Billions of dollars will be spent to Fukushima proof nuclear reactors, regardless of the fact that existing reactors already had proper safegards to such instances. But the NRC doesn't care about facts too much, they care much more about perception, specially when it comes to further ratcheting nuclear regulations.
What it takes to "Fukushima proof" reactors is just a change in policy. When the earthquake was detected an automated system shut down the reactor, putting it in a state where external power was required to restart the reactor and to cool it. When the wave hit and flooded the generators and took out the utility power lines all that was left to operate the facility was a backup battery.
I can only assume that the batteries could not provide the power needed to restart the reactor, there was damage to the turbines, or it was somehow decided that it would have been unsafe to restart any of the reactors. The earthquake and tsunami did not damage the reactor, it was the lack of cooling power. Had the reactor been put in a low power mode when the earthquake hit, instead of shut down to the point where criticality was lost, the power plant would have been able to operate until the utility lines were repaired. After the power plant was reconnected to the power grid they could have chosen a safe shut down or return the power plant to full power.
I suspect that had the reactors not been shut down by the automated systems it would have been shut down manually anyway. The damage to the backup power systems would likely have been sufficient that continued operation of the plant would have been deemed unsafe.
It just amazes me that we have nuclear reactors still in operation that are capable of melting down in such a spectacular fashion only because power was lost. One would think that a facility designed to produce power would never need to have power provided to it.
Getting back to the cost of power in the future I see a nuclear powered future as nearly inevitable.
The price of traditional sources of energy are only going to increase. More people are seeking utility electricity, and those that have it want more. The more we dig and drill the harder it becomes to find more coal, oil, and gas, that translates into higher costs. As we build up more wind, solar, geothermal, and hydro the surface area on the planet for that energy gets consumed, and land costs money. Nuclear power is so dense and plentiful that it is effectively infinite. The fuel needed for nuclear power is right now a byproduct of minerals we mine for other reasons, so it effectively costs nothing. Since nuclear reactors can be buried they take no effective space. They may even take what is effectively negative
space as small modular reactors do not require the use of long transmission lines, switching and transformer yards, and other infrastructure to support large, gigawatt scale, power plants.
I see one of two outcomes. First, the price will increase until the threat of public unrest forces governments to allow nuclear power to be developed more freely. Second, the price of energy will inevitably and slowly increase until we reach a point where things like wind and solar become viable, which is about three times what energy costs now. After we consume all the easily available fossil fuels society would, for the most part, revert to the technology of an earlier age. We might not light our homes with whale oil, solar panels and batteries would do for that, but other things might be much like how things were done a century or even a millennia ago. Busses and automobiles would be replaced by streetcars, horses, and bicycles. We'd heat our buildings with wood and only the very wealthy could afford air conditioning.
Fossil fuels are a gift but one that can only last for so long. Once we use that up it is going to be very hard to get from a society powered by wood, wind, and water to one powered by nuclear power.
Disclaimer: I am an engineer but not a nuclear engineer, mechanical engineer, chemical engineer, or industrial engineer. My education included electrical, computer, and software engineering.