Archive for the ‘fusion’ Category
nuclear fusion 3 – developing technologies
something to do with laser confinement fusion energy
Ways of producing nuclear fusion:
- High-temperature superconductors (HTS) for magnetic confinement fusion.
HTS is all about producing more powerful magnets, in order to effectively confine super-hot (100 million degrees Celsius) plasma. Traditional electrically conducting materials such as copper will lose conductivity and become resistant at high temperatures, causing them to over-heat. To eliminate electrical resistance from potential superconducting materials, they need to be cooled to -269 Celsius. I’m trying to get my head around this, so I’m following the demo in the Royal Institution lecture linked below. A small but powerful magnet was dropped into a hollow copper tube, held vertically. It finally emerged from the bottom, but not at the pace of gravity. It’s all about the peculiar relationship between magnetism and electricity. The magnet creates a moving magnetic field inside the copper tube, inducing an electrical current, which, somehow, creates its own magnetic field in opposition to the field from the magnet, pushing back… (somehow I feel I should’ve done a Canto and Jacinta on this one!)
So, as the demonstrator tells us, we can vary the electrical resistance of metals, for example by increasing or reducing their temperature, as described above. Warming the copper tube increases its resistance, cooling it will decrease its resistance. A further demonstration with the same magnet and a very much cooled copper tube (-196 Celsius) showed that the magnet took longer to move down the tube. I don’t really understand how that proves decreased resistance, but then I’m no physicist… But the demonstrator explains:
So with the reduction in the resistance of the copper, those currents are able to form and flow more easily, and therefore they have a stronger magnetic field, opposing the falling magnetic field of the magnet [my emphasis].
So that clarifies things a bit. And the aim is to remove all electrical resistance, if possible. This can’t be done with most metals, including copper. And so – superconductors. There are apparently, high-temperature superconductors and low-temperature superconductors, the latter being the ones that need to be cooled down to -269 Celsius. So the demonstrator proceeds to demonstrate the effect of a dose of liquid nitrogen on a potential HTS, described rather vaguely as a ‘ small chip of super[lux??]’. I’ve tried looking up what he meant here (the captions didn’t help), but have come up empty. I’m guessing that he’s simply doused the same ‘small but powerful’ magnet. Anyway, the doused chip sits in a polystyrene cup which is sitting on a circular magnetic track. The supercooling is designed to turn it into a HTS, presumably. The aim is to repel the field from the magnetic track ‘by setting up its own internal currents’ in balanced opposition. The chip has to be doused a couple of times with the liquid nitrogen to get it to the right temperature, but the demonstrator soon has the cup with its ‘chip’ riding on the magnetic rail like a wee whited coaltruck, back and forth with a fingerpush.
Presumably the chip will have to be kept at this temperature to maintain this internal current. It will regain its electrical resistance upon warming up to a certain point. The second demonstrator shows us a HTS tape, which, when cooled down to 20 degrees Kelvin (that’s less than -250 celsius), will carry five times its normal electric current, with no resistance. Wound into a tight coil, the material, which is super-thin, will have a much higher energy or current density, which can be used to generate a strong magnetic field. The more material in the coil, the greater the current density, until the magnetic field is strong enough to safely confine the plasma from nuclear fusion. A scaled-up version of this type of coil is used at ITER. They require far less energy to cool them down too. Tokamak Energy is using these coils, combined with a spherical ‘cored apple’ tokamak shape, which apparently makes more effective use of the magnetic field. Altogether, a more efficient design – they hope. Developed in he UK, it’s being used also by the STEP plant (ST for Spherical Tokamak).
