US boffins: We're close to fusion ignition in the lab – as seen in stars and thermonuclear weapons The US government's nuclear physicists say they are closing in on fusion ignition – the point at which a fusion reaction becomes self-sustaining – in the lab by compressing matter with lasers. We're told they were able to produce more than 1.3 megajoules of energy in 89 picoseconds – that's 89 trillionths of a second – at …
Doesn't mean what you think it means.
It doesn't mean you have a power station, it just means you are (momentarily) getting more energy out then you spend heating the sample. It doesn't count what you are using to keep the sample compressed into this state.
Claiming "self sustaining" is common in Fusion PR releases
Who's "you" in this context?
FWIW I would imagine a self-sustaining reaction in this lab would last a fraction of a second -- no one's given any lengths of time beyond the 89ps this one shot lasted.
It's pretty clear this is science experimentation for things like nuclear weapon stuff rather than experimentation for making power reactors, as I thought the article was at pains to point out.
C.
How dare you sir! The NIF is a totally peaceful nuclear power experiment and in no way a careful skirting of arms treaties to do thermo nuclear weapons research.
Ironically there are European partners to NIF who explicitly call it something like, "nuclear weapons secret project" (but in French)
Heh, eh no. I mean, it's all over the NIF site that they do nuke research, with some bits about the cosmos, future energy, and national security sprinkled in.
Thing is, we saw other publications writing about this as if this was useful for fusion. But if you look at the info and the quotes - and Katyanna did speak to them - there's little tying it to sustained power generation.
I am quietly fascinated by weapons testing, and the lengths the US etc go to test their designs without breaking treaties. Eg, primary stage implosion tests, just without the fissile material in it, using x-rays.
C.
I thought French secret project/mission names were more obscure now ever since Operation Sink The Boat (YouTube)
> Presumably in the same vein as "Iraqi Freedom" and "Desert Storm" they would have had "Operation invade Normandy on 6 June"
No, no, an US operation name has to sound badass, manly, aggressive and resolute - or, if by chance it's not a simple kill-them-all operation, it definitely has to include the word "free" or "freedom" (you know, those words which mean "good" and "USA-like"). You gave a good example of each.
In this perspective, "Market Garden" is for sissies. How is that supposed to induce shock and awe?
The occupation of Afghanistan was called Operation Enduring Freedom. This was only four years after the Ian McKewan novel Enduring Love. In both cases 'enduring' was a pun, not something that lasts forever but something you struggle to survive.
Soon followed by Operation Iraqi Liberation (OIL).
For me too, and in that definition inertial confinement fusion is nigh-impossible to make self-sustaining, because the engineering problem of transferring energy from an exploding discrete packet of fuel to the upcoming ones isn't exactly trivial...
Leaving aside the fact that even once you achieve ignition (i.e. output energy > input energy), you're not even halfway there; given that the fusion energy mostly leaves the reactor in the form of heat, and in existing power stations the conversion efficiency is typically around 30%, to get power out to the grid you need your fusion reaction to output at least 300% of the energy used to start it...
So many issues with this article:
Not differentiating between self-sustaining (it clearly isn't - it is a one-shot system)
Mixing that up with net-positive (only 70% so not that either)
Described as a big milestone, some sort of 'first' - but not at all clear how/what/why: hasn't all of this been done before, (possibly with lower numbers)?
Ignition and breakeven are two very different concepts. In the ignition experiment, they are concerned with simulating the radiation driven inertial implosion that occurs in a thermonuclear weapon. So they are really only concerned with the energy output as compared to the x-ray radiation generated. Ignition is the point at which sufficient heat is generated and briefly confined that, were there more fusion fuel, it would result in a runaway reaction, or in other words, it would "ignite" a thermonuclear explosion.
By contrast, the National Spherical Torus Experiment (NSTX) is a US magnetic confinement experiment and is similar to the Mega Ampre Spherical Tokamak (MAST) experiment being conducted in Oxfordshire, although both of those are a bit behind the Joint European Torus (JET) experiment. These are energy production experiments, so are more concerned with the breakeven concept, or the ability to generate a net energy gain in a controlled manner.
I’m 56, it has been 50 years away for my entire lifetime. With Tokamaks like ITER there’s a big problem with the material used to line the fusion chamber. It gets hammered by neutrons which means it begins to break down. So, periodically you have to shut down your tokamak to reline it. What you do with the reasonably radioactive old lining material is another question again.
Meanwhile a tokamak needs a fusion reactor handy to keep firing it up.
Compared to Thorium reactors which the Indians are developing which don’t produce weapons grade material (no plutonium) and are very unlikely to meltdown (3 Mile Island) or explode (Windscale, Chernobyl) fusion looks like a dead duck.
The end of the movie "Dr. Strangelove" comes to mind - Vera Lynn singing "We'll meet again..." as mushroom clouds erupt all over the planet.
