diff --git a/docs/source/pythonapi/base.rst b/docs/source/pythonapi/base.rst
index d0e7d2439..2a9d0876c 100644
--- a/docs/source/pythonapi/base.rst
+++ b/docs/source/pythonapi/base.rst
@@ -37,7 +37,6 @@ Simulation Settings
 
    openmc.read_source_file
    openmc.write_source_file
-   openmc.wwinp_to_wws
 
 Material Specification
 ----------------------
@@ -259,8 +258,16 @@ Variance Reduction
    :template: myclass
 
    openmc.WeightWindows
+   openmc.WeightWindowsList
    openmc.WeightWindowGenerator
+
+.. autosummary::
+   :toctree: generated
+   :nosignatures:
+   :template: myfunction.rst
+
    openmc.hdf5_to_wws
+   openmc.wwinp_to_wws
 
 
 Coarse Mesh Finite Difference Acceleration
diff --git a/docs/source/usersguide/variance_reduction.rst b/docs/source/usersguide/variance_reduction.rst
index 3256fa35f..369e33e2d 100644
--- a/docs/source/usersguide/variance_reduction.rst
+++ b/docs/source/usersguide/variance_reduction.rst
@@ -162,7 +162,7 @@ solver, the Python input just needs to load the h5 file::
 
     settings.weight_window_checkpoints = {'collision': True, 'surface': True}
     settings.survival_biasing = False
-    settings.weight_windows = openmc.hdf5_to_wws('weight_windows.h5')
+    settings.weight_windows = openmc.WeightWindowsList.from_hdf5('weight_windows.h5')
     settings.weight_windows_on = True
 
 The :class:`~openmc.WeightWindowGenerator` instance is not needed to load an
diff --git a/openmc/settings.py b/openmc/settings.py
index bd3a89e11..36eaec6cb 100644
--- a/openmc/settings.py
+++ b/openmc/settings.py
@@ -16,7 +16,7 @@ from .mesh import _read_meshes, RegularMesh, MeshBase
 from .source import SourceBase, MeshSource, IndependentSource
 from .utility_funcs import input_path
 from .volume import VolumeCalculation
-from .weight_windows import WeightWindows, WeightWindowGenerator
+from .weight_windows import WeightWindows, WeightWindowGenerator, WeightWindowsList
 
 
 class RunMode(Enum):
@@ -313,7 +313,7 @@ class Settings:
         described in :ref:`verbosity`.
     volume_calculations : VolumeCalculation or iterable of VolumeCalculation
         Stochastic volume calculation specifications
-    weight_windows : WeightWindows or iterable of WeightWindows
+    weight_windows : WeightWindowsList
         Weight windows to use for variance reduction
 
         .. versionadded:: 0.13
@@ -424,7 +424,7 @@ class Settings:
         self._max_particles_in_flight = None
         self._max_particle_events = None
         self._write_initial_source = None
-        self._weight_windows = cv.CheckedList(WeightWindows, 'weight windows')
+        self._weight_windows = WeightWindowsList()
         self._weight_window_generators = cv.CheckedList(WeightWindowGenerator, 'weight window generators')
         self._weight_windows_on = None
         self._weight_windows_file = None
@@ -1095,14 +1095,14 @@ class Settings:
         self._write_initial_source = value
 
     @property
-    def weight_windows(self) -> list[WeightWindows]:
+    def weight_windows(self) -> WeightWindowsList:
         return self._weight_windows
 
     @weight_windows.setter
-    def weight_windows(self, value: WeightWindows | Iterable[WeightWindows]):
-        if not isinstance(value, MutableSequence):
+    def weight_windows(self, value: WeightWindows | Sequence[WeightWindows]):
+        if not isinstance(value, Sequence):
             value = [value]
-        self._weight_windows = cv.CheckedList(WeightWindows, 'weight windows', value)
+        self._weight_windows = WeightWindowsList(value)
 
     @property
     def weight_windows_on(self) -> bool:
diff --git a/openmc/weight_windows.py b/openmc/weight_windows.py
index d52b81925..1b44747d5 100644
--- a/openmc/weight_windows.py
+++ b/openmc/weight_windows.py
@@ -1,6 +1,8 @@
 from __future__ import annotations
 from numbers import Real, Integral
 from collections.abc import Iterable, Sequence
+from pathlib import Path
+from typing import Self
 import warnings
 
 import lxml.etree as ET
@@ -14,6 +16,7 @@ import openmc.checkvalue as cv
 from openmc.checkvalue import PathLike
 from ._xml import get_text, clean_indentation
 from .mixin import IDManagerMixin
+from .utility_funcs import change_directory
 
