The assemblies in Fast Breeder Reactor (FBR) core are deformed and shock each other under the earthquake.At the same time the fuel will be relocated, which results in variation of core reactivity.

• 快堆堆芯在地震激励下各组件相互碰撞，组件发生各种变形，活性区燃料在空间的分布也发生变化，从而导致堆芯物理反应性的变化。