2. Laser fusion with diode pumps
Laser fusion is the next technology Windridge discusses. So how do lasers work? From memory, LASER stands for Light Amplification through Stimulated Emission of Radiation, but that don’t tell me much. Anyway it’s all about diode pumps. Wikipedia gives this elaboration:
A diode-pumped solid-state laser (DPSSL) is a solid-state laser made by pumping a solid gain medium, for example, a ruby or a neodymium-doped YAG crystal, with a laser diode
I think I’ll stick with Windridge’s description. We see some images, first of a pink rod of ruby crystal, the ‘lasing material’, wrapped round by a coil of incandescent lighting, which sends a flash of light into the crystal, exciting its atoms and somehow generating photons, all of the same wavelength. The ruby and the coil are enclosed in a capsule, and the generated photons bounce back and forth between mirrors at either end of the capsule, triggering the release of more photons in a build-up of energy. Finally, a beam of energy emerges ‘through a partially reflective mirror at one end’. How this creates fusion energy, I’ve no idea. I vaguely get the sense of pumping but…
Here’s a useful definition of a diode from a website called Fluke:
A diode is a semiconductor device that essentially acts as a one-way switch for current. It allows current to flow easily in one direction, but severely restricts current from flowing in the opposite direction.
It seems that the key here is to produce photons of a particular wavelength. Windridge compares a diode pump with a flash lamp or incandescent bulb. While the flash lamp produces this wide range of energies or wavelengths, but a more targeted, precisely defined energy level is all that is required to excite the crystal photons, meaning it can be done with less waste of heat-energy. Diode lasers are many times more efficient than the NIF laser, for example – nearly 40 times more efficient (the NIF laser uses flash lamps). Remember, NIF (the National Ignition Facility) made headlines some months ago by getting more energy out of their fusion experiment than they put into targeting and ‘igniting’ the fusion pellet, but critics noted that the energy needed to drive the laser was orders of magnitude greater than the energy produced. The diode pump may, if found to be workable, reduce those orders of magnitude considerably.
So, although I don’t quite understand all the details, to put it mildly. I do get a strong sense that progress is being made. We seem to have gone beyond proof of concept, and are entering the engineering phase, and it looks like the next couple of decades will some exciting results. Tritium breeding and handling (it’s extremely rare and radioactive) is a big issue, and new materials science will be required to deal with high-energy neutrons and the damage they cause. Producing and testing such materials will be a high priority, but the pay-off can hardly be calculated. High-temperature superconductors are a relatively new development, and perhaps more breakthroughs can be made there. With more money being poured in, there will be more jobs for smart people – can-do problem solvers.
So, after watching this video a couple of times and trying with limited success to understand the science, but understanding enough to be aware of the viability of something that once would have seemed the most impossible of dreams – replicating the vast power of the stars – I read many of the comments, and was dismayed by the high level of negativity. An almost ferocious naysaying. I could respond with Kafka’s ‘genius doesn’t complain, but runs straight against the wind’, or ‘We choose to go to the moon, not because it is easy but because it is hard’, by that Kennedy bloke. It was just a little less than a century ago that Hubble provided convincing evidence that other galaxies existed. Two centuries ago we knew nothing of atoms or genes or space-time. The progress we’ve made science since then is – well, astronomical. Of course, new breakthroughs tend to create new problems, and I can imagine science-fiction scenarios in which our play with fusion ends up in our going up in a sunburst of glory – ‘Out, brief candle!’
We shall see. I hope I can live so long…
References
https://en.wikipedia.org/wiki/Diode-pumped_solid-state_laser
https://www.fluke.com/en-au/learn/blog/electrical/what-is-a-diode
nuclear fusion developments 2 – replicating the stars
ITER, in southern France, while under construction
Returning to nuclear fusion, I’m focussing here on the recent Royal Institute lecture mentioned in my previous fusion post (all links below). Dr Melanie Windridge starts off with the well-known point that we’re currently failing to reach projected targets for the reduction of global warming, with current national pledges taking us to 2.4 degrees C by century’s end (the target, remember, is/was 1.5°C), with energy demand rising, and energy security issues due to political instability, among other problems.