 
 class WeightWindows(IDManagerMixin):
@@ -90,7 +93,7 @@ class WeightWindows(IDManagerMixin):
     survival_ratio : float
         Ratio of the survival weight to the lower weight window bound for
         rouletting
-    max_lower_bound_ratio: float
+    max_lower_bound_ratio : float
         Maximum allowed ratio of a particle's weight to the weight window's
         lower bound. (Default: 1.0)
     max_split : int
@@ -114,7 +117,7 @@ class WeightWindows(IDManagerMixin):
         upper_bound_ratio: float | None = None,
         energy_bounds: Iterable[Real] | None = None,
         particle_type: str = 'neutron',
-        survival_ratio: float = 3,
+        survival_ratio: float = 3.0,
         max_lower_bound_ratio: float | None = None,
         max_split: int = 10,
         weight_cutoff: float = 1.e-38,
@@ -354,7 +357,7 @@ class WeightWindows(IDManagerMixin):
         return element
 
     @classmethod
-    def from_xml_element(cls, elem: ET.Element, meshes: dict[int, MeshBase]) -> WeightWindows:
+    def from_xml_element(cls, elem: ET.Element, meshes: dict[int, MeshBase]) -> Self:
         """Generate weight window settings from an XML element
 
         Parameters
@@ -408,7 +411,7 @@ class WeightWindows(IDManagerMixin):
         )
 
     @classmethod
-    def from_hdf5(cls, group: h5py.Group, meshes: dict[int, MeshBase]) -> WeightWindows:
+    def from_hdf5(cls, group: h5py.Group, meshes: dict[int, MeshBase]) -> Self:
         """Create weight windows from HDF5 group
 
         Parameters
@@ -458,7 +461,7 @@ class WeightWindows(IDManagerMixin):
         )
 
 
-def wwinp_to_wws(path: PathLike) -> list[WeightWindows]:
+def wwinp_to_wws(path: PathLike) -> WeightWindowsList:
     """Create WeightWindows instances from a wwinp file
 
     .. versionadded:: 0.13.1
@@ -470,190 +473,13 @@ def wwinp_to_wws(path: PathLike) -> list[WeightWindows]:
 
