Which substance is a fuel used in nuclear power plant

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Nuclear fuel is a substance that is used in nuclear power stations to produce heat to power turbines. Heat is created when nuclear fuel undergoes nuclear fission. Most nuclear fuels contain heavy fissile elements that are capable of nuclear fission, such as uranium-235 or plutonium-239

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Most nuclear fuels contain heavy fissile elements that are capable of nuclear fission, such asuranium-235 or plutonium-239.