diff --git a/openmc/material.py b/openmc/material.py
index e26b996d56..0b295ba98e 100644
--- a/openmc/material.py
+++ b/openmc/material.py
@@ -464,11 +464,11 @@ class Material(object):
 
             if enrichment > 0.05:
                 msg = 'A uranium enrichment of {0} was given for Material ID='\
-                      '"{0}". OpenMC assumes the U234/U235 mass ratio is '\
+                      '"{1}". OpenMC assumes the U234/U235 mass ratio is '\
                       'constant at 0.008, which is only valid at low ' \
                       'enrichments. Consider setting the isotopic ' \
                       'composition manually for enrichments over 5%.'.\
-                      format(self._id)
+                      format(enrichment, self._id)
                 warnings.warn(msg)
 
         if expand or enrichment is not None:
diff --git a/tests/test_element_wo/inputs_true.dat b/tests/test_element_wo/inputs_true.dat
index db45f358b8..adfd1742a2 100644
--- a/tests/test_element_wo/inputs_true.dat
+++ b/tests/test_element_wo/inputs_true.dat
@@ -1 +1 @@
-6f1239c0f681f0bf405bcf090d4ec88c8a551ba4f4d49679fcbd6394b15d12e562d792c74dffbdd8f2b5e7945432d3fcea57922e4fe9d8e88fdc6741870cd366
\ No newline at end of file
+0d54ed29b2a348854d99d36f602b188766465b41e70536647578c61d076909a2351b5c4cafbbdc62dd00f36bf2685f231fae7c75d1289befddd2da79042e31a7
\ No newline at end of file
diff --git a/tests/test_element_wo/results_true.dat b/tests/test_element_wo/results_true.dat
index aa5a71a7bd..ad5a0c2280 100644
--- a/tests/test_element_wo/results_true.dat
+++ b/tests/test_element_wo/results_true.dat
@@ -1,5 +1,5 @@
 k-combined:
-8.318639E-01 1.165753E-01
+8.617147E-01 2.915803E-02
 tally 1:
-8.059858E+01
-1.299961E+03
+7.879002E+01
+1.242562E+03
diff --git a/tests/test_element_wo/test_element_wo.py b/tests/test_element_wo/test_element_wo.py
index bcccb3183e..a5d35f4c56 100644
--- a/tests/test_element_wo/test_element_wo.py
+++ b/tests/test_element_wo/test_element_wo.py
@@ -24,7 +24,7 @@ class ElementWOTestHarness(PyAPITestHarness):
         fuel.add_element("O", 0.12, 'wo')
 
         # Add some natural elements to the fuel
-        for element in [ 'Ir', 'Au', 'Hg', 'Tl', 'Pb', 'Bi', 'Th', 'Pa']:
+        for element in ['Ir', 'Au', 'Hg', 'Tl', 'Pb', 'Bi', 'Th', 'Pa']:
             fuel.add_element(element, 1.e-8, 'wo')
 
         clad = openmc.Material(name='Cladding')
@@ -33,8 +33,8 @@ class ElementWOTestHarness(PyAPITestHarness):
 
         hot_water = openmc.Material(name='Hot borated water')
         hot_water.set_density('g/cm3', 0.740582)
-        hot_water.add_element("H",  2./18., 'wo')
-        hot_water.add_element("O", 16./18., 'wo')
+        hot_water.add_element("H", 0.1111, 'wo')
+        hot_water.add_element("O", 0.8889, 'wo')
         hot_water.add_s_alpha_beta('c_H_in_H2O')
 
         # Define the materials file.
diff --git a/tests/test_enrichment/inputs_true.dat b/tests/test_enrichment/inputs_true.dat
index 25091b440a..572a4e1ff0 100644
--- a/tests/test_enrichment/inputs_true.dat
+++ b/tests/test_enrichment/inputs_true.dat
@@ -1 +1 @@
-1fe2d58365b5c8baf45766e788815bef715805ca96bb63480f50b2283b34c90408c19b52996e2b0da6afe1595b94a43aef7a72a3f47513131784275ed9092e89
\ No newline at end of file
+47d753380f995651e6cec8e3648ff9e4ac254fc80919014124f4f6674afc95262006eda3821b4d6dcf09e29f28f5e21840c9b76b95c1c7f8ae522faac2386090
\ No newline at end of file
diff --git a/tests/test_enrichment/results_true.dat b/tests/test_enrichment/results_true.dat
index cd84b2d40d..347c39ff3c 100644
--- a/tests/test_enrichment/results_true.dat
+++ b/tests/test_enrichment/results_true.dat
@@ -1,5 +1,5 @@
 k-combined:
-1.457508E+00 5.577598E-02
+1.385412E+00 1.198466E-01
 tally 1:
-6.199709E+01
-7.692381E+02
+6.197393E+01
+7.688717E+02
diff --git a/tests/test_enrichment/test_enrichment.py b/tests/test_enrichment/test_enrichment.py
index 85d88e7ec8..8d04112edd 100644
--- a/tests/test_enrichment/test_enrichment.py
+++ b/tests/test_enrichment/test_enrichment.py
@@ -20,7 +20,7 @@ class EnrichmentTestHarness(PyAPITestHarness):
         # Define materials.
         fuel = openmc.Material(name='Fuel')
         fuel.set_density('g/cm3', 10.29769)
-        fuel.add_element("U", 0.88, 'wo', enrichment=0.05)
+        fuel.add_element("U", 0.88, 'wo', enrichment=0.0495)
         fuel.add_element("O", 0.12, 'wo')
 
         clad = openmc.Material(name='Cladding')
@@ -29,8 +29,8 @@ class EnrichmentTestHarness(PyAPITestHarness):
 
         hot_water = openmc.Material(name='Hot borated water')
         hot_water.set_density('g/cm3', 0.740582)
-        hot_water.add_element("H",  2./18., 'wo')
-        hot_water.add_element("O", 16./18., 'wo')
+        hot_water.add_element("H", 0.1111, 'wo')
+        hot_water.add_element("O", 0.8889, 'wo')
         hot_water.add_s_alpha_beta('c_H_in_H2O')
 
         # Define the materials file.