     Returns
     -------
-    list of openmc.WeightWindows
+    WeightWindowsList
     """
-
-    with open(path) as wwinp:
-        # BLOCK 1
-        header = wwinp.readline().split(None, 4)
-        # read file type, time-dependence, number of
-        # particles, mesh type and problem identifier
-        _if, iv, ni, nr = [int(x) for x in header[:4]]
-
-        # header value checks
-        if _if != 1:
-            raise ValueError(f'Found incorrect file type, if: {_if}')
-
-        if iv > 1:
-            # read number of time bins for each particle, 'nt(1...ni)'
-            nt = np.fromstring(wwinp.readline(), sep=' ', dtype=int)
-
-            # raise error if time bins are present for now
-            raise ValueError('Time-dependent weight windows '
-                             'are not yet supported')
-        else:
-            nt = ni * [1]
-
-        # read number of energy bins for each particle, 'ne(1...ni)'
-        ne = np.fromstring(wwinp.readline(), sep=' ', dtype=int)
-
-        # read coarse mesh dimensions and lower left corner
-        mesh_description = np.fromstring(wwinp.readline(), sep=' ')
-        nfx, nfy, nfz = mesh_description[:3].astype(int)
-        xyz0 = mesh_description[3:]
-
-        # read cylindrical and spherical mesh vectors if present
-        if nr == 16:
-            # read number of coarse bins
-            line_arr = np.fromstring(wwinp.readline(), sep=' ')
-            ncx, ncy, ncz = line_arr[:3].astype(int)
-            # read polar vector (x1, y1, z1)
-            xyz1 = line_arr[3:]
-            # read azimuthal vector (x2, y2, z2)
-            line_arr = np.fromstring(wwinp.readline(), sep=' ')
-            xyz2 = line_arr[:3]
-
-            # Get polar and azimuthal axes
-            polar_axis = xyz1 - xyz0
-            azimuthal_axis = xyz2 - xyz0
-
-            # Check for polar axis other than (0, 0, 1)
-            norm = np.linalg.norm(polar_axis)
-            if not np.isclose(polar_axis[2]/norm, 1.0):
-                raise NotImplementedError('Polar axis not aligned to z-axis not supported')
-
-            # Check for azimuthal axis other than (1, 0, 0)
-            norm = np.linalg.norm(azimuthal_axis)
-            if not np.isclose(azimuthal_axis[0]/norm, 1.0):
-                raise NotImplementedError('Azimuthal axis not aligned to x-axis not supported')
-
-            # read geometry type
-            nwg = int(line_arr[-1])
-
-        elif nr == 10:
-            # read rectilinear data:
-            # number of coarse mesh bins and mesh type
-            ncx, ncy, ncz, nwg = \
-                np.fromstring(wwinp.readline(), sep=' ').astype(int)
-        else:
-            raise RuntimeError(f'Invalid mesh description (nr) found: {nr}')
-
-        # read BLOCK 2 and BLOCK 3 data into a single array
-        ww_data = np.fromstring(wwinp.read(), sep=' ')
-
-    # extract mesh data from the ww_data array
-    start_idx = 0
-
-    # first values in the mesh definition arrays are the first
-    # coordinate of the grid
-    end_idx = start_idx + 1 + 3 * ncx
-    i0, i_vals = ww_data[start_idx], ww_data[start_idx+1:end_idx]
-    start_idx = end_idx
-
-    end_idx = start_idx + 1 + 3 * ncy
-    j0, j_vals = ww_data[start_idx], ww_data[start_idx+1:end_idx]
-    start_idx = end_idx
-
-    end_idx = start_idx + 1 + 3 * ncz
-    k0, k_vals = ww_data[start_idx], ww_data[start_idx+1:end_idx]
-    start_idx = end_idx
-
-    # mesh consistency checks
-    if nr == 16 and nwg == 1 or nr == 10 and nwg != 1:
-        raise ValueError(f'Mesh description in header ({nr}) '
-                         f'does not match the mesh type ({nwg})')
-
-    if nr == 10 and (xyz0 != (i0, j0, k0)).any():
-        raise ValueError(f'Mesh origin in the header ({xyz0}) '
-                         f' does not match the origin in the mesh '
-                         f' description ({i0, j0, k0})')
-
-    # create openmc mesh object
-    grids = []
-    mesh_definition = [(i0, i_vals, nfx), (j0, j_vals, nfy), (k0, k_vals, nfz)]
-    for grid0, grid_vals, n_pnts in mesh_definition:
-        # file spec checks for the mesh definition
-        if (grid_vals[2::3] != 1.0).any():
-            raise ValueError('One or more mesh ratio value, qx, '
-                             'is not equal to one')
-
-        s = int(grid_vals[::3].sum())
-        if s != n_pnts:
-            raise ValueError(f'Sum of the fine bin entries, {s}, does '
-                             f'not match the number of fine bins, {n_pnts}')
-
-        # extend the grid based on the next coarse bin endpoint, px
-        # and the number of fine bins in the coarse bin, sx
-        intervals = grid_vals.reshape(-1, 3)
-        coords = [grid0]
-        for sx, px, qx in intervals:
-            coords += np.linspace(coords[-1], px, int(sx + 1)).tolist()[1:]
-
-        grids.append(np.array(coords))
-
-    if nwg == 1:
-        mesh = RectilinearMesh()
-        mesh.x_grid, mesh.y_grid, mesh.z_grid = grids
-    elif nwg == 2:
-        mesh = CylindricalMesh(
-            r_grid=grids[0],
-            z_grid=grids[1],
-            phi_grid=grids[2],
-            origin = xyz0,
-        )
-    elif nwg == 3:
-        mesh = SphericalMesh(
-            r_grid=grids[0],
-            theta_grid=grids[1],
-            phi_grid=grids[2],
-            origin = xyz0
-        )
-
-    # extract weight window values from array
-    wws = []
-    for ne_i, nt_i, particle_type in zip(ne, nt, ('neutron', 'photon')):
-        # no information to read for this particle if
-        # either the energy bins or time bins are empty
-        if ne_i == 0 or nt_i == 0:
-            continue
-
-        if iv > 1:
-            # time bins are parsed but unused for now
-            end_idx = start_idx + nt_i
-            time_bounds = ww_data[start_idx:end_idx]
-            np.insert(time_bounds, (0,), (0.0,))
-            start_idx = end_idx
-
-        # read energy boundaries
-        end_idx = start_idx + ne_i
-        energy_bounds = np.insert(ww_data[start_idx:end_idx], (0,), (0.0,))
-        # convert from MeV to eV
-        energy_bounds *= 1e6
-        start_idx = end_idx
-
-        # read weight window values
-        end_idx = start_idx + (nfx * nfy * nfz) * nt_i * ne_i
-
-        # read values and reshape according to ordering
-        # slowest to fastest: t, e, z, y, x
-        # reorder with transpose since our ordering is x, y, z, e, t
-        ww_shape = (nt_i, ne_i, nfz, nfy, nfx)
-        ww_values = ww_data[start_idx:end_idx].reshape(ww_shape).T
-        # Only use first time bin since we don't support time dependent weight
-        # windows yet.
-        ww_values = ww_values[:, :, :, :, 0]
-        start_idx = end_idx
-
-        # create a weight window object
-        ww = WeightWindows(id=None,
-                           mesh=mesh,
-                           lower_ww_bounds=ww_values,
-                           upper_bound_ratio=5.0,
-                           energy_bounds=energy_bounds,
-                           particle_type=particle_type)
-        wws.append(ww)
-
-    return wws
+    warnings.warn(
+        "This function is deprecated in favor of 'WeightWindowsList.from_wwinp'",
+        FutureWarning
+    )
+    return WeightWindowsList.from_wwinp(path)
 
 
 class WeightWindowGenerator:
@@ -886,7 +712,7 @@ class WeightWindowGenerator:
         return element
 
