diff --git a/openmc/arithmetic.py b/openmc/arithmetic.py
index 5869cad80..f9ef58db8 100644
--- a/openmc/arithmetic.py
+++ b/openmc/arithmetic.py
@@ -67,24 +67,6 @@ class CrossScore(object):
     def __ne__(self, other):
         return not self == other
 
-    def __deepcopy__(self, memo):
-        existing = memo.get(id(self))
-
-        # If this is the first time we have tried to copy this object, create a copy
-        if existing is None:
-            clone = type(self).__new__(type(self))
-            clone._left_score = self.left_score
-            clone._right_score = self.right_score
-            clone._binary_op = self.binary_op
-
-            memo[id(self)] = clone
-
-            return clone
-
-        # If this object has been copied before, return the first copy made
-        else:
-            return existing
-
     def __repr__(self):
         string = '({0} {1} {2})'.format(self.left_score,
                                         self.binary_op, self.right_score)
@@ -169,28 +151,9 @@ class CrossNuclide(object):
     def __ne__(self, other):
         return not self == other
 
-    def __deepcopy__(self, memo):
-        existing = memo.get(id(self))
-
-        # If this is the first time we have tried to copy this object, create a copy
-        if existing is None:
-            clone = type(self).__new__(type(self))
-            clone._left_nuclide = self.left_nuclide
-            clone._right_nuclide = self.right_nuclide
-            clone._binary_op = self.binary_op
-
-            memo[id(self)] = clone
-
-            return clone
-
-        # If this object has been copied before, return the first copy made
-        else:
-            return existing
-
     def __repr__(self):
         return self.name
 
-
     @property
     def left_nuclide(self):
         return self._left_nuclide
@@ -325,27 +288,6 @@ class CrossFilter(object):
         string += '{0: <16}{1}{2}\n'.format('\tBins', '=\t', filter_bins)
         return string
 
-    def __deepcopy__(self, memo):
-        existing = memo.get(id(self))
-
-        # If this is the first time we have tried to copy this object, create a copy
-        if existing is None:
-            clone = type(self).__new__(type(self))
-            clone._left_filter = self.left_filter
-            clone._right_filter = self.right_filter
-            clone._binary_op = self.binary_op
-            clone._type = self.type
-            clone._bins = self._bins
-            clone._stride = self.stride
-
-            memo[id(self)] = clone
-
-            return clone
-
-        # If this object has been copied before, return the first copy made
-        else:
-            return existing
-
     @property
     def left_filter(self):
         return self._left_filter
@@ -532,23 +474,6 @@ class AggregateScore(object):
     def __ne__(self, other):
         return not self == other
 
-    def __deepcopy__(self, memo):
-        existing = memo.get(id(self))
-
-        # If this is the first time we have tried to copy this object, create a copy
-        if existing is None:
-            clone = type(self).__new__(type(self))
-            clone._scores = self.scores
-            clone._aggregate_op = self.aggregate_op
-
-            memo[id(self)] = clone
-
-            return clone
-
-        # If this object has been copied before, return the first copy made
-        else:
-            return existing
-
     def __repr__(self):
         string = ', '.join(map(str, self.scores))
         string = '{0}({1})'.format(self.aggregate_op, string)
@@ -622,23 +547,6 @@ class AggregateNuclide(object):
     def __ne__(self, other):
         return not self == other
 
-    def __deepcopy__(self, memo):
-        existing = memo.get(id(self))
-
-        # If this is the first time we have tried to copy this object, create a copy
-        if existing is None:
-            clone = type(self).__new__(type(self))
-            clone._nuclides = self.nuclides
-            clone._aggregate_op = self._aggregate_op
-
-            memo[id(self)] = clone
-
-            return clone
-
-        # If this object has been copied before, return the first copy made
-        else:
-            return existing
-
     def __repr__(self):
 
         # Append each nuclide in the aggregate to the string
@@ -757,26 +665,6 @@ class AggregateFilter(object):
         string += '{0: <16}{1}{2}\n'.format('\tBins', '=\t', self.bins)
         return string
 
-    def __deepcopy__(self, memo):
-        existing = memo.get(id(self))
-
-        # If this is the first time we have tried to copy this object, create a copy
-        if existing is None:
-            clone = type(self).__new__(type(self))
-            clone._type = self.type
-            clone._aggregate_filter = self.aggregate_filter
-            clone._aggregate_op = self.aggregate_op
-            clone._bins = self._bins
-            clone._stride = self.stride
-
-            memo[id(self)] = clone
-
-            return clone
-
-        # If this object has been copied before, return the first copy made
-        else:
-            return existing
-
     @property
     def aggregate_filter(self):
         return self._aggregate_filter
diff --git a/openmc/filter.py b/openmc/filter.py
index 52560a193..e06958490 100644
--- a/openmc/filter.py
+++ b/openmc/filter.py
@@ -104,27 +104,6 @@ class Filter(object):
     def __hash__(self):
         return hash(repr(self))
 
