There have also been reactors in the Arctic and Antarctic bases. Neither of which were capable of being done as a full spec sealed concrete containment.
What's novel here, is bringing mobile reactors into the modern age, not the mobility per se.
It will become politicised very quickly once the Murdoch press decides it's worth it, because SMR are a hot topic (sorry) in Australia, as the Oil and Mining sector rah-rah squad fights back on the push to wind and solar and batteries.