CFS claims that it's manageable, although I don't know enough to evaluate that claim. It's also not clear from this quote if the once/twice per year is referring to full replacement of the vacuum vessel, or maybe just to inspection or replacement of a subset of components.

"Bob Mumgaard, CEO of Commomwealth Fusion Systems, regards neutron flux as part of a fusion power plant’s wear-and-tear—a routine aspect of its servicing cycle, happening perhaps once or twice a year. “We can simplify the internal components, develop maintenance scenarios,” he says. “We have such a scheme substantially in place.”" https://nautil.us/issue/86/energy/the-road-less-traveled-to-...