There is more to it than federal research subsidies and politics. There is genuine fear. Fear does not need a basis in fact to be real.
A large part of the public is afraid of anything radioactive. It's invisible, has no smell, can not be felt or heard and it can kill you. It's the perfect bogey-man. I have found that facts don't usually matter when someone is truly afraid.
Then there's the Nuclear Regulatory Commission. The people there are afraid for their jobs. The result is paranoia in regulation. If they decide that high-tech pipe B might possibly be even slightly better than high-tech pipe A, they will mandate an upgrade for all plants still under construction, even if it means jack-hammering 12 ft of reinforced concrete to replace the pipes.
When you factor in the lawsuits from self-appointed watchdog groups it becomes impossible to estimate either the total cost or when the plant will come online. With those in doubt it is impossible to determine whether the plant will be a good investment, and thus no private firm will take the risk.