Hacker News Reader

The studies done ten years ago suggested that the best case scenario was about thirty years( one demonstration phase of 15 years and another development phase of 15 years). This was premised on the INF demonstrating ignition using indirect drive soon after operation. There was also an expectation that the INF would transistion to researching other, possibly more promising technologies like direct drive ignition.

Instead, it took over ten years to simply demonstrate ignition using the indirect drive method which was chosen specifically because it was seen as being more technologically viable. This "big breakthrough" was supposed to happen immediately after operation!

No one knows whether commercialization of inertial confinement fusion is even possible. Laser efficiency is just one small part; the work to produce and develop a system to reliably shoot hohlraum targets is an order of magnitude harder than shooting a static target in ideal conditions.

Compared to these engineering challenges demonstrating ignition is the easy part.

> Compared to these engineering challenges demonstrating ignition is the easy part.

Again, let's discuss what those challenges are. A bunch of talk about how hard it might be with no detail on what makes it hard isn't really informative to anyone.

> the work to produce and develop a system to reliably shoot hohlraum targets is an order of magnitude harder than shooting a static target in ideal conditions.

Please see my note #2 about EUV light sources and similar technology. My understanding is the timing and precision requirements are much higher here, but on the other hand the "rate" of fire would be necessarily much lower making something perhaps feasible.

From the presentation and panel today, one of the key drivers seems to be the purity of the capsules and the ability to correct for asymmetries in the implosion caused by them. The results announced today where not because of the purity of the capsule, but instead because of the correct prediction of the asymmetries in the implosion and the ability to counter that with modifications to the laser strength and timing.

The NIF isn't (as others have noted) necessarily focused on bettering these two factors.

What I'd like to understand is what are the major tradeoffs in ICF vs MCF that would drive pursuing the difficult engineering problems of one vs another.

>> My understanding is the timing and precision requirements are much higher here, but on the other hand the "rate" of fire would be necessarily much lower making something perhaps feasible.

Leaving aside rate of fire and energy efficiency you have to develop a system that can shoot the hohlraum into the reactor chamber such that the lasers can be steered onto the target with enough precision to produce ignition. I believe 100um is the miniumum for the type of targets used in the INF. This all needs to occur within the reaction chamber. Besides the thermal loads you also have residual gases within the chamber. These conditions somehow have to be accounted for or you won't get ignition.

The work they did in demonstrating ignition is great but the engineering challenges for commericalization are immense. EUV lithography took decades to develop and perfect.

>>What I'd like to understand is what are the major tradeoffs in ICF vs MCF that would drive pursuing the difficult engineering problems of one vs another.

MCF is generally seen as a much easier approach because you avoid the problems with repeatedly generating fusion conditions and you remain in the ballpark of what can be solved with better technology. You can come up with a tokamak that you can be absolutely sure will probably work with enough money; but I'm not sure the same is true with ICF.

https://www-pub.iaea.org/MTCD/Publications/PDF/TE_1704_web.p...

and

https://www-pub.iaea.org/MTCD/Publications/PDF/TE-1911_web.p...

actually layout some of the challenges. they are not as you state and there ARE tradeoffs between MCF and ICF. Most experts agree MCF is closer to realization, but that's a very well educated guess not a surity.

https://scientific-publications.ukaea.uk/wp-content/uploads/...

lays out some of the differences and tradeoffs

Even more interesting is to look at approaches which might combine the two: https://medium.com/fusion-energy-league/the-fundamental-para...

from a brief look, both publications prominently feature discussions about target survival within the reaction vessel.

Of course there are tradeoffs between MCF and ICF. They involve different sets of challenges to achieve viable fusion energy production. Neither has been demonstrated to have commercial viability to date. The consensus view that MCF is more viable is rooted in the much better understanding of how to comercialize a MCF reactor.

The issue is the NIF isn't trying to study power generation, their mission is determining the health of our weapons stockpile. This experiment is a lab where they can test different casings and different hydrogen mixtures and this probably feeds real-world data into their supercomputer models. All this to determine how a 50 year old h-bomb would operate now. They also can find out how they can improve them without being able to go to Nevada and detonate one underground.

> 3. Power extraction from a bundle of hot material is not a particularly unknown problem. It's in fact how every power plant on the planet works.

Coal and nuclear are uncompetitive simply from the cost of the steam side. Today you can just about give a steam plant free energy and it still makes a loss.

Solar or wind does not have this limitation. CCGT gas plants gets around it by having a turbine giving raw mechanical power and then utilizing the same awful steam side to get the last percentage points of efficiency at a much smaller required scale.

