True. Japan is not a big country. So they dont have many places to build nuclear power. Since nuclear power are able to give that much power to satisfy 130 million people, it is almost the first option to choose if you want to generate much power.

Even if we placed nuclear power by the oceans, a spill there would be even more catastrophic than on land. It would poison the water which takes 70% of our planet. Plus, for living so long off of nuclear power, it would be very hard for humans to adapt without it; unless we can find another source of power that will work just as well but be more environmentally friendly.

The reason Nuclear power plants are near to the water is for the fact that if they are near to the water it makes it easier to transport needed goods to run a power plant. Also for the reason about fault lines that is just coincidence that all fault lines are near water.