aiming at the same system as ITER will be testing, a Lithium based blanket, that catches the heat and neutrons, and produces Tritium for the manufacture of new fuel. I can't picture how they would supply a stream of fuel pellets, perfectly positioned for the next laser shot, just split seconds after the last one went off. But I'm sure they have it covered. 

I'm similarly surprised that they will be able to run lasers at that type of output, for continuous output. But again, they obviously don't see that as a major hurdle. 

The combination of temperature and pressure probably explains why bigger stars burn out so much faster. It looks ready made for a positive feedback loop. More pressure, more heat, more fusion, more heat, more heat, more fusion. So stars that are a bit bigger than the Sun burn much brighter. 

[mistermack]

The JET (joint european taurus) at Culham Oxford announced today that they made what they call a "breakthrough" with the latest run doubling the results of their previous world record plasma. It's good to hear, but it's laying it on a bit strong. 

I would have called it significant progress rather than a breakthrough. What they achieved was a five second plasma, I'm not sure what was doubled. But it is real progress. They set the JET up to run with a  beryllium/tungsten wall which is ten times less absorbent of tritium than the carbon that was used previously. There was uncertainty about the effect of that change so it is big progress. (in a fusion power station, tritium will need to be saved as future fuel ) 

So the doubling of their previous record is significant with that in mind. 

Five seconds doesn't sound much, but it's the current limit at JET because their copper electromagnets can't run any longer without overheating. But ITER will use superconducting magnets, that won't suffer that problem. 

"It's a landmark because they demonstrated stability of the plasma over five seconds. That doesn't sound very long, but on a nuclear timescale, it's a very, very long time indeed. And it's very easy then to go from five seconds to five minutes, or five hours, or even longer."

BBC Link :  https://www.bbc.co.uk/news/science-environment-60312633   

 

 

[swansont]

It only took them 25 years to double the power, and no mention about how far from the end line they are. Though they did admit to being >25 years away from that.

[mistermack]

1 hour ago, swansont said:

It only took them 25 years to double the power, and no mention about how far from the end line they are. Though they did admit to being >25 years away from that.

It's the same machine, so it's not surprising. Considering the total energy budget of the planet, the investment in fusion has been pretty derisory. I think it's beginning to accelerate now though. The warming scare is giving it a boost. 

[exchemist]

9 hours ago, mistermack said:

It's the same machine, so it's not surprising. Considering the total energy budget of the planet, the investment in fusion has been pretty derisory. I think it's beginning to accelerate now though. The warming scare is giving it a boost. 

In fact, though, these projects were decided upon years ago. ITER - which JET will hand on to - was effectively started back in 1987. Though it is true that more partner countries (e.g. India, Australia) have joined the project in the last decade or so.

But fusion remains a "jam tomorrow" energy source that will only contribute, if it ever does, in the 2nd half of the century. Given that state of affairs, it is actually quite remarkable that there has been the - global - political will to fund something so expensive, so long term and so uncertain.  

Edited February 10, 2022 by exchemist

[swansont]

I agree with exchemist here – this is a longstanding project. I doubt global warming has done anything to speed up results. I did a postdoc at an accelerator lab, which is another example of a large project. The pace is dictated by technical and logistical issues.

[mistermack]

I would stop all money spent on climate research, and spend it on fusion. It must be a win/win. If climate change is a real threat, then your money spent on fusion might make a difference. Instead of modelling the problem, your money might actually solve the problem. If climate change didn't turn out to be as bad as you thought, your money isn't wasted, it's still well-spent on cheap and limitless energy. After all, what more, of any practical use, is there to be learned about GW? C02 is bad. Methane is bad. We know that now. 

[exchemist]

34 minutes ago, mistermack said:

I would stop all money spent on climate research, and spend it on fusion. It must be a win/win. If climate change is a real threat, then your money spent on fusion might make a difference. Instead of modelling the problem, your money might actually solve the problem. If climate change didn't turn out to be as bad as you thought, your money isn't wasted, it's still well-spent on cheap and limitless energy. After all, what more, of any practical use, is there to be learned about GW? C02 is bad. Methane is bad. We know that now. 

There is no real evidence that throwing more money at fusion would speed anything up. The science goes at the rate it goes. And what we spend on climate research is probably fairly small, by comparison with the cost of ITER. Most of the climate change expenditure seems to be on what to do about it, which you have to keep spending.  

Edited February 10, 2022 by exchemist

[mistermack]

4 hours ago, exchemist said:

There is no real evidence that throwing more money at fusion would speed anything up.

They used to say that about vaccines. 

[CharonY]

16 minutes ago, mistermack said:

They used to say that about vaccines. 

Actually folks knew for years that we need to put more money into vaccines to speed up development. Folks were just not that interested until recently.

Quote

Over half of the candidate vaccines analyzed in the 1985 report on vaccine priorities have not yet been licensed. Several are still 15 years from licensure, in this committee's opinion. Although the committee did not analyze in depth each unlicensed candidate vaccine from 1985, obvious factors hindering progress toward licensure include unexpected obstacles in research progress (either in the more basic research phases, in clinical trials, or in scale-up processes for development and production). Alternatively, steady progress could have been made but at a much slower pace than expected. Slow progress could be attributed to either lack of scientific interest on the part of researchers or lack of adequate funding for the R&D. As discussed in Chapter 7 of the report, inadequate interest on the part of funders, such as private vaccine R&D companies, can reflect concerns about profitability because of either small market potential or possible costs due to liability for adverse events.