Windridge’s pitch is that, yes, we must keep on with all the possible green solutions, but fusion is the transformational solution the world needs. It potentially produces no CO2, an abundant supply of fuel, in a safe, controlled process with no long-term radioactive waste. It would also potentially produce firm, non-intermittent, base-load power – less redundancy in the grid (I probably need to do a whole post on this) – which would be more economical in the long term. Also, decarbonisation is about much more than electricity, which apparently is only about 20% of the electricity market. The other 80% is much harder to decarbonise. Windridge lists some of them – industrial heat, aviation and shipping fuels, and desalination – which I hope to explore further in another post. There’s also the opportunity, if we could develop an effective fusion energy system, with limitless clean energy, of undoing the damage already done. Current projections show that there will still be fossil fuel-based energy in the mix in 2050. This is a challenge for those interested in pursuing the fusion solution. ‘Fusion can address the fossil fuel gap’, one of Windridge’s graphs suggests. The aim, it seems to me, is that fusion will be ‘ready’ by mid-century, at which time it will be transformative or, as Windridge says ‘we need a solution with immense potential’. But prediction is tricky, especially about the future, and as a sixty-something optimist, I can only hope that I can live and be compos mentis enough to witness this transformation.
Frankly, it’s amazing that we can be considering this type of energy, a result of relatively recent understanding of our universe. As Windridge points out, the only other form of energy that is more energy-dense is matter-anti-matter annihilation (from the first few seconds after the ‘Big Bang’) – I can well imagine future researchers and engineers trying to create a Big Bang under controlled conditions in some hyper-complex cybernetic laboratory. I wouldn’t be surprised if an SF author has already written a story…
High energy density is doubtless the holy grail of future energy technology. Windridge gives a nice historical account of this – something that Gaia Vince’s Transcendence has helped me to focus on. The industrial revolution, which began in Britain, moved us from animal energy in joules per gramme to chemical energy in kilojoules (one thousand joules per gramme). This gave Britain a fantastic edge over the rest of the world, and was the vital element in creating the British Empire. Nuclear energy, which takes us to gigajoules (billions of joules) per gramme, and which, thankfully, is being pursued internationally, and hopefully collaboratively, is a breakthrough, if it works out, comparable to the invention of fire. One kg of fusion fuel can provide as much energy as 10 million kg of coal, so it would make sense to concentrate much of our collective ingenuity on this zero-carbon form of fuel.
There are different pathways. Aneutronic fusion, as the name suggests, doesn’t rely so much on neutron energy, with its associated ionising radiation. Alpha particles or protons carry the energy. An Australian company, HB11 Energy, is using lasers to drive a low-temperature proton-boron fusion system, which is showing some promise, and deuterium-helium-3 is another combination, but currently deuterium and tritium is the easiest reaction to obtain results from. Now, considering the power of the sun, which is so energetic that, according to BBC Science Focus, ‘the Earth would become uninhabitable if its average distance from the Sun was reduced by as little as 1.5 million km – which is only about four times the Moon’s distance from Earth’, it should be pretty clear that recreating that kind of energy here on Earth’s surface is fraught with problems. The fusion ‘triple product’ for producing this energy is apparently heat, density and time. So to achieve the product in a ‘short’ time, for example, we need to tighten the other parameters – more heat and density. Safely producing temperatures much higher than those in the sun for any extended period would presumably be quite a feat of engineering. The different designs and approaches currently include tokamaks, stellarators, inertial confinement (using lasers) and magneto-inertial fusion. The inertial confinement laser model focuses lasers on a small fuel pellet, causing it to implode and produce ‘fusion conditions’.
It’s all about producing plasma of course – the so-called fourth and most energetic state of matter. Electrically-charged particles which make up over 99% of the visible universe. These charged particles spin around magnetic field lines, so allowing us to use magnetic systems to control the material. We’ve used plasma in neon lights for over a century, and its production was first demonstrated by Humphrey Davy in the early 1900s – something to explore…. Plasma is also a feature of lightning, a ‘bolt’ of which can strip electrons from the immediately surrounding air. This means that air is ionised and can be manipulated magnetically. Tokamaks and other magnetic devices operate on this principle.
