
Breakthrough in Nuclear Fusion? - Prof. Dennis Whyte
About this video
MIT's Prof. Dennis Whyte explains the ARC/SPARC compact tokamak approach, in which new high-temperature superconducting magnets allow smaller and cheaper fusion reactors. He covers fusion physics, performance trends and the engineering path to net energy.
Why it appears in the archive
HN points to it as the grounded, approachable explanation of why REBCO magnets changed the outlook for fusion.
AI-generated summary and labels from the source dataset; verify important details against the video. Source & credits.
From the Hacker News discussion
Watch Robert Whyte's presentation. [VIDEO] The basic problems have all been solved, the science has been solved too. Tokamaks have already made net fusion power. The only difference between JET, which already succeeded, and ARC, is using Magnets with 2.6x the field strength. The B^4 power scaling, gives you about 50x the power, so ARC will generate 500 MW of power whereas JET (remember, already proven engineering), generated 10MW. So without a doubt, this is just an engineering problem at this point. A prototype device that didn't have to be maintained, could be built exactly like any other Tokamak, just with REBCO magnets, and you'd have the required fusion power. To get the required electric power, and add in maintenance, you need to at the FliBe liquid blanket, replacable toroid sections, and a heat exchanger, but again, these are known engineering problems with known solutions, akin to knowing that landing a rocket is possible, but figuring out the grid fins, heat shield, landing legs, and guidance software. Fusion devices on a small scale have been proving the plasma physics since the 90s. We don't have fusion yet simply because of people being conservative and sticking with traditional "known to work" magnets, which is why ITER is a huge, hulking monstrosity. As Dr Whyte says, cost scales by R, R can be reduced by a factor of 10 from ITER simply by using different magnets, so ARC will produce the same power as ITER, but significantly smaller and cheaper. The basic paper
Read original comment ↗> “People say nuclear is expensive in the West, but they forget to say it’s expensive because of interest rates,” Morin said. It's still a valid criticism if: - They could get those high interest rates from the return on other capital projects (nuclear less return than something else) - All externalities are included in costs We only have so much labor/material/energy available, and we do have to have some way of allocating them to the things with the most return. The big issue, obviously, is that tons and tons of negative externalities aren't priced in to most economic endeavors, that might make fission look a lot better. It might make it look a lot worse. Personally I'm hoping Elon/Mackenzie/Gates/Buffet/etc decide to throw a few dozen billion at fusion. I think its time truly is nigh. If you haven't watched this yet, it's definitely worth your time. Rather than being a super opinionated think-piece, it instead does a fantastic job walking the viewer through: - high level nuclear fusion engineering performance curves / the engineering design contraint space - the current state of nuclear fusion research (as of 5 years ago) and - breaks down why some new smaller reactors will likely begin construction soon and counter-intuitively, the most recently started ones may be completed before a fusion reactor that first broke ground 25 years ago and is still very much being actively built [VIDEO] Also worth noting that interesting things happen when you assume you can have "large" a
Read original comment ↗Commonwealth Fusion Systems has addressed all of those issues: 1. The higher field strength from the new HTS magnets eliminates turbulence. 2. The ARC reactor will use a FLiBe molten salt blanket to capture energy from neutrons and breed tritium to be used in the fusion reaction. 3. The ARC reactor is designed to have a swappable 2cm thick vacuum chamber, which is the component subjected to the most neutron radiation (everything else is shielded by the molten salt blanket). These chambers are expected to last a year, and while they are moderately radioactive waste, the amount of material is relatively small and they should become safe in the order of a decade. I highly recommend watching Dr. Whyte's talks on YouTube, he discusses the challenges, design, and performance in an approachable way. There's a timestamp index in the comments on this video: [VIDEO]
Read original comment ↗Instead of trying to reduce options for people, why not put your energy toward something positive, like this? [VIDEO]
Read original comment ↗The real deal is here, from MIT: [VIDEO] Apparently there was a recent breakthrough in superconductors, which allows significantly more current in the inductor coils while still maintaining superconductivity. This in turn allows for much stronger magnetic fields, hence tighter confinement of the plasma and therefore more fusion. A standard tokamak with these new superconductors should produce more energy out than energy in, and be a viable source of energy.
Read original comment ↗Eye opener is the chart at 18:03: "from 1970 to 1995, [fusion] power and energy increased much faster than computing power (Moore's Law)" [1]. Magnetic-confinement fusion stalled, according to Dr. Whyte, because to get more power (and efficiency) we need stronger fields. To get stronger fields we needed bigger magnets. To support bigger magnets one needs bigger structures. Big magnets and big structures will absorb more magnetic and neutron flux; that increases maintenance frequency, complexity and cost. Better superconductors let us get stronger fields without bigger magnets. That changes the cost function. [1] [VIDEO]
Read original comment ↗"Breakthrough in Nuclear Fusion?" - Professor Dennis Whyte. [VIDEO] The title threw me off, but it's a very interesting and grounded talk about the different approaches to scaling fusion energy.
Read original comment ↗yes thats true. ITER is obsolete already because it actually cannot use these high-temp-high-Tesla superconductors. at the moment ITERs best hope is that it 'proves' that fusion is viable & then do a full redesign for DEMO to do proper scaled operation. here is the original presentation by Dr Whyte of MIT behind this Sparc project: [VIDEO] he talks about the impact of these newer magnets at around 26min mark.
Read original comment ↗