This will probably need to be updated soon. There are rumors NIF recently achieved a gain of ~4.4 and ~10% fuel burn up. Being able to ignite more fuel is notable in and of itself.
what "gain" means.
Progress toward fusion energy gain as measured against the Lawson criteria
111–120 of 148 posts
Re: Progress toward fusion energy gain as measured against the Lawson criteria
#112Earlier quoted context omitted.
> ITER is NOT designed for power generation. It's essentially a lab experiment to see how plasma behaves in magnetic confinement and test various technologies. That's the go-to excuse. But if you look at DEMO, it's power density is not enormously greater. ITER is so far out of the running that DEMO (or PROTO, etc.) will be too. We're learning a great deal about something that's largely irrelevant.
DEMO concept sketches are completely obsolete at this point. It's not going to look anything like this. They're based on the state-of-the art from about 2005. Since then, a lot of improvements happened. A more realistic power plant design is going to use a thinner center column (because of better superconducting magnets), resulting in a smaller cryostat volume. Possibly high-TC magnets. It can also be made more compa…
It's my understanding that neutron wall loading of DEMO concepts had been trending downward (due to materials limits), the opposite of the trend you're trying to portray there. And in no future world is the power density of DEMO going to be anywhere close to that of a fission reactor.
Re: Progress toward fusion energy gain as measured against the Lawson criteria
#113Earlier quoted context omitted.
ITER doesn't use high temperature superconductors. It uses niobium-tin and niobium-titanium low temperature superconductors in its magnets. ITER has been criticized since early days as a dead end, for example because of its enormous size relative to the power produced. A commercial follow-on would not be much better by that power density metric, certainly far worse than a fission reactor. There is basically no chance…
> I call things like ITER "Blazing Saddles" projects. "We have to protect our phony baloney jobs, gentlemen!" I think this is overly harsh and somewhat unfair. You could make the same argument that anything operating in a regime similar to the Chicago Pile 1 could never be an economical reactor nor a bomb, but that does not mean skipping that particular development step is viable. As far as fusion reporting goes, art…
conceptually sure; but size-wise they are so different as to warrant valid questions about ROI.
Chicago Pile 1 ran for 12 years, ITER started ~12 years ago and plans to run into the 2030s at least. Budget and headcount would likely be vastly different too, I’d welcome any educated guesses. Sometimes quantity has a quality of its own, as they say.
Re: Progress toward fusion energy gain as measured against the Lawson criteria
#114It should be noted that "breakeven" is often misleading. There's "breakeven" as in "the reaction produces more energy than put into it", and there's breakeven as in "the entire reactor system produces more energy than put into it", which isn't quite the same thing.
We are careful to always specify what kind of “breakeven” or “gain” is being referred to on all graphs and statements about the performance of specific experiments in this paper.
Energy gain (in the general sense) is the ratio of fusion energy released to the incoming heating energy crossing some closed boundary.
The right question to ask is then: “what is the closed boundary across which the heating energy is being measured?” For scientific gain, this boundary is the vacuum vessel wall. For facility gain, it is the facility boundary.
Re: Progress toward fusion energy gain as measured against the Lawson criteria
#115Earlier quoted context omitted.
it is not in most us areas. only problem is area covered, NOT price of technology. solar with 12 hour of storage was lower price than fission before covid hit. TCO, not one time nonsense. fission has relatively low temperature heat, i.e. no metal reduction, no "concrete" production. you can cook hot dogs with it. also electrification of heat can provide lower losses stemming from regulation or lack thereof. with elec…
I am no fan of fission (I strongly oppose new fission plants). But one problem with solar+storage is that the cost of the storage component increases roughly linearly with the desired storage duration. That's not true of a fueled power plant (fission or fossil).
this is manipulative
coal power plant needs to have 100 or so rail cars worth of material brought every single day. so you are simplifying too much.
every person doing anything with power generation should put into spreadsheet, what quantities of material is needed to provide power capacity for entire grid.
and you need people, infrastructure to bring, prepare, load that material. which adds COST OF LOCKING PEOPLE, locking workforce for nonsensical jobs. so if someone drives train supplying coal plant with coal he can not do programming job, job in services etc... labor/workforce "opportunity cost"
with PV + battery you bring material once per 10-15 years. and it is not in quantities as in fossil. and one coal plant worth of personnel can manage higher amount of generating capacity in PV/battery
Nuclear plant of ANY KIND will have to have even bigger workforce than whole coal plant, just to do NONTRIVIAL maintenance. just simple microcontroller, sensor.... used in nuclear power plant has to be made available for duration of plant lifetime 30-40 years. you can use any inverter, solar panel in pv, you can interchange them, mix them, this is not as simple with nuclear plant.
people involved in providing energy services and citizens drawing energy from grid, should start think like producers AND consumer, not only like consumers. that way a lot of "grid problem" will be easier to deal with.
Re: Progress toward fusion energy gain as measured against the Lawson criteria
#116It should be noted that "breakeven" is often misleading. There's "breakeven" as in "the reaction produces more energy than put into it", and there's breakeven as in "the entire reactor system produces more energy than put into it", which isn't quite the same thing.
