Density of a custom material is zero despite knowing the density

[drewj-usnctech]

Related to #1682: Material.density returns zero, probably under the assumption a subclass will override the method. And most cases that's true.

But, if you make a custom material in the blueprint file and provide a mass density, the CustomMaterial object does not override the density and will return zero. This is despite the fact that is known by the class

armi/armi/materials/custom.py

Line 40 in 7b26f79

self.customDensity = 1.0

and used in the pseudoDensity method

armi/armi/materials/custom.py

Lines 42 to 50 in 7b26f79

	def pseudoDensity(self, Tk=None, Tc=None):
	"""
	The density value is set in the loading input.
	In some cases it needs to be set after full core assemblies are populated (e.g. for
	CustomLocation materials), so the missing density warning will appear no matter
	what.
	"""
	return self.customDensity

But, if you have a routine that does something with a subclass of Material and relies on Material.density, you can see strange problems because CustomMaterial.density falls back to Material.density which relies on the refDens property

armi/armi/materials/material.py

Lines 492 to 514 in 7b26f79

	def density(self, Tk: float = None, Tc: float = None) -> float:
	"""
	Return density that preserves mass when thermally expanded in 3D (in g/cm^3).
	Notes
	-----
	Since refDens is specified at the material-dep reference case, we don't need to specify the
	reference temperature. It is already consistent with linearExpansion Percent.
	- p*(dp/p(T) + 1) =p*( p + dp(T) )/p = p + dp(T) = p(T)
	- dp/p = (1-(1 + dL/L)**3)/(1 + dL/L)**3
	"""
	Tk = getTk(Tc, Tk)
	dLL = self.linearExpansionPercent(Tk=Tk)
	refD = self.refDens
	if refD is None:
	runLog.warning(
	"{0} has no reference density".format(self),
	single=True,
	label="No refD " + self.getName(),
	)
	return None
	f = (1.0 + dLL / 100.0) ** 3
	return refD / f

which defaults to zero

armi/armi/materials/material.py

Line 101 in 7b26f79

self.refDens = 0.0

[john-science]

@drewj-usnctech Just to be sure. This features is meant to support "custom isotopics" in our blueprints:

armi/armi/reactor/blueprints/tests/test_componentBlueprint.py

Lines 290 to 293 in 7b26f79

	custom isotopics:
	Thorium:
	input format: number densities
	TH232: 1.0

Is that how you're using the Custom(Material) class?

[drewj-usnctech]

@drewj-usnctech Just to be sure. This features is meant to support "custom isotopics" in our blueprints:

armi/armi/reactor/blueprints/tests/test_componentBlueprint.py

Lines 290 to 293 in 7b26f79

	custom isotopics:
	Thorium:
	input format: number densities
	TH232: 1.0

Is that how you're using the Custom(Material) class?

That is correct