It is a daughter product of nuclear fission reactions.

This was the world's first recorded nuclear fission reaction.

A typical critical mass for a fission reaction would be several kilograms.

Management problems were like a fission reaction, each one triggering a dozen more.

In order to start up a controllable fission reaction, the assembly must be delayed-critical.

Fusion provided only 15-20% of its yield, most coming from boosted fission reactions.

The fission reaction would be one of many possible if your initial probe had enough energy to break apart the helium.

Thus, normal tissues, if they have not taken up boron-10, can be spared from the nuclear capture and fission reactions.

The fission reaction was sustained for hundreds of thousands of years.

The heat of the fission reaction is removed by the water, which also acts to moderate the neutron reactions.