 

[swansont]

14 hours ago, mistermack said:

I would stop all money spent on climate research, and spend it on fusion.

Adding money only solves a problem if you are underfunded - that you can't buy some equipment or there's labor not happening and you can hire people to do it. So yes, if you need flanges and gaskets for your vacuum system because you lack funding, then more money helps. If you need someone to tighten the bolts because you can't fund that job, then adding money helps. Do you have any evidence that this is an actual bottleneck?

Adding money can actually slow you down, since you need to figure out what to spend it on. If you're already adequately funded, it won't be obvious what should be on your shopping list. We've had times in my current job where the research ground to a halt because we were handed money (often at the end of the fiscal year, where not spending it runs the risk of future budget cuts) and had to figure out what to spend it on, look at equipment specs, get the required quotes, etc. There are things you shouldn't buy in advance, so "let's buy a spare <whatever>" may not be a good use of money.

Some things in research just take time. As the saying goes, it takes 9 months for a woman to make a baby. You can't use 9 women to make a baby in one month.

 

 

 

 

[CharonY]

3 hours ago, swansont said:

We've had times in my current job where the research ground to a halt because we were handed money (often at the end of the fiscal year, where not spending it runs the risk of future budget cuts)

Hey, you know, just saying, but we can help with excess funding...

[mistermack]

Governments are proceeding cautiously, because there is more than one approach that's being pursued. There is the danger that if you put your money in too early, you will be committed, when somebody else makes a major progress leap that leaves you with a redundant project on your hands that's never going to beat it's rival. 

On top of that is the uncertainty of the fuel prices, which can dive as well as rise. 

Then there's the renewable industries, that can also make major breakthroughs that affect the viability of nuclear of any sort. And tightly bound to that is the energy storage field. If somebody makes a major breakthrough there, it will massively affect the attraction of nuclear of all types, as it would take away the trump card of technologies that can generate electricity when the sun doesn't shine, and the wind doesn't blow.

That's the real reason that progress is slow. It's down to money, and financial uncertainty. Nobody wants to go in too deep, and end up holding a damp squib. If they take it slowly, they can keep an eye on the competition.

Hence the vaccine comparison. If it became really urgent, they could easily gear it up. Not necessarily the ITER project, but the ones that follow on, in the thirties. 

What I found a bit disappointing about the JET announcement was the lack of techincal detail. They said that they'd doubled the record for the output, but that's really just a reflection of how they kept the plasma steady for five seconds. I'd be more interested in the ratio of power in to power out, and whether there was any improvement in that. This test involved a tritium/deuterium ideal mix, so the value of Q that they achieved would have been of interest, but I haven't seen any reference to it. 

[mistermack]

Update to previous post :

They have updated the wikipedia page for the JET taurus, and the value of Q for that run was 0.33, which is rather unspectacular, considering that it was 0.67 when they set their previous record. It's not surprising, if it had been more, they would have published it straight away. They were obviously aiming at something else with the latest run. Mainly bumping up the record for fusion energy, which they achieved, but it's still disappointing to the likes of me. 

It would be surprising to make spectacular gains with the same machine. The main thing they should be aiming at, is to learn what is best to put in the next design, and what to avoid. The JET tokamak has made a major contribution to progress, not just by setting records, but by the invention and development of the plama diverter which was a big step in the stability of plasmas. 

The major conditions for fusion are a combination of density, temperature, and plasma time. They all involve energy input, so more time costs more energy, as does higher temperatures, and pressures. If you raise one of the parameters, you can afford a lower value for the others. It's the value of the combined parameters that gives the level of fusion. 

Seperately, plasmas have been run with much higher temperatures than necessary. And density and time of plasmas have been run higher than needed. It's keeping a stable plasma, while all three are raised that is the objective. 

Pressure is the combination of temperature and density.   The rate of fusion increases with the square of pressure, not linearly. Big designs like ITER were thought to be the only way to raise the plasma pressure without instability, but the latest advances hold the promise of other ways of raising pressure. The spherical tokamak design, and the high-temperature superconductors being developed, promise to make big forward steps in raising stable plasma pressures. 

On the plasma pressure subject, the record is held now at the Alcator C-Mod tokamak at MIT, it set a record of 1.77 atmospheres in 2005, then last year they got 2.05, which doesn't sound a lot, but it's the square that counts, so it's comparing 3.13 to 4.2. 

https://news.mit.edu/2016/alcator-c-mod-tokamak-nuclear-fusion-world-record-1014   

The ITER is expected to reach 2.6 atmospheres in 2032, the square of which is about 6.8, and consequently to achieve a Q of 10. With that sort of performance, it would be well into the region of generating net electrical power, once the systems were proved and improved. That would be for the next version, the DEMO class.

With such a large Q, the heat output is more than enough to be able to reduce the input electrical power, IF the heat can be kept long enough in the fuel, rather than rapidly escaping to the walls. So once you are into that kind of value of Q, you are really fine-tuning and perfecting, rather than chasing unknown performance levels. The real breakthrough comes when the fusion heat can be made to stay around long enough, that you can start reducing the input power, and still maintain the burning plasma. Like lighting a log fire with a blow torch. Once you get to a point where you can take the blow-torch away, you have a self-sustaining fire, and just need to keep adding fuel. 

Being able to reduce the input power automatically raises the Q value still further, so there is a sort of critical point, where the Q value naturally takes off, and the output rises, and the inputs fall. Hopefully, the ITER will take fusion all the way into that zone. 

Edited February 14, 2022 by mistermack
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