The argument that governments aren't letting reactors melt down enough is a nonstarter. If nuclear proponents have to resort to that, you might as well give up.
I suggest instead pushing for designs that can achieve acceptable levels of safety at lower cost. In particular, molten salt designs, such as the one from Moltex, that allow the size of the containment building to be shrunk by a factor of five from that of an LWR (for a given power output). Moltex's design does not dissolve the fuel in the primary coolant and has other attractive features vs. other MSR designs.
Such designs are not on the market today, and will take time and money to bring to market. I think R&D on them is a good idea, and supporting that is a proper role for governments, just as it was for renewables, but they are still something of a longshot, given where the competition is likely to be in 20 years.