If they think they can get a working fusion reactor capable of powering 80,000 homes into a shipping container, I'd suggest not building them any bigger. Being able to scale in container sized units over time via the existing transport links sounds just peachy. Is quite a big 'if' there.
Not sure how much maintenance will factor in, but a reactor that size sounds already practical.
There is now a new theory to handle this, which is to build smaller reactors and put them on barges or railcars. Then you can mass produce them in one place with one regulatory approval and the time it takes to go from there to supplying power to a new city is the 24 hours it takes to tow in the barge. Which deprives NIMBYs of one of their most annoying obstruction methods -- raising construction costs through intentional red tape and changing requirements after construction has already begun. That can't happen if you can go from local approval of operations to selling power in the course of an afternoon. And then you can't lose your investment due to an unfavorable or changing regulatory environment because in the worst case you tow the barge to some other place with lower hostility.
Hopefully that will work better.
This is the real reason why fission reactors are either large, or military. The organisational capabilities that are required to manage them safely require scale and funding.
Another benefit of smaller scalable units would be the ability to readily transport aging units back to a central factory that routinely handles old units before major structural degradation occurs. One issue at Fukushima (and a majority of other nuclear reactors) is that the size and scale of each one is enormous requiring a lot of one-off resources to clean up, and so the incentives are to run them far past designed lifetimes and safety recommendations. Nuclear fission is very detrimental to materials, even in modern failsafe designs. But having an organization which routinely “recycles” units long before failure could allow both economic efficiencies, better safety due to constant practice, and dealing with smaller units which could be largely handled with industrial robotic systems.
The issue I’d worry about with such units would be security. Smaller units could mean potentially less security which would make for easier targets for motivated terrorists or rebels.
https://spectrum.ieee.org/tech-history/heroic-failures/the-f...
McMurdo ice camp in Antarctica briefly was run via contained nuclear reactor.
I also wouldn't call it a Nimby issue. If a disaffected terrorist decided to blow up a small nuclear unit the issues would be considerable. Currently nuclear power plants are guarded like wartime POW camps.
The army did also try to build portable nuclear power generators
One might be able to evade that if one could have a large number of tiny, or at least thin, reactors sharing a common blanket, much as the fuel rods of fission reactor share a common moderator. However, it's still likely to be inferior to a fission reactor in power density, as these tiny reactors would irradiate each other.
Beyond that, there's the need to confine the plasma to these very small reactors. Even in complete absence of plasma instability and turbulence, ions will scatter off each other and diffuse out and be lost. This classic diffusion takes time proportional to the square of the minimum reactor dimension / ion gyroradius.