From 2e358a2ca474371298dbbbe954527a3bcd764f78 Mon Sep 17 00:00:00 2001
From: Paul Romano <paul.k.romano@gmail.com>
Date: Fri, 9 Feb 2018 16:48:32 -0600
Subject: [PATCH] Release resources properly from Operator class

---
 openmc/deplete/integrator/cecm.py      | 3 +++
 openmc/deplete/integrator/predictor.py | 3 +++
 openmc/deplete/openmc_wrapper.py       | 7 ++++---
 tests/dummy_geometry.py                | 3 +++
 tests/unit_tests/test_capi.py          | 2 +-
 5 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/openmc/deplete/integrator/cecm.py b/openmc/deplete/integrator/cecm.py
index 4d9baebb2..699ccc203 100644
--- a/openmc/deplete/integrator/cecm.py
+++ b/openmc/deplete/integrator/cecm.py
@@ -131,3 +131,6 @@ def cecm(operator, print_out=True):
 
     # Return to origin
     os.chdir(dir_home)
+
+    # Release resources
+    operator.finalize()
diff --git a/openmc/deplete/integrator/predictor.py b/openmc/deplete/integrator/predictor.py
index 6c9d538fd..7b41e6649 100644
--- a/openmc/deplete/integrator/predictor.py
+++ b/openmc/deplete/integrator/predictor.py
@@ -98,3 +98,6 @@ def predictor(operator, print_out=True):
 
     # Return to origin
     os.chdir(dir_home)
+
+    # Release resources
+    operator.finalize()
diff --git a/openmc/deplete/openmc_wrapper.py b/openmc/deplete/openmc_wrapper.py
index 05b5057d2..5955a5def 100644
--- a/openmc/deplete/openmc_wrapper.py
+++ b/openmc/deplete/openmc_wrapper.py
@@ -219,9 +219,6 @@ class OpenMCOperator(Operator):
         # Create reaction rate tables
         self.initialize_reaction_rates()
 
-    def __del__(self):
-        openmc.capi.finalize()
-
     def extract_mat_ids(self):
         """Extracts materials and assigns them to processes.
 
@@ -475,6 +472,10 @@ class OpenMCOperator(Operator):
         # Return number density vector
         return self.total_density_list()
 
+    def finalize(self):
+        """Finalize a depletion simulation and release resources."""
+        openmc.capi.finalize()
+
     def _update_materials(self):
         """Updates material compositions in OpenMC on all processes."""
 
diff --git a/tests/dummy_geometry.py b/tests/dummy_geometry.py
index 614cc726e..ecdce567d 100644
--- a/tests/dummy_geometry.py
+++ b/tests/dummy_geometry.py
@@ -21,6 +21,9 @@ class DummyGeometry(Operator):
     def __init__(self, settings):
         super().__init__(settings)
 
+    def finalize(self):
+        pass
+
     @property
     def chain(self):
         return self
diff --git a/tests/unit_tests/test_capi.py b/tests/unit_tests/test_capi.py
index 618f54e4f..8bc6c3d15 100644
--- a/tests/unit_tests/test_capi.py
+++ b/tests/unit_tests/test_capi.py
@@ -1,4 +1,4 @@
-from collections import Mapping
+from collections.abc import Mapping
 import os
 
 import numpy as np