Yeah, so, this is not true.
First off, turning it "to powder" is hyperbole; metals just become increasingly brittle.
Secondly, claiming that there's "no solution" is not just wrong (there are many), the particular solutions used by Commonwealth are literally discussed in the papers that this Slashdot article is about. Specifically, they use a molten FLiBe breeder blanket to absorb the fast neurons, which also breeds tritium. Since it's molten, there are no "structural" issues with it at all. The inner core (mainly tungsten) does need periodic replacements (every 1-2 years), but the reactor is designed to be easy to open up for swap-outs. It is treated as an expendable consumable, and is melted down and recast/rebuilt for the next replacement. In terms of complexity, cost, and downtime, it's probably roughly on par with fission reactor maintenance periods, perhaps superior.
Third, there are many types of magnetic confinement fusion, not just magnetized target fusion. These are less mature than tokamaks, and generally considered more longshots. Even ignoring that the fusion itself is more challenging, they trade something relatively simple - materials science and swapping - for something much harder (immense mechanical and fluid dynamics challenges)
Fourth, if you really hate neutrons, there are also aneutronic fusion designs. Again, though, less mature.