diff --git a/armi/physics/neutronics/tests/test_crossSectionManager.py b/armi/physics/neutronics/tests/test_crossSectionManager.py
index 219d852fb..955b0158a 100644
--- a/armi/physics/neutronics/tests/test_crossSectionManager.py
+++ b/armi/physics/neutronics/tests/test_crossSectionManager.py
@@ -868,6 +868,13 @@ def test_getNextAvailableXsType(self):
         self.assertEqual("C", xsType2)
         self.assertEqual("D", xsType3)
 
+        # verify that we can get lowercase letters
+        xsTypes = self.csm.getNextAvailableXsTypes(27)
+        self.assertEqual("Y", xsTypes[-4])
+        self.assertEqual("a", xsTypes[-3])
+        self.assertEqual("b", xsTypes[-2])
+        self.assertEqual("c", xsTypes[-1])
+
     def test_getRepresentativeBlocks(self):
         """Test that we can create the representative blocks for a reactor.