It might eventually be noted that there are cheaper ways of killing people that also leave the land accessible to invading forces. As war is mostly about acquisition of territory or resources, that's quite an important point.
"Why do you think North Korea has never been invaded?"
Why do you think that? The territory that is now North Korea was invaded by UN forces during the Korean War 70+ years ago. At least one of its allies (Russia) did have nukes at that time. Maybe China had them by then too. The Norks didn't get invaded over the next 60 years or so when it didn't have its own nukes.
The point of having nuclear weapons is actually defense. If you have working nukes, then other nations cannot make existential threats at you.
That's basically the only realistic use case of nukes; they're useless for conquest. I don't think they can even be credibly used to back a regular (non-existential) threat. I'm not sure why the USA keeps quite so many; I guess it's to maintain deterrence even in the face of other nations developing nuke defenses.
> I'm not sure why the USA keeps quite so many
Because there is big money in making and maintaining them, and entities which get awarded those gravy trains know how to show their gratitude. Also it gives generals more bearing and improves their self-confidence. You perform much better in bed when you know you can wipe out whole countries with a couple keystrokes (while sipping your grain alcohol with rainwater).
But they do. And every current or recent conflict has come down to bad old fashioned shooting war. It seems from appraisal of history that escalation feeds itself, to some extent independent of utility.
>I'm not sure why the USA keeps quite so many<
Multiple reasons, I think:
(i) commitment to the trinity of delivery systems for strategic use: Air-dropped munitions, land based missiles and sub-based missiles, which in turn is partly a services rivalry thing, potentially, with both USAF and USN having weapons.
(ii) strategic vs tactical weapons (hence battlefield nukes for the US Army and smaller air dropped munitions for the USAF/USN)
(iii) redundancies to ensure a minimum number of weapon systems that actually hit the target - allowing for possible 'first strike' against the US that destroys some of the weapons; lack of reliability or lack of accuracy (yes, even Nuke's need to have a degree of accuracy) which means that some weapons fail or miss; possible counter-measures deployed by the enemy (including a what-if they have something developed in secret type concerns)
(iv) deploying them where they are 'needed' (so warheads on bases and ships worldwide)
(v) (and possibly the main reason) Because 'our nuclear stockpile is bigger than your nuclear stockpile': I think more a 1950's - 1980's mentality than now, but it leaves a legacy - we need to replace these weapons, not just scrap them, because if we used to need them, we obviously still do.
To compare with your car, you need to look at how much energy goes from the battery to the spark plugs, fuel pumps and so on, vs how much energy is released from the petrol when it burns. The answer, I hope, to this question, is a lot more, enough to keep the battery fully charged, and shift a couple of tonnes of metal around the place.
I don't doubt that a very substantial portion of the energy released from the petrol gets wasted, but that is a different issue. It is still way more than the energy required to start the reaction.
In order to get your car engine running, you need some electricity to start the process. Same as with the fusion reaction.
Once the car engine is running, it will self-sustain for many hours, until the fuel runs out, or you stall the engine, because the energy you get out of the petrol is a lot more than the energy you put in from the battery. This is not the case for the fusion reaction
According to the info out there, the fogbank material absorbs the X rays and turns into a plasma which helps confine the thermo-nuclear fuel while its being heated by the plutonium 'sparkplug' in the middle of it
thus boosting the pressures so that more of the fuel is turned into energy (and if you wanta really big bang, surround the whole lot in a depleted uranium cylinder that catches the high speed neutrons emitted from the reation, turns into plutonium which then fissions extremely well in the high density neutron flux.
See russian "Tsar Bomb" for more details...
Even in 20 years' time when someone manages to develop a viable fusion power plant, it won't be that green. Sure, it won't generate carbon (other than very minor amounts indirectly) but it will irradiate the hell out of the containment vessel walls. This material will be degraded by the intense radiation generated by the fusion reaction and becomes brittle and weakened. So it will be periodically replaced. The surprising outcome is that the 'green' fusion reactors will be burying radioactive waste for generations.
"The surprising outcome is that the 'green' fusion reactors will be burying radioactive waste for generations."
Fusion reactors will generate radioactive waste. But purportedly few or none of the fairly long half-life heavy element fragments like Cs134, Cs137 and Sr90 that make nuclear waste from fission power such a nuisance. If you believe the glossy brochures, the principle radioactive in the fusion mix is Tritium which is a weak beta emitter with a half-life of 12 years. My impression is that the electrons (beta radiation) from Tritium decay are no more energetic than the the occasional electron that escapes from the tube of an old-fashioned CRT monitor or TV. But I could easily be wrong about that. Tritium does appear to be about the least harmful radioactive material one is likely to encounter in daily life which is why it has replaced Radium in glow-in-the-dark instruments.