It's always confused me a bit. It's not like if you put 10kWh into the reactor, that 10kWh goes away. You still lose a significant fraction of it in inefficiency of the cycle but it still goes towards heat which can be used to heat steam and turn a turbine. iirc, you can get about 4kWh back. On the other side of the coin, if you put 10kWh in and get 10kWh of fusion out, that's 20kWh to run a steam turbine, which nets…
You can't always get this much energy back. Sometimes your waste heat is an enormous pool of warm water.
Re: Progress toward fusion energy gain as measured against the Lawson criteria
#117Earlier quoted context omitted.
> I call things like ITER "Blazing Saddles" projects. "We have to protect our phony baloney jobs, gentlemen!" I think this is overly harsh and somewhat unfair. You could make the same argument that anything operating in a regime similar to the Chicago Pile 1 could never be an economical reactor nor a bomb, but that does not mean skipping that particular development step is viable. As far as fusion reporting goes, art…
I don't think it's unfair at all. And I don't see ITER as an "honest attempt", far from it. The initial cost figures for ITER were obviously deliberate lies. When the true costs inevitably came out (after commitment had been made) this led to alternative approaches being canned. ITER has done grievous damage to fusion as a field, in a way eerily similar to how the Space Shuttle and ISS have done damage to NASA. The t…
As an engineer, the difference between "deliberate lies" and "overoptimistic estimates" is often just in the eye of the beholder; Hanlons Razor should be applied IMO.
Was ITER overambitious? Timeline and budget unrealistic from the start? Maybe. But I'm fairly confident that most people involved had perfectly defensible intentions.
I also think that if the goal is commercial fusion, small reactors (100MW and below) are nothing but a stepping stone and inherently commercially useless; I don't see the output (hundreds of termal megawatts) ever justifying the "fixed" overhead costs, and a scale at least close to GW scale seems completely inevitable to me.
If you agree with that premise, then building a reactor that size has a lot of utility already that you'd never achieve from building Wendelstein 7x equivalents or whatever at 50 different university campuses (or however else you'd want to spend the funds instead).
> The true purpose of ITER wasn't to achieve fusion or push forward fusion; it was to preserve funding until those making the decisions had retired. If this required sacrificing long term goals, like actually delivering competitive energy (or, really, delivering anything at all), so be it.
This is what I most disagree with; if commercial fusion is viable (I believe it really isn't) then I think ITER (or an equivalent of its size) is a very necessary, if expensive, step to make, and spending the money on dozens of smaller projects is not an "obviously better long term approach" at all in my view.
I also think that speaking about "true purpose" of the whole project is personifying the output of a complex process way too much, where individual actors in that scheme just want to make ITER happen (for very defensible reasons IMO).
Re: Progress toward fusion energy gain as measured against the Lawson criteria
#118Earlier quoted context omitted.
I am no fan of fission (I strongly oppose new fission plants). But one problem with solar+storage is that the cost of the storage component increases roughly linearly with the desired storage duration. That's not true of a fueled power plant (fission or fossil).
Where are the flow batteries? (fuel cells) Lithium ion batteries are light with a high energy density, so are great for cars. Flow batteries have a low energy density, but increasing the duration means a bigger tank, and the cost of bigger tanks increases as a function of the cube root (?) of their volume Flow batteries are well over a century old, but I have been reading about improvements over the last two decades.…
flow batteries are "controlled" by US patents. solar + batteries are not limited in bad way by US companies grip on patents.
china makes all panels, asia is making all batteries. so US utilities / energy providers can not have harmful grip on PV + batteries.
US utilities / energy providers want to have docile customer who only pays every month. they do not want to invest money into grid and have customer not only demand but also supply grid. because they do not understand how to benefit from that. they can, it is just mental limit for them.
utilities / energy providers were too lazy to think about proper decentralized grid so every participant in us grid will suffer more because of that.
this will be flagged as conspiracy, be cause it is conspiracy, conspiracy against US citizen by US companies / US interests"
Re: Progress toward fusion energy gain as measured against the Lawson criteria
#119If you don’t need a mobile power plant why bother with fusion power instead of something like geothermal? At the end of the day we’re just turning water into steam.
no variant of fusion power is smaller than current coal plant.
Re: Progress toward fusion energy gain as measured against the Lawson criteria
#120Earlier quoted context omitted.
It's an experimental facility. Yes, a power plant would need much more efficient lasers, but NIF's lasers date back to the 1990s, equivalent modern lasers are about 40X more efficient, and for an experiment it's easy enough to do a multiplication to see what the net result would have been with modern lasers. Modern lasers can also repeat shots much more quickly. Power gain on the capsules appears to scale faster than…
From what I understood, laser fusion needs laser efficiencies not just 40x better than what NIF uses, but like 3 or 4 orders of magnitude more efficient than the state of the art. Seems like a non-starter.
NIF's lasers are 0.5% efficient. Equivalent modern lasers are 20% efficient. Both of these sources have both numbers:
https://physicsworld.com/a/national-ignition-facilitys-ignit...
https://pubs.aip.org/physicstoday/Online/31501/The-commercia...