A faster, cheaper path to fusion energy
phys.org
phys.org
1) Estimated $40 billion USD need to build a test reactor.
2) Not enough FLiBe fluid (Low-Z fluid) on the planet for the reaction chamber. Would need large scale manufacturing.
Source: https://youtu.be/KkpqA8yG9T4
The zirconium does not have to be "nuclear grade", since the design not only tolerates hafnium (a strong thermal neutron absorber) in the coolant salt, it depends on it to shield the reactor structure from thermal neutron degradation.
Lithium-7 will still lead to production of some tritium. Any MSR using lithium is going to need a tritium separation and capture system.
https://arxiv.org/pdf/1409.3540.pdf
I presume that the breeding ratio would fall below 1.0 with natural lithium.
DT fusion has the nasty circular dependency that breeding blankets are needed to make tritium, but they cannot be tested without working high intensity DT fusion neutron sources.
The demonstration reactor is the SPARC which is based on a scaled down half-sized (but 1/8 the mass and 1/8 the cost) version of ARC. While the main goal of SPARC is to achieve significant net power output, along with a proof-of-concept for many of the design features of ARC, some features may have to be left out for lack of space.
So I don't know if SPARC will be able to achieve net tritium breeding, but I presume they will be testing as many of the features as they can along with taking measurements and verifying the model. It is also noteworthy that the ARC/SPARC design allows for replacement of the vacuum vessel and cooling blanket without complete removal of the outside magnetic coils, so they foresee design iteration of those components unlike the ITER design which will be pretty much locked in.
A single ARC reactor would use 40% of this.
The total world Be resource is estimated at 100,000 tonnes, and if fully used in ARC reactors would supply just 1% of the world's primary energy demand.
Uranium was produced at a level of only hundreds of tonnes per year before the development of nuclear weapons and reactors. Now it is produced in quantities of tens of thousands of tonnes per year. Obviously the terrestrial geology of uranium did not change quickly; industrial demand is what changed. Uranium's crustal abundance is comparable to that of beryllium.
Despite cumulative production of more than 2.2 million tonnes uranium through 2003, additions to resource totals have kept pace with production so that overall resource levels have remained level or have increased over time. The ratio between Known Conventional Resources and reactor-related uranium requirements in 2003 was 52 compared to an average of 47 since 1985.
...
Uranium production in 1945 is estimated to have totaled 507 tonnes uranium. By 1965, when the first Red Book was published, production totaled 31,564 tonnes. Production peaked in 1980 at 69,692 tonnes from 22 countries. In 2003, uranium production was reported by 19 countries with output totaling 35,492 tonnes. Cumulative worldwide uranium production between 1945 and 2003 totaled 2,204,732 tonnes...
"Forty Years of Uranium Resources, Production and Demand in Perspective: The Red Book Retrospective"
https://www.oecd-nea.org/ndd/pubs/2006/6096-40-years-uranium...
It's a fair point that beryllium exploration and extraction would have to increase tremendously for routine construction of these reactors. But putting 100,000 tonnes of beryllium in ARC reactors would not mean that the Earth has then run out of beryllium.
If you look at the history of the price for aluminium, it has steadily dropped as production has risen, which is the opposite of what you are saying. And to pick another metal, the lowest copper price of the last 100 years was around the year 2000.
I'm not trying to make predictions about the price movement of beryllium following a very successful ARC demonstration. I'm just pointing out that you can't look at current resource levels and divide by annual production rates to learn when resources will fall to 0. Making predictions about future prices is particularly hard when an element currently has only niche uses (e.g. beryllium, thorium, thallium, rubidium).
That said, if Fusion power ever becomes a reality I hope it doesn't depend on some difficult to source material.
Sodium and potassium are pretty abundant.
That of course leaves the problem of needing relatively large amounts of 6Li, but that's something one has to live with as long as one wants DT fusion, I guess. And it seems this is more with building up the enrichment capacity rather than some fundamental geological limits.
It might be possible to use lead for neutron multiplication (it has a nice high cross section for (n,2n) reactions above 8 MeV), but it would not moderate the neutrons much, and 6Li breeds best off thermal neutrons. So the blanket and reactor would have to be bigger.
The MIT ARC design is half the size using high temperature superconductors and should be in the $1-2 billion range for a full-scale 500MW pilot production fusion reactor.