Inertial confinement uses shock waves or lasers to ‘squeeze’ energy out of a pellet of fusion fuel. The point at which such energy is produced is called ignition. Think of a bicycle tyre heating up as you pump it up to a higher pressure, until the tyre explodes – sort of.
So – and I’m heavily relying on the Windridge public lecture here – fusion research really began in the fifties, generally in universities and public labs. This early work has culminated in two major public projects, ITER (the International Thermonuclear Experimental Reactor), with its ultra-massive tokamak located in the south of France, and NIF, the National Ignition Facility, located in California. which made headlines last December for ‘the first instance of scientific breakeven controlled fusion’. This involved bombardment of a pellet ‘smaller than a peppercorn’ to produce a non-negligable energy output for a very brief period.
All of this has been at great public expense (why weren’t we told?), so in more recent times, private investment is moving things along. The last couple of years has seen quite a bit of progress, in both public and private facilities. For example, JET, in Oxfordshire, produced 59 megajoules (59,000,000 joules) of fusion energy, sustained for 5 seconds, a world record and a proof of concept for more sustainable energy production. And at NIF last year they produced ‘ignition’, the whole point of the facility, producing more fusion energy than the laser energy used to drive the process, a proof of concept for controlled fusion. And even more recently, China set a new record at their EAST tokamak (don’t you just love these territorial names), attaining steady-state ‘high performance’ plasma for about 6.5 minutes (I don’t know what high performance plasma is, but I can perhaps guess). And there is a lot of work going on in the private space too (I’ll be looking at Sabine Hossenfelder’s appraisal of the field in a future post, all in the name of education), with a really notable increase in private investment and start-ups – about half of the world’s private fusion companies today are less than 5 years old. Some $5 billion has been invested, from energy companies like Shell and Chevron, but also a variety of other organisations familiar to capitalists like me.
Why is this happening? Clearly we have a greater consensus about global warming than existed a decade ago. Also the science of fusion has reached a stage where rich people and organisations are sensing the opportunity to make even more money. Windridge also talks about ‘enabling technologies’, recent engineering and technological developments such as high-temperature superconductors, diode pumps for lasers, and various AI breakthroughs and improvements. Mastering and streamlining these developments will ultimately reduce costs, as well as expanding the range of the possible. National governments are developing regulatory frameworks and ‘fusion strategies’ – the latest coming from Japan – often involving public-private partnerships, such as the UK’s Fusion Industry Programme. The UK has also created a facility called STEP – the Spherical Tokamak for Energy Production – run by the Atomic Energy Authority, which is described by Windridge as the world’s first pilot nuclear energy plant.
So in the next post on this topic I’ll be trying to get my head around the developments mentioned above, FWIW. And it is definitely worth something. If we can get it all right.
References
Gaia Vince, Transcendence, 2019
https://en.wikipedia.org/wiki/Aneutronic_fusion
https://www.psfc.mit.edu/vision/what_is_plasma
https://fusionenergyinsights.com/blog
Exploring the future of nuclear fusion
Canto: So, with Christmas cookery and indulgence behind us, it’s time to focus on another topic we know little about, nuclear fusion – or I should say human-engineered nuclear fusion. Ignition has recently been achieved for the first time, so where do we go from here?
Jacinta: Well I listened to Dr Becky the astrophysicist on this and other topics, and she puts the ignition thing into perspective. So it occurred back on December 5 at the National Ignition Facility in California. As Dr Becky explains it, it involves ‘taking 4 atoms of hydrogen and forcing them together to make helium’, which is slightly lighter than the four hydrogens, and this mass difference can, and in this case has, produced energy according to special relativity. Of course fusion occurs in stars (not just involving hydrogen into helium) and it can potentially produce huge volumes of clean energy. But there’s a big but, and that’s about the high temperatures and densities needed for ignition. Those conditions are needed to overcome the forces that keep atoms apart.
