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This topic is inspired by an observation of Calliban, that fusion (when it is achieved) will be able to produce Tritium in abundance.
Tritium appears to be a useful material for safely delivering heat and small amounts of electricity to billions of Earth citizens, as an alternative to fossil fuel.
The first post in this new topic will be a copy of a post by Calliban in the Fission topic for Tritium production.
(th)
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The following is a quote from the Fission topic devoted to production of Tritium for the home heating and power market.
I note that this post is about consumption of Tritium, so some adjustment is needed, to adapt the post to this new topic.
TH, world lithium mining is over 100,000 tonnes of metal per year.
https://www.reuters.com/markets/commodi … 023-04-21/A 1GWe fusion reactor, will consume ~60kg tritium per year, requiring some 120kg of lithium. If we powered the entire world in this way, it would consume <1% of lithium mined at present. And in a fusion-fission hybrid system, the fusion reaction is providing the neutrons rather than the energy itself. So we don't need anywhere near 1% of present lithium mining to power the world in this way. Lithium is not a limited resource as a nuclear fuel. It is in short supply because idiots need megatonnes of the stuff to produce batteries. But in fusion reactors, a few hundred tonnes a year woukd power the world!
(th)
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I think excess tritium breeding would only work in a fusion-fission hybrid system. A pure fusion system doesn't have enough spare neutrons for this sort of scheme to work. Within a hybrid system, we surround the fusion reaction chamber with rods containing uranium-zirconium alloy. The fast 14-MeV neutrons produced by each fusion reaction will fast-fission the uranium, producing up to five additional neutrons. Some of these will cause secondary fission, but most will be absorbed by uranium-238, which decays into Pu-239. So for each fusion event that takes place, we can expect to generate 10x more power from direct fission and perhaps 4 Pu-239 atoms with which to make nuclear fuel. So for each 17.6MeV of fusion energy we get ~200MeV of direct fission energy yield and enough plutonium to yield 800MeV in downstream reactors.
If plutonium is burned in lithium cooled fast reactors, each fission will yield ~3 neutrons. So four plutonium atoms will yield a total of 12 neutrons, some four of which are used to sustain fission. The other eight are available to support tritium breeding in the lithium coolant. If all of them are absorbed in lithium 6 or lithium 7, we get 8 tritium atoms from each initial fusion event. At least one tritium atom is needed to keep the fusion reaction going. But a maximum of seven additional couod be available for other uses. Due to neutron losses and tritium decay, we can expect lower yields than this. But the overall multiplication could still be substantial.
Last edited by Calliban (2024-01-03 12:40:05)
"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."
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For Calliban re #3
Thank you for taking up the opportunity this new topic offers ...
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(th)
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We have three topics that contain "tritium" in the title:
Tritium to Helium-3 Nuclear Battery by tahanson43206
Science, Technology, and Astronomy 20 2024-01-31 19:09:13 by SpaceNut
Fission Reactor Design to produce Tritium via Desalination Market by tahanson43206
Science, Technology, and Astronomy 17 2024-01-31 06:33:06 by Calliban
Fusion Reactor Design: Produce Tritium - Global Energy Storage Market by tahanson43206
Science, Technology, and Astronomy 3 2024-01-03 15:17:28 by tahanson43206
The method of production of Tritium that has come into view in May of 2024, is treatment of Thorium with a particle accelerator.
Thus, the process would consume Thorium and produce Tritium, and (if I understand the process correctly) it would cover it's own energy costs.
In short, (again if I understand the process which is NOT guaranteed) we would be transmuting a material of limited value into a product with great value, and having to add NO fossil fuel to achieve the objective.
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Yes, it could work. The most obvious way would be to use 233U as a spallation target. That way you get at least one fission even in the target, per spallation neutron. The secondary fission neutrons would them breed enough 233U in a surrounding thorium blanket, to replace the atoms fissioned in the spallation target. This gives us somewhere between 1 and 2 spare neutrons that can be used to breed tritium. The easiest way of doing this is to use molten lithium to cool the spallation target and thorium blanket. The facility should generate twice as much power as needed to run the accelerator, with the balance being sold to the grid. The tritium would be a byproduct. You can tweak the design to produce more power or more tritium by adjusting the volume fraction of coolant and fuel.
Last edited by Calliban (2024-05-28 07:30:59)
"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."
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For Calliban re #6
Thank you for taking another look at the transmutation idea.... I get the impression that substituting 233U as the target for the particle beam would improve performance of the system. The tritium I am looking for would be the deliverable. The ability of the system to pay for itself is a nice surprise.
However, I am wondering about the abundance of 233U compared to 238U and 235U.
I asked Google and learned about 234U which I did not realize is a naturally occurring isotope.
Google quickly explained that 233U is produced from Thorium 232
OK ... multiple steps are involved, but Thorium is the key ingredient.
I'm now wondering how much Tritium is produced per unit of Thorium?
Are there other daughter products that are useful, or on the other hand, worrisome?
