NE571 Reactor Theory and Design

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Homework

Please write and run a FORTRAN code to:

Part A. Calculate the Maxwellian thermal flux spectrum for a hydrogen moderator using the free gas model.

Structure your code to accomplish the following:
1. Divide the energy range from 0-1 eV into 1000 segments of width 0.001 eV.
2. Compute a 1000x1000 point-to-point scattering matrix from Equation 12.10 from the text.  (Use a free scattering cross section of 20 and T=293 K.)
3. Create a 1000 point total cross section matrix by summing over the destination energy points for the matrix from step 2.
4. Create a 1000 point energy flux file that has 1 for each energy point.
5. Iteratively solve for the energy-dependent flux shape that evolves from this guess (should settle down within 30 iterations).

Verify that the resulting flux shape is Maxwellian by comparing relative shape to phi(E)=Eexp(-E/kT).

Part B. Modify the code from Part A for a realistic neutron spectrum.

1. Create a uniform source that is 20 in each group.  (Corresponds to elastic scattering from a 1/E flux above 1 eV.)
2. Add a 1/v absorption (10 at 0.0253 eV) to the total cross section.
3. Iterate to compute the flux shape from this source/absorption situation.

Verify that the new peak has shifted up to 0.0325 eV

.
Please e-mail your results (with your code attached, if possible) to me:
 
 

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