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Merge pull request #852 from paulromano/model

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Model class and test suite improvements
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Will Boyd 2017-04-11 09:02:44 -04:00 • committed by GitHub
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24
docs/source/usersguide/cross_sections.rst
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@ -199,6 +199,30 @@ OpenMC.
etc. For a more thorough overview of the capabilities of this class,
see the :ref:`notebook_nuclear_data` example notebook.
Enabling Resonance Scattering Treatments
----------------------------------------
In order for OpenMC to correctly treat elastic scattering in heavy nuclides
where low-lying resonances might be present (see
:ref:`energy_dependent_xs_model`), the elastic scattering cross section at 0 K
must be present. To add the 0 K elastic scattering cross section to existing
:class:`IncidentNeutron` instance, you can use the
:meth:`IncidentNeutron.add_elastic_0K_from_endf` method which requires an ENDF
file for the nuclide you are modifying::
u238 = openmc.data.IncidentNeutron.from_hdf5('U238.h5')
u238.add_elastic_0K_from_endf('n-092_U_238.endf')
u238.export_to_hdf5('U238_with_0K.h5')
With 0 K elastic scattering data present, you can turn on a resonance scattering
method using :attr:`Settings.resonance_scattering`.
.. note:: The process of reconstructing resonances and generating tabulated 0 K
cross sections can be computationally expensive, especially for
nuclides like U-238 where thousands of resonances are present. Thus,
running the :meth:`IncidentNeutron.add_elastic_0K_from_endf` method
may take several minutes to complete.
-----------------------
Windowed Multipole Data
-----------------------