| environ. |
nuclear fuel Nuclear fuels are obtained from inorganic minerals extracted by mining. Although they are at least partially consumed when used in nuclear reactors for the production of heat, they differ from fossil fuels in the way they release energy. Burning of fossil fuels, such as coal, oil and gas, is a chemical reaction. Nuclear fuels, such as uranium, are destroyed by a process of spontaneous disintegration, called fission, and prompted by natural radioactivity. If the process is left to occur naturally in uranium-bearing rock, the rate of change is imperceptibly small. In a man-made nuclear reactor the energy-releasing processes of disintegration, which in the natural state happen slowly over thousands of millions of years, are compressed into minutes. The release of energy is harnessed to generate steam which drives electricity generators (核燃料是从开采提取的无机矿产品中得到。虽然它们都至少有部分消耗用于核反应堆生产热能，但它们与化石燃料在释放能量方式上有所差别。化石燃料的燃烧，如煤、石油和天然气，是一种化学反应。核子燃料，例如铀，由称为裂变的自发衰变过程所消耗并由天然放射性引起。如果这个过程是自然发生在含铀岩石中，其变化率很小。在人造核反应堆中，在自然状态下发生缓慢长达数千万年的能量释放的衰变过程，被压缩到几分钟。释放的能量是用来产生驱动电力发电机的蒸汽。) |
