As regards putting reactors on the back of lorries and moving them around the country, that would also require a significant shift in public opinion, which I don’t see happening any time soon. Also there are the practical issues. Obviously such a road convoy would need to be conducted safely, so as to prevent a simple road crash creating a major radiological disaster. It would be difficult to see how this could be cheaper than shipping diesel generators around, or indeed renewable systems.
I also doubt whether you could ever get a self contained nuclear reactor onto the back of a lorry, at least a reactor that’s of some practical use at the other end. Bear in mind, that its not just an issue of volume, but also weight. The bridges on most “B” roads in the UK (and many of the A roads too) are designed for a maximum vehicle weight of 60 tons or less, and many smaller roads have even lower weight limits (under 15 tons). This would restrict a heavy single trailer reactor (as shown below) to travel on a handful of major “A” roads and motorways, which would probably have to be closed off for it to use them, and such roads rarely travel through locations where the electrical/heat load it is meant to satisfy would be located.
A proposed Soviet “road mobile” nuclear reactor
Then there’s the matter of shielding, i.e. the containment dome. It would probably be more practical to build that on site, though with a small reactor it wouldn’t be terribly large and could probably be put up by local building contractors reasonably quickly (so long as the reactor has a good, proven “passively safe” capability). In all likelihood you’d be spreading the power plant out over several trucks, so it’s more a sort of “nuclear circus” than a single 18 wheeler. Even so, I’m not sure how useful this would be. Most power demand in the sort of range than these modular micro-nuclear plants are pitched at are often more or less permanent installations. In such a situation, it would be more sensible in economic terms to just build a permanent power source (nuclear, fossil fuel, renewable, which ever works out best) on site, than stringing something together with a portable power station.
10.3.6 – The life atomic
Of course the most obvious use for a portable reactor is to power a ship. As with our artic bases, the extra crewing costs of nuclear combined with the higher capital costs of ship’s construction have often outweighted any benefits, except where performance is an issue, as would be the case for Arctic Icebreakers or nuclear powered warships. The size of the reactor also leads to a reduction in cargo carrying capacity. While these conditions may change in the future, particularly if a cheap, compact and reliable nuclear reactor becomes available, but again the scope is likely to be fairly limited in scale (in global terms). And again, public acceptance would need to be forthcoming.