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Bloody Pom posted:Isn't one of the big hurdles with getting fusion off the ground dealing with the crazy amounts of neutron flux generated by D-T fusion, something like a hundred times that observed in fission reactors? Seems like it would make performing maintenance on the (now highly irradiated) reactor vessel an absolute nightmare. Each fission process releases a fast neutron that cannot be confined like the hot bulk plasma. These are most certainly capable of activating the reactor walls. The current favoured research is that you would blanket the inner walls of the reactor with Lithium which would capture the neutron and break down into Helium and Tritium, creating a continuous supply of the latter for further reactions. However, this still means that fusion power plants would generate radioactive waste. Although the decay time to safe levels is on the order of hundreds of years rather than hundreds of thousands for fission plant.
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Nov 4, 2022 09:23
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Phanatic posted:You cannot blanket the inner wall with lithium; lithium is completely mechanically incapable of acting as a plasma-facing component; it's a soft metal that melts at only slightly above the boiling point of water; the radiant energy alone coming off the plasma would vaporize your lithium blanket, sputter it all off into the plasma, and shut down the reaction. The idea is that you surround the reactor vessel itself, which is made out of something else entirely(*), with lithium, which absorbs neutrons and heat and melts and you circulate it as your coolant. The lithium would be fixed in something else. This is one of the aims of ITER to test the different blanket candidates; lithium enriched ceramics, alloys of lithium-metal, pebble bed etc. https://www.iter.org/newsline/-/2572
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Nov 9, 2022 18:05
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Liquid or gas hydrogen is definitely not an effective storage option due to the inherent low energy density and challenges in storage. Hydrogen is much better suited as a feedstock to produce something like methanol that is liquid at room temperature, utilizes captured carbon and is both safer and better understood for storage.
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Dec 1, 2022 17:10
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Figure out a way to weaponize a magnetically confined fusion device and we will have unlimited clean energy by 2030.
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Dec 12, 2022 22:06
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China are already doing massive quantities of coal to methanol conversion. It's reached an extremely mature stage with widespread thermal application. But for E-fuels from renewable energy, the bottleneck is the intermediate reaction that creates the feedstock, either hydrogen or carbon monoxide. There are a lot of companies trying to do this with electrolysis but it's still expensive. There was a report from a couple of years ago about it which is quite interesting: https://www.irena.org/publications/2021/Jan/Innovation-Outlook-Renewable-Methanol
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Feb 22, 2023 14:15
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Does anyone think CCS and flue gas capture is a reasonable approach for the concrete or steelmaking (or some other process that can't be electrified) industries?
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Mar 20, 2023 16:36
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Family Values posted:I'm of course hopeful, but let's just say I'll believe it when I see it. There'd better be a lot more to their system than what they've disclosed to the public. This is quite good. It's short and covers the main problems because the obstacles here really are that basic. Some things the video didn't really address is the heating and confinement. Most tokamaks use a combination of a huge MegaAmpere pulse from a central solonoid, radiowave & microwave heating, firing MegaWatt particles into the plasma to even come close to the 100 million Kelvin needed for D-T reactivity to become significant and you need a factor of 10 (1 billion Kelvin) again for D-He3 to peak. It doesn't seem possible to achieve that with pulsed heating as they call it. You have to consider the collisions of all the particles in the individual "plasmoids" aswell. They are bouncing off each other and changing the magnitude of their velocity along the length of the device to velocity in the radial and perpendicular directions. Since the individual particles in the "plasmoids" have a significantly broadened velocity distribution, not all of them are going to make it through this compressed magnetic field at the centre and a lot of them are going to be reflected back to where they came from. The plasma that does make it to the centre need 3 things to achieve a sustained fusion: high temperature, high density and high enough confinement time before the particles are lost to the walls of the reactor. Even by their own numbers (submillisecond confinement time, 10^22 m^-3 density, ion temp 8keV) they would be far below the x-axis for the Lawson critereon which puts them in the 1960s or 50s:  Magnetic confinement fusion works because a low density plasma can have confinement time of up to 1 second to sustain fusion reactions. Inertial confinement fusion works because you have a plasma at such extreme densities (think the sun) that confinement doesn't matter. What Helion is doing is really like the worst of both worlds here. breadshaped fucked around with this message at 11:50 on May 12, 2023 |
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May 12, 2023 11:47
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Besides E-Fuels what are some things you can blow a massive overproduction of electricity on? We could set up massive electrical corona discharges to create a crapton of ozone.
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Jun 20, 2023 14:47
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in a well actually posted:Carrying around the weight of solar panels doesn’t make any sense (a theoretical maximum of ~1 KW/m^2 vs a 80KW motor on a Nissan Leaf); the extra weight costs you more energy to cart around than it generates, even in the Sonora. Their claim of 1000 miles of range would mean they’re carrying way more batteries than they need. Even state of the art NASA solar cells aren't coming close to that number. You'd need about 500m^2 of solar cells to power a Nissan Leaf continuously on the go.
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Aug 8, 2023 11:08
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If the production capacity for YBCO tape is really increasing exponentially year-on-year, it's going to be incredibly positive for fusion. And maybe one of those "this changes everything" technologies. A high magnetic field of 13 Tesla means reaching a plasma density great enough for a self-sustaining fusion reaction. Then you can finally get to work on researching, in power-plant conditions, what could be the real showstoppers for fusion: turbulence, instabilities, neutrons and impurities.
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Sep 19, 2023 18:32
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TheMuffinMan posted:if it's a more efficient way to create laser pulses then you can make nuclear fusion happen for less? The power of a laser pulse is nothing to do with efficiency, it's about taking the total laser energy and squeezing it into a narrower and narrower time band. The efficiency of an Inertial Confinement Fusion process is still tiny (40% thermal to electricity efficiency * 10% laser efficiency * 5% laser radiation to pellet = 0.2% total efficiency) and shorter laser pulses aren't going to change that. The major obstacle to ICF is in the repitition rate. The only ICF research facility to achieve breakeven fusion (not really breakeven for the efficiency reasons above) can manage about one laser pulse per day, whereas a viable inertial fusion power plant is going to need approximately 10 pulses per second.
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Nov 17, 2023 20:41
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Never understood this hydrogen obsession. Didn't we already figure out how to work with methanol one hundred years ago and that's much safer and easier to handle than gaseous hydrogen? You have half the energy density of fossil fuels with methanol but at least you have something that's liquid at atmospheric pressure and even water soluable so it's safer than petrol/diesel. Plus you don't need to dismantle and rebuild the last century of petrochemical infrastructure because of a buzzword.
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Mar 20, 2024 11:40
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