Canto: Yes they used high-powered lasers, which together focus on heavy hydrogen isotopes – deuterium and tritium – to produce helium. And this has been achieved before a number of times, but ignition specifically occurs when the energy output is greater than the input, potentially creating a self-sustaining cycle of fusion reactions. And the difficulties in getting to that output – that is, in creating the most effective input – have been astronomical, apparently. They’ve involved configuring the set of nearly 200 lasers in the right way, using ultra-complex computational analysis, recently guided by machine learning. And this has finally led to the recent breakthrough, in which an energy input of 2.05 megajoules produced an output of 3.15 megajoules…
Jacinta: 1.1 megajoules means ignition, though it’s nothing earth-shattering energy-wise. It’s apparently equivalent to about 0.3 kilowatt-hours (kWh) – enough energy for about two hours of TV watching according to Dr Becky. And also this was about the energy delivered to the particles to create the reaction, it didn’t include the amount of energy required to power the lasers themselves – approximately 300 megajoules. So, good proof-of-concept stuff, but scaling up will be a long and winding road, wethinks.
Canto: Another favourite broadcaster of ours, theoretical physicist Sabine Hossenfelder, also covers this story, and provides much the same figures (400 megajoules for the lasers). She also points out that, though it’s a breakthrough, it’s hardly surprising given how close experimenters have been getting to ignition in recent attempts. And she is probably even more emphatic about the long road ahead – we need to ramp up the output more than a hundred-fold to achieve anything like nuclear fusion energy at economically viable levels.
Jacinta: I’m interested in the further detail Dr Hossenfelder supplies. For example the NIF lasers were fired at a tiny golden cylinder of isotopes. There must be a good reason for the use of gold here. She also describes the isotopes as ‘a tiny coated pellet’. What’s the coating and why? She further explains ‘the lasers heat the pellet until it becomes a plasma, which in turn produces x-rays that attempt to escape in all directions’. This method of arriving at fusion is called ‘inertial confinement’. Another competing method is magnetic confinement, which uses tokamaks and stellarators. A tokamak – the word comes from a Russian acronym meaning ‘toroidal chamber with magnetic coils’ – uses magnetism to confine plasma in a torus – a doughnut shape. A stellarator…
Canto: Here’s the difference apparently:
In the tokamak, the rotational transform of a helical magnetic field is formed by a toroidal field generated by external coils together with a poloidal field generated by the plasma current. In the stellarator, the twisting field is produced entirely by external non-axisymmetric coils.
Jacinta: Ah, right, we’ll get back to that shortly. The Joint European Torus (JET) holds the record for toroidal systems at 0.7, which presumably means they’re a little over two thirds of the way to ignition.
Canto: A poloidal field (such as the geomagnetic field at the Earth’s surface) is a magnetic field with radial and tangential components. Radial fields are generated from a central point and weaken as they move outward.
Jacinta: PBS also reports this, citing precisely 192 lasers, and a 1mm pellet of deuterium and tritium fuel inside a gold cannister:
When the lasers hit the canister, they produce X-rays that heat and compress the fuel pellet to about 20 times the density of lead and to more than 5 million degrees Fahrenheit (3 million Celsius) – about 100 times hotter than the surface of the Sun. If you can maintain these conditions for a long enough time, the fuel will fuse and release energy.
Canto: So the question is, does nuclear fusion have a realistic future as a fuel?
Jacinta: Well, did the internet have a realistic future 50 years ago? We’ve had a breakthrough recently, and the only way is up.
Canto: Yeah the future looks interesting after I’m dead. Still, it’s worth following the progress. Back in February The Guardian reported that JET had smashed its own world record, producing ’59 megajoules of energy over five seconds (11 megawatts of power)’. Whatever that means, it wasn’t ignition – it might’ve been the .7 you mentioned earlier. Creating a mini-star for five seconds was what one experimenter called it, which I think was in some ways better than the current effort, in that it created more energy in absolutes terms, but less energy than the input.
