Japan and the US both use large amounts of nuclear power. The reason for this is both are highly populated, industrial countries. They use a lot of power, so they need efficient energy sources like nuclear power.
That released by fission in a nuclear reactor
it is nuclear
The USA
Most uses include energy and weapons although some nuclear energy is used for materials.
The USA uses the most nuclear energy. There is the highest number of Nuclear Power Plants in the world. The reason is simple: USA needs energy and the easiest way to get it is building nuclear power plants.
Most commonly used material to produce nuclear energy in Uranium.
Nuclear energy is used to power most modern submarines
Uranium is used as nuclear fuel in nuclear reactors.
Magnesium is not used in the nuclear energy.
That released by fission in a nuclear reactor
Nuclear fuel is the fuel used to produce nuclear energy.
Nuclear energy is not collected, it is released and used. Most often the use is to boil water for a steam generator of electricity.