Unless you can step around the steam turbine I do not see this becoming anything outside of incredibly small niches.

Neither coal nor nuclear are uncompetitive.

Compare newly built renewables with all costs included to the marginal cost of paid of coal and nuclear. [1] Today it is often better to simply shut down your existing nuclear plant and build a renewable instead. For a more comprehensive look see [2].

[1]: https://www.lazard.com/media/451885/grphx_lcoe-07.png

[2]: https://www.lazard.com/perspective/levelized-cost-of-energy-...

Looks like you'll pay the same price if you shut down an existing nuclear plant for wind/solar, unless you can bag some subsidies.

>...Today it is often better to simply shut down your existing nuclear plant and build a renewable instead.

That is ignoring capacity factor.

From your link we see that the most expensive power generation of all is residential rooftop solar. If cost is the concern, why support the most expensive option that also has a low capacity factor?

This always makes me laugh.

What other power source is accessible to the home owner?

If we are going nuclear and it’s so efficient and cost effective, why is it always subsidised so heavily? Its full cost has never been paid anywhere, as storage etc stretch off way into the future.

It seems eternally close to being cheap and reliable, but we keep screwing it up.

Meanwhile what’s left of European nuclear industry is keeping the lights on

You mean half the French nuclear fleet which is out of commission causing much of the current problems?

France has gone from the largest electricity exporter in Europe to an importer.

Which is due to the irrational fear caused by Harrisburg. The required production of new plants was halted, and now we are stuck with these aging plants.

I reckon solar is competitive in the day time without storage or peaker plants to support low generation time. I’d love to see the analysis of solar with the built in assumption of burdening the hourly cost with the infrastructure required to generate the required power at 10pm.

The generation during the day will not be burdened by that infrastructure. The night time generation will simply be day time cost + infrastructure.

Theoretically, you can bet that your traditional power plant only runs at night. But now your capacity factor is less than half the available hours for the same capital investment and it looks even bleaker.

This is where I think it probably should be. Solar w/o another generation or storage source doesn't accurately represent the full picture of what is really required to support the a whole day of electricity. So the combined total cost is probably what should be shown to represent the costs of a full day cycle of solar, or a rainy day.

The problem I have with this announcement is how limiting this technology path is to the future generation of power. If you look at the details, they imploded a sphere containing hydrogen with X-rays created by the interaction of the lasers with an outer casing. As a reminder, the second stage of an hbomb is the implosion of a cylinder of hydrogen, encased by uranium, by x-rays ablating the outer case. X-Rays produced by the explosion of a A-Bomb. The lasers are thus serving as a proxy for the first stage of a H-bomb.

The critical question, how much of this design is to figure out how to produce energy from fusion with the aim of powerplant design, and how much of the design is to better replicate the second stage of a h-bomb?

Edit: I'll have to research, but I would have to expect that the announcement of the h-bomb had language that also heralded this as the beginning of a 'fusion age' of power generation.

Sketch thing is that perhaps they're try to design an hydrogen bomb that doesn't require a fission primary. Use a laser to ignite the first stage, which ignites the next and so on. What if you can get 100X boost per stage, three stages gives you a gain of 1 million.

There is just basic h-bomb efficiency gains here. By lowering the energy requirement for the fission primary by finding more efficient ways to control/generate the X-Rays you can use a smaller and smaller primary. It also occurs to me how analogous this research is to the early x-ray laser tech, that Teller claimed could shoot down warheads for the Star Wars program in the 80s. Those designs had rods that would amplify and focus the x-rays from a nuclear bomb on incoming warheads. If you could initiate the x-ray chain reaction from a laser, you would be able to launch these without breaking the 'no nuclear weapons in space' treaty.

> Power extraction from a bundle of hot material is not a particularly unknown problem. It's in fact how every power plant on the planet works.

River power spinning a generator? Wind farm power? Are those counterexamples?

Well, these aren't "bundles" per-se, but as I understand it, both are relying on the Earth-as-a-system converting heat from the sun falling on particular areas into large-scale flows, which we humans can then hook into.

GP was likely referring to power plants that burn things in order to heat up water to make steam in order to rotate an iron core encircled by copper wire. Using kinetic energy like wind or flowing water is a nice shortcut to the rotating iron core. Even nicer: Cut out the rotating iron core and directly produce voltage via photons hitting a semiconductor.

I share GP‘s sentiment though that, in the end, there are remarkably few concepts at the bottom layer of electricity production.

