How Do Nuclear Fusion and Fission Release Energy?

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Discussion Overview

The discussion centers on the mechanisms by which nuclear fusion and fission release energy, exploring concepts related to binding energy, mass defect, and the conditions under which these processes occur. Participants delve into the theoretical underpinnings and implications of both fusion and fission.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant inquires about the energy extraction process in nuclear fusion and fission, questioning the role of binding energy.
  • Another participant explains that binding energy per nucleon peaks around iron, indicating that fission occurs in heavier elements like uranium, while fusion occurs in lighter elements like hydrogen, both processes converting mass into energy.
  • A participant attempts to clarify fusion as the combination of light nucleons, suggesting that energy is released due to mass defect, and seeks confirmation on their understanding of binding energy and the relationship between fission and fusion.
  • A later reply emphasizes that fission occurs in heavy nuclei and describes the process of neutron absorption leading to fission, noting that the mass of the resulting fragments is less than the original nucleus, which is converted to energy, while also correcting the notion of "refusion."

Areas of Agreement / Disagreement

Participants express varying levels of understanding regarding the processes of fusion and fission, with some points of clarification provided, but no consensus is reached on all aspects of the discussion.

Contextual Notes

Some assumptions about the nature of binding energy and the specifics of nuclear reactions remain unaddressed, and the discussion includes varying interpretations of the processes involved.

expscv
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could anyone explian how do we get energy from the nuclear fusion and fission
thx

isnt that fission requires bindling energy which use up energy
 
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If you look at the graph of binding energy per nulceon against atomic number, you'll realize that elements around the position of iron have the highest binding energy. Fission occurs only in elements which have an atomic number much larger than iron(ie. uranium), and fusion occurs in elements with a smaller atomic number compared to iron(i.e. hydrogen). Both extract energy through converting part of their mass into energy.
 
great thx, in my knowledge (correct me if i am wrong)

fusion is when combines light nucleon or elements and realese of energy due to mass defec.

Bindling energy is the energy needed to separate all nucleons from nucleus.
(now i try to describe fission in terms of bindlng energy and fusion)

so when separate each nucleon from the nucleus, energy is applied, but some nucleson re-jion after that , so fusion takes place and some mass is lost, therefore the energy must be realsed as well.

did i got anything wrong?

thx
 
expscv said:
so when separate each nucleon from the nucleus, energy is applied, but some nucleson re-jion after that , so fusion takes place and some mass is lost, therefore the energy must be realsed as well.

did i got anything wrong?

thx

First fission occurs only in very heavy nuclei such as uranium, thorium, or plutonium. Although there is some spontaneous fission in both uranium and plutonium (not sure about thorium), most fission events occur when one of these nuclei absorbs a free neutron. When one of these nuclei fission, they generally split into two large fragments and they release some more neutrons. If you add up the masses of the fragments and the released neutrons, you will find that the total mass is less than the mass of the original nucleus and the neutron that initiated the fission. This mass defect is converted to energy in accordance with Einstein's famous relationship.

So, no "refusion" occurs.
 

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