     @classmethod
-    def from_xml_element(cls, elem: ET.Element, meshes: dict) -> WeightWindowGenerator:
+    def from_xml_element(cls, elem: ET.Element, meshes: dict) -> Self:
         """
         Create a weight window generation object from an XML element
 
@@ -929,8 +755,8 @@ class WeightWindowGenerator:
 
         return wwg
 
-def hdf5_to_wws(path='weight_windows.h5'):
-    """Create WeightWindows instances from a weight windows HDF5 file
+def hdf5_to_wws(path='weight_windows.h5') -> WeightWindowsList:
+    """Create a WeightWindowsList from a weight windows HDF5 file
 
     .. versionadded:: 0.14.0
 
@@ -941,13 +767,284 @@ def hdf5_to_wws(path='weight_windows.h5'):
 
     Returns
     -------
-    list of openmc.WeightWindows
+    WeightWindowsList
     """
+    warnings.warn(
+        "This function is deprecated in favor of 'WeightWindowsList.from_hdf5'",
+        FutureWarning
+    )
+    return WeightWindowsList.from_hdf5(path)
 
-    with h5py.File(path) as h5_file:
-        # read in all of the meshes in the mesh node
-        meshes = {}
-        for mesh_group in h5_file['meshes']:
-            mesh = MeshBase.from_hdf5(h5_file['meshes'][mesh_group])
-            meshes[mesh.id] = mesh
-        return [WeightWindows.from_hdf5(ww, meshes) for ww in h5_file['weight_windows'].values()]
+
+class WeightWindowsList(list):
+    """A list of WeightWindows objects.
+
+    .. versionadded:: 0.15.3
+
+    Parameters
+    ----------
+    iterable : iterable of openmc.WeightWindows
+        An iterable of WeightWindows objects to initialize the list with
+
+    """
+    def __init__(self, iterable: Iterable[WeightWindows] = ()):
+        super().__init__(iterable)
+
+    @classmethod
+    def from_hdf5(cls, path: PathLike = 'weight_windows.h5') -> Self:
+        """Create WeightWindowsList from a weight windows HDF5 file.
+
+        Parameters
+        ----------
+        path : PathLike
+            Path to the weight windows hdf5 file
+
+        Returns
+        -------
+        WeightWindowsList
+            A list of WeightWindows objects read from the file
+        """
+
+        with h5py.File(path) as h5_file:
+            # read in all of the meshes in the mesh node
+            meshes = {}
+            for mesh_group in h5_file['meshes']:
+                mesh = MeshBase.from_hdf5(h5_file['meshes'][mesh_group])
+                meshes[mesh.id] = mesh
+            wws = [
+                WeightWindows.from_hdf5(ww, meshes)
+                for ww in h5_file['weight_windows'].values()
+            ]
+
+        return cls(wws)
+
+    @classmethod
+    def from_wwinp(cls, path: PathLike) -> Self:
+        """Create WeightWindowsList from a wwinp file.
+
+        Parameters
+        ----------
+        path : PathLike
+            Path to the wwinp file
+
+        Returns
+        -------
+        WeightWindowsList
+            A list of WeightWindows objects read from the file
+        """
+
+        with open(path) as wwinp:
+            # BLOCK 1
+            header = wwinp.readline().split(None, 4)
+            # read file type, time-dependence, number of
+            # particles, mesh type and problem identifier
+            _if, iv, ni, nr = [int(x) for x in header[:4]]
+
+            # header value checks
+            if _if != 1:
+                raise ValueError(f'Found incorrect file type, if: {_if}')
+
+            if iv > 1:
+                # read number of time bins for each particle, 'nt(1...ni)'
+                nt = np.fromstring(wwinp.readline(), sep=' ', dtype=int)
+
+                # raise error if time bins are present for now
+                raise ValueError('Time-dependent weight windows '
+                                'are not yet supported')
+            else:
+                nt = ni * [1]
+
+            # read number of energy bins for each particle, 'ne(1...ni)'
+            ne = np.fromstring(wwinp.readline(), sep=' ', dtype=int)
+
+            # read coarse mesh dimensions and lower left corner
+            mesh_description = np.fromstring(wwinp.readline(), sep=' ')
+            nfx, nfy, nfz = mesh_description[:3].astype(int)
+            xyz0 = mesh_description[3:]
+
+            # read cylindrical and spherical mesh vectors if present
+            if nr == 16:
+                # read number of coarse bins
