[zaking17]

Would anyone knowledgeable about the field update their priors about whether we’ll see commercial fusion in the next 30 years, after seeing these results? If not, is there a big milestone we’re waiting for? Or will fusion advancement be a slow grind with many small improvements over decades?

[ak217]

I'm not an expert but I've been following the field for a while. It's telling that negligible venture capital is pursuing this route to commercial fusion, and the only cheerleading for it comes from DOE lab press releases. That's because the NIF is a thermonuclear bomb simulator developed by a lab tasked with both thermonuclear bomb development and also developing a portfolio of civilian applications for its technologies. Even if the NIF were to break even on the entire power plant package in theory, harvesting energy from fast fusion neutrons is hard enough in magnetic confinement designs without them pulsing like a bomb as they do in ignition designs.

Meanwhile the VC money is quietly piling into tokamak and stellarator magnetic confinement designs, driven by high expectations from real breakthroughs in ReBCO tape manufacturing technology. These superconducting tapes can be manufactured like semiconductors and can develop magnetic fields that were previously impossible, which is a key manufacturability enabler in a design whose path to commercialization is far better de-risked overall. There are still concerns with the durability of equipment needed to capture the neutrons in these designs too, but ReBCO tapes were the real prior changer.

[DennisP]

Funding is starting to kick in for private laser fusion attempts. Over the past couple decades, lasers have advanced even more dramatically than superconductors.

https://physicstoday.scitation.org/do/10.1063/pt.6.2.2021102...

[donkeyd]

Currently, about $3B is invested in fusion per year, while about $6000B is spent on oil subsidies. That's just to show how little we spend on fusion. Any decent increase in spending would really help speeding up the process. I think that's something we should all be promoting!

[zaking17]

Thank you - exactly what I was curious to learn more about!!

[pfdietz]

I don't see this as dealing with the considerable obstacles to inertial fusion. In particular: cost of lasers, size of the system with survivable final optics, cost of manufacturing the targets, and targeting of moving targets with sufficient accuracy.

[simne]

Big milestone is construction materials, could long enough withstand neutron stream, which is about two magnitudes more, than in fission reactors.

This is last unknown in this equation. All others are already known, from achievements of last few years.

Materials research is one of primary targets of ITER.

If good enough materials will not being found fast enough, will need to use clear reactions like boron-carbon fusion, in which need magnitude higher temperature, so practical device will be few times larger (because x-ray losses, proportional to surface square of plasma configuration).

[pfdietz]

ITER will only operate for a few weeks total at full power. It's not intended for materials development. For that, a Fusion Nuclear Science Facility (FNSF) would be needed.

[simne]

You don't understand. ITER will RESEARCH, how existing materials withstand in real fusion reactor, and gather parameters of real fusion reactor, so other science facilities will have benchmarks.

[pfdietz]

ITER is fundamentally unable to replicate the conditions that materials will be subjected to in an actual commercial fusion reactor. It cannot achieve the same cumulative neutrons dose that a real reactor can experience. It will not be able to answer the questions that need to be answered to prove out the materials for first walls or blankets, and it will not be able to establish reliability metrics for these structures.

For this reason, there has long been a call for a FNSF. This facility is likely to be needed to establish designs for components that would go into the putative successor to ITER (DEMO).

[simne]

> ITER is fundamentally unable to replicate the conditions that materials will be subjected to in an actual commercial fusion reactor

Are You joking? Or You just don't know physics?

What REALLY differ ITER (DEMO) from real commercial reactor?

[pfdietz]

No, I'm not joking.

ITER fails in at least two ways. First, the intensity of neutron radiation at the first wall is far too low for a viable commercial reactor. It cannot simulate the heat load a commercially viable breeding module would encounter. Second, ITER cannot operate for more than a few weeks, so it cannot simulate the integrated radiation load a commercial first wall would have to be able to withstand. It also cannot operate with enough blanket modules, for long enough, to move the designs down experience curves for reliability growth to occur so they are sufficiently robust for a commercial reactor (this is a huge looming problem, as they will be very difficult to repair.)

Abdou at UCLA has been beating the drum for a FNSF to actually address these issues. He's been beating this drum for DECADES.