I also understand that fusion in general is unlikely to be an economically-viable energy source anyway, since the reactor and any surrounding material will be relatively quickly (~few years) be made brittle by the neutron bombardment, while also becoming radioactive - meaning any fusion plant will have to be carefully and constantly torn down and rebuilt, and materials from the old plant securely stored for large amounts of time (not as large as fission waste, but still in the order of decades or centuries). There are other concerns with hydrogen escape etc, but this one seems completely fundamental.

Some methods of fusion solve this in varying ways, with liquid metal blankets, etc, or using non-neutron is fusion fuels. But that’s missing the point. There’s no path to these more viable methods of economically producing power that don’t run through the path of generating more fusion energy than it absorbs, so we start with the easier fuels first to prove we can do sustained fusion before worrying too much about neutron embrittlement.

Even if we had unobtainium that was free of radiation degradation, fusion reactors would still be unlikely to be competitive -- they're just too large and complex, and hence expensive.

The problem is that ITER is funded as a science project, and the researchers want to get as much research as possible.

So they are going to spend a lot of time studying plasma before they irradiate the vessel with fusion byproducts and it's no longer safe to take apart (for example, to add new sensors).

It's the only facility of this size so the research program is completely sequential.

We could have fusion, we just need to spend $20 billion a year for 10 years. Not $1 billion a year for 200 years.

The first job of ITER is to show that disruptions can be controlled. This is absolutely necessary, and requires access to the machine to repair it when disruptions occur. So this had better be done without tritium (or possibly even deuterium). And if they can't do it, they will never be allowed to operate the machine with tritium.

They could spend the same amount per year and get results in 5-10 years if it were being run competently.

There’s no point in babying a facility if it means taking decades too long to get useful results!

What about "magnetic mirrors"? https://www.llnl.gov/archives/1980s/mirror-fusion-test-facil...

I recall hearing a scientist from the lab say that was the way to go and they mothballed it because they wanted to focus on weapons research.

Mirrors are interesting. They hit very high performance metrics in a small budget. However they have this pesky issue of requiring an electrostatic field. Conduction losses are a killer, scale up in nasty ways, and ablate material quickly.

In terms of inexpensive neutron sources: they're perhaps some of the best we have.