+                line_arr = np.fromstring(wwinp.readline(), sep=' ')
+                ncx, ncy, ncz = line_arr[:3].astype(int)
+                # read polar vector (x1, y1, z1)
+                xyz1 = line_arr[3:]
+                # read azimuthal vector (x2, y2, z2)
+                line_arr = np.fromstring(wwinp.readline(), sep=' ')
+                xyz2 = line_arr[:3]
+
+                # Get polar and azimuthal axes
+                polar_axis = xyz1 - xyz0
+                azimuthal_axis = xyz2 - xyz0
+
+                # Check for polar axis other than (0, 0, 1)
+                norm = np.linalg.norm(polar_axis)
+                if not np.isclose(polar_axis[2]/norm, 1.0):
+                    raise NotImplementedError('Polar axis not aligned to z-axis not supported')
+
+                # Check for azimuthal axis other than (1, 0, 0)
+                norm = np.linalg.norm(azimuthal_axis)
+                if not np.isclose(azimuthal_axis[0]/norm, 1.0):
+                    raise NotImplementedError('Azimuthal axis not aligned to x-axis not supported')
+
+                # read geometry type
+                nwg = int(line_arr[-1])
+
+            elif nr == 10:
+                # read rectilinear data:
+                # number of coarse mesh bins and mesh type
+                ncx, ncy, ncz, nwg = \
+                    np.fromstring(wwinp.readline(), sep=' ').astype(int)
+            else:
+                raise RuntimeError(f'Invalid mesh description (nr) found: {nr}')
+
+            # read BLOCK 2 and BLOCK 3 data into a single array
+            ww_data = np.fromstring(wwinp.read(), sep=' ')
+
+        # extract mesh data from the ww_data array
+        start_idx = 0
+
+        # first values in the mesh definition arrays are the first
+        # coordinate of the grid
+        end_idx = start_idx + 1 + 3 * ncx
+        i0, i_vals = ww_data[start_idx], ww_data[start_idx+1:end_idx]
+        start_idx = end_idx
+
+        end_idx = start_idx + 1 + 3 * ncy
+        j0, j_vals = ww_data[start_idx], ww_data[start_idx+1:end_idx]
+        start_idx = end_idx
+
+        end_idx = start_idx + 1 + 3 * ncz
+        k0, k_vals = ww_data[start_idx], ww_data[start_idx+1:end_idx]
+        start_idx = end_idx
+
+        # mesh consistency checks
+        if nr == 16 and nwg == 1 or nr == 10 and nwg != 1:
+            raise ValueError(f'Mesh description in header ({nr}) '
+                            f'does not match the mesh type ({nwg})')
+
+        if nr == 10 and (xyz0 != (i0, j0, k0)).any():
+            raise ValueError(f'Mesh origin in the header ({xyz0}) '
+                            f' does not match the origin in the mesh '
+                            f' description ({i0, j0, k0})')
+
+        # create openmc mesh object
+        grids = []
+        mesh_definition = [(i0, i_vals, nfx), (j0, j_vals, nfy), (k0, k_vals, nfz)]
+        for grid0, grid_vals, n_pnts in mesh_definition:
+            # file spec checks for the mesh definition
+            if (grid_vals[2::3] != 1.0).any():
+                raise ValueError('One or more mesh ratio value, qx, '
+                                'is not equal to one')
+
+            s = int(grid_vals[::3].sum())
+            if s != n_pnts:
+                raise ValueError(f'Sum of the fine bin entries, {s}, does '
+                                f'not match the number of fine bins, {n_pnts}')
+
+            # extend the grid based on the next coarse bin endpoint, px
+            # and the number of fine bins in the coarse bin, sx
+            intervals = grid_vals.reshape(-1, 3)
+            coords = [grid0]
+            for sx, px, qx in intervals:
+                coords += np.linspace(coords[-1], px, int(sx + 1)).tolist()[1:]
+
+            grids.append(np.array(coords))
+
+        if nwg == 1:
+            mesh = RectilinearMesh()
+            mesh.x_grid, mesh.y_grid, mesh.z_grid = grids
+        elif nwg == 2:
+            mesh = CylindricalMesh(
+                r_grid=grids[0],
+                z_grid=grids[1],
+                phi_grid=grids[2],
+                origin = xyz0,
+            )
+        elif nwg == 3:
+            mesh = SphericalMesh(
+                r_grid=grids[0],
+                theta_grid=grids[1],
+                phi_grid=grids[2],
+                origin = xyz0
