evilgenius wrote:Fusion is the answer. It is also nuclear. It just doesn't, for power generation purposes, come with any waste problems.
I was thinking, though, that humanity will go beyond power generation. Being able to make a working fusion reactor for energy purposes will be one thing. Then they will discover that they can make them for other things too.
They will be able to make things. They will be able to make anything, from basic building blocks. Discovering fusion reaction will begin something more. Things like lithium, which might be otherwise mined, could be made. It's a lighter element, so you might think it would be easier to make?
I'm, obviously, not thinking about any of the constraints upon being able to do this. How big would an actual factory that made lithium be? Would it have to exist in space? If so, would the tradeoff allow for the expense of the transportation of the new materials to earth, and still leave room for companies to make a profit? You can certainly see them pulling it off in conjunction with a space elevator.
The real challenge might become one of how to distribute the profits? That is to say, what a society that could do those things ought to look like, presuming it had avoided slipping back into barbarism while, yet, having that sort of technology. I think history teaches us that sort of thing is possible. As long as we are dreaming, we might as well dream big, and imagine the best sort of world, including how we might better share the wealth.
I think we could find ways that honored some people's 'go getter' attitudes toward life. We need those people, just like we need everybody else. An economy needs everybody. It has a sort of mechanics. It is driven by activities that people join in, that cause them to spend money. The size of the money supply is dependent, largely, upon the relative view that people take over the cost of money vs. what it means not to participate. Emotionally, though, people love to participate. When it comes to assigning importance, if we understand how important emotion is, then we know the masses are important. We want to see ourselves, in most ways, as standing out from everyone else, but also as fitting in, in essential ways.
People weigh how much they are willing to borrow, in order to engage in the economy. The money supply is connected to that level of borrowing for business, and that for real estate. Both causes weigh upon the result. It's good, to keep things in perspective, to consider the effect that things like monetary policy would still have in a world like that because more people might actually participate in such a way where costs were more important to them than they are today.
When the cost of employing people is no longer the fulcrum, it will be tempting to find another, that is to say. What the people collectively see as important will always drive the borrowing activity around which people engage the economy. Housing is just the main thing that people can agree upon is basically important. If we escape barbarism, you have to wonder what else man will come up with to redefine what he does with his time, with what he considers important?
I moved your post over to the Fusion thread to avoid derailing the Fission topic before answering.
As I pointed out in response to another of your posts on this energy source Fusion is NOT waste free. It like Fission is relatively low waste for the quantity of energy it can potentially supply but low wast is not no waste and I would appreciate it if you accepted that reality before you draw perfect scenarios.
Secondly, Lithium is a fusion fuel in its own right. The original reason we explored for Lithium minerals and started developing extraction techniques is for use in nuclear explosives. Lithium-6+Hydrogen-2 aka Lithium Deuteride is the fusion fuel for hydrogen bombs. Lithium Deuteride is also the fusion fuel for use in laser confinement fusion reactors.
Thirdly, the fusion reactors we have are still a long way from "unity" which is the point when they produce at least as much energy as they consume in the process. Yes the media has glowing stories every few months to few years about breakthroughs an advances but in the last 70 years this has been the consistent pattern of unscientific non-mathematically gifted reporters trying to explain fusion to the lay public. In simple terms fusion is very hard to achieve in a controlled harnessable fashion. You have to create an environment in your media of Lithium Deuteride or Tritium Deuterium plasma (depending on which approach you use) where temperatures and pressure resemble the core of a Red Dwarf star or higher. A red dwarf is the smallest type of self sustaining star and in even that case the pressures and temperatures needed to enable the basic fusion process are out of the imagination of most humans big.
In an H-bomb you use a small fission bomb to generate the heat and pressure to ignite the fusion fuel. There were even proposals back in the 1950's and 1960's to drill a very deep well and set off an H-bomb at very great depth which would trap all the generated heat in the form of a pocket of artificial magma. Then more wells would be drilled down to extract the trapped heat in a kind of artificially powered geothermal heat source. When the magma insulated by the surrounding rock cooled off too much to provide geothermal heat you would drill a new well down to the center of the pocket and set off a new H-bomb to remelt the magma restoring its usefulness as a geothermal powerplant heat source. These schemes were never put into practice because it would have cost more for the drilling and H-bombs needed than the energy provided by the geothermal power plant could ever pay back.
