Nuclear power in Japan is like a giant machine that makes electricity by using little pieces called atoms. These atoms are very small and can't be seen with our eyes. They are found in something called uranium, which is a special rock that is dug up from the ground.
There are special places in Japan called nuclear power plants that have many machines that help break up the uranium into its little pieces. When the uranium breaks up, it makes a lot of heat that turns water into steam. The steam goes up and turns special turbines, which are like big fans that can help make electricity.
Nuclear power in Japan is important because it helps to provide electricity to many people. However, there are some problems with nuclear power too. Sometimes, the machines in the nuclear power plants can have accidents, and this can make a lot of bad stuff come out that can hurt people and the environment.
After a big accident happened in Japan in 2011, many people were worried about nuclear power, so the country decided to close some of its nuclear power plants. However, there are still some nuclear power plants in Japan that are being used to make electricity, and the government is working to make them safer.