armi.physics.neutronics.energyGroups module

Energy group structures for multigroup neutronics calculations.

armi.physics.neutronics.energyGroups.getFastFluxGroupCutoff(eGrpStruc)

Given a constant “fast” energy threshold, return which ARMI energy group index contains this threshold.

Implementation: Return the energy group index which contains a given energy threshold. I_ARMI_EG_FE

signature: getFastFluxGroupCutoff requirements: R_ARMI_EG_FE

This function returns the energy group within a given group structure that contains the fast flux threshold energy. The threshold energy is imported from the constants in the neutronics module, where it is defined as 100 keV. This is a standard definition for fast flux. This function also calculates and returns the fraction of the threshold energy group that is above the 100 keV threshold.

armi.physics.neutronics.energyGroups.getGroupStructure(name)

Return descending neutron energy group upper bounds in eV for a given structure name.

Implementation: Provide the neutron energy group bounds for a given group structure. I_ARMI_EG_NE

signature: getGroupStructure requirements: R_ARMI_EG_NE

There are several built-in group structures that are defined in this module, which are stored in a dictionary. This function takes a group structure name as an input parameter, which it uses as a key for the group structure dictionary. If the group structure name is valid, it returns a copy of the energy group structure resulting from the dictionary lookup. Otherwise, it throws an error.

Notes

Copy of the group structure is return so that modifications of the energy bounds does not propagate back to the GROUP_STRUCTURE dictionary.

armi.physics.neutronics.energyGroups.getGroupStructureType(neutronEnergyBoundsInEv)

Return neutron energy group structure name for a given set of neutron energy group bounds in eV.

armi.physics.neutronics.energyGroups.GROUP_STRUCTURE

Energy groups for use in multigroup neutronics.

Values are the upper bound of each energy in eV from highest energy to lowest (because neutrons typically downscatter…)