What is currently being proposed (the subject of the papers being delivered tomorrow) and funded with private money is a $200-250 million SPARC (Smallest Possible ARC) that is half the size again of the full-size ARC.
So yeah, you are off by a factor of 160.
Maybe if I said it would cost more to build, people would think it more likely to work.
I had many discussions with the head of the physics department at the local university who is a specialist in plasma physics. He was of the opinion that it would work at very low pressures/densities, but that the total output would not be high enough to be commercially viable. What is the actual benefit of a room sized $100k fusion reactor that can only put out 100 watts of energy?
I believe I've solved many of those problems, but building a prototype costs $$ that I don't have to spare...
I could bankrupt myself to build the prototype but I can't gamble like that with assets that currently feed my family.
Though I strongly believe it will work, I'm not going to go down the same hole that Tesla went down. I have no intention of dying penniless surrounded by pigeons. I am on track to build the prototype myself without going into debt in several years once a few of my mortgages are paid off.
Right now I own 100% of the IP, and have a submitted patent. I'm not actively looking for funding that would dilute me unless it's a very good deal. I'm kind of stuck bootstrapping unless I can get a grant. I have applied for several in the past, but to no effect.
Being more expensive doesn't make people think it is more likely to work. The easiest way to make people think your design will work is to take an existing design with known parameters and make it 'better'. Unfortunately, 'better' often means bigger and more expensive, which is how we get to projects like ITER. SPARC is a version of a compact tokamak using advances in high temperature superconductors - thus, 'better'.
A different way is to propose something completely different than what has been done before. Then, if it is cheap enough, people may be willing to take a chance on it. This is what I did. However, it needs to be different enough to not be easily dismissable as having the same problems as an earlier design. For example, if you are doing a mirror design, you better have a good answer for fixing the ends.
One thing that often gets overlooked when talking about cheaper fusion designs is speed. Big projects like ITER take a long time to build, and then a lot of experiments get done on them, taking more years, because you need to get your money's worth from them. Smaller designs get the knowledge gains out of the design much faster. Robert Hirsch has been trying to bring this to our collective attention ever since he converted from a tokamak proponent to opponent decades ago.
My answers to the questions in the video are:
Fuel: D-D
Temperature target: 15kev
Confinement: hopefully approaching ideal at small ion counts. (penning traps are very good at trapping particles for long periods of time)
Instabilities: unknown but probable at high ion counts. I know there will be challenges to solve, but hopefully they are not fatal problems.
I believe the first prototype could achieve Q>1
And so if SPARC does end up working you will have member companies who are well placed to capitalise on it.
I don't get why you're being downvoted. If not for massive RnD investment none of the technologies we are using now to send and read bits to each other would have ever been invented.
(/sarcasm)
The conductivity of the molten salt is low, so JxB forces will be low. But this means there will be a voltage drop across the salt as it flows in the magnetic field. On one side of that circuit, there will be energy available to oxidize the metal past which the salt is flowing.
Now, from what I see, they're keeping the flow rate low enough that they don't produce elemental fluorine on that side. But there's still a voltage there, and the corrosive behavior of FLiBe hasn't been tested, as far as I know, in systems with that extra bit of energy available (nor with that extra energy + strong neutron radiation).
> ITER was designed before the newest generations of superconductors were available. ITER is now succumbing to the escalation of commitment that sunk-costs engender. SPARK [sic] has the advantage of an agile development model and new materials and technology that combined, dramatically shortens the path to breakeven and the reduction in costs to do so.
Just imagine where we'd be if fusion science were given equal footing with other investment endeavors.
Yes, be careful what you wish for.
[0] https://www.cnbc.com/2018/02/07/united-states-will-be-a-net-...
Initial production after fracking is high, but drops off fast.
it is unknown! but we certainly shouldn't make long term 10-20-50 year plans on the assumption that the USA will be energy independent due to oil.
Because you don't want your only options for dealing with other countries to be "do nothing" and "start a nuclear war".
What if the invaders are non-nuclear armed?
There is a wide range of responses between nothing and total nuclear annihilation, even without world police status.
You deliver an ultimatum, wait for the invader to withdraw. If they call your bluff, you level them. Just a city at a time if they don't have nukes. Wholly if they do. I mean if your going to rely on a nuclear self defense, when someone attacks you, you have to be willing to use it.
Now let's say you don't have conventional weapons.
China invades all South East Asia progressively. Would you nuke them? Russia invades Eastern Europe. Would you nuke them? If yes why hasn't the US nuked Russia yet?
