diff --git a/openmc/material.py b/openmc/material.py
index ba70e09b5a..e336156428 100644
--- a/openmc/material.py
+++ b/openmc/material.py
@@ -587,9 +587,9 @@ class Material(object):
 
         if not distrib:
             if nuclide[2] == 'ao':
-                xml_element.set("ao", '{0:.12f}'.format(nuclide[1]))
+                xml_element.set("ao", str(nuclide[1]))
             else:
-                xml_element.set("wo", '{0:.12f}'.format(nuclide[1]))
+                xml_element.set("wo", str(nuclide[1]))
 
         if not nuclide[0].scattering is None:
             xml_element.set("scattering", nuclide[0].scattering)
diff --git a/tests/test_triso/inputs_true.dat b/tests/test_triso/inputs_true.dat
index f4d79a7ab6..856581fdef 100644
--- a/tests/test_triso/inputs_true.dat
+++ b/tests/test_triso/inputs_true.dat
@@ -1 +1 @@
-790bb9e31e72798b9407e5daba696fa35f7240feb59a99c081b96afdd5120aa9afe45b791e3293e01ae699512567feaeb7c4a77a592f781bd70a7900c9e28eae
\ No newline at end of file
+5859cd73807c74cce612275817d3e1c6a2b55a347b31925115dbda2d83df60345ea4617cbc3b057a2fcfef4242f0e53d66d569ecffaeed35975ca28307b354c4
\ No newline at end of file
diff --git a/tests/test_triso/results_true.dat b/tests/test_triso/results_true.dat
index 71805055c6..1716b67f53 100644
--- a/tests/test_triso/results_true.dat
+++ b/tests/test_triso/results_true.dat
@@ -1,2 +1,2 @@
 k-combined:
-1.572877E+00 1.337067E-02
+1.643727E+00 5.233644E-02