[pfdietz]

This is projection. The irrationality is thinking that fusion is something desirable. I suspect this follows from exposure to fusion reactors as a trope in SF stories. From a hard nosed engineering point of view fusion is just terrible.

[phscguy]

I can understand that from an enginneering perspective ITER is terrible, but fusion in general?

There are all sorts of approaches to fusion, and things such as type 2 superconductors were undiscovered 30 ago and uneconomic/unpractical 10 years ago. Timing control systems for magnetised target fusion were impossible but now are doable. Our understanding of plasma has been advancing a lot, simulations are good now, we can control plasmas much better. Chirped pulsed laser amplification is a thing now and really good at making high amplitude pulsed lasers for inertial approaches...

I could go on and on. This isn't the 90s anymore, and our technology is still rapidly advancing. What happens if we find more efficient/cheap/high power density thermocouples, or find a direct energy electrostatic power capture method?

Fusion's economic realities today may be overcome soon, we really do not know what we can do in even 20 years from now. The fundamental truth is that there is vast amounts of energy available in hydrogen, and all it takes is 100MK to ignite it.

[pfdietz]

DT fusion looks bad even if you totally ignore anything related to plasma physics or magnetic fields. Simply handling the heat flow and neutrons from the reactor looks to make the reactor too big to compete, compared to fission reactors.

And then you have the problem of having to stick sophisticated stuff in the hot zone where hands-on maintenance is impossible (compared to a fission reactor, where just the fuel and relatively simple hardware is in that zone.)

[gfodor]

Fusion doesn’t have the stigma of fission, or a lot of the risks, and so if we can get to a point where we are actually building new fusion reactors, we should assume the technology will improve rapidly.

[pfdietz]

It's a common error to think that fission power plants aren't being built because of "stigma". The actual problem is failed economics. Fusion promises to be even more expensive, for the reasons I explained.

It's not clear why one should expect fusion to have good experience effects. Fission didn't, and the non-nuclear parts of fusion power plants will be mature technologies.

[gfodor]

Your argument is that the stigma of nuclear meltdowns hasn’t impeded the deployment of nuclear energy?

[pfdietz]

If reactors were ten times safer but no cheaper, they still wouldn't be being built.

If reactors were ten times cheaper but no safer, we'd be building them like hotcakes.

[sprafa]

Please tell me how it’s terrible, Mr Hard Nosed Engineer ?

[pfdietz]

Low power density (at least an order of magnitude worse than fission), high complexity, need to maintain large complex objects for which hands-on maintenance is impossible and for which there are many parts for which no redundancy is possible. Fusion reactors are the opposite of "Keep It Simple, Stupid".

The engineering undesirability of DT fusion has been known for decades. All the recent excitement doesn't address any of the known showstoppers.