<p><pre><code> Fusion of tritium and deuterium
Input:
- 1 deuterium atom: 1 proton and 1 neutron
- 1 tritium atom: 1 proton and 2 neutrons
Output:
- 1 helium atom: 2 protons and 2 neutrons
Overall: 5 particles become 4, 20% become free to hit other atoms or turn into energy.
Decay of uranium-235 into barium and krypton
Input:
- 1 atom of uranium: 235 particles
Output:
- 1 atom of barium: 144 particles
- 1 atom of krypton: 89 particles
Overall: 235 particles become 233, less than 1% become free to hit other atoms or turn into energy.
</code></pre>
Fission is much more similar to radioactive decay: big atoms turn into smaller atoms releasing a few free particles. Fusion releases basically the same amount of particles with much smaller atoms.<p>Of course, this is an extreme simplification of the process. Energy required to start each reaction is ignored, but the idea is mostly correct, I think.<p>EDIT: fixed tritium number of protons and neutrons and grammar.
I sometimes see the argument "fusion produces more energy per mass than fission, therefore fusion is better than fission."<p>This is a completely dumb argument.
I was watching "Undecided with Matt Ferrell" on it Dr. Martin Greenwald said that 0.1g deuterium and 0.3 lithium fused in a fusion power plant would release enough energy to power a typical US home for a year. Actually he said energy needs for an American so he may have meant more than electrical power.<p>From what I can see the typical US home uses 10,715kWh/year which is 38,574,000,000 Joules.
Good explanation, but it kind of buried the lede. The answer is way down at the bottom:<p>> Fission releases the energy of the electromagnetic force when positively charged parts of the nucleus fly away from one another. Fusion releases the energy of the strong force (much stronger at short distances than the EM force) when the small pieces are captured and held into one nucleus.
One could think that all energy generated by nuclear fission is just energy stored from fusion. So it should be pretty clear fusion yields more as it is input for all fission.