Jacinta: Perhaps, but what they call ‘gain’ is an important measure. This recent experiment created a gain of about 1.5 – remember just over 3 megajoules of energy was put out from just over 2 megajoules of input. It’s a start but a much bigger gain is required, and the cost and efficiency of the lasers – or alternative technologies – needs to be much reduced.
Canto: Apparently deuterium and tritium are both needed for effective fusion, but tritium is quite rare, unlike deuterium, which abounds in ocean waters. Tritium is also a byproduct of the fusion process, so the hope is that it can be harvested along the way.
Jacinta: Of course the costs are enormous, but the benefits could easily outweigh them – if only we could come together, like bonobos, and combine our wits and resources. Here’s an interesting quote from the International Atomic Energy Agency:
In theory, with just a few grams of these reactants [deuterium and tritium], it is possible to produce a terajoule of energy, which is approximately the energy one person in a developed country needs over sixty years.
Canto: Really? Who will be that lucky person? But you’re right – collaboration on a grand scale is what this kind of project requires, and that requires a thoroughly human bonoboism married to a fully bonoboesque humanism….
References
https://www.theguardian.com/commentisfree/2022/dec/13/carbon-free-energy-fusion-reaction-scientists
https://www.iaea.org/bulletin/what-is-fusion-and-why-is-it-so-difficult-to-achieve
more on nuclear fusion: towards ignition!
I recently wrote about and tried to get a handle on the nuclear fusion facility, ITER, being built in southern France, but I barely mentioned the importance of magnets, and I didn’t mention another essential feature or factor in nuclear fusion – called ignition. That’s because I’m still a learner after all these years. But some news broke recently regarding a completely different experimental fusion facility in the USA, which uses lasers rather than magnets to control and focus the energy, which, as previously described, needs to be – a lot.
The National Ignition Facility (NIF) at the Lawrence Livermore National Lab in California is designed, it seems, to try and achieve exactly that – ignition. The term is kind of self-explanatory, as when you ignite something you get a burst of energy, seemingly more than you put into the igniting, like when you strike a match. But ignition in nuclear fusion is a really difficult thing to achieve, which is presumably why they had to build a whole national facility around it. They’ve been trying to achieve it for decades.
I did write that to achieve fusion – ignition? – required temps of around 150,000,000 celsius, and obviously to sustain such temperatures requires a fair amount of energy, ten times that at the sun’s centre. Did I get that figure wrong? Pressure comes into it too (there’s a direct proportionality between temperature and pressure at any given volume).
I’ve found a great video explainer of the ignition breakthrough, presented by Anton Petrov, and a recent New Scientist podcast (no 81) also discusses it. So basically the possibilities of nuclear fusion as an energy technology have been on the cards since the development of the H-bomb in the late forties and early fifties. The energy required to set off an H-bomb, and for subsequent neutron bomb technology, was derived from nuclear fission. So that’s a lot of energy to make more energy. Since then, the aim, the holy grail, has been to find a way to create ignition, an energy output that is greater than, and preferably much greater than, the energy input. This is, of course,, essential for real-use thermonuclear energy. A number of technologies for creating thermonuclear fusion have proved successful, except insofar as the input-output ratio is concerned. Out of all these experiments chasing this elusive ignition, two models seemed most promising. Firstly, the toroidal fusion reactor (eg ITER), which is a magnetic confinement reactor, in which super-heated plasma is spun very quickly around a magnetically confined chamber, to create higher-than-the-centre-of-the-sun energy/temperatures. A number of these reactors, or tokamaks, have been built around the world and have successfully created fusion, but not ignition.
