Allow mesh domain in get_microxs_and_flux (#2700)

openmc/deplete/microxs.py

@@ -39,7 +39,7 @@ def get_microxs_and_flux(
     ----------
     model : openmc.Model
         OpenMC model object. Must contain geometry, materials, and settings.
-    domains : list of openmc.Material or openmc.Cell or openmc.Universe
+    domains : list of openmc.Material or openmc.Cell or openmc.Universe, or openmc.MeshBase
         Domains in which to tally reaction rates.
     nuclides : list of str
         Nuclides to get cross sections for. If not specified, all burnable
@@ -92,7 +92,9 @@ def get_microxs_and_flux(
         energy_filter = openmc.EnergyFilter.from_group_structure(energies)
     else:
         energy_filter = openmc.EnergyFilter(energies)
-    if isinstance(domains[0], openmc.Material):
+    if isinstance(domains, openmc.MeshBase):
+        domain_filter = openmc.MeshFilter(domains)
+    elif isinstance(domains[0], openmc.Material):
         domain_filter = openmc.MaterialFilter(domains)
     elif isinstance(domains[0], openmc.Cell):
         domain_filter = openmc.CellFilter(domains)

tests/regression_tests/microxs/test.py

@@ -46,14 +46,22 @@ def model():
     return openmc.Model(geometry, materials, settings)
 
 
-def test_from_model(model):
-    domains = model.materials[:1]
+@pytest.mark.parametrize("domain_type", ["materials", "mesh"])
+def test_from_model(model, domain_type):
+    if domain_type == 'materials':
+        domains = model.materials[:1]
+    elif domain_type == 'mesh':
+        mesh = openmc.RegularMesh()
+        mesh.lower_left = (-0.62, -0.62)
+        mesh.upper_right = (0.62, 0.62)
+        mesh.dimension = (3, 3)
+        domains = mesh
     nuclides = ['U234', 'U235', 'U238', 'U236', 'O16', 'O17', 'I135', 'Xe135',
                 'Xe136', 'Cs135', 'Gd157', 'Gd156']
     _, test_xs = get_microxs_and_flux(model, domains, nuclides, chain_file=CHAIN_FILE)
     if config['update']:
-        test_xs[0].to_csv('test_reference.csv')
+        test_xs[0].to_csv(f'test_reference_{domain_type}.csv')
 
-    ref_xs = MicroXS.from_csv('test_reference.csv')
+    ref_xs = MicroXS.from_csv(f'test_reference_{domain_type}.csv')
 
     np.testing.assert_allclose(test_xs[0].data, ref_xs.data, rtol=1e-11)

tests/regression_tests/microxs/test_reference_mesh.csv

@@ -0,0 +1,25 @@
+nuclides,reactions,groups,xs
+U234,"(n,gamma)",1,27.027171724208227
+U234,fission,1,0.04333740860093498
+U235,"(n,gamma)",1,12.683875995776193
+U235,fission,1,4.2596665957162605
+U238,"(n,gamma)",1,4.479719141496804
+U238,fission,1,0.009460665924409056
+U236,"(n,gamma)",1,8.469286849810802
+U236,fission,1,0.027373590840715795
+O16,"(n,gamma)",1,7.478160204479271e-05
+O16,fission,1,0.0
+O17,"(n,gamma)",1,0.0004743959164164789
+O17,fission,1,0.0
+I135,"(n,gamma)",1,8.33959524761822
+I135,fission,1,0.0
+Xe135,"(n,gamma)",1,282068.447252079
+Xe135,fission,1,0.0
+Xe136,"(n,gamma)",1,0.02888928065916194
+Xe136,fission,1,0.0
+Cs135,"(n,gamma)",1,2.5863526577468408
+Cs135,fission,1,0.0
+Gd157,"(n,gamma)",1,16518.24083307153
+Gd157,fission,1,0.0
+Gd156,"(n,gamma)",1,2.838514589417232
+Gd156,fission,1,0.0