The nuclei of their atoms usually decay into two smaller nuclei and a couple of neutrons, releasing many million times more energy than any chemical process ever could. Heavy elements contain so much energy because they stored a fraction of the energy released in the supernova explosion that created our Earth and the solar system around five billion years ago.amp#160;
核能是由铀和钍这类重元素的裂变反应所产生的。反应中，这些元素的原子核通常会裂变成两个较小的原子核以及两三个中子，并释放出比任何化学反应都大几百万倍的能量。而重元素之所以中拥有如此巨大的能量，就是因为其内部储存了超新星爆发时所释放出来的一小部分能量，要知道正是这种能量在大约50亿年前创造了地球和整个太阳系。