Henning wrote: You could maybe use just boron, but this adds inefficiency and shortens the lifetime of the parts involved. But if the beryllium is handled in a cleanroom, or like radioactive material is handled, that should not be a big issue in my opinion. The problem arises if you handle beryllium like any other nontoxic metal.

That’s right, if you handle beryllium very carefully, most problems can be avoided. But, of course, Murphy’s Law applies. People will be careless and accidents will happen. Both, at the factories that manufacture the Beryllium parts and at the generation sites.
That’s another reason why you won’t be hooking up a FF generator in your garage anytime soon.

Just because FF, if we can make it work, is far superior to any other energy source we know about it doesn’t mean it is exempt from any drawbacks. In balance there is no doubt that the advantages far outweigh the drawbacks, especially when compared with the alternatives.