Why is nuclear power usually not classified as renewable energy?

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Study how a series of gears in a waterwheel translates a stream's energy to a millstone — energy conversion Before the Industrial Revolution, power came from three main sources: humans, draft animals, and water.
The ingenuity people used in harnessing waterpower can be seen in this medieval-style mill. The waterwheel is turned by a stream and is connected to a shaft that leads into the building. At the other end of the shaft is a gear. The connection of a series of gears translates the power from the stream to a shaft that drives a millstone, which grinds flour from grain.
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Nuclear power is generally not classified as renewable energy because it relies on finite resources that are not naturally replenished on human timescales.12

While renewable energy sources—such as solar, wind, and hydroelectric power—are continuously renewed by natural processes, nuclear power depends on uranium and other fissile fuels. These materials must be mined and processed, and their supply is limited. Although nuclear energy is often categorized as a low-carbon alternative to fossil fuels because it generates electricity with very low direct greenhouse gas emissions, it does not meet the fundamental definition of a renewable source that is naturally and rapidly replenished.12