1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Diffusion Theory

  1. Apr 20, 2008 #1
    This is in the beginning of a long set of problems, and I am lost. I don't get anything like this answer. Any guidance? I have a feeling its simple but haven't done much of these.

    Write down the diffusion equation for the neutron flux in a multiplying sphere of radius R containing a constant distributed source of strength Q neutrons/cm3/s. Assuming that the flux vanishes at the sphere surface and that it remains finite at the origin:
    Solve the diffusion equation when k inf = 1 and show that the neutron flux is given by:
    (Q/6D)(R^2 − r^2)
     
  2. jcsd
  3. Apr 20, 2008 #2

    Astronuc

    User Avatar

    Staff: Mentor

    One has to write the diffusion equation (in spherical coordinates) with a constant, distributed source, and apply the boundary conditions, that the flux [tex]\phi[/tex] is finite at r = 0, and 0 at r = R.

    The current should also be 0 at r = 0.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Diffusion Theory
  1. Diffusion Equation (Replies: 4)

  2. Two Group Diffusion (Replies: 1)

Loading...