Have unpack_tallies_and_normalize return an OperatorResult

openmc/deplete/abc.py

@@ -58,7 +58,7 @@ OperatorResult = namedtuple('OperatorResult', ['k', 'rates'])
 
 
 class Operator(metaclass=ABCMeta):
-    """Abstract class defining all methods needed for the integrator.
+    """Abstract class defining a transport operator
 
     Attributes
     ----------
@@ -82,12 +82,9 @@ class Operator(metaclass=ABCMeta):
 
         Returns
         -------
-        k : float
-            Eigenvalue of the problem.
-        rates : ReactionRates
-            Reaction rates from this simulation.
-        seed : int
-            Seed for this simulation.
+        openmc.deplete.OperatorResult
+            Eigenvalue and reaction rates resulting from transport operator
+
         """
         pass
 

openmc/deplete/openmc_wrapper.py

@@ -98,9 +98,7 @@ class OpenMCSettings(Settings):
 
 
 class OpenMCOperator(Operator):
-    """The OpenMC Operator class.
-
-    Provides Operator functions for OpenMC.
+    """OpenMC transport operator
 
     Parameters
     ----------
@@ -210,7 +208,7 @@ class OpenMCOperator(Operator):
         time_openmc = time.time()
 
         # Extract results
-        k = self.unpack_tallies_and_normalize()
+        op_result = self.unpack_tallies_and_normalize()
 
         if comm.rank == 0:
             time_unpack = time.time()
@@ -219,7 +217,7 @@ class OpenMCOperator(Operator):
                 print("Time to openmc: ", time_openmc - time_start)
                 print("Time to unpack: ", time_unpack - time_openmc)
 
-        return OperatorResult(k, copy.deepcopy(self.reaction_rates))
+        return copy.deepcopy(op_result)
 
     def extract_mat_ids(self):
         """Extracts materials and assigns them to processes.
@@ -561,23 +559,19 @@ class OpenMCOperator(Operator):
             self.number.set_mat_slice(i, total_density[i])
 
     def unpack_tallies_and_normalize(self):
-        """Unpack tallies from OpenMC
+        """Unpack tallies from OpenMC and return an operator result
 
-        This function reads the tallies generated by OpenMC (from the tally.xml
-        file generated in generate_tally_xml) normalizes them so that the total
-        power generated is new_power, and then stores them in the reaction rate
-        database.
+        This method uses OpenMC's C API bindings to determine the k-effective
+        value and reaction rates from the simulation. The reaction rates are
+        normalized by the user-specified power, summing the product of the
+        fission reaction rate times the fission Q value for each material.
 
         Returns
         -------
-        k : float
-            Eigenvalue of the last simulation.
+        openmc.deplete.OperatorResult
+            Eigenvalue and reaction rates resulting from transport operator
 
-        Todo
-        ----
-            Provide units for power
         """
-
         rates = self.reaction_rates
         rates[:, :, :] = 0.0
 
@@ -655,7 +649,7 @@ class OpenMCOperator(Operator):
         # Scale reaction rates to obtain units of reactions/sec
         rates[:, :, :] *= power / energy
 
-        return k_combined
+        return OperatorResult(k_combined, rates)
 
     def load_participating(self):
         """Loads a cross_sections.xml file to find participating nuclides.

openmc/deplete/reaction_rates.py

@@ -23,7 +23,7 @@ class ReactionRates(object):
     Attributes
     ----------
     mat_to_ind : OrderedDict of str to int
-        A dictionary mapping cell ID as string to index.
+        A dictionary mapping material ID as string to index.
     nuc_to_ind : OrderedDict of str to int
         A dictionary mapping nuclide name as string to index.
     react_to_ind : OrderedDict of str to int