Questions about the energy released by nuclear fission

Click For Summary

Discussion Overview

The discussion revolves around the energy released during nuclear fission, including the contributions from the fission process itself and subsequent beta decay of fission products. Participants explore the mechanisms of energy release, the nature of kinetic energy involved, and the relative significance of fission versus beta decay in energy production.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant describes nuclear fission as the splitting of a heavy nucleus due to an added neutron, emphasizing that energy is derived from the lost mass associated with binding energy.
  • Another participant questions the relative contributions of heat from kinetic energy during fission versus that from beta decay of fission products.
  • A participant asserts that fission energy is prompt, while beta decay occurs over a longer timescale, suggesting that beta decay is less relevant in the context of nuclear weapons.
  • It is noted that most energy from fission is released directly, primarily as kinetic energy of the fission nuclei, with estimates of around 200 MeV from fission and approximately 10-20 MeV from beta decays.
  • There is a mention of the broader implications of energy release in the context of nuclear weapon design, although this point is more anecdotal.

Areas of Agreement / Disagreement

Participants generally agree that most energy comes from the fission process itself, but there is some uncertainty regarding the exact contributions of beta decay and the nature of kinetic energy released during fission.

Contextual Notes

Some assumptions about the definitions of energy types and the specifics of energy transfer mechanisms remain unresolved, as well as the implications of these energy contributions in different contexts (e.g., bombs versus reactors).

brent1369
Messages
9
Reaction score
0
as far as i understand nuclear fission is the splitting of a heavy nucleus cause of a added neutron
the energy you get is cause of the lost mass from binding energy.
but i also read that the nuclear fission products undergo beta decay which emits beta particles gamma rays and antineutrinos

so how much of the heat is from the kinetic energy from fission and from the beta decay from the fission product?

also what is the "kinetic energy" that gets released from fission, do the neutrons "take" that kinetic energy or do the 2 split nuclei,
and is that kinetic energy just the speed they move away or momentum or ... ?
 
Last edited by a moderator:
Physics news on Phys.org
Everybody in the pool gets some of the energy. In fact one of the design problems to make the Hydrogen bomb was to get that energy into the fusion process for bigger and better bombs...the details are both fascinating and simply depressing.
 
ah ok, but does the fission create most energy or beta decay
 
Fission energy is prompt. Beta decay takes a while. For bombs beta decay is irrelevant.
 
Most of the energy comes from fission directly, and most of that energy goes to the kinetic energy of the fission nuclei. Something like 200 MeV is released from the fission event, and maybe ~10-20 MeV from beta decays.
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 9 ·
Replies
9
Views
4K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K