armi.utils.densityTools module¶

Assorted utilities to help with basic density calculations.

armi.utils.densityTools.getNDensFromMasses(rho, massFracs, normalize=False)[source]¶

Convert density (g/cc) and massFracs vector into a number densities vector (#/bn-cm).

Parameters

rho (float) – density in (g/cc)
massFracs (dict) – vector of mass fractions – normalized to 1 – keyed by their nuclide name

Returns

numberDensities – vector of number densities (#/bn-cm) keyed by their nuclide name

Return type

dict

armi.utils.densityTools.getMassFractions(numberDensities)[source]¶

Convert number densities (#/bn-cm) into mass fractions.

Parameters: numberDensities (dict) – number densities (#/bn-cm) keyed by their nuclide name
Returns: massFracs – mass fractions – normalized to 1 – keyed by their nuclide name
Return type: dict

armi.utils.densityTools.calculateMassDensity(numberDensities)[source]¶

Calculates the mass density.

Parameters: numberDensities (dict) – vector of number densities (atom/bn-cm) indexed by nuclides names
Returns: rho – density in (g/cc)
Return type: float

armi.utils.densityTools.calculateNumberDensity(nucName, mass, volume)[source]¶

Calculates the number density.

Parameters

mass (float) –
volume (volume) –
nucName (armi nuclide name -- e.g. 'U235') –

Returns

number density – number density (#/bn-cm)

Return type

float

See also

armi.reactor.blocks.Block.setMass

armi.utils.densityTools.getMassInGrams(nucName, volume, numberDensity=None)[source]¶

Gets mass of a nuclide of a known volume and know number density.

Parameters

nucName (str) – name of nuclide – e.g. ‘U235’
volume (float) – volume in (cm3)
numberDensity (float) – number density in (at/bn-cm)

Returns

mass – mass of nuclide (g)

Return type

float

armi.utils.densityTools.formatMaterialCard(densities, matNum=0, minDens=1e-15, sigFigs=8, mcnp6Compatible=False, mcnpLibrary=None)[source]¶

Formats nuclides and densities into a MCNP material card.

Parameters

densities (dict) – number densities indexed by nuclideBase
matNum (int) – mcnp material number
minDens (float) – minimum density
sigFigs (int) – significant figures for the material card

Returns

mCard – list of material card strings

Return type

list

armi.utils.densityTools.filterNuclideList(nuclideVector, nuclides)[source]¶

Filter out nuclides not in the nuclide vector.

Parameters

nuclideVector (dict) – dictionary of values indexed by nuclide identifiers – e.g. nucNames or nuclideBases
nuclides (list) – list of nuclide identifiers

Returns

nuclideVector – dictionary of values indexed by nuclide identifiers – e.g. nucNames or nuclideBases

Return type

dict

armi.utils.densityTools.normalizeNuclideList(nuclideVector, normalization=1.0)[source]¶

normalize the nuclide vector.

Parameters

nuclideVector (dict) – dictionary of values – e.g. floats, ints – indexed by nuclide identifiers – e.g. nucNames or nuclideBases
normalization (float) –

Returns

nuclideVector – dictionary of values indexed by nuclide identifiers – e.g. nucNames or nuclideBases

Return type

dict

armi.utils.densityTools.expandElementalMassFracsToNuclides(massFracs: dict, elementExpansionPairs: Tuple[armi.nucDirectory.elements.Element, List[armi.nucDirectory.nuclideBases.NuclideBase]])[source]¶

Expand elemental mass fractions to natural nuclides.

Modifies the input massFracs in place to contain nuclides.

Notes

This indirectly updates number densities through mass fractions.

Parameters

massFracs (dict(str, float)) – dictionary of nuclide or element names with mass fractions. Elements will be expanded in place using natural isotopics.
elementExpansionPairs ((Element, [NuclideBase]) pairs) – element objects to expand (from nuclidBase.element) and list of NuclideBases to expand into (or None for all natural)

armi.utils.densityTools.expandElementalNuclideMassFracs(element: armi.nucDirectory.elements.Element, massFrac: dict, isotopicSubset: Optional[List[armi.nucDirectory.nuclideBases.NuclideBase]] = None)[source]¶

Return a dictionary of nuclide names to isotopic mass fractions.

If an isotopic subset is passed in, the mass fractions get scaled up s.t. the total mass fraction remains constant.

Parameters

element (Element) – The element to expand to natural isotopics
massFrac (float) – Mass fraction of the initial element
isotopicSubset (list of NuclideBases) – Natural isotopes to include in the expansion. Useful e.g. for excluding O18 from an expansion of Oxygen.

armi.utils.densityTools.getChemicals(nuclideInventory)[source]¶

Groups the inventories of nuclides by their elements.

Parameters: nuclideInventory (dict) – nuclide inventories indexed by nuc – either nucNames or nuclideBases
Returns: chemicals – inventory of elements indexed by element symbol – e.g. ‘U’ or ‘PU’
Return type: dict

armi.utils.densityTools.applyIsotopicsMix(material, enrichedMassFracs: Dict[str, float], fertileMassFracs: Dict[str, float])[source]¶

Update material heavy metal mass fractions based on its enrichment and two nuclide feeds.

This will remix the heavy metal in a Material object based on the object’s class1_wt_frac parameter and the input nuclide information.

This can be used for inputting mixtures of two external custom isotopic feeds as well as for fabricating assemblies from two closed-cycle collections of material.