+            )
+
+        # extract weight window values from array
+        wws = cls()
+        for ne_i, nt_i, particle_type in zip(ne, nt, ('neutron', 'photon')):
+            # no information to read for this particle if
+            # either the energy bins or time bins are empty
+            if ne_i == 0 or nt_i == 0:
+                continue
+
+            if iv > 1:
+                # time bins are parsed but unused for now
+                end_idx = start_idx + nt_i
+                time_bounds = ww_data[start_idx:end_idx]
+                np.insert(time_bounds, (0,), (0.0,))
+                start_idx = end_idx
+
+            # read energy boundaries
+            end_idx = start_idx + ne_i
+            energy_bounds = np.insert(ww_data[start_idx:end_idx], (0,), (0.0,))
+            # convert from MeV to eV
+            energy_bounds *= 1e6
+            start_idx = end_idx
+
+            # read weight window values
+            end_idx = start_idx + (nfx * nfy * nfz) * nt_i * ne_i
+
+            # read values and reshape according to ordering
+            # slowest to fastest: t, e, z, y, x
+            # reorder with transpose since our ordering is x, y, z, e, t
+            ww_shape = (nt_i, ne_i, nfz, nfy, nfx)
+            ww_values = ww_data[start_idx:end_idx].reshape(ww_shape).T
+            # Only use first time bin since we don't support time dependent weight
+            # windows yet.
+            ww_values = ww_values[:, :, :, :, 0]
+            start_idx = end_idx
+
+            # create a weight window object
+            ww = WeightWindows(id=None,
+                            mesh=mesh,
+                            lower_ww_bounds=ww_values,
+                            upper_bound_ratio=5.0,
+                            energy_bounds=energy_bounds,
+                            particle_type=particle_type)
+            wws.append(ww)
+
+        return wws
+
+    def export_to_hdf5(self, path: PathLike = 'weight_windows.h5', **init_kwargs):
+        """Write weight windows to an HDF5 file.
+
+        Parameters
+        ----------
+        path : PathLike
+            Path to the file to write weight windows to
+        **init_kwargs
+            Keyword arguments passed to :func:`openmc.lib.init`
+
+        """
+        import openmc.lib
+        cv.check_type('path', path, PathLike)
+
+        # Create a temporary model with the weight windows
+        model = openmc.Model()
+        sph = openmc.Sphere(boundary_type='vacuum')
+        cell = openmc.Cell(region=-sph)
+        model.geometry = openmc.Geometry([cell])
+        model.settings.weight_windows = self
+        model.settings.particles = 100
+        model.settings.batches = 1
+
+        # Get absolute path before moving to temporary directory
+        path = Path(path).resolve()
+
+        with change_directory(tmpdir=True):
+            # Write the model to an XML file
+            model.export_to_model_xml()
+
+            # Load the model with openmc.lib and then export it to an HDF5 file
+            with openmc.lib.run_in_memory(**init_kwargs):
+                openmc.lib.export_weight_windows(path)
diff --git a/tests/regression_tests/weightwindows/inputs_true.dat b/tests/regression_tests/weightwindows/inputs_true.dat
index dcc41ae84..91fec4af9 100644
--- a/tests/regression_tests/weightwindows/inputs_true.dat
+++ b/tests/regression_tests/weightwindows/inputs_true.dat
@@ -49,7 +49,7 @@
       <energy_bounds>0.0 0.5 20000000.0</energy_bounds>
       <lower_ww_bounds>-1.0 0.007673145137236567 6.542700644645627e-07 0.0017541380096893788 0.0007245451610090619 7.476545089278482e-06 2.253382683081525e-06 2.1040609012865134e-05 0.08285899874014539 -1.0 1.0262431550731535e-13 3.3164825349503764e-16 0.0064803314120165335 3.5981031766416143e-06 -1.0 1.6205064883026195e-11 1.7770136411255912e-05 0.0001670700632870335 4.323138781337963e-05 -1.0 -1.0 6.922231352729155e-05 0.06550426960512012 -1.0 2.5639656866250453e-06 1.4508262073256659e-13 -1.0 -1.0 0.0009127050763987511 3.8523247550378815e-12 -1.0 0.0008175033526488423 -1.0 0.015148978428271613 2.5157355790201773e-07 2.1612150425221703e-06 1.3181562352445092e-10 2.9282097947816224e-05 2.762955748645507e-05 2.936268747135548e-14 1.6859219614058024e-19 3.937160538176268e-07 2.6011787393916806e-06 0.001570829313580841 -1.0 1.7041669224797384e-09 1.6421491993751715e-11 0.4899999304038166 6.948292975998466e-07 -1.0 -1.0 0.08657573566388353 0.006639379668946672 1.681305446488884e-11 2.2487617828938326e-05 4.109066205029878e-05 0.08288806458368345 -1.0 0.007385384405891666 -1.0 -1.0 1.008394964750947e-06 6.655926357459275e-08 0.0016279794552427574 1.4825219199133353e-12 -1.0 1.93847081892941e-05 1.284759166582202e-05 5.1161740516205715e-05 2.5447281241730366e-07 3.853097455417877e-06 -1.0 8.887234042637684e-05 0.01621821782442112 -1.0 1.8747824667478637e-14 5.97653814110781e-06 -1.0 -1.0 1.2296747260635405e-06 -1.0 -1.0 7.754700849337902e-06 7.091263906557291e-05 3.2799045883372075e-06 0.00020573181450240786 5.6949597066784976e-05 1.271128669411295e-07 0.0010019432401508087 -1.0 -1.0 6.848642863465585e-07 5.783974359937857e-06 2.380955631371226e-06 4.756872959630257e-05 2.1360401784344975e-18 0.00046029617115127556 1.0092905083158804e-11 0.08095280568305474 3.89841667138598e-08 4.354946981329799e-05 -1.0 0.5 0.0015447823995470042 -1.0 -1.0 0.001959411999677113 0.48573842213878143 -1.0 7.962899789920809e-06 5.619835883512353e-14 0.0835648710074336 2.7207433165796702e-11 0.00027464244062887683 4.076762579823379e-17 2.124999182004655e-05 8.037131813528501e-07 8.846493399850663e-06 1.080711295768551e-05 -1.0 -1.0 0.0010737081832502356 2.679340942769232e-06 2.1648918040467363e-05 0.0002668579837809081 1.3455341306162382e-05 2.5629068330446215e-05 1.3228013765525015e-05 -1.0 -1.0 7.002861620919232e-08 1.5172912057312398e-14 -1.0 7.989579285134734e-06 2.639268952045579e-10 -1.0 0.013330619853379314 0.00021534568699157805 2.4469456008493614e-09 8.211982683649991e-09 1.951356547084204e-15 0.00016419031150495913 5.985108617124989e-06 1.28584557092134e-05 1.5476769237571295e-14 5.5379154134462336e-08 0.0016637126543321873 2.499931357628383e-07 8.020767115181574e-07 2.7697233171399416e-13 -1.0 0.007197662162700777 -1.0 0.0833931797381589 2.8226276944532696e-05 3.353295403842037e-05 5.504813693036933e-12 0.007136750029575816 0.08636569925236791 -1.0 -1.0 6.315154082213375e-07 0.4877856021170283 -1.0 3.7051518220083886e-06 -1.0 0.0017950613169359904 7.84289689494925e-06 9.041149893307806e-07 -1.0 8.48176145671274e-10 9.03108551826469e-05 3.634644995026692e-05 2.0295213621716706e-09 1.0305672698745657e-11 1.5550455959178486e-06 0.01664109232689093 8.533030345699353e-17 0.0009252532821720597 -1.0 7.695031155172816e-14 0.0007151459162818186 -1.0 -1.0 5.182269672663266e-10 3.0160758454323657e-07 -1.0 0.06539005235506369 3.452537179033895e-05 -1.0 -1.0 3.855884234344845e-06 0.00017699858357744463 2.594951085377588e-06 1.1333627604823673e-09 -1.0 2.4306375693722205e-06 0.0063790654507599135 2.2060992580622125e-11 -1.0 -1.0 0.0848872967381878 3.932389299316285e-06 1.2911827198500372e-08 1.957092814065688e-05 0.0007213722022489493 0.0018327593437608 1.6699254277734109e-06 0.007188410694198128 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0</lower_ww_bounds>
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-      <survival_ratio>3</survival_ratio>
+      <survival_ratio>3.0</survival_ratio>
       <max_lower_bound_ratio>1.5</max_lower_bound_ratio>
       <max_split>10</max_split>
       <weight_cutoff>1e-38</weight_cutoff>
@@ -65,7 +65,7 @@
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4.233410073487772e-06 0.0051513292132259495 8.616027294555462e-07 0.4873897581604287 2.9093345975075226e-05 0.000469589568463265 -1.0 -1.0 0.017802624844035688 1.3116807133030035e-15 2.617878055106949e-16 0.01884234453311008 -1.0 2.027381220364608e-16 0.0004299195570308035 1.4628847959717225e-05 0.4899952354672477 2.774067049392004e-07 0.004441328419270369 4.279460329782799e-09 0.0012297303081805393 0.0002792896409558745 0.0006934466049804711 8.370896020975689e-05 3.8270536025799805e-15 -1.0 0.01208261392046878 0.0001497958445994315 0.0015016500045374082 0.005384625561469684 0.00025519632243117644 0.0011028020390507682 0.0002362355168421952 -1.0 -1.0 8.862760180332873e-05 1.3806577785135177e-06 -1.0 0.0001319677450153934 2.6866894852481906e-05 -1.0 0.11510120013926417 0.002672923773363389 1.2257360246712472e-05 8.544159282151438e-05 2.777791741571174e-05 0.0014957033281168012 0.0003257646134837451 0.0008919466185572302 1.2907171695294846e-13 4.6842350882367666e-05 0.01721806295736377 