def METHOD_NAME():
    f = openmc.Material(name="f")
    f.add_element("U", 1, percent_type="ao", enrichment=4.25)
    f.add_element("O", 2)
    f.set_density("g/cc", 10.4)
    w = openmc.Material(name="w")
    w.add_element("O", 1)
    w.add_element("H", 2)
    w.set_density("g/cc", 1.0)
    w.depletable = True
    radii = [0.42, 0.45]
    f.volume = np.pi * radii[0] ** 2
    w.volume = np.pi * (radii[1]**2 - radii[0]**2)
    materials = openmc.Materials([f, w])
    surf_f = openmc.Sphere(r=radii[0])
    surf_w = openmc.Sphere(r=radii[1], boundary_type='vacuum')
    cell_f = openmc.Cell(fill=f, region=-surf_f)
    cell_w = openmc.Cell(fill=w, region=+surf_f & -surf_w)
    geometry = openmc.Geometry([cell_f, cell_w])
    settings = openmc.Settings()
    settings.particles = 1000
    settings.inactive = 10
    settings.batches = 50
    return openmc.Model(geometry, materials, settings)