1 / 28

Nuclear Fission

Nuclear Fission. Historic Dates Fission Mechanism Binding Energy Liquid-Drop Model Classification of Heavy Nuclides Prompt Neutrons Delayed Neutrons. Historic Introduction. 1932: The neutron is discovered by J.Chadwick → experiments with neutrons.

sevita
Download Presentation

Nuclear Fission

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Nuclear Fission • Historic Dates • Fission Mechanism • Binding Energy • Liquid-Drop Model • Classification of Heavy Nuclides • Prompt Neutrons • Delayed Neutrons T8: Fission

  2. Historic Introduction • 1932: The neutron is discovered byJ.Chadwick → experiments with neutrons. • 1939: Bombardment of U gives medium-heavy atoms (Ba), O.Hahn and F.Strassman; L.Meitner explains; E.Fermi and co-workers did not recognize fission. • 1940: Spontaneous Fission (SF) is discovered by G.N.Flerov and K.A.Petrzhak. • 1947: Ternary fission is discovered by Qian Sabqiang and He Zehui. T8: Fission

  3. Basic Notation • Z is the number of protons, charge number or atomic number • N is the number of neutrons • A = Z + N is the number of nucleons,A is called the mass number • is a specific nucleus, X– chem. sym. • is in an excited state T8: Fission

  4. Nuclides and Isotopes • Isotope ≡ atoms with same Z and A • Nuclide = atoms/nuclei with same Z and A and being in a specific energy state • Isomer = long-lived excited states, T8: Fission

  5. Nuclear Energy Production T8: Fission

  6. Fission Process Ternary: 1/400 0.00650.7% T8: Fission

  7. Compound Nucleus T8: Fission

  8. Binding Energy T8: Fission

  9. Energy Release T8: Fission

  10. Fission Energy T8: Fission

  11. Liquid-Drop Model Nuclear force Surface force Coulomb repulsion Stability maximum Spin factor T8: Fission

  12. Fissionable Ratio T8: Fission

  13. Excitation Energy AX A+1X* T8: Fission

  14. Classification of Heavy Nuclides T8: Fission

  15. Examples of Fission T8: Fission

  16. Fission Product Yield T8: Fission

  17. Kinetic Energy Distribution T8: Fission

  18. Energy Released in Fission T8: Fission

  19. Prompt Neutrons 239Pu 235U 233U E = 1 T8: Fission

  20. Prompt Neutron Energy T8: Fission

  21. E 87Br T½ = 54.5s β– (2%) 87Kr* 86Kr + n β– (98%) 87Kr 87Rb 87Sr t Delayed Neutron Precursors T8: Fission

  22. Delayed Neutron Groups T8: Fission

  23. Delayed Neutron Spectra T8: Fission

  24. Microscopic Cross Section Background material detector Δx Reaction rate R = #/(sm2sec) θ Monoenergetic beam of neutrons I = n/(sm2 sec) x detector cross section σ Microscopic cross section σ is defined by R = σ× I × NB [#/(sm2 sec)] = [sm2] ×[#/(sm2sec)]×[#/sm2] σ/A = Probability per nucleus that a neutron in the beam will interact with it T8: Fission

  25. Fission Cross Section T8: Fission

  26. Resonances T8: Fission

  27. 235U vs. 238U T8: Fission

  28. The END T8: Fission

More Related