The second model is very different. It’s called inertial confinement fusion, and it uses tiny hydrogen pellets. The idea came from observation of the H-bomb: a small enough hydrogen pellet would require a minimum energy of 1.6 megajoules (million joules) of energy to initiate an explosion – essentially, an ignition. This energy could be provided by lasers. Now this process is complicated – it’s not simply a matter of fusioning hydrogen into helium because, as described in my previous post about ITER, there are isotopes involved. These isotopes (deuterium and tritium) are used to overcome the electrostatic repulsion which would normally occur when using proteum, the common form of hydrogen. This repulsive force between protons is known as the Coulomb force. The attractive force between protons and neutrons, called the nuclear force, acts against the electrostatic repulsion force, and this helps in overcoming the Coulomb barrier, and facilitating a fusion energy greater than that inside our sun, where plasma particles may not fuse at all over long periods. We’re basically looking at creating a more efficient kind of fusion, which requires the kinds of temperatures and pressures found inside much larger stars than our sun.
The key to the elusive status or point known as ignition is a concept called the Lawson criterion. Wikipedia describes it thus:
The Lawson criterion ….compares the rate of energy being generated by fusion reactions within the fusion fuel to the rate of energy losses to the environment. When the rate of production is higher than the rate of loss, and enough of that energy is captured by the system, the system is said to be ignited.
We haven’t achieved ignition yet, but it seems another baby step has been taken. One of the researchers at the NIF has described it as a ‘Wright brothers moment’, which has led to a bit of head-scratching. Basically, what was achieved at the NIF was a ‘momentary’ ignition – very momentary, and still only releasing some 70% to 80% of the energy input. Yet this was the most significant achievement in 60 years of work – a proof of concept achievement, which is built on previous experiments yielding increasing levels of energy. The process involved almost 200 super-amplified lasers confining and directing energy at a tiny hydrogen pellet for a period of 3 nanoseconds. That’s 3 billionths of a second. This required excruciating accuracy, coordination and timing, with everything – the lasers, the amplifiers, the pellet, the hohlraum chamber (holding the pellet) and so forth, being executed precisely. The precision level has improved markedly in recent times, leading to this breakthrough moment (after all, the ‘Wright brothers moment’ wasn’t exactly the first commercial passenger flight). The 1.3 megajoules released in this most recent ignition experiment was some 25 times what the facility could muster only three years ago. So there doesn’t seem far to go.
And yet. The energy input required is enormous. The lasers would need to fire more or less constantly – machine-gun-like – to produce the output required for human use (the current record of 1.3 megajoules has been described as ‘just enough to boil a kettle’. So we’re talking orders of magnitude, not just for the laser energy but for the hydrogen pellets, which need to be produced en masse at a teeny fraction of current costs. And so on.
This not to minimise the achievement. The publicity already being generated augurs well for the future of a technology that has for so long failed to live up to expectations. Those at ITER and other labs around the world will receive a great fillip from this, not to mention some small mountains of cash. Looking forward to it.
References
Major Breakthrough in Nuclear Fusion After Decades of Research (Anton Petrov video)
https://en.wikipedia.org/wiki/Lawson_criterion
movements in nuclear fusion: ITER
the world’s biggest clean energy project? ITER in southern France
Geographical, the magazine of the UK’s Royal Geographical Society, had an article in its April 2021 edition entitled ‘Caging a Star’, all about the International Thermonuclear Experimental Reactor (ITER) project in Provence, France. Thermonuclear fusion has of course been talked up as an ultimate solution to our energy needs for decades, to the extent that it’s become something of a joke, but in the meantime, practical movements are underway. In fact, they’ve been under way for a long time. An international contract was signed in 1986 to implement research on fusion, though it took another twenty years to agree on the site for ITER. The project now involves 35 countries – largely WEIRD ones (Western Educated Industrial Rich Democracies), producing 85% of global GDP. It’s a long-term project, certainly, but it’s being taken seriously, and construction is happening, big-time.