(There are other means of course, but they are not in use for power generation in amounts that can drive even one household, AFAIK)

My cynical take is a lot of people are subconsciously unhappy with how BS and mundane their "tech" jobs are. They chose money+cool, only it turns out the 'cool' part was a lie to get them to churn out as much useless BS work as possible. So they get through the day by fooling themselves: slap a cool tech name on your product, make trendy graphics ( https://traefik.io https://github.com ), pretend you're doing some sci fi shit. Then any real tech happening in the world exposes your BS so you need it to be framed as a disappointment.

I'm 42 and there have been "breakthroughs" in fusion announced at least once per decade of my life. There's a very real chance that this breakthrough means the first fusion power plant will open after I'm dead, as none of the men in my family have reached 80.

So, the issue is that the community here has grown old, cynical and unable to appreciate anything that might only help the next generations?

No, the community here is skeptical of science reporting that seems too good to be true and progress in fusion energy production fits the mould. I’m not an expert on fusion or the physics, so the best I can do is agree with this sentiment and note details from skeptical comments.

Hey, if we’re wrong life will change for the better for billions of people. I like being surprised with good news more than disappointment.

certainly the need to exaggerate the news has crept through all facets of media in this annoying "attention is our commodity" era. even the most "boring" outlet has its more subtle versions of the cringey YT "wow face" thumbnail.

but just because fusion energy will not be responsible for warming your frozen pizza next week does not mean we need to belittle a major milestone like this one. sure some damn reporter has a quota to hit and metrics to game. it just means we need to dedicate a bit more effort to read the article, read between the lines, and apply critical thinking.

this is the dream technology of the far future we're talking about. it doesnt even need to happen for 1000 years. if we nail it we are set for Billions of years. but obviously people are not accustomed or incentivized to think about things on that sort of timeline.

> but just because fusion energy will not be responsible for warming your frozen pizza next week does not mean we need to belittle a major milestone like this one. sure some damn reporter has a quota to hit and metrics to game. it just means we need to dedicate a bit more effort to read the article, read between the lines, and apply critical thinking.

When everything is presented as a "major milestone" then the term starts to lose meaning. Those with finite resources need to use imperfect heuristics to decide when to spend those resources, including the time and energy required to "read between the lines and apply critical thinking" For the majority of Gen X, "major milestone in fusion energy" has gotten the bogobit enabled by this point.

> this is the dream technology of the far future we're talking about. it doesnt even need to happen for 1000 years. if we nail it we are set for Billions of years. but obviously people are not accustomed or incentivized to think about things on that sort of timeline.

The main two issues I see with this are:

1. Maintaining a civilization capable of performing fusion research for 1000 years is an open problem

2. The estimates for how long fusion energy will last us are wildly optimistic. When you say "billions" I hear "maybe several thousand." At one point there was enough petroleum on this planet to replace all the whale-oil in use for thousands of years, and look at where we are now. Providing energy for several thousand years is great! But if we are going to think about "that sort of timeline" then fusion is a bridge-technology and with the improvements in renewables and chemical energy storage over my lifetime (which have been nothing short of astonishing!), I'm starting to suspect that it's an unneeded bridge.

I think "old and cynical" is correct, inasmuch as the human brain operates largely on pattern-matching and given that "scientists report breakthrough in X" gets proven to have a very small chance of actually affecting our lives, it becomes easy to be dismissive.

As far as "appreciate anything that might only help the next generations" I think if we are still significantly burning fossil fuels 40 years from now, the next generations are in for a lot of pain even if the very next day they get replaced by fusion, so fusion just feels like it's coming too late to make a major impact.

At the same time you are complaining about how the media handle scientific milestones (and this is unquestionably a major one), you are adopting the short term, one track, 24 hour news cycle perspective the media has spoonfed you. Global warming is only one problem. We don't need to give it a monopoly on concern. We need to push for a more nuanced, sophisticated longer term view on the major obstacles that guide a civilization. "Energy" in the public conversation should be about more than global warming.

Fusion is an energy solution that would set us up for billions of years. If we figure it out any time in the next millennium we'll have hit the jackpot.

Your take is like getting upset someone mentioned computing but didn't talk about javascript. You'd rather articles not be written about fusion until it's ready to heat your frozen pizza? God forbid we flood the news cycle with scienific progress and detract from what Elon thinks about cabbage.

Edit: for those of you feeling slightly anxious you missed new Elon gossip about cabbage, I made that up.