Title, how can such a small amount of metal be so powerful/potentially destructive? How is the power extracted? What makes it so dangerous? Any other interesting facts?
In: Physics
isotopes of plutonium and uranium are fissile material which means we can split them into multiple smaller elements. The reason this releases so much energy has to do with the average binding energy in the nucleus of an atom. this is essentially the energy that keeps the nucleus of an atom together and is different for each isotope.
where does this binding energy come from?
this energy comes from the difference in the weight of the atom and its individual parts. We know the weight of an individual proton and an individual neutron. you would assume that if we multiply the weight of a proton by the number of protons, do the same for the neutrons and add the together you would get the mass of the nucleus. However, experiments have showed that there is a difference between the theoretical mass (calculated as i explained) and the actual mass of nuclei. the difference in mass gets converted to the binding energy via Einstein’s equation E=mc^2.
Fission
During fission we split atoms, this is typically done by bombarding a nucleus with neutrons. the neutron is absorbed by the nucleus which becomes unstable and then splits into typically 2 smaller nuclei plus 2-3 neutrons.
How does fission release energy?
we take a mass balance of what came out (2 small nuclei + 2-3 neutron) and what we put in (1 big nucleus and 1 neutron) and subtract them. Because different isotopes have different binding energies we see a difference in the mass between products and reagents. This difference again gets converted to energy via Einstein’s equation.
Important to note is that the difference is mass is absolutely tiny like 10^-28 kg tiny, but c^2 is extremely large plus this is only for 1 atom. there are about 6.23*10^23 atoms in one mol (1 mol of u235 would be 235 gram). This means that the potential energy released per mol of atoms from a fission reaction is orders of magnitude greater than for a chemical reaction.
below is a link which shows a graph of the average binding energy per nucleon for all the different isotopes. This graph is important because the slope of this graphs indicates whether fission will release energy or fusion will release energy, and how much ( steeper = more energy released). A positive slope => fusion releases energy, negative slope => fission releases energy. As you can see the left side of the graph (positive slope => fusion releases energy) is much steeper than the right side which means per atom fusion releases much more energy than fission which is one of the reason to develop fusion reactor (besides being safer and not producing nuclear waste).
link graph binding energy per nucleon: [https://www.miniphysics.com/binding-energy-per-nucleon-and-nuclear.html#:~:text=%20Important%20features%20of%20the%20graph%3A%20%201,and%20are%20less%20stable%20because%20the…%20More%20](https://www.miniphysics.com/binding-energy-per-nucleon-and-nuclear.html#:~:text=%20Important%20features%20of%20the%20graph%3A%20%201,and%20are%20less%20stable%20because%20the…%20More%20)
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