With the IPCC having recently come out with its 2021 report, nations are looking to their targets and feeling concerned – some more than others (wake up Australia). Boštjan Videmšek, the author of the Geographical article, assesses the current situation in stark terms:
70% of all CO2 emissions pumped into the atmosphere are created through energy consumption; 80% of all the energy we consume is derived from fossil fuels. The EU has formally pledged to start producing half of its electric energy from renewable resources by 2030. By 2050, the bloc’s members are planning to hoist themselves into a fully carbon-neutral society. But, given current trends, this seems like wishful thinking. Renewable energy resources simply won’t be enough for the task.
The ITER project came out of the closet, so to speak, in late July 2020, when the heart of the project, the tokamak, began to be assembled onsite – though construction of various elements of the program have been going on for years. A tokamak is a toroidal or doughnut-shaped chamber, controlled by huge, powerful magnets, in which hydrogen plasma is manipulated to produce energy according to Einstein’s mass-energy equation. We all know, I hope, that fusion is constantly happening in the sun, and in all suns throughout the universe, and that its energy is essential to our existence, but ITER’s scientists are hoping to improve on the sun’s processes. Hydrogen collisions inside the sun don’t always result in fusion – the fusion process is quite slow. Recognising this, researchers looked to isotopes of hydrogen to speed up the process. Hydrogen’s most common form, consisting simply of a proton and an electron, is called protium. However, there are two other isotopes, deuterium and tritium, containing an additional one and two neutrons respectively. The best form of fusion reaction for producing energy is DT fusion, using deuterium and tritium. This produces more energy, at a lower temperature. The problem is with the tritium, a highly radioactive and unstable isotope, which is both rare and expensive, at about US$30,000 per gram. The rarity, though, is related to low demand, and there is potential for ITER to produce its own supply of the isotope.
Of course, none of this is expected to be ready in the near future. ITER is essentially a proof-of-concept project for future power plants, and is expected to spend a decade in testing, finalising in around 2035. Those future power plants are already ready and waiting, at least in terms of design. The key to achieving fusion is a sufficiently high temperature (150,000,000 degrees celsius!) and high particle density, for an optimum fusion rate. Containment of the volatile plasma will also, of course, be an issue. ITER’s experiments will also be about capturing and utilising the energy produced. As Videmšek describes it:
The idea is that heat will build up along the sides of the tokamak, where it will be captured by the cooling water circling the reactor. As in a normal power station, the heat will be used to produce steam and – by way of turbines and alternators – electricity. The water will eventually be released with the help of vast cooling towers. These have already been put in place…
The science itself, as researchers told Videmšek, is straightforward enough, but the infrastructure, the international nature of the project, the politics and the funding can all provide obstacles. The siting in Provence has helped, as France has successfully embraced nuclear fission technology for decades, and the project is a boon for the Provençal economy. And of course there’s the global warming issue. The IPCC has just released its 6th Assessment Report and, among other findings, has confirmed what we here in Australia have experienced regarding extreme weather events:
Human-induced climate change is already affecting many weather and climate extremes in every region across the globe. Evidence of observed changes in extremes such as heatwaves, heavy precipitation, droughts, and tropical cyclones, and, in particular, their attribution to human influence, has strengthened since the Fifth Assessment Report (AR5).
The report argues that, ‘unless deep reductions in carbon dioxide (CO2) and other greenhouse gas emissions occur in the coming decades’, this scenario of extreme weather events will continue into the foreseeable future. These deep reductions, it seems, are a matter of political will, not to mention recognition of the crisis, which is clearly not universal. The way that many nations, including some of the most powerful and impactful on climate, have dealt with the clear and present threat of the SARS-CoV-2 virus, doesn’t provide much cause for optimism. If the ITER project, mostly funded by EU nations, goes off without a hitch over the next few decades, it may just put another nail in the coffin of our self-destructive exploitation of fossil fuels. Better late than never I suppose…
References
Boštjan Videmšek, ‘Caging a star’, in Geographical, April 2021
https://www.ipcc.ch/report/ar6/wg1/#SPM