Then all your allies suddenly switch side after being overthrown by dictators who are in favor of your enemies. Would you nuke them?
Another one: you are terrorists associations preparing attacks against you in camps all across middle east. Who do you nuke to defend yourself?
Conventional weapons are actually the only useful tools nowadays, because war is much more sneaky than it used to be, and it is much more about fighting for influence than really invading countries or defending you territory.
On the other hand let's say all had the bomb but are reluctant to use it. The nation's fight it out with conventional weaponry until the axis powers, realizing they have lost and with invasion in progress finally feel they have no other choice and commit mutually assured destruction. I think it would be hard to claim that wouldn't have happened given the temperament of some of their leaders. Perhaps in this case the allies would have showed restraint and not invaded to end the war - perhaps they would have been willing to negotiate terms.
I think basically my idea is a terrible one. But I also think the world war II scenario would end in nuclear exchange - the only way to avoid that is not push any power to the point of last resort, and negotiate an unsatisfying agreement that leaves the aggressors in power, no matter what horrible things they do. Would all have shown such restraint, would cooler heads have prevailed amid the terrible atrocities of total war? I'm not particularly optimistic of the chances.
Sometimes doing nothing is the best response. I didn't say it never was. I just said you don't want that or nuclear war to be your only options.
> What business is of the US what happens in the rest of the world?
Do you use anything not made in the US? If you do, then you care what happens in the rest of the world. Even if you personally don't, enough other people in the US do that you need to care what happens in the rest of the world, because you depend on those other people in the US and they use things from the rest of the world. The world is highly interconnected.
I think this was addressed quite well 32 years ago -- when everybody was thinking a lot harder about it due to the Cold War -- by the wonderful British comedy series "Yes, Minister":
https://www.youtube.com/watch?v=6Y-yyaWCgiQ
I considered a TLDW, but I don't think I can do it justice.
In any given encounter, they'll steal a minority of your stuff unopposed, and you'll refrain from the murder-suicide button because staying alive with majority of your stuff is still a better outcome for you.
The pattern will continue until someone acts irrationally and then you've got a lot of people dead for reasons that have more to do with pride than logic.
The big money holders only think about incrementing some integers in their bank account. Yeah, yeah, I know why. It's just so... lame. Build a moon colony! Cure cancer! Create free energy! Make experimental cities! Push the limits of human civilization! No, let's instead dump the fruits of society into optimizing ads and making our phones 20 microns thinner and bombing some poor people.
- It is not viable yet, and probably won't be for decades, if at all
- Funding necessary to explore fusion energy's viability is at least order of magnitude $10^10
- The 'steady-state' economics of fusion energy, should it become viable, cannot presently be estimated with any real fidelity
Not only will each commercial reactor, should anybody attempt one, be extremely complex and therefore non-robust, but there's still the issue of neutron contamination, making the whole thing brittle and ready for the nuclear waste disposal team to rip out most of it in a few years time.
Production systems would likely have much higher gas contamination for example and operate at a steady state for months.
Also, ITER is actually rather small from a power production standpoint, 500MW thermal power ~= 150MW of electricity where we have plenty of fusion reactors several times that size. Luckily things get much easier when you scale fusion power.
As you scale up the power of a fusion reactor, the volumetric power density goes DOWN. This is because it becomes limited by the power/area through the first wall. Square/cube law in action.
ITER has full remote handling as it's expected to get extremely radioactive. Scaling reactors up does not really mean increasing the neutron load on the walls as you want to keep that fairly steady per surface area.
Tritium production has ~zero impact on operation. The breeding blankets are really simple, you take lithium and enclose it in a metal of some type. Replace after a few months.
Also, a ~10x device is unlikely to be 50-50 DT as while hard to operate on pure DD fusion it's not that hard to get when you have some tritium in the mix.
It's not designed to replace everything, but I doubt commercial designs would go that far either.
They've already tested joints in the REBCO tape, and found that they introduce very little electrical resistance.
These failings have been known for 35 years or more, and yet still they're largely ignored. If there is a thing called "pathological technology" (in analogy with pathological science) then fusion must qualify.
That's only 10 billion dollars. Far more than that has already been spent on fusion.
Are you asking where the energy comes from?
Fusion is simply a reaction in which a higher amount of the mass of the involved matter is transformed to energy.