Is it possible to imagine a mass production facility on Earth that yields many tons of Tritium?
Tritium is, as pointed out in other (related) topics, and potentially benign energy delivery device for the mass market.
(th)
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Each fission event produces 2.5 neutrons. At least one neutron is needed to transmute another 232Th atom into 233U. Of the 1.5 neutrons remaining, a proportion will cause another fission within the 233U. Others will leak out into the blanket. So in a well designed system you could get up to 2 atoms of tritium for each thorium atom transmuted into 233U and fissioned. Using a plutonium or other heavy actinide spallation target may give you even better results, as these nuclides will produce more neutrons when they fission.
Tritium is indeed a potentially valuable product of this process. For all the hype around aneutronic fusion, tritium is a lot more useful than He-3 precisely because it does produce high energy neutrons. Those neutrons can be used for a lot of things, like driving fast-fission or transmuting one element into another. This makes tritium a much more valuable product than He-3. As you have probably realised by now, the rate at which we can produce transmutation products using nuclear reactions is constrained by the number of spare neutrons we are able to generate.
Last edited by Calliban (2024-05-28 08:10:26)
"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."
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For Calliban re #8 ... thanks for this post on Thorium and Tritium...
This post is about a detail of how to (potentially) collect Tritium if it is ever produced in volume by a fusion reactor....
https://www.yahoo.com/tech/startup-deve … 00612.html
Startup develops promising solution to one of the biggest obstacles in harnessing energy from nuclear fusion — here's how it works
Katie Dupere
Sun, August 18, 2024 at 5:00 AM EDT·4 min read
14You might have learned about nuclear fusion in high school science class; it's the energy-releasing reaction that powers the sun. For a long time, scientists have worked to harness nuclear fusion as an essentially limitless energy source. The hope is to create sustainable nuclear fusion plants around the globe, making polluting dirty energy a thing of the past.
While it sounds like a stellar idea, there are a lot of hurdles to making the theoretical concept a reality. But a new startup has a promising potential solution to one of nuclear fusion's biggest commercial barriers.
Marathon Fusion is refining a process that purifies tritium, a rare hydrogen isotope essential for most nuclear fusion concepts. Fusion reactors generally run on tritium and another hydrogen isotope, deuterium. While deuterium is abundantly found in seawater, tritium is exceedingly rare. And you can't have nuclear fusion without the isotopes needed to cause the reaction.
"There's only 20 kilograms [about 44 pounds] of tritium anywhere in the world right now," Kyle Schiller, CEO of Marathon Fusion, told TechCrunch.
The news outlet reported that the current global supply of tritium is created as a waste byproduct of nuclear plants running on fission, which splits a heavy element with a high atomic mass number into fragments. To date, there are only about 440 nuclear fission reactors around the world, providing about 9% of the planet's electricity, according to the World Nuclear Association.
To merely start operations, a single fusion power plant would likely require a few kilograms of tritium — then it would have to produce more tritium to both power itself and future reactors, as TechCrunch explained.
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"Deployment of fusion devices is this doubling process," Adam Rutkowski, Marathon Fusion's chief technology officer, said in the TechCrunch report. "You're breeding enough tritium to maintain the steady state consumption by the device, but you also need to breed excess tritium to start up the next reactor."To help with this "doubling process," Marathon Fusion is working to refine the capabilities of superpermeation, a roughly 40-year-old technology that uses solid metal to filter impurities from hydrogen. The startup hopes to use the process to filter out tritium for use in fusion reactions.
To understand how this all works, it's helpful to have a basic understanding of nuclear fusion.
Per the U.S. Department of Energy, nuclear fusion occurs when "two light nuclei merge to form a single heavier nucleus." Fusion happens when — in a common example — tritium and deuterium merge to form helium, as the International Atomic Energy Agency explains. The reaction releases energy because the total mass of the helium nucleus is less than the mass of the two original lighter nuclei. In this process, a single neutron is also released — and that single neutron is key to creating more tritium.
As TechCrunch explained, to create more tritium in a fusion reactor, neutrons released during fusion will strike "a blanket of lithium," with the impact releasing more helium and tritium. Some of this created tritium will be injected back into the reactor to cause more nuclear reactions while the rest will be reserved as fuel starting other reactors. But before this can happen, the tritium needs to be filtered out from the reactor.
Existing equipment can do this filtering but only for experimental work. Running a reactor for a longer period of time on a commercial scale requires much more finesse. To make that commercial-level refinement a reality, Marathon Fusion is banking on superpermeation.
In overly simplified terms, superpermeation turns hydrogen and everything else needing filtering into a plasma. That plasma is then pressed up against a metal membrane, per TechCrunch, which allows only the hydrogen — including tritium — to pass through while blocking everything else. The result: Tritium is created and isolated for further fusion reactions.
Marathon Fusion has received early support from the Department of Energy and the Breakthrough Energy Fellows program. Now going public with its work, Marathon Fusion recently raised a $5.9 million seed round, the company exclusively told TechCrunch.
