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A faster, cheaper path to fusion energy
- xutopia 8y agoCan someone explain to me why fusion energy isn't violating the laws of physics?
- ianferrel 8y agoWhich laws do you think it violates? Are you asking where the energy comes from?
- simonebrunozzi 8y agoThe Sun emanates energy using fusion. Why should it violate the laws of physics?
- turbinerneiter 8y agoE=m*c^2 Fusion is simply a reaction in which a higher amount of the mass of the involved matter is transformed to energy.
- mikeyouse 8y agoThink of it like rubbing two sticks together to start a fire -- You need to put enough energy into a system to maintain the subsequent high-energy reaction. 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).
- gpderetta 8y agohttps://en.m.wikipedia.org/wiki/Activation_energy https://en.m.wikipedia.org/wiki/Activation_energy
- i_am_proteus 8y agoTwo light things[+] are fused[++] into one heavy thing[+] 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
- jimmcslim 8y agoProbably dumb question... and one I probably knew the answer to at some stage... why does the equation showing the conversion from mass to energy involve the constant of the speed of light?
- maxxxxx 8y agoE=mc2. The amount of energy in mass is determined by the speed of light. Not sure if I am phrasing this correctly...
- mikekchar 8y agoI wonder if it would be more understandable to say that m = E/c2. In other words what we think of as mass is really just a measure of energy bound up in particles. 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 :-)
- empath75 8y agoIt’s releasing energy contained within the mass of atomic nuclei
- cookingrobot 8y agoI used to be confused about how both fission and fusion can release energy. 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 https://en.wikipedia.org/wiki/Iron_peak
- Roboprog 8y agoThere’s a certain amount of irony (iron-y?) that heavy fissionable materials are formed when fusion stalls: the core of a large star is turned into iron, fusion “goes out”, then the star collapses and goes supernova. Heavier elements are formed in the “bounce” when the outer layers of the star crush down the suddenly cold(er) core, converting the kinetic energy into reactions that absorb energy by fusing heavy elements. Or something along that line, anyway.
- noetic_techy 8y agoDo you think the sun violates the laws of physics? Fusion is a well known phenomena. https://en.wikipedia.org/wiki/Nuclear_fusion https://en.wikipedia.org/wiki/Nuclear_fusion
- leephillips 8y agoIt doesn't; it only violates the laws of economics: https://progressive.org/op-eds/let-cut-our-losses-on-fusion-energy-180313/ https://progressive.org/op-eds/let-cut-our-losses-on-fusion-...
- adrianmonk 8y agoNot a physicist, but as I recall it's because the relevant curve describing energy states doesn't slope just one direction. It goes up and then down again: http://hyperphysics.phy-astr.gsu.edu/hbase/NucEne/nucbin.html#c2 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.
- heimdall 8y agoFrom the comments: > 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.
- tasty_freeze 8y agoThe US spends more than $850B every single year on the military. If a tiny fraction of that was spent in gaining complete energy independence, it would pay for itself in that we wouldn't need as big of a military.
- reubenswartz 8y agoA wonderful thought, but the size of the military budget is a feature, not a bug, for those who allocate it.
- jacobush 8y agoMaybe we can get the military industrial complex into the nuclear industrial complex instead? Though one must be careful what one is wishing for I guess.
- AnimalMuppet 8y agoFrom the "Schlock Mercenary" web comic: "Any sufficiently advanced technology is indistinguishable from a really big gun." Yes, be careful what you wish for.
- reubenswartz 8y agoFor the trillions we have flushed down the drain in the Middle East, we could have weaned ourselves off foreign oil with renewables, without even getting into nuclear. Sadly, it goes back to the “feature, not a big” thing. :(
- threeseed 8y agoWhat people forget about massive projects like ITER is that it is almost irrelevant whether it works or not. It is a highly technical construction project involving dozens of countries mostly in the EU. So the return on investment comes not just directly from increased economic activity but also from levelling up the skill of member companies. And so if SPARC does end up working you will have member companies who are well placed to capitalise on it.
- maxxxxx 8y agoI think it's pretty natural that first-mover projects quickly become obsolete. The problem with ITER, from what I know, is that it was set up in a very political way and is therefore years behind of where it could be if it had been run more efficiently.
- andygates 8y agoIt had leadership problems, but those have been corrected with the new boss. That's not a political problem per se, it's really just a "big project with a bad boss" problem.
- maxxxxx 8y agoThe boss may help but it's still a very complex setup from what I know. They have the same parts produced independently by different countries for example. That's good for knowledge transfer but probably not very efficient for being cost effective or quick.
- antt 8y agoUnix happened because Multics didn't. 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.
- maxxxxx 8y agoOften you need a clunky expensive version first so others can learn and do something better. I bet SpaceX couldn't do their rockets without all the expensive lessons NASA and others have learned before.
- opwieurposiu 8y agoThis talk explains the advantages of the new YBCO tape superconductors in a lot more detail. https://youtu.be/KkpqA8yG9T4 https://youtu.be/KkpqA8yG9T4
- zyxzevn 8y agoI think there is still the problem that very strong magnetic fields are causing "magnetic breaking".
- noetic_techy 8y agoI've seen the MIT lecture that presented this. Here are the main hurdles: 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 https://youtu.be/KkpqA8yG9T4
- gameswithgo 8y agoHow hard is it to make FLiBe?
- pfdietz 8y agoThe enriched 6Li in a single reactor would correspond to 1/4 of that produced for the entire US hydrogen bomb program. There is no facility in the world that could make the 6Li required, and the technology that was used in the US is now prohibited due to large leakag of elemental mercury into the environment (the plant used thousands of tons of liquid mercury metal.)
- MertsA 8y agoAs a neat coincidence, molten salt fueled fission reactors also need enriched Lithium. However, those need Lithium 7 which would essentially be the depleted Lithium from enriching Lithium 6.
- pfdietz 8y agoNo, MSRs do not necessarily need enriched lithium. For example, Moltex's fast MSR uses no lithium whatsoever. The (barren) coolant salt is zirconium sodium potassium fluoride, and the fuel salt (in tubes, where it does not mix with the coolant) is a mixture of sodium, zirconium, uranium, and plutonium chlorides, as well as fission products. 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.
- newnewpdro 8y ago> A faster, cheaper path to fusion energy Yeah, solar panels.
- naasking 8y agoAlternative approaches to fusion need to be explored, like focus fusion, polywell, ICF, etc. ITER and the like are great for physics and for the engineering challenges it presents that will likely be applicable elsewhere, but the complexity means it probably won't be viable as a generator for decades to come.
- pfdietz 8y agoAnother potential problem with this idea is enhanced corrosion by the molten salt flowing in the strong magnetic field. 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).