def _initializeMassFracs(self):
self.massFracs = dict() # defaults to 0.0, __init__ is not called
if any(v < 0.0 for v in self.values()):
raise ValueError(
"Custom isotopic input for {} is negative".format(self.name)
)
valSum = sum(self.values())
if not abs(valSum - 1.0) < 1e-5 and "fractions" in self.inputFormat:
raise ValueError(
"Fractional custom isotopic input values must sum to 1.0 in: {}".format(
self.name
)
)
if self.inputFormat == "number fractions":
sumNjAj = 0.0
for nuc, nj in self.items():
if nj:
sumNjAj += nj * nucDir.getAtomicWeight(nuc)
for nuc, value in self.items():
massFrac = value * nucDir.getAtomicWeight(nuc) / sumNjAj
self.massFracs[nuc] = massFrac
elif self.inputFormat == "number densities":
if self._density is not None:
raise exceptions.InputError(
"Custom isotopic `{}` is over-specified. It was provided as number "
"densities, and but density ({}) was also provided. Is the input format "
"correct?".format(self.name, self.density)
)
M = {
nuc: Ni
/ units.MOLES_PER_CC_TO_ATOMS_PER_BARN_CM
* nucDir.getAtomicWeight(nuc)
for nuc, Ni in self.items()
}
densityTotal = sum(M.values())
if densityTotal < 0:
raise ValueError("Computed density is negative")
for nuc, Mi in M.items():
self.massFracs[nuc] = Mi / densityTotal
self._computedDensity = densityTotal
elif self.inputFormat == "mass fractions":
self.massFracs = dict(self) # as input
else:
raise ValueError(
"Unrecognized custom isotopics input format {}.".format(
self.inputFormat
)
)
def getMassFractions(numberDensities):
"""
Convert number densities (#/bn-cm) into mass fractions.
Parameters
----------
numberDensities : dict
number densities (#/bn-cm) keyed by their nuclide name
Returns
-------
massFracs : dict
mass fractions -- normalized to 1 -- keyed by their nuclide
name
"""
nucMassFracs = {}
totalWeight = 0.0
for nucName, numDensity in numberDensities.items():
weightI = numDensity * nucDir.getAtomicWeight(nucName)
nucMassFracs[nucName] = weightI # will be normalized at end
totalWeight += weightI
if totalWeight != 0:
for nucName in numberDensities:
nucMassFracs[nucName] /= totalWeight
else:
for nucName in numberDensities:
nucMassFracs[nucName] = 0.0
return nucMassFracs
def calculateNumberDensity(nucName, mass, volume):
"""
Calculates the number density.
Parameters
----------
mass : float
volume : volume
nucName : armi nuclide name -- e.g. 'U235'
Returns
-------
number density : float
number density (#/bn-cm)
See Also
--------
armi.reactor.blocks.Block.setMass
"""
A = nucDir.getAtomicWeight(nucName)
try:
return units.MOLES_PER_CC_TO_ATOMS_PER_BARN_CM * mass / (volume * A)
except ZeroDivisionError:
if mass == 0 and volume == 0:
return 0
raise ValueError("Could not calculate number density with input.\n"
"mass : {}\nvolume : {}\natomic weight : {}\n".format(
mass, volume, A))
def getMassInGrams(nucName, volume, numberDensity=None):
"""
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 : float
mass of nuclide (g)
"""
if not numberDensity:
return 0.0
A = nucDir.getAtomicWeight(nucName)
return numberDensity * volume * A / units.MOLES_PER_CC_TO_ATOMS_PER_BARN_CM