While all of this may sound promising, there are still barriers to harnessing nuclear fusion for limitless power. A lot of the process is currently still theoretical, working in labs in the short term but not viable in the long term commercially.
That's because current projects currently take more power to run than they create, requiring a huge amount of heat and pressure to cause a reaction. Only a few fusion projects have ever hit "breakeven," creating as much power as the process needs to run — or very limited and brief "ignition," outputting more energy than was put in to start the process.
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I am interested in mass production of Tritium for a nuclear battery, as described in another topic.
We appear to be a long way from mass production of Tritium, but on the other hand, the prospects seem to look favorable for continued progress in that direction.
(th)
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Uhhhhh... breed tritium from lithium? Fission (splitting atoms) produces energy with extremely heavy atoms such as uranium or plutonium. The lighter the element, the less energy. You can't get energy from anything lighter than lead. Fusion (combining atoms) produces energy with extremely light atoms such as hydrogen. The heavier the element, the less energy. You can't get energy from anything heavier than iron. So between iron and lead is the "dead" zone. Making elements in the dead zone is only possible by adding energy. For example, a star may fuse deuterium (²H) with Tritium (³H) to become an alpha particle (high speed nucleus of helium, ⁴He), releasing one neutron. That neutron could hit iron-58 (⁵⁸Fe) to become ⁵⁹Fe. That isn't stable, it will decay with a half-life of 44.51 days by releasing a beta particle (high speed electron). When a neutron releases a beta particle, it becomes a proton. So ⁵⁹Fe → ⁵⁹Co (cobalt) + β⁻. That is the stable isotope of cobalt, so not radioactive.
The way to breed tritium is from deuterium. A heavy water fission reactor uses uranium as fuel. Heavy water is both coolant and moderator to slow neutrons to the correct speed to be absorbed by another uranium atom. So if the reactor loses coolant, that removes the moderator. Without the moderator the nuclear reaction slows down and stops. So a melt-down is very difficult, almost impossible. It's a safety feature. Heavy water uses deuterium oxide (D₂O) instead of H₂O. Deuterium (D) is also know has hydrogen-2 (²H). While normal hydrogen has just one proton, deuterium has one proton and one neutron. Since heavy water is itself the moderator, it will be exposed to moderated neutrons. If a moderated neutron hits deuterium just right, it is absorbed. This turns deuterium into tritium (²H + n → ³H).
Canada's CanDU reactor uses non-enriched uranium, and it's a heavy water reactor. The name means CANada Deuterium Uranium. Uranium must be refined from ore, but isotopes are the same balance as the uranium comes out of the ground. Uranium enrichment is expensive, so this reduces cost to operate the reactor. But mostly, it means a country can operate a nuclear reactor without technology necessary to make a nuclear weapon. No enrichment, no bomb. Well... that was the idea. It turns out that it is the world's most efficient producer of tritium. Oops!
0.0115% of hydrogen atoms on Earth are deuterium. That's one part in 8,695.652. Since water has 2 hydrogen atoms (H₂O), chances are one molecule in 4,347.826 has a single deuterium atom. So deuterium can be extracted from water. This is true for every drop of water on Earth.
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For RobertDyck re interesting post about pre-fusion technology....
Fusion does not exist on Earth(*), so the only way to make tritium is by using fission reactors.
After fusion succeeds (assuming it ** ever ** succeeds) fission reactors will be dropped like the ancient pre-cursor technology they are.
Obviously fusion reactors will not involve heavy atoms in any way, shape or form, except possibly as part of the structure, so there will be no fission happening.
Your description of ancient technology is accurate as far as i can see, but (of course) that is NOT the point of the article.
Making Tritium from Lithium appears to be easier than making Tritium from Deuterium in a fusion reactor. As the article tries to explain (obviously without universal success) the problem for fusion plant operators will be how to pull the Tritium out of the plasma they will (hopefully) be producing.
(th)
(*) discounting research reactors, which are far from breakeven.
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Deuterium-Tritium: ²H + ³H → ⁴He + n + 17.59 MeV
Deuterium-Helium3: ²H + ³He → ⁴He + p + 18.3 MeV
Deuterium-Deuterium, 50% of the time: ²H + ²H → ³He + n + 3.27 MeV
other 50%: ²H + ²H → ³H + p + 4.03 MeV
Temperature to initiate fusion. D-T is lowest, then D-He3, highest is D-D. Image from Wikipedia...
The fusion reaction rate increases rapidly with temperature until it maximizes and then gradually drops off. The deuterium-tritium (D-T) fusion rate peaks at a lower temperature (about 70 keV, or 800 million kelvin) and at a higher value than other reactions commonly considered for fusion energy.
Note: byproduct of double-deuterium fusion is inputs to the other two. In a nuclear fusion reactor with sufficient temperature to initiate double-deuterium fusion, all 3 reactions will occur at the same time. So all the reactor needs is deuterium, and most of the energy comes from secondary reactions.
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