In a fusion reaction, we're supplying the fuel (Deuterium/Tritium/Helium instead of wood) and the spark (electromagnetic/laser instead of fire) to provide enough energy for the fuel to sustain an ongoing energetic reaction. The primary difference is instead of the fuel disassembling due to the reaction (carbon chains in the wood combining with oxygen to form heat, CO2, ash and H2O), in a fusion reaction the energy is used to combine two molecules (usually two isotopes of hydrogen combining to make a single helium atom with excess energy/heat).
The total mass of the (new) heavy thing is a little bit less than the total mass of the (original) two light things. There is some missing mass!
That missing mass is converted into energy in the process. The oft-quoted formula is: E = m * c^2 ('E' is the energy, 'm' is that missing mass, 'c' is the speed of light[+++])
This happens naturally in the sun (and other stars). It happens artificially in hydrogen bombs. Making it happen artificially in ways that let people harness the energy (and aren't just explosions) is the hard part, which is why the article is interesting.
+atomic nuclei, typically isotopes of hydrogen and helium
++hence "fusion"
+++in a vacuum
There is a relationship between mass and the speed of light that people may or may not know about. As you accelerate a particle towards the speed of light, the mass actually increases. Since the mass increases, it's harder to accelerate, which means that you need more energy to make it go faster. To get it to the speed of light you would need infinite energy and it would have infinite mass.
We can also rewrite the equation as c = sqrt(E/m). In other words, the speed of light is determined from the ratio of energy to mass in the system. When looked at from this perspective, it's not really that surprising that the ratio of energy to mass is a constant. What's kind of surprising is that this constant is the speed of light. Even just trying to figure out how the units might work is a bit mind bending -- m/s = sqrt(g/J)
I think this is where you start to understand that the concept of space, time, energy and mass are all intertwined. We kind of think of them as separate things because from our macro perspective, that's how they look. Under the hood, though, they are all intricately bound together. The consequences of special relativity (where this equation came from) is that space, time, and mass are functions of energy, which is both super cool and super confusing :-)
I can't think of a concise/non-technical explanation. This Feynman lecture is about as close as you'll get: http://www.feynmanlectures.caltech.edu/I_15.html
If you trade away all the time, you get a maximum velocity: c. So the things moving at c don't experience time, and have momentum but not mass.
http://www.math.ucr.edu/home/baez/physics/ParticleAndNuclear...
In the same direction, if you take a mass and accelerate it, it experiences less time. There you have relativistic time dilation, as beloved by science fiction stories.
https://en.wikipedia.org/wiki/Time_dilation
And you simultaneously get length contraction in the direction of each velocity:
https://en.wikipedia.org/wiki/Length_contraction
These are all aspects of the same thing.
Really not a dumb question at all.
For historical reasons we measure time and space using different units (seconds and meters in SI) but phisically space and time ought to be measured with the same unit. It is possible to construct such a measurement system, indeed many of them, known as natural units[1]. In natural units, c, i.e the ratio between the space and time unit, would be simply be set to dimensionless 1. In such a measurement system the E=mc^2 equation simply reduces to E=m i.e. each unit of max correspond to one unit of energy.
E=mc^2 cosh(eta)
where eta is the velocity parameter. https://en.wikipedia.org/wiki/Proper_velocity
In terms of the coordinate velocity v,
E=mc^2 cosh(atanh(v/c))=mc^2 / sqrt(1-(v/c)^2) = mc^2 (1 + 1/2 (v/c)^2 + 3/8 (v/c)^4 + ...
So mc^2 is the irreducible energy due to mass and isn't relevant at low speeds because it doesn't change; the first-order approximation of kinetic energy is just 1/2 mv^2 and higher order terms aren't significant at low speeds.
It turns out elements lighter than Iron release energy when they combine (fusion), and elements heavier than Iron release it when they split (fission). So for any element, it only releases energy as it gets closer to becoming Iron. https://en.wikipedia.org/wiki/Iron_peak
Or something along that line, anyway.
Fusion is a well known phenomena.
http://hyperphysics.phy-astr.gsu.edu/hbase/NucEne/nucbin.htm...
This means when talking about tiny nuclei (hydrogen and helium), moving to a bigger nucleus (fusion) takes you to lower energy (more stable) state and releases energy.
But when you're talking huge nuclei, it's the opposite, and moving to a smaller nucleus takes you to a lower energy state and releases energy.
Yeah, solar panels.