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Multi-group Model

Multi-group Model. Wide neutron spectrum. One-group, two-group? Should be generalized. Fraction of an eV. Identify the terms, NOW. Multi-group Model. Fraction. Other sources. Scattering in. Total fission. Absorption. Scattering out. Leakage. Fraction of an eV. Multi-group Model.

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Multi-group Model

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  1. Multi-group Model • Wide neutron spectrum. • One-group, two-group? Should be generalized. Fraction of an eV Identify the terms, NOW. Nuclear Reactors, BAU, 1st Semester, 2008-2009 (Saed Dababneh).

  2. Multi-group Model Fraction Other sources Scattering in Total fission Absorption Scattering out Leakage Fraction of an eV Nuclear Reactors, BAU, 1st Semester, 2008-2009 (Saed Dababneh).

  3. Multi-group Model Maxwellian Fission 1/E 5-group example. Nuclear Reactors, BAU, 1st Semester, 2008-2009 (Saed Dababneh).

  4. Multi-group Model Total fission Thermal fission (~ 97%) Fast fission (~ 3%) Nuclear Reactors, BAU, 1st Semester, 2008-2009 (Saed Dababneh).

  5. Multi-group Model Scattering in Upscattering!!??? Nuclear Reactors, BAU, 1st Semester, 2008-2009 (Saed Dababneh).

  6. Multi-group Model Scattering out Nuclear Reactors, BAU, 1st Semester, 2008-2009 (Saed Dababneh).

  7. Multi-group Model Group 3 Removal cross section Nuclear Reactors, BAU, 1st Semester, 2008-2009 (Saed Dababneh).

  8. Multi-group Model Fraction Other sources Total fission Scattering in Removal In-group Scattering Leakage Net Scattering in Nuclear Reactors, BAU, 1st Semester, 2008-2009 (Saed Dababneh).

  9. Multi-group Model Calculate group-averaged: Or for, we need group-averaged Nuclear Reactors, BAU, 1st Semester, 2008-2009 (Saed Dababneh).

  10. Multi-group Model • Group-averaged parameters? • ENDF. • Integrate term by term over groups and equate to equation of multi-group model. Units! Nuclear Reactors, BAU, 1st Semester, 2008-2009 (Saed Dababneh).

  11. Multi-group Model • Define group flux  Nuclear Reactors, BAU, 1st Semester, 2008-2009 (Saed Dababneh).

  12. Multi-group Model  Nuclear Reactors, BAU, 1st Semester, 2008-2009 (Saed Dababneh).

  13. Multi-group Model  Nuclear Reactors, BAU, 1st Semester, 2008-2009 (Saed Dababneh).

  14. Multi-group Model  Nuclear Reactors, BAU, 1st Semester, 2008-2009 (Saed Dababneh).

  15. Multi-group Model  Nuclear Reactors, BAU, 1st Semester, 2008-2009 (Saed Dababneh).

  16. Multi-group Model  Nuclear Reactors, BAU, 1st Semester, 2008-2009 (Saed Dababneh).

  17. Multi-group Model ENDF High G, few mesh points. Flux Poison, burnup (or better consumption), temperature, control rod position, etc… Small G, more mesh points. Flux Nuclear Reactors, BAU, 1st Semester, 2008-2009 (Saed Dababneh).

  18. Multi-group Model • What could make life a little easier?! • No upscattering • set group G to include neutrons up to ~1 eV. • No group skipping when scattering down (directly coupled). Your choice of how to tackle in-scattering. HW 27 How can we pledge this? What about H? Nuclear Reactors, BAU, 1st Semester, 2008-2009 (Saed Dababneh).

  19. Multi-group Model Criticality Not all sources, only fission. Not only sinks Iterations. No upscatter Redundant when no upscatter. Nuclear Reactors, BAU, 1st Semester, 2008-2009 (Saed Dababneh).

  20. Multi-group Model No upscatter Iterations. Nuclear Reactors, BAU, 1st Semester, 2008-2009 (Saed Dababneh).

  21. Multi-group Model No upscatter Directly coupled Iterations. Nuclear Reactors, BAU, 1st Semester, 2008-2009 (Saed Dababneh).

  22. Multi-group Model Multi-group  one-group Nuclear Reactors, BAU, 1st Semester, 2008-2009 (Saed Dababneh).

  23. Multi-group Model Nuclear Reactors, BAU, 1st Semester, 2008-2009 (Saed Dababneh).

  24. Multi-group Model Nuclear Reactors, BAU, 1st Semester, 2008-2009 (Saed Dababneh).

  25. Multi-group Model Substituting all of the above into yields which is the one-group diffusion equation. Nuclear Reactors, BAU, 1st Semester, 2008-2009 (Saed Dababneh).

  26. Multi-group Model Project 3 Work out the multi-group to two-group collapsing and investigate criticality. Write down the appropriate matrices. Nuclear Reactors, BAU, 1st Semester, 2008-2009 (Saed Dababneh).

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