So far right up to 2022 every attempt at producing usable energy from hydrogen fusion has had the same economic problem. The energy you put in, so far, has always exceeded the energy you get back out. Once upon a time I was very optimistic that scientists would figure out a way to do fusion in an energy positive fashion. Unfortunately the two methods currently under testing/development are the same methods being tested in 1985. What this means is no breakthrough new law of physics has arrived to permit useful energy extraction from fusion. The plant currently being built as a minimum scale test unit is based on the Tokamak system originally proposed almost 60 years ago in Russia which is why it has a name English speakers find mysterious. In essence the plan is to use new warmer temperature superconducting magnets to produce the plasma bottle needed to sustain the fusion reaction for more than a fraction of a second. I wish them all the luck in the world because if they can make it work then in 15-20 years we might have fusion powered electricity. But that doesn't mean I think it will work because the math is just not supportive of it. Sure you might power up for a few seconds, but you have to extract the excess energy from the system at a very precisely balanced rate so that the plasma stays in the range where the reaction can continue without the reaction rate climbing too high and melting your magnetic confinement system.
One proposed system for doing this is to have the plasma itself act as both reaction mass and coolant by circling around a torus, a magnetic bottle shaped like a ring doughnut. Over most of the circle the plasma is inside a cooling jacket that picks up the excess energy and in one very small section the jacket system is replaced with extra superconducting magnets that pulse to squeeze the plasma tighter in that spot causing a flash of fusion then relaxing so the plasma spreads the heat away from the magnets into the jacket with the pulses timed to control the rate of fusion and rate of energy extraction in the cooling jacket.
The cooling jacket has a working fluid which can be helium gas, nitrogen gas, water, or molten salt. The fluid is circulated out to a generation system that can be many option depending on the fluid and can be direct or indirect. Direct means the working fluid is used in the generator like a Boiling Water Reactor system, indirect means the working fluid is used to heat a second loop like the system in a Pressurized Water Reactor.
Alternatives include technology like using helium as primary coolant heated up to plasma temperatures by the fusion bottle being sent through a Mageto-Hydro-Dynamic energy extraction system but that requires a bunch more superconducting magnets to guide and contain the Helium plasma. Most Molten Salt systems I have seen use two extraction systems working in series, first an inert gas is passed through the salt heat exchanger and then fed through a standard gas turbine generator in a Brayton cycle, then the still hot gas is passed through a second heat exchanger to vaporize water into steam to run a steam turbine generator before being passed back through the molten salt heat exchanger in a complex loop arrangement. When using molten salt you can get the heat way up to around 900 C in the salt loop but you need to keep it up around 650 C at the end of the gas heat exchanger so it stays very fluid and is easy to return to the cooling jacket.
Anyhow your plans to make Lithium which is element 3 are fordoomed by its abundance on Earth and the fact that it is a fusion fuel for laser confinement fusion which I personally think is a much better system than the plasma torus approach currently getting major funding.
Lithium is the 33rd most abundant element in crustal rock. That makes it more common than Lead the 36th, Argon the 44th, or Tungsten the 56th all of which are used all over the place in hundreds of everyday items. Well if you still have any old fashion light bulbs or tool steel quality drill bits. Gold is 29th but for emotional reasons much more expensive than the rarer Lead, Argon or Tungsten.
In laser confinement fusion a tiny bead of fusion fuel, which in different experiments has used Deuterium gas, Deuterium-Tritium gas and Lithium-6 Deuteride or even Lithium-7 Hydride, works by dropping the bead down a tube and when it gets to the reaction spot multiple lasers focused on the spot from different direction pulse on crushing the bead from all directions heating it and confining it for a few nanoseconds. The heat and crushing ignite the mass into a fusion reaction that ends almost as quickly as it starts because the fuel is in a very small bead that is quickly consumed. The resulting plasma spread out contacting the sides of the tube which are another cooling jacket just like the one used in the plasma torus fusion concept but the tube is much smaller and the pulse is very brief. To generate steady energy flow beads are dropped once ever second or so resulting in energy pulses as each is consumed in a tiny fusion reaction and a good quality pump system is use pull the condensed plasma out of the tube after each pulse. The easiest way to do that is to have a low pressure tank attached to the fusion tubes with a valve that pulses in time with the lasers so that the plasma has time to expand transferring energy and then being extracted as reaction products and unconsumed fuel. Depending on the choice of fusion fuel consumed in the pulses the reaction products will be Helium-3, Helium-4 and the reactants will be Deuterium, Tritium and Lithium.
