Chemistry · Chapter 21

Fission, Fusion and the Chain Reaction

Split a heavy nucleus, then join two light ones, and compare what each pays per nucleon. The energy figures come from real nuclear masses, worked out as you click.

Pick a direction

The nuclear event, drawn stage by stage

The equation and the energy

Energy per nucleon, side by side

Energy released per nucleon, fission against fusion

Which way did it split?

Uranium-235 does not split the same way twice. These are three of the pairs that really turn up.

Steering the chain reaction

1.000multiplication factor k critical
Fissions per generation at the chosen multiplication factor

Inside the reactor

A reactor core, its control rods and its steam loop

The water is both coolant and moderator. It slows fresh neutrons down, and uranium-235 catches slow neutrons far more readily than fast ones.

What you are looking at

Stage
A slow neutron drifts in
Uranium-235 is waiting. Press next stage to walk through the split one step at a time.