diff --git a/openmc/cell.py b/openmc/cell.py
index 956d727d74f..0af6ea2b451 100644
--- a/openmc/cell.py
+++ b/openmc/cell.py
@@ -1,8 +1,8 @@
 from collections.abc import Iterable
 from math import cos, sin, pi
 from numbers import Real
-import lxml.etree as ET
 
+import lxml.etree as ET
 import numpy as np
 from uncertainties import UFloat
 
diff --git a/openmc/data/library.py b/openmc/data/library.py
index 397be3faf19..de9de27443d 100644
--- a/openmc/data/library.py
+++ b/openmc/data/library.py
@@ -1,8 +1,8 @@
 import os
-import lxml.etree as ET
 import pathlib
 
 import h5py
+import lxml.etree as ET
 
 import openmc
 from openmc._xml import clean_indentation, reorder_attributes
diff --git a/openmc/deplete/nuclide.py b/openmc/deplete/nuclide.py
index e2067a8e359..d055c2e3751 100644
--- a/openmc/deplete/nuclide.py
+++ b/openmc/deplete/nuclide.py
@@ -8,8 +8,8 @@
 from collections import namedtuple, defaultdict
 from warnings import warn
 from numbers import Real
-import lxml.etree as ET
 
+import lxml.etree as ET
 import numpy as np
 
 from openmc.checkvalue import check_type
diff --git a/openmc/element.py b/openmc/element.py
index 01651bebb6f..f9cf102f7ce 100644
--- a/openmc/element.py
+++ b/openmc/element.py
@@ -1,4 +1,5 @@
 import re
+
 import lxml.etree as ET
 
 import openmc.checkvalue as cv
diff --git a/openmc/filter.py b/openmc/filter.py
index 8eb81432ff9..f2bbf2f5050 100644
--- a/openmc/filter.py
+++ b/openmc/filter.py
@@ -3,9 +3,9 @@
 import hashlib
 from itertools import product
 from numbers import Real, Integral
-import lxml.etree as ET
 import warnings
 
+import lxml.etree as ET
 import numpy as np
 import pandas as pd
 
diff --git a/openmc/filter_expansion.py b/openmc/filter_expansion.py
index f05f39fe9b6..b9860846fda 100644
--- a/openmc/filter_expansion.py
+++ b/openmc/filter_expansion.py
@@ -1,4 +1,5 @@
 from numbers import Integral, Real
+
 import lxml.etree as ET
 
 import openmc.checkvalue as cv
diff --git a/openmc/lattice.py b/openmc/lattice.py
index 926a016efe3..d281f6e7692 100644
--- a/openmc/lattice.py
+++ b/openmc/lattice.py
@@ -4,8 +4,8 @@
 from math import sqrt, floor
 from numbers import Real
 import types
-import lxml.etree as ET
 
+import lxml.etree as ET
 import numpy as np
 
 import openmc
diff --git a/openmc/material.py b/openmc/material.py
index 6b71f56a8d0..1f5496f15ea 100644
--- a/openmc/material.py
+++ b/openmc/material.py
@@ -8,8 +8,8 @@
 import typing  # imported separately as py3.8 requires typing.Iterable
 import warnings
 from typing import Optional, List, Union, Dict
-import lxml.etree as ET
 
+import lxml.etree as ET
 import numpy as np
 import h5py
 
diff --git a/openmc/model/model.py b/openmc/model/model.py
index 9da834e139e..a60960b2bad 100644
--- a/openmc/model/model.py
+++ b/openmc/model/model.py
@@ -7,10 +7,10 @@
 from numbers import Integral
 from tempfile import NamedTemporaryFile
 import warnings
-import lxml.etree as ET
 from typing import Optional, Dict
 
 import h5py
+import lxml.etree as ET
 
 import openmc
 import openmc._xml as xml
diff --git a/openmc/plots.py b/openmc/plots.py
index 626056d79ae..b38b51a59c6 100644
--- a/openmc/plots.py
+++ b/openmc/plots.py
@@ -1,10 +1,10 @@
 from collections.abc import Iterable, Mapping
 from numbers import Integral, Real
 from pathlib import Path
-import lxml.etree as ET
 from typing import Optional
 
 import h5py
+import lxml.etree as ET
 import numpy as np
 
 import openmc
diff --git a/openmc/settings.py b/openmc/settings.py
index 5d0800ac13d..b4e615a2a17 100644
--- a/openmc/settings.py
+++ b/openmc/settings.py
@@ -1,4 +1,3 @@
-import os
 from collections.abc import Iterable, Mapping, MutableSequence
 from enum import Enum
 import itertools
@@ -7,11 +6,11 @@
 from pathlib import Path
 import typing  # required to prevent typing.Union namespace overwriting Union
 from typing import Optional
+
 import lxml.etree as ET
 
 import openmc.checkvalue as cv
 from openmc.stats.multivariate import MeshSpatial
-
 from . import (RegularMesh, SourceBase, MeshSource, IndependentSource,
                VolumeCalculation, WeightWindows, WeightWindowGenerator)
 from ._xml import clean_indentation, get_text, reorder_attributes
diff --git a/openmc/source.py b/openmc/source.py
index c339d6ed806..1ba90c92130 100644
--- a/openmc/source.py
+++ b/openmc/source.py
@@ -7,8 +7,8 @@
 import typing  # imported separately as py3.8 requires typing.Iterable
 # also required to prevent typing.Union namespace overwriting Union
 from typing import Optional, Sequence
-import lxml.etree as ET
 
