There was a Isaac Asimov short story, the Dead Past, about an invention that the government did not want to get out called a ‘Time Viewer’. It was a really simple device that allowed people to see into the past, on a TV screen.
https://en.wikipedia.org/wiki/The_Dead_Past
The gist of the story was the government had a section of people whose sole job was to prevent this device or any of its components from getting out to the public. They ultimate failed because some amateurs were able to piece one together with different parts and they published the schematics and plans on the equivalent of what would be the Internet today.
The government wanted to suppress this machine because it allowed people to see into the past. Now when does the ‘past’ start? Yesterday? This morning? a second ago?...
People could use the machine to spy on each other with perfect clarity, every action every place at any time.
I fear that is what the government will do to anyone who finally does build a fusion generator of whatever sort that works. It will be denied a patent, it will be ridiculed as a hoax, as a fake, as a con artist selling snake oil.
They will not allow fusion to be generally available to the populace, not now not ever..................
Ya, but just like in “Dead Past”, China will steal the design and build them anyway.