armi.physics.neutronics.crossSectionSettings module¶

The data structures and schema of the cross section modeling options.

These are advanced/compound settings that are carried along in the normal cs object but aren’t simple key/value pairs.

The cs object could either hold the base data (dicts) and create instances of these data structure objects as needed, or the settings system could actually hold instances of these data structures. It is most convenient to let the cs object hold actual instances of these data.

See detailed docs in :doc: Lattice Physics <reference/physics/neutronics/latticePhysics/latticePhysics>.

class armi.physics.neutronics.crossSectionSettings.XSSettings(*args, **kwargs)[source]¶

Bases: dict

Container for holding multiple cross section settings based on their XSID.

This is intended to be stored as part of a case settings and to be used for cross section modeling within a run.

Notes

This is a specialized dictionary that functions in a similar manner as a defaultdict where if a key (i.e., XSID) is missing then a default will be set. If a missing key is being added before the setDefaults method is called then this will produce an error.

This cannot just be a defaultdict because the creation of new cross section settings are dependent on user settings.

__getitem__(xsID)[source]¶

Return the stored settings of the same xs type and the lowest burnup group if they exist.

Notes

If AA and AB exist, but AC is created, then the intended behavior is that AC settings will be set to the settings in AA.
If only YZ exists and YA is created, then the intended behavior is that YA settings will NOT be set to the settings in YZ
Requirements for using the existing cross section settings:
1. The existing XS ID must match the current XS ID.
2. The current xs burnup group must be larger than the lowest burnup group for the existing XS ID
3. If 3a. and 3b. are not met, then the default cross section settings will be set for the current XS ID

setDefaults(blockRepresentation, validBlockTypes)[source]¶

Set defaults for current and future xsIDs based user settings.

This must be delayed past read-time since the settings that effect this may not be loaded yet and could still be at their own defaults when this input is being processed. Thus, defaults are set at a later time.

Parameters

blockRepresentation (str) – Valid options are provided in CrossSectionGroupManager.BLOCK_COLLECTIONS
validBlockTypes (list of str or bool) – This configures which blocks (by their type) that the cross section group manager will merge together to create a representative block. If set to None or True then all block types in the XS ID will be considered. If this is set to False then a default of [“fuel”] will be used. If this is set to a list of strings then the specific list will be used. A typical input may be [“fuel”] to just consider the fuel blocks.

See also

armi.physics.neutronics.crossSectionGroupManager.CrossSectionGroupManager.interactBOL(): calls this

_getDefault(xsID)[source]¶

Process the optional crossSectionControl setting.

This input allows users to override global defaults for specific cross section IDs (xsID).

To simplify downstream handling of the various XS controls, we build a full data structure here that should fully define the settings for each individual cross section ID.

class armi.physics.neutronics.crossSectionSettings.XSModelingOptions(xsID, geometry=None, fileLocation=None, validBlockTypes=None, blockRepresentation=None, driverID=None, criticalBuckling=None, nuclideReactionDriver=None, externalDriver=None, useHomogenizedBlockComposition=None, numInternalRings=None, numExternalRings=None, mergeIntoClad=None, meshSubdivisionsPerCm=None)[source]¶

Bases: object

Cross section modeling options for a particular XS ID.

xsID¶

Cross section ID that is two characters maximum (i.e., AA).

Type: str

geometry¶

The geometry modeling approximation for regions of the core with this assigned xsID. This is required if the fileLocation attribute is not provided. This cannot be set if the fileLocation is provided.

Type: str

fileLocation¶

This should be a list of paths where the cross sections for this xsID can be copied from. This is required if the geometry attribute is not provided. This cannot be set if the geometry is provided.

Type: list of str

validBlockTypes¶

This is a configuration option for how the cross section group manager determines which blocks/regions to manage as part of the same collection for the current xsID. If this is set to None then all blocks/regions with the current xsID will be considered.

Type: str or None

blockRepresentation¶

This is a configuration option for how the cross section group manager will select how to create a representative block based on the collection within the same xsID. See: crossSectionGroupManager.BLOCK_COLLECTIONS.

Type: str

driverID¶

This is a lattice physics configuration option used to determine which representative block can be used as a “fixed source” driver for another composition. This is particularly useful for non-fuel or highly subcritical regions.

Type: str

criticalBuckling¶

This is a lattice physics configuration option used to enable or disable the critical buckling search option.

Type: bool

nuclideReactionDriver¶

This is a lattice physics configuration option that is similar to the driverID, but rather than applying the source from a specific representative block, the neutron source is taken from a single nuclides fission spectrum (i.e., U235). This is particularly useful for configuring SERPENT 2 lattice physics calculations.

Type: str

externalDriver¶

This is a lattice physics configuration option that can be used to determine if the fixed source problem is internally driven or externally driven by the driverID region. Externally driven means that the region will be placed on the outside of the current xsID block/region. If this is False then the driver region will be “inside” (i.e., an inner ring in a cylindrical model).