It has been proposed that such a system might be fueled by Boron-11 Hydride resulting in Carbon-12 plasma. The goal of Boron Hydride fusion is to avoid producing free neutrons which are not trapped by the magnet confinement system and therefore cause neutron activated radioactive isotopes in the fusion chamber materials. This gets us back to my statement that fusion produces waste, the proponents just do their best to not talk about it leading people like yourself to the false conclusion that it is a waste free energy system. The truth is no reaction using Deuterium-Tritium-Lithium is perfect. Ideally you react Lithium Deuteride and the fusion products are two atoms of Helium plasma, two Alpha particles, with no free neutrons. However when you use Lithium-6 Deuteride as your fuel inevitable a moderate percentage of the Deuterium reacts with other Deuterium instead of with the Lithium. This leaves the Lithium-6 in the plasma exhaust where it can be recovered and recycled but the issue is Deuterium-Deuterium fusion has three potential end products. Ideally you get an alpha particle, an ionize Helium nucleus just like you get from the Lithium Deuteride reaction, but this is the rarest of the three results. The vast majority of the reactions split up nearly half and half with Tritium and a free Proton being one reaction and Helium-3 and a free neutron being the other possible reaction. That Helium-3 free neutron reaction is where the trouble comes from because those free neutrons fly out with high energy and a 15 minute half life. Free neutrons at high energy will interact with many other atoms as they travel losing energy and they often get absorbed in structural materials making them into radioactive isotopes. With a half life of 15 minutes that means an hour after they are formed there are still about 8% of those free neutrons flying around able to activate structural materials. Once they decay into Hydroden-1 plasma they quickly bind chemically to other materials like Oxygen or Nitrogen in the air. But it is two hours after shutdown of a fusion reactor before they have gone through eight decay cycles and you can confidently say the free neutron population is approaching zero. To an extent the same s true of a fission reactor but everyone knows they are radioactive, they just do not realize fusion reactors are also radioactive and produce neutron activated structural materials the same way.
Other fusion fuel choices are also likely to release neutrons. Deuterium-Tritium fuel results in some D+D reactions as discussed above. They also produce D+T reaction which usually produce a Helium-4 aka Alpha particle and and one free neutron. The mixture also produced T+T reactions with several outcomes, you can get Helium-4 and two free neutrons, (rarely) Helium-3 with three free neutrons, or occasionally a Deuterium nucleus and a Hydrogen-4 nucleus that quickly ejects the extra neutron returning to Tritium and a free neutron. The conclusion is most of these reactions result in free neutrons.
I mentioned earlier the possibility of Lithium-7 Hydride as a fuel and this is sort of my preferred fuel. Lithium-7 is the more abundant isotope and when you fuse Lithium-7 and Hydrogen you get Beryllium-8 which immediately splits into two Helium-4 or Alpha particles. The chances of free neutrons from this combination is very much lower because P-P fusion rarely occurs and when it does the resulting Helium-2 decays into Deuterium with no free neutrons. The Lithium-7 is unlikely to fuse with itself because that requires very high energy and occasionally a Lithium-7 Hydride fusion will result in a Helium-4+Helium-3+Free neutron or Helium-4+Tritium+Free Proton but those reactions are less common than the two Alpha reaction. Boron-11 Hydride fusion is like the Lithium-7 Hydride reaction in that the Boron is unlikely to fuse with itself as it needs even higher energy than the Lithium to self fuse and the Protons of hydrogen rarely fuse and when they do the result is new Deuterium. The Carbon-12 end product is possible to fuse with the freed Protons resulting in Nitrogen-13 with a half life under ten minutes decays quickly into Carbon-13 which is stable and safe as well.
So I hope this clears up your mistaken impression about Fusion being waste free. The activated structural materials will need a long delay time in decommissioning for exactly the same reason fission power stations do, neutron activated materials are radioactive and depending on the materials the half lives can be moderately long usually requiring a 30 year pause in decommissioning of reactors in the USA and western nations.