We know how to contain strong neutron flux. We know how to contain short to medium lived activated materials, we know to avoid cobalt is hardened materials, we don't have to deal with water based corrosion in a fusion containment, though neutron embitterment may be a similar issue.
It is very unclean, especially since it requires conventional fission reactors to produce the tritium. It’s theoretically possibl to breed tritium in the reactor blanket of the fusion reactor, but that’s a totally unsolved problem. The high neutron flux of the D-T reaction also destroys all known materials in short order by disrupting the atomic structure of the materials through atomic spallation. There are plenty of other hurdles to making a fusion power plant as oppposed to just a research reactor, but those are big ones.