translation.en: So the core of this reactor, since it's not under pressure and it doesn't have this chemical reactivity, means that there's no inclination for the fission products to leave this reactor.
translation.zh: 所以这个反应堆的堆芯，因为不受压力 而且没有化学反应活性， 裂变产物不会倾向于 离开反应堆。