-    def __deepcopy__(self, memo):
-        existing = memo.get(id(self))
-
-        # If this is the first time we have tried to copy this object, create a copy
-        if existing is None:
-            clone = type(self).__new__(type(self))
-            clone._type = self.type
-            clone._bins = copy.deepcopy(self.bins, memo)
-            clone._num_bins = self.num_bins
-            clone._mesh = copy.deepcopy(self.mesh, memo)
-            clone._stride = self.stride
-            clone._distribcell_paths = copy.deepcopy(self.distribcell_paths)
-
-            memo[id(self)] = clone
-
-            return clone
-
-        # If this object has been copied before, return the first copy made
-        else:
-            return existing
-
     def __repr__(self):
         string = 'Filter\n'
         string += '{0: <16}{1}{2}\n'.format('\tType', '=\t', self.type)
diff --git a/openmc/material.py b/openmc/material.py
index 6b2b07f2d..f29a42117 100644
--- a/openmc/material.py
+++ b/openmc/material.py
@@ -154,31 +154,6 @@ class Material(object):
 
         return string
 
-    def __deepcopy__(self, memo):
-        existing = memo.get(id(self))
-
-        if existing is None:
-            # If this is the first time we have tried to copy this object, create a copy
-            clone = type(self).__new__(type(self))
-            clone._id = self._id
-            clone._name = self._name
-            clone._density = self._density
-            clone._density_units = self._density_units
-            clone._nuclides = deepcopy(self._nuclides, memo)
-            clone._macroscopic = self._macroscopic
-            clone._elements = deepcopy(self._elements, memo)
-            clone._sab = deepcopy(self._sab, memo)
-            clone._convert_to_distrib_comps = self._convert_to_distrib_comps
-            clone._distrib_otf_file = self._distrib_otf_file
-
-            memo[id(self)] = clone
-
-            return clone
-
-        else:
-            # If this object has been copied before, return the first copy made
-            return existing
-
     @property
     def id(self):
         return self._id
diff --git a/openmc/mesh.py b/openmc/mesh.py
index 8bad6c537..0c88d4a68 100644
--- a/openmc/mesh.py
+++ b/openmc/mesh.py
@@ -1,5 +1,4 @@
 from collections import Iterable
-import copy
 from numbers import Real, Integral
 from xml.etree import ElementTree as ET
 import sys
@@ -83,28 +82,6 @@ class Mesh(object):
         else:
             return True
 
-    def __deepcopy__(self, memo):
-        existing = memo.get(id(self))
-
-        # If this is the first time we have tried to copy this object, create a copy
-        if existing is None:
-            clone = type(self).__new__(type(self))
-            clone._id = self._id
-            clone._name = self._name
-            clone._type = self._type
-            clone._dimension = copy.deepcopy(self._dimension, memo)
-            clone._lower_left = copy.deepcopy(self._lower_left, memo)
-            clone._upper_right = copy.deepcopy(self._upper_right, memo)
-            clone._width = copy.deepcopy(self._width, memo)
-
-            memo[id(self)] = clone
-
-            return clone
-
-        # If this object has been copied before, return the first copy made
-        else:
-            return existing
-
     @property
     def id(self):
         return self._id
diff --git a/openmc/tallies.py b/openmc/tallies.py
index 2313a6173..1d895022c 100644
--- a/openmc/tallies.py
+++ b/openmc/tallies.py
@@ -129,51 +129,6 @@ class Tally(object):
         self._sp_filename = None
         self._results_read = False
 
-    def __deepcopy__(self, memo):
-        existing = memo.get(id(self))
-
-        # If this is the first time we have tried to copy this object, create a copy
-        if existing is None:
-            clone = type(self).__new__(type(self))
-            clone.id = self.id
-            clone.name = self.name
-            clone.estimator = self.estimator
-            clone.num_realizations = self.num_realizations
-            clone._sum = copy.deepcopy(self._sum, memo)
-            clone._sum_sq = copy.deepcopy(self._sum_sq, memo)
-            clone._mean = copy.deepcopy(self._mean, memo)
-            clone._std_dev = copy.deepcopy(self._std_dev, memo)
-            clone._with_summary = self.with_summary
-            clone._with_batch_statistics = self.with_batch_statistics
-            clone._derived = self.derived
-            clone._sparse = self.sparse
-            clone._sp_filename = self._sp_filename
-            clone._results_read = self._results_read
-
-            clone._filters = []
-            for self_filter in self.filters:
-                clone.filters.append(copy.deepcopy(self_filter, memo))
-
-            clone._nuclides = []
-            for nuclide in self.nuclides:
-                clone.nuclides.append(copy.deepcopy(nuclide, memo))
-
-            clone._scores = []
-            for score in self.scores:
-                clone.scores.append(score)
-
-            clone._triggers = []
-            for trigger in self.triggers:
-                clone.triggers.append(trigger)
-
-            memo[id(self)] = clone
-
-            return clone
-
-        # If this object has been copied before, return the first copy made
-        else:
-            return existing
-
     def __eq__(self, other):
         if not isinstance(other, Tally):
             return False
@@ -2875,7 +2830,7 @@ class Tally(object):
 
         return other * self**-1
 
-    def __pos__(self):
+    def __abs__(self):
         """The absolute value of this tally.
 
         Returns
diff --git a/openmc/trigger.py b/openmc/trigger.py
index b8383bd27..537af1c8d 100644
--- a/openmc/trigger.py
+++ b/openmc/trigger.py
@@ -39,25 +39,6 @@ class Trigger(object):
         self.threshold = threshold
         self._scores = []
 
-    def __deepcopy__(self, memo):
-        existing = memo.get(id(self))
-
-        # If this is first time we have tried to copy this object, create a copy
-        if existing is None:
-            clone = type(self).__new__(type(self))
-            clone._trigger_type = self._trigger_type
-            clone._threshold = self._threshold
-
-            clone.scores = self.scores
-
-            memo[id(self)] = clone
-
-            return clone
-
-        # If this object has been copied before, return the first copy made
-        else:
-            return existing
-
     def __eq__(self, other):
         if str(self) == str(other):
             return True