How do fission and fusion produce energy?

Question

I've come to understand that in fission, the nucleus of an atom such as U-238 splits, and some mass is converted into energy, which brings Einstein's famous equation into play. But what mass is converted into energy exactly?

Also, with fusion, I've come to understand that two atoms such as deuterium collide with incredible force and their nucleii basically fuse to create a heavier element such as helium. But is there mass loss in that reaction as well? Where exactly does the energy come from in that fusion?

Answer 1

In case of fission one atom splits into 2 and some mass is lost in the process. But in case of fusion 2 or more atom combine and some mass is lost. That mass gets converted to energy.

Answer 2

Atomic Fission And Fusion Produce

Answer 3

In addition to the above answers:

Wjhen uranium decays, it releases a neutron and some of the "binding" energy as heat. This occurs naturally, but we can speed it up to a chain reaction in a nuclear reactor if we pack so much uranium together that the neutrons flying off knock loose other neutrons in nearby atoms. Lots of heat is released, which turns water to steam, which turns a turbine.

In an atomic explosion, lots of unstable radioactive particles are also released, along with the heat and shock wave. These will kill you, even if the heat and shockwave don't.

And atom of helium needs less "binding" energy that two deuterium atoms do, so when they are fused energy is released. Great source of energy for us, the problem being that forcing the deuterium atoms to fuse requires a lot of input energy--more then we get back from the reaction. Not true for a star, which has all that enormous gravitational pressure jamming the hydrogen atoms together.

Answer 4

Mass is lost from the particles themselves. The combined mass of the products of fission is less than the mass of the original U-238 + 1 neutron. Similarly, the mass of helium is less than the combined mass of two deuterium atoms.

But that doesn't really answer your question; what you're asking is why this is the case. Well it has to do with the energy of the bond between the particles in question.

Do you remember energy diagrams in chemical reactions where you have a reactant with some energy contained and a product with some different energy contained, and that reactions tend towards products that have lower energy than the reactants, and that when this occurs, energy is released? This is very similar, but the energy in question is not stored in the bonds between atoms, but in the bonds between protons and neutrons instead.

Entities (in this case, nuclei) which contain more energy are more unstable. This energy, because it is contained, adds to the entity's mass, equivalent to m=E/c^2. When the unstable particle changes to a more stable, less energetic form, it releases this energy and loses the equivalent amount of mass. In fact, this difference in mass occurs in the chemical reactions example above, but the energy differences are so small compared to those in nuclear reactions that the mass change would be very hard to measure precisely.

So, U-238 has more mass than the combination of its products because its products are more stable and contain less total energy than U-238. Similarly, helium is more stable than 2 separate atoms of deuterium, and thus contains less energy -- and thus less mass -- than the combined energy of the two atoms.

I hope this helps!

Answer 5

In the conditions of neutronically unstable materials such as uranium and plutonium and others, the neutrons that are lost in their natural rate of break down are artificially excellerated in human technology so that atomic fission is increased or descreased as is needed. Atomic fission is atom destruction through the imposition of an alien neutron of an other proximate atom. At atomic destruction electrons and protons are released that are symptomatically expressed as energy. Photo energy is released inclusive with its broad band of frequencies including heat (infra red light), ultraviolet, gamma etc.. Envolved in every energy generation the wave partical definitive is induced. Exactly which subatomic particals are converted (if they are converted, or redefined temporarily as wave partical definitions) I don't know. I know electrons are already defined as energy because of their regular sensed realization.

The assumption is that if there is atomic fusion or fission and energy is observed, then mass in the form of energy departs the atomic definitive. I don't know fussion atomic description, but freed subatomic particals from their atoms are the norm in the observation energy.