[tsimionescu]

> That is not the timeline of a project where scientific results or technological success actually matter to the folks in charge.

What is the correct time-line for a project that exists at the boundaries of theoretical physics and mega-engineering?

In the history of humanity's major projects, 50 years is not even a blip. Europe's grand cathedrals took centuries to complete.

[bell-cot]

If you are building a cathedral - in theory to glorify God, in practice as a prestige item for your municipality and its ruling classes, and social unifier, and make-work project for your working classes, and etc. - then "it will take 250 years to complete" is a feature. It's not like your dead will be sent to wait in the fires of Hell until the day when the cathedral is finished.

If your degrading climate and straining electrical grid need economical & at-scale fusion power NOW, that's a rather different situation.

When stimulated by burning military needs, fission technology went from the the first fission experiments in the US in Jan'39, to the Chicago Pile (first nuclear chain reaction) in Jan'42, to military use of fission bombs in Aug'45, to routine operational deployments of fission-powered military submarines (a very demanding application) the late 1950's.

[tsimionescu]

> If your degrading climate and straining electrical grid need economical & at-scale fusion power NOW, that's a rather different situation.

Fusion power is not a realistic solution to global warming. Even in the most optimistic scenarios, where every single current fusion power project hits its declared milestones successfully, fusion power will not be a major part (say, more than 1%) of global electricity production by 2100. Renewables, fission, and degrowth are the only possible solutions to avoid climate catastrophe. Fusion might be a path to greater reliability and prosperity in the subsequent centuries, if we avoid the worse outcomes of global warming.

> When stimulated by burning military needs, fission technology went from the the first fission experiments in the US in Jan'39, to the Chicago Pile (first nuclear chain reaction) in Jan'42, to military use of fission bombs in Aug'45, to routine operational deployments of fission-powered military submarines (a very demanding application) the late 1950's.

Fusion reactions are incredibly more complex than fission. All you need to make a fission power plant is a large-ish mass of fissile material clumped together - it heats up and boils water. The rest is control to prevent various runoffs or runaway reactions.

In contrast, fusion requires inchomprenaibly large pressures applied to a gas to even get one pair of atoms to fuse. Then, the energy of the fusion event tends to push other atoms away, requiring even more pressure to keep the reaction going. The only conceivable way to achieve this is using extraordinarily powerful magnets, and even the most powerful we know how to make require special shapes to actually achieve the required pressures in a relatively tiny volume. Then of course, they need cooling, and the whole structure needs to be solid enough to hold the mass of the magnets.

So, fusion needs special magnets, special mathematical shapes, and numerous engineering challenges to contain all of these. It's not in any way surprising that it is going to take much more time to develop than fission took.

Not to mention, the atom bomb was developed using enormous resources. The paultry 100B dollars over 50 years that ITER will probably take is nothing compared to the Manhattan Project (compared to the GDP of the time). The Manhattan Project at one time employed 133,000 people. Give ITER 65,000 employees and see if they can accelerate their time-line.

[bell-cot]

Short answer: You are correct.

Nitpick: Yes, the Manhattan Project got far more money and people than ITER. But:

- ITER is merely one of >100 fusion power experiments - https://en.wikipedia.org/wiki/List_of_fusion_experiments

- Cost/time trade-offs are not linear. The MP's war-priority timeline created enormous inefficiencies. Vs. fusion power research has been going for ~7 decades now. If you add up the budgets of the >100 experiments, over 70 years - then what's the comparison?