+import lxml.etree as ET
 import numpy as np
 import h5py
 
diff --git a/openmc/surface.py b/openmc/surface.py
index a684f83feaf..a16b6712d6c 100644
--- a/openmc/surface.py
+++ b/openmc/surface.py
@@ -3,9 +3,9 @@
 from copy import deepcopy
 import math
 from numbers import Real
-import lxml.etree as ET
 from warnings import warn, catch_warnings, simplefilter
 
+import lxml.etree as ET
 import numpy as np
 
 from .checkvalue import check_type, check_value, check_length, check_greater_than
diff --git a/openmc/tally_derivative.py b/openmc/tally_derivative.py
index 779ca619f2a..ff918c1b3c6 100644
--- a/openmc/tally_derivative.py
+++ b/openmc/tally_derivative.py
@@ -1,4 +1,5 @@
 from numbers import Integral
+
 import lxml.etree as ET
 
 import openmc.checkvalue as cv
diff --git a/openmc/trigger.py b/openmc/trigger.py
index 8a165526cf6..c7d9e9240bb 100644
--- a/openmc/trigger.py
+++ b/openmc/trigger.py
@@ -1,5 +1,6 @@
 from collections.abc import Iterable
 from numbers import Real
+
 import lxml.etree as ET
 
 import openmc.checkvalue as cv
diff --git a/openmc/universe.py b/openmc/universe.py
index bc122b03dc7..2e86ab05a9b 100644
--- a/openmc/universe.py
+++ b/openmc/universe.py
@@ -1,24 +1,20 @@
 import math
-import typing
 from abc import ABC, abstractmethod
 from collections.abc import Iterable
-from copy import deepcopy
 from numbers import Integral, Real
 from pathlib import Path
 from tempfile import TemporaryDirectory
-import lxml.etree as ET
 import warnings
 
 import h5py
+import lxml.etree as ET
 import numpy as np
 
 import openmc
 import openmc.checkvalue as cv
-
 from ._xml import get_text
 from .checkvalue import check_type, check_value
 from .mixin import IDManagerMixin
-from .plots import _SVG_COLORS
 from .surface import _BOUNDARY_TYPES
 
 
diff --git a/openmc/volume.py b/openmc/volume.py
index 90882267d7b..df19def1eac 100644
--- a/openmc/volume.py
+++ b/openmc/volume.py
@@ -1,11 +1,11 @@
 from collections.abc import Iterable, Mapping
 from numbers import Real, Integral
-import lxml.etree as ET
 import warnings
 
+import h5py
+import lxml.etree as ET
 import numpy as np
 import pandas as pd
-import h5py
 from uncertainties import ufloat
 
 import openmc
diff --git a/openmc/weight_windows.py b/openmc/weight_windows.py
index 2b545a976ee..f5936438977 100644
--- a/openmc/weight_windows.py
+++ b/openmc/weight_windows.py
@@ -12,7 +12,6 @@
 from openmc.mesh import MeshBase, RectilinearMesh, CylindricalMesh, SphericalMesh, UnstructuredMesh
 import openmc.checkvalue as cv
 from openmc.checkvalue import PathLike
-
 from ._xml import get_text, clean_indentation
 from .mixin import IDManagerMixin
 
diff --git a/tests/unit_tests/test_cell.py b/tests/unit_tests/test_cell.py
index 888a0ef88f3..95c8249bb33 100644
--- a/tests/unit_tests/test_cell.py
+++ b/tests/unit_tests/test_cell.py
@@ -1,11 +1,9 @@
 import lxml.etree as ET
-
 import numpy as np
 from uncertainties import ufloat
 import openmc
 import pytest
 
-
 from tests.unit_tests import assert_unbounded
 from openmc.data import atomic_mass, AVOGADRO
 
diff --git a/tests/unit_tests/test_deplete_nuclide.py b/tests/unit_tests/test_deplete_nuclide.py
index 07db57bd6d1..6482d76a592 100644
--- a/tests/unit_tests/test_deplete_nuclide.py
+++ b/tests/unit_tests/test_deplete_nuclide.py
@@ -1,7 +1,8 @@
 """Tests for the openmc.deplete.Nuclide class."""
 
-import lxml.etree as ET
 import copy
+
+import lxml.etree as ET
 import numpy as np
 import pytest
 from openmc.deplete import nuclide
diff --git a/tests/unit_tests/test_lattice.py b/tests/unit_tests/test_lattice.py
index 97cd898435f..6fa32760e65 100644
--- a/tests/unit_tests/test_lattice.py
+++ b/tests/unit_tests/test_lattice.py
@@ -1,6 +1,6 @@
 from math import sqrt
-import lxml.etree as ET
 
+import lxml.etree as ET
 import openmc
 import pytest
 
diff --git a/tests/unit_tests/test_universe.py b/tests/unit_tests/test_universe.py
index 630e66df3ab..46d4ec3f734 100644
--- a/tests/unit_tests/test_universe.py
+++ b/tests/unit_tests/test_universe.py
@@ -1,5 +1,4 @@
 import lxml.etree as ET
-
 import numpy as np
 import openmc
 import pytest