From 86351747e72b9d90ec9a7b33eef1496d3a41fb7b Mon Sep 17 00:00:00 2001
From: Paul Romano <paul.k.romano@gmail.com>
Date: Wed, 25 Mar 2020 09:37:00 -0500
Subject: [PATCH] Ensure remove_nuclide removes all matching nuclides. Closes
 #1532

---
 openmc/material.py                |  5 ++---
 tests/unit_tests/test_material.py | 17 ++++++++++++++---
 2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/openmc/material.py b/openmc/material.py
index b0d5cb2229..cbd002c0bd 100644
--- a/openmc/material.py
+++ b/openmc/material.py
@@ -402,10 +402,9 @@ class Material(IDManagerMixin):
         cv.check_type('nuclide', nuclide, str)
 
         # If the Material contains the Nuclide, delete it
-        for nuc in self._nuclides:
+        for nuc in reversed(self.nuclides):
             if nuclide == nuc.name:
-                self._nuclides.remove(nuc)
-                break
+                self.nuclides.remove(nuc)
 
     def add_macroscopic(self, macroscopic):
         """Add a macroscopic to the material.  This will also set the
diff --git a/tests/unit_tests/test_material.py b/tests/unit_tests/test_material.py
index 6f51135ab2..65fdb26239 100644
--- a/tests/unit_tests/test_material.py
+++ b/tests/unit_tests/test_material.py
@@ -11,8 +11,8 @@ def test_attributes(uo2):
     assert uo2.depletable
 
 
-def test_nuclides(uo2):
-    """Test adding/removing nuclides."""
+def test_add_nuclide():
+    """Test adding nuclides."""
     m = openmc.Material()
     m.add_nuclide('U235', 1.0)
     with pytest.raises(TypeError):
@@ -21,7 +21,18 @@ def test_nuclides(uo2):
         m.add_nuclide(1.0, 'H1')
     with pytest.raises(ValueError):
         m.add_nuclide('H1', 1.0, 'oa')
-    m.remove_nuclide('U235')
+
+
+def test_remove_nuclide():
+    """Test removing nuclides."""
+    m = openmc.Material()
+    for nuc, percent in [('H1', 1.0), ('H2', 1.0), ('H1', 2.0), ('H2', 2.0)]:
+        m.add_nuclide(nuc, percent)
+    m.remove_nuclide('H1')
+    assert len(m.nuclides) == 2
+    assert all(nuc.name == 'H2' for nuc in m.nuclides)
+    assert m.nuclides[0].percent == 1.0
+    assert m.nuclides[1].percent == 2.0
 
 
 def test_elements():