Add methods on Material to get mass (if volume specified)

docs/source/pythonapi/data.rst

@@ -36,6 +36,7 @@ Core Functions
     openmc.data.thin
     openmc.data.water_density
     openmc.data.write_compact_458_library
+    openmc.data.zam
 
 Angle-Energy Distributions
 --------------------------

openmc/data/data.py

@@ -313,6 +313,26 @@ def water_density(temperature, pressure=0.1013):
     return coeff / pi / gamma1_pi
 
 
+def zam(name):
+    """Return tuple of (atomic number, mass number, metastable state)
+
+    Parameters
+    ----------
+    name : str
+        Name of nuclide using GND convention, e.g., 'Am242m1'
+
+    Returns
+    -------
+    3-tuple of int
+        Atomic number, mass number, and metastable state
+
+    """
+    symbol, A, state = re.match(r'([A-Zn][a-z]*)(\d+)((?:_[em]\d+)?)',
+                                name).groups()
+    metastable = int(state[2:]) if state else 0
+    return (ATOMIC_NUMBER[symbol], int(A), metastable)
+
+
 # Values here are from the Committee on Data for Science and Technology
 # (CODATA) 2014 recommendation (doi:10.1103/RevModPhys.88.035009).
 

openmc/deplete/chain.py

@@ -40,15 +40,6 @@ _REACTIONS = [
 ]
 
 
-def _get_zai(s):
-    """Get ZAI value (10000*z + 10*A + metastable state) for sorting purposes"""
-    symbol, A, state = re.match(r'([A-Zn][a-z]*)(\d+)((?:_[em]\d+)?)', s).groups()
-    Z = openmc.data.ATOMIC_NUMBER[symbol]
-    A = int(A)
-    state = int(state[2:]) if state else 0
-    return 10000*Z + 10*A + state
-
-
 def replace_missing(product, decay_data):
     """Replace missing product with suitable decay daughter.
 
@@ -197,7 +188,7 @@ class Chain(object):
         missing_fpy = []
         missing_fp = []
 
-        for idx, parent in enumerate(sorted(decay_data, key=_get_zai)):
+        for idx, parent in enumerate(sorted(decay_data, key=openmc.data.zam)):
             data = decay_data[parent]
 
             nuclide = Nuclide()
@@ -290,7 +281,7 @@ class Chain(object):
                         missing_fp.append((parent, E, yield_replace))
 
                     nuclide.yield_data[E] = []
-                    for k in sorted(yields, key=_get_zai):
+                    for k in sorted(yields, key=openmc.data.zam):
                         nuclide.yield_data[E].append((k, yields[k]))
 
         # Display warnings

openmc/material.py

@@ -52,8 +52,7 @@ class Material(IDManagerMixin):
         'atom/b-cm', 'atom/cm3', 'sum', or 'macro'.  The 'macro' unit only
         applies in the case of a multi-group calculation.
     depletable : bool
-        Indicate whether the material is depletable. This attribute can be used
-        by downstream depletion applications.
+        Indicate whether the material is depletable.
     nuclides : list of tuple
         List in which each item is a 3-tuple consisting of a nuclide string, the
         percent density, and the percent type ('ao' or 'wo').
@@ -74,6 +73,9 @@ class Material(IDManagerMixin):
         :meth:`Geometry.determine_paths` method.
     num_instances : int
         The number of instances of this material throughout the geometry.
+    fissionable_mass : float
+        Mass of fissionable nuclides in the material in [g]. Requires that the
+        :attr:`volume` attribute is set.
 
     """
 
@@ -245,6 +247,18 @@ class Material(IDManagerMixin):
                                str)
         self._isotropic = list(isotropic)
 
+    @property
+    def fissionable_mass(self):
+        if self.volume is None:
+            raise ValueError("Volume must be set in order to determine mass.")
+        density = 0.0
+        for nuc, atoms_per_cc in self.get_nuclide_atom_densities().values():
+            Z = openmc.data.zam(nuc)[0]
+            if Z >= 90:
+                density += 1e24 * atoms_per_cc * openmc.data.atomic_mass(nuc) \
+                           / openmc.data.AVOGADRO
+        return density*self.volume
+
     @classmethod
     def from_hdf5(cls, group):
         """Create material from HDF5 group
@@ -687,7 +701,53 @@ class Material(IDManagerMixin):
 
         return nuclides
 
+    def get_mass_density(self, nuclide=None):
+        """Return mass density of one or all nuclides
+
+        Parameters
+        ----------
+        nuclides : str, optional
+            Nuclide for which density is desired. If not specified, the density
+            for the entire material is given.
+
+        Returns
+        -------
+        float
+            Density of the nuclide/material in [g/cm^3]
+
+        """
+        mass_density = 0.0
+        for nuc, atoms_per_cc in self.get_nuclide_atom_densities().values():
+            density_i = 1e24 * atoms_per_cc * openmc.data.atomic_mass(nuc) \
+                        / openmc.data.AVOGADRO
+            if nuclide is None or nuclide == nuc:
+                mass_density += density_i
+        return mass_density
+
+    def get_mass(self, nuclide=None):
+        """Return mass of one or all nuclides.
+
+        Note that this method requires that the :attr:`Material.volume` has
+        already been set.
+
+        Parameters
+        ----------
+        nuclides : str, optional
+            Nuclide for which mass is desired. If not specified, the density
+            for the entire material is given.
+
+        Returns
+        -------
+        float
+            Mass of the nuclide/material in [g]
+
+        """
+        if self.volume is None:
+            raise ValueError("Volume must be set in order to determine mass.")
+        return self.volume*self.get_mass_density(nuclide)
+
     def clone(self, memo=None):
+
         """Create a copy of this material with a new unique ID.
 
         Parameters

tests/unit_tests/test_data_misc.py

@@ -58,3 +58,11 @@ def test_water_density():
     assert dens(300.0, 3.0) == pytest.approx(1e-3/0.100215168e-2, 1e-6)
     assert dens(300.0, 80.0) == pytest.approx(1e-3/0.971180894e-3, 1e-6)
     assert dens(500.0, 3.0) == pytest.approx(1e-3/0.120241800e-2, 1e-6)
+
+
+def test_zam():
+    assert openmc.data.zam('H1') == (1, 1, 0)
+    assert openmc.data.zam('Zr90') == (40, 90, 0)
+    assert openmc.data.zam('Am242') == (95, 242, 0)
+    assert openmc.data.zam('Am242_m1') == (95, 242, 1)
+    assert openmc.data.zam('Am242_m10') == (95, 242, 10)

tests/unit_tests/test_material.py

@@ -121,6 +121,23 @@ def test_get_nuclide_atom_densities(uo2):
         assert density > 0
 
 
+def test_mass():
+    m = openmc.Material()
+    m.add_nuclide('Zr90', 1.0, 'wo')
+    m.add_nuclide('U235', 1.0, 'wo')
+    m.set_density('g/cm3', 2.0)
+    m.volume = 10.0
+
+    assert m.get_mass_density('Zr90') == pytest.approx(1.0)
+    assert m.get_mass_density('U235') == pytest.approx(1.0)
+    assert m.get_mass_density() == pytest.approx(2.0)
+
+    assert m.get_mass('Zr90') == pytest.approx(10.0)
+    assert m.get_mass('U235') == pytest.approx(10.0)
+    assert m.get_mass() == pytest.approx(20.0)
+    assert m.fissionable_mass == pytest.approx(10.0)
+
+
 def test_materials(run_in_tmpdir):
     m1 = openmc.Material()
     m1.add_nuclide('U235', 1.0, 'wo')