Bump up tolerance for flaky activation test (#3560)

Author: paulromano

tests/unit_tests/test_deplete_activation.py

@@ -45,7 +45,7 @@ def model():
 
 @pytest.mark.parametrize("reaction_rate_mode,reaction_rate_opts,tolerance", [
     ("direct", {}, 1e-5),
-    ("flux", {'energies': ENERGIES}, 0.01),
+    ("flux", {'energies': ENERGIES}, 0.1),
     ("flux", {'energies': ENERGIES, 'reactions': ['(n,gamma)']}, 1e-5),
     ("flux", {'energies': ENERGIES, 'reactions': ['(n,gamma)'], 'nuclides': ['W186', 'H3']}, 1e-2),
 ])
@@ -61,11 +61,10 @@ def test_activation(run_in_tmpdir, model, reaction_rate_mode, reaction_rate_opts
     w186 = openmc.deplete.Nuclide('W186')
     w186.add_reaction('(n,gamma)', None, 0.0, 1.0)
     chain.add_nuclide(w186)
-    chain.export_to_xml('test_chain.xml')
 
     # Create transport operator
     op = openmc.deplete.CoupledOperator(
-        model, 'test_chain.xml',
+        model, chain,
         normalization_mode="source-rate",
         reaction_rate_mode=reaction_rate_mode,
         reaction_rate_opts=reaction_rate_opts,