And even if that's true, "they" could be misrepresenting the situation a bit since the premise here is that the reactor itself will likely be exposed continuously to lots of energetic neutrons. Of course those will be pacifist neutrons that work only for good and socially beneficial purposes ... Or so we're told.
Is a lot better to create relatively tiny amounts of relatively safe (anything very radioactive has short half life and thus goes away quite fast) waste which is dangerous for a few hundred or a few thousand years than a vast amount of CO2 (35 billion tonnes a year) which either will end most civilisation in less than a century, or, if we store it will be deadly for ever. Oh, and, no-one knows how to store it really, and remember is many billions of tonnes each year to store.
Nuclear power is absurdly green soon as you get over fear of spooky radiation you can't see (CO2 also you can't see by the way) and properly disconnect it from nuclear weapons.
"Oh, and, no-one knows how to store it really"
Trees. Lots and lots and lots of them. In Europe we point at forest loss in the Amazon and other tropical countries and sometimes forget that the farmlands and rolling hills all over the continent used to be mostly forest before h. sapiens arrived.
The problem isn't how to restore nature to a proper balance - we know how to do that. The real problem is social and political acceptance of the solution, which involves giving back land (and ocean) to nature, restricting human access to vast parts of the world, getting humans to reproduce less and/or having the remaining humans live with more inconvenience/less luxury than the current average westerner.
Trees sadly are not enough. All forests in the world at present sink about 10^12kgC/y. (this is apparently about 1 PgC/y, gramme 1/1000 kg, don't know why climate science people don't use proper SI). Human emissions are about 10^13kgC/y: we would need about ten times the area of forest that we now have. This is not likely practical.
One thing makes it better is that new forests sink more as trees grow, so can help get us over bump in emissions. But trees also take too long to even do that sadly.
Not against trees! Just they're not the whole answer or even very close to it. Big part of whole answer, obviously, is dramatically reduce fossil fuel use.
We're only a small step to nuclear fusion plants and infinite, clean energy. We have been there for how long? Fifty years? But this time it's for real because we're close to fusion ignition in the lab. Like every year. We just haven't found the fool to actually ignite it because we still don't haven't found a material to keep the neutrons in there for longer than a few seconds before turning into radioactive waste. Which is not unexpected because "fusion" and "matter" are mutually exlusive - well known those masterminds selflessly researching for a better future as "a key aim of the NIF is researching the design and maintenance of thermonuclear weapons". And that's the actual message: Idiots find even better way to themselves (and everybody else) up.
And, of course, "we are one step away from" last years promise.
For decades, lots of physicists in the US would routinely write '...and may have military applications' when applying for grants since the money largely came from the DoD.
WW2 in the US was known as the physicist's war, not because if Oppenheimer et al, but for the huge effort to train ordinary soldiers in the high school physics required for the mechanised battlefield. Radio operation, echo-range finding etc.
SO - tomorrow we get FUSION ..............
then next week it's onto Dyson Spheres
https://en.wikipedia.org/wiki/Dyson_sphere
as much as I would LOVE to see fusion cracked, I am doubtful it will be in my lifetime :o(
but, we can but wait
and I am certain of one thing, once it IS sorted, it will be classified, and hidden DEEP in the bowels of the Pentagon so them goddammned pesky commies don't get THEIR filthy hands on it
only part said in jest :o(
>> This is a notably milestone, the scientists said, because it puts them at the threshold of fusion ignition, which is the point where a fusion reaction becomes self-sustaining
I am pretty sure this milestone has been repeatedly reported over the past 40+ years.
It's almost as if fusion research is stuck in a temporal loop and keep emitting the same press releases.
Fusion output > fusion input is a great milestone, but still far to go.
In this experiment fusion output is 70% of total input.
But even getting from there to fusion output >= to total input isn't enough
There's still the small matter of harnessing the output energy and converting it into usable energy that can be fed back in. For true self-sustainability, the net usable output has to be >= to total input.
The output is essentially heat, and the most efficient combined cycle turbines can convert about 40% heat into electricity (and AFAIK that is pushing the theaoretical limit). So for a truly self-sustainable reaction, the fusion output has to be at least 2.5X the total input.
Next, you need it to be continuous, not a simple one-off shot. So you need ways of feeding in new fuel while keeping the reaction going (which is a huge engineering challenge), and you now also need energy for containment not only for ignition.
I expect the '20'years away' will hold for a couple hundred years more at least
In other words, it is only a *theoretically* self-sustaining reaction due to the incredible losses in the stages. It is also impractical, because you can't stop generating power for your customers by swapping out fuel pellets.
I'm much more interested in what that monster reactor their building in Europe ends up being able to do - THAT is a design that could produce useful power generation in the future. Fuel pellets are not.
The Register 
Biting the hand that feeds IT
Copyright. All rights reserved © 1998–2024