0.00025106741008066317 0.00022234471595443313 2.101790478097517e-09 5.752120832330886e-11 0.06428782790571179 3.2478301680021854e-08 0.4903495510314233 0.001146714816952061 0.0004777967757842694 1.0882011018684852e-06 0.05708498338352203 0.4981497862127628 -1.0 3.2790914744011534e-06 0.00010077009726691265 -1.0 2.210707325798542e-07 4.3166052799897375e-05 -1.0 0.01825795827020865 0.0003182108781955478 3.8561696337086434e-05 1.0995322456277382e-06 9.53380658669839e-06 0.001550036616828061 0.0012648333883989995 5.272021975060514e-06 1.9257248009114363e-05 0.00016757997590048827 0.11891251244906934 5.515522196186723e-06 0.01102706140784316 9.904481358675478e-13 3.520674728719278e-05 0.011294708566804167 7.239087311622819e-08 -1.0 3.5740607788414942e-06 0.00035983547999740665 1.0588257623722672e-07 0.42372713683725016 0.0011273340972061078 8.582011716859219e-15 1.1514579117272292e-10 0.00043130977711323417 0.0027847329307350423 0.00017287873387910357 6.401055165502384e-06 1.722191123879782e-08 0.00020848309220162036 0.05639071613735579 1.8064550990294753e-05 1.289814511028015e-06 1.078687446476881e-14 0.4897735047310072 0.0002981891705231209 0.00016079768514218546 9.332371598523186e-05 0.011724714376848187 0.019040707071165303 0.00014242053195529864 0.06684484191345574 -1.0</lower_ww_bounds>
       <upper_ww_bounds>-10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 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0.0002777791741571174 0.014957033281168012 0.0032576461348374514 0.008919466185572301 1.2907171695294846e-12 0.00046842350882367664 0.17218062957363772 0.0025106741008066318 0.0022234471595443312 2.101790478097517e-08 5.752120832330886e-10 0.6428782790571179 3.2478301680021856e-07 4.903495510314233 0.01146714816952061 0.004777967757842694 1.0882011018684853e-05 0.5708498338352204 4.981497862127628 -10.0 3.279091474401153e-05 0.0010077009726691265 -10.0 2.210707325798542e-06 0.00043166052799897375 -10.0 0.1825795827020865 0.0031821087819554777 0.00038561696337086434 1.0995322456277382e-05 9.53380658669839e-05 0.01550036616828061 0.012648333883989995 5.272021975060514e-05 0.00019257248009114364 0.0016757997590048828 1.1891251244906933 5.515522196186723e-05 0.1102706140784316 9.904481358675478e-12 0.0003520674728719278 0.11294708566804167 7.239087311622819e-07 -10.0 3.574060778841494e-05 0.0035983547999740664 1.0588257623722672e-06 4.237271368372502 0.011273340972061077 8.582011716859219e-14 1.151457911727229e-09 0.004313097771132342 0.027847329307350423 0.0017287873387910357 6.401055165502385e-05 1.722191123879782e-07 0.0020848309220162036 0.5639071613735579 0.00018064550990294753 1.289814511028015e-05 1.078687446476881e-13 4.897735047310072 0.002981891705231209 0.0016079768514218546 0.0009332371598523186 0.11724714376848187 0.19040707071165303 0.0014242053195529865 0.6684484191345574 -10.0</upper_ww_bounds>
-      <survival_ratio>3</survival_ratio>
+      <survival_ratio>3.0</survival_ratio>
       <max_lower_bound_ratio>1.5</max_lower_bound_ratio>
       <max_split>10</max_split>
       <weight_cutoff>1e-38</weight_cutoff>
diff --git a/tests/unit_tests/weightwindows/test_ww_list.py b/tests/unit_tests/weightwindows/test_ww_list.py
new file mode 100644
index 000000000..d148f382a
--- /dev/null
+++ b/tests/unit_tests/weightwindows/test_ww_list.py
@@ -0,0 +1,23 @@
+import openmc
+
+
+def test_ww_roundtrip(request, run_in_tmpdir):
+    # Load weight windows from a wwinp file
+    wwinp_file = request.path.with_name('wwinp_n')
+    wws = openmc.WeightWindowsList.from_wwinp(wwinp_file)
+
+    # Roundtrip them, writing to HDF5 and reading back in
+    wws.export_to_hdf5('ww.h5')
+    wws_new = openmc.WeightWindowsList.from_hdf5('ww.h5')
+
+    # Check that the new weight windows are the same as the original
+    assert len(wws) == len(wws_new)
+    for ww, ww_new in zip(wws, wws_new):
+        assert ww.particle_type == ww_new.particle_type
+        assert (ww.lower_ww_bounds == ww_new.lower_ww_bounds).all()
+        assert (ww.upper_ww_bounds == ww_new.upper_ww_bounds).all()
+        assert ww.survival_ratio == ww_new.survival_ratio
+        assert ww.num_energy_bins == ww_new.num_energy_bins
+        assert ww.max_split == ww_new.max_split
+        assert ww.weight_cutoff == ww_new.weight_cutoff
+        assert ww.mesh.id == ww_new.mesh.id