核反应器(nuclear reactor)

能够启动并控制自持链式核裂变反应的装置。一次裂变反应中释放的中子可以撞击其他的重核，使它们发生裂变。这种链锁反应的速率以导入通常制成棒状的材料来控制，这些材料很容易吸收中子。典型地说，如果链式裂变开始向太高的速率发展，有可能导致堆芯熔毁时，就将用镉或硼做成的棒逐渐插入堆芯。裂变释放的热量通过在堆芯中回圈流动的冷却剂带走。冷却剂中的部分热能用来加热水，将水转变成高压蒸汽。用这些蒸汽来推动涡轮机，然後，通过发动机再把涡轮机的机械能转变为电能。除了向各种商业用途提供有价值的电力资源外，核反应炉还用来推动某些类型的地面军用车辆、潜水艇以及某些无人驾驶的飞机。反应堆的另一个主要用途是生产放射性同位素，被广泛地用於科学研究、医学治疗以及工业中。

English version：

nuclear reactor

Device that can initiate and control a self-sustaining series of nuclear-fission reactions. Neutrons released in one fission reaction may strike other heavy nuclei, causing them to fission. The rate of this chain reaction is controlled by introducing materials, usually in the form of rods, that readily absorb neutrons. Typically, control rods made of cadmium or boron are gradually inserted into the core if the series of fissions begins to proceed at too great a rate, which could lead to meltdown of the core. The heat released by fission is removed from the reactor core by a coolant circulated through the core. Some of the thermal energy in the coolant is used to heat water and convert it to high-pressure steam. This steam drives a turbine, and the turbine's mechanical energy is then converted into electricity by means of a generator. Besides providing a valuable source of electric power for commercial use, nuclear reactors also serve to propel certain types of military surface vessels, submarines, and some unmanned spacecraft. Another major application of reactors is the production of radioactive isotopes that are used extensively in scientific research, medical therapy, and industry.