I think some proposals on the design include a barrier material around the reactor chamber that would capture the neutrons and thusly convert them to heat, which can be used to drive a turbine.
IIRC the aim was to find a material that would convert to a shortlived radioactive isotope instead of a long lived one, so you can simply remove the barrier and have it sit in a quiet place for a few years, then recycle it.
The "blanket" (pumped molten salt is frequently cited, or more exotic material, many feet thick) is needed to turn fast neutrons into heat, thence to boil water to drive a turbine.
But the equipment to contain the plasma, many, many tons of expensive stuff, has to be inside the blanket, and is destroyed in short order by neutron flux.
The "envelope" that keeps your "blanket" from spilling out all over the floor, a monstrous apparatus of pipes, is also being irradiated, but there are materials for the pipes that can stand up to it for a while.
This envelope is made in hundred-ton sections bolted together so it can be drained periodically and sections replaced. The used ones are radioactive and need to be kept somewhere safe.
This is all hugely expensive, finicky work that is very dangerous to be around, so you need even bigger remote-operated machines to do it.
Of course. Such a blanket is absolutely needed in a DT reactor, to regenerate the tritium that the reactor needs to keep running. But the materials from which that blanket is made, and the first wall separating the blanket from the vacuum vessel, are among the things that would be degraded by neutron exposure.
IIRC the aim was to find a material that would convert to a shortlived radioactive isotope instead of a long lived one, so you can simply remove the barrier and have it sit in a quiet place for a few years, then recycle it.