Type: bool

useHomogenizedBlockComposition¶

This is a lattice physics configuration option that is useful for modeling spatially dependent problems (i.e., 1D/2D). If this is True then the representative block for the current xsID will be be a homogenized region. If this is False then the block will be represented in the geometry type selected. This is mainly used for 1D cylindrical problems.

Type: bool

numInternalRings¶

This is a lattice physics configuration option that is used to specify the number of grid-based rings for the representative block.

Type: int

numExternalRings¶

This is a lattice physics configuration option that is used to specify the number of grid-based rings for the driver block.

Type: int

mergeIntoClad¶

This is a lattice physics configuration option that is a list of component names to merge into a “clad” component. This is highly-design specific and is sometimes used to merge a “gap” or low-density region into a “clad” region to avoid numerical issues.

Type: list of str

meshSubdivisionsPerCm¶

This is a lattice physics configuration option that can be used to control subregion meshing of the representative block in 1D problems.

Type: float

Notes

Not all default attributes may be useful for your specific application and you may require other types of configuration options. These are provided as examples since the base latticePhysicsInterface does not implement models that use these. For additional options, consider subclassing the base Setting object and using this model as a template.

property xsType¶: Return the single-char cross section type indicator.

property buGroup¶: Return the single-char burnup group indicator.

property isPregenerated¶: True if this points to a pre-generated XS file.

serialize()[source]¶: Return as a dictionary without xsID and with None values excluded.

validate()[source]¶

Performs validation checks on the inputs and provides warnings for option inconsistencies.

Raises: ValueError – When the mutually exclusive fileLocation and geometry attributes are provided or when neither are provided.

setDefaults(blockRepresentation, validBlockTypes)[source]¶

This sets the defaults based on some recommended values based on the geometry type.

Parameters

blockRepresentation (str) – Valid options are provided in CrossSectionGroupManager.BLOCK_COLLECTIONS
validBlockTypes (list of str or bool) – This configures which blocks (by their type) that the cross section group manager will merge together to create a representative block. If set to None or True then all block types in the XS ID will be considered. If this is set to False then a default of [“fuel”] will be used. If this is set to a list of strings then the specific list will be used. A typical input may be [“fuel”] to just consider the fuel blocks.

Notes

These defaults are application-specific and design specific. They are included to provide an example and are tuned to fit the internal needs of TerraPower. Consider a separate implementation/subclass if you would like different behavior.

armi.physics.neutronics.crossSectionSettings.serializeXSSettings(xsSettingsDict: Union[armi.physics.neutronics.crossSectionSettings.XSSettings, Dict]) → Dict[str, Dict][source]¶: Return a serialized form of the XSSettings as a dictionary.

Notes

Attributes that are not set (i.e., set to None) will be skipped.

class armi.physics.neutronics.crossSectionSettings.XSSettingDef(name)[source]¶

Bases: armi.settings.setting.Setting

Custom setting object to manage the cross section dictionary-like inputs.

Notes

This uses the xsSettingsValidator schema to validate the inputs and will automatically coerce the value into a XSSettings dictionary.

Initialize a Setting object.

Parameters

name (str) – the setting’s name
default (object) – The setting’s default value
description (str, optional) – The description of the setting
label (str, optional) – the shorter description used for the ARMI GUI
options (list, optional) – Legal values (useful in GUI drop-downs)
schema (callable, optional) – A function that gets called with the configuration VALUES that build this setting. The callable will either raise an exception, safely modify/update, or leave unchanged the value. If left blank, a type check will be performed against the default.
enforcedOptions (bool, optional) – Require that the value be one of the valid options.
subLabels (tuple, optional) – The names of the fields in each tuple for a setting that accepts a list of tuples. For example, if a setting is a list of (assembly name, file name) tuples, the sublabels would be (“assembly name”, “file name”). This is needed for building GUI widgets to input such data.
isEnvironment (bool, optional) – Whether this should be considered an “environment” setting. These can be used by the Case system to propagate environment options through command-line flags.
oldNames (list of tuple, optional) – List of previous names that this setting used to have, along with optional expiration dates. These can aid in automatic migration of old inputs. When provided, if it is appears that the expiration date has passed, old names will result in errors, requiring to user to update their input by hand to use more current settings.

dump()[source]¶: Return a serialized version of the XSSetting object.

armi.physics.neutronics.crossSectionSettings.xsSettingsValidator(xsSettingsDict: Dict[str, Dict]) → armi.physics.neutronics.crossSectionSettings.XSSettings[source]¶: Returns a XSSettings object if validation is successful.

Notes

This provides two levels of checks. The first check is that the attributes provided as user input contains the correct key/values and the values are of the correct type. The second check uses the XSModelingOptions.validate method to check for input inconsistencies and provides warnings if there are any issues.