In fusion, light nuclei merge — or " fuse" — to form one heavier nucleus.

在核聚变过程中，轻的原子核合并——或者“聚变”——形成一个较重的原子核。

Fusion is the opposite when two light nuclei join together to form a heavier one.

当两个轻核结合在一起形成一个较重的核时， 聚变则相反。

One reason is, as you can see on the mass-energy graph, light nuclei that fuse together undergo a much larger energy change than heavy nuclei that break apart.

原因之一是， 正如您在质能图上看到的那样，聚变在一起的轻核比分裂的重核经历的能量变化大得多。