From 0b77cc7edc6ec1d83a45e10a4beb2ebbf0aba34b Mon Sep 17 00:00:00 2001
From: Paul Romano <paul.k.romano@gmail.com>
Date: Thu, 28 Apr 2022 17:11:21 -0500
Subject: [PATCH 1/9] Allow normal instantiation of ResultsList (instead of
 from_hdf5)

---
 docs/source/usersguide/depletion.rst          |  2 +-
 .../pincell_depletion/restart_depletion.py    |  4 +--
 examples/pincell_depletion/run_depletion.py   |  2 +-
 openmc/deplete/abc.py                         |  2 +-
 openmc/deplete/results.py                     |  7 +++-
 openmc/deplete/results_list.py                | 36 ++++++++++++-------
 tests/regression_tests/deplete/test.py        |  6 ++--
 tests/unit_tests/test_deplete_activation.py   |  4 +--
 tests/unit_tests/test_deplete_integrator.py   |  5 ++-
 tests/unit_tests/test_deplete_restart.py      | 10 +++---
 tests/unit_tests/test_deplete_resultslist.py  |  2 +-
 tests/unit_tests/test_transfer_volumes.py     |  2 +-
 12 files changed, 48 insertions(+), 34 deletions(-)

diff --git a/docs/source/usersguide/depletion.rst b/docs/source/usersguide/depletion.rst
index 78a12c4ca..e3f4017f2 100644
--- a/docs/source/usersguide/depletion.rst
+++ b/docs/source/usersguide/depletion.rst
@@ -53,7 +53,7 @@ The coupled transport-depletion problem is executed, and once it is done a
 easy retrieval of k-effective, nuclide concentrations, and reaction rates over
 time::
 
-    results = openmc.deplete.ResultsList.from_hdf5("depletion_results.h5")
+    results = openmc.deplete.ResultsList("depletion_results.h5")
     time, keff = results.get_keff()
 
 Note that the coupling between the transport solver and the transmutation solver
diff --git a/examples/pincell_depletion/restart_depletion.py b/examples/pincell_depletion/restart_depletion.py
index 72209d2ab..45bb4343d 100644
--- a/examples/pincell_depletion/restart_depletion.py
+++ b/examples/pincell_depletion/restart_depletion.py
@@ -12,7 +12,7 @@ with openmc.StatePoint(statepoint) as sp:
     geometry = sp.summary.geometry
 
 # Load previous depletion results
-previous_results = openmc.deplete.ResultsList.from_hdf5("depletion_results.h5")
+previous_results = openmc.deplete.ResultsList("depletion_results.h5")
 
 ###############################################################################
 #                      Transport calculation settings
@@ -56,7 +56,7 @@ integrator.integrate()
 ###############################################################################
 
 # Open results file
-results = openmc.deplete.ResultsList.from_hdf5("depletion_results.h5")
+results = openmc.deplete.ResultsList("depletion_results.h5")
 
 # Obtain K_eff as a function of time
 time, keff = results.get_keff(time_units='d')
diff --git a/examples/pincell_depletion/run_depletion.py b/examples/pincell_depletion/run_depletion.py
index 53b0614d1..727039a29 100644
--- a/examples/pincell_depletion/run_depletion.py
+++ b/examples/pincell_depletion/run_depletion.py
@@ -101,7 +101,7 @@ integrator.integrate()
 ###############################################################################
 
 # Open results file
-results = openmc.deplete.ResultsList.from_hdf5("depletion_results.h5")
+results = openmc.deplete.ResultsList("depletion_results.h5")
 
 # Obtain K_eff as a function of time
 time, keff = results.get_keff(time_units='d')
diff --git a/openmc/deplete/abc.py b/openmc/deplete/abc.py
index 0d1e8ad41..7c3fc42f7 100644
--- a/openmc/deplete/abc.py
+++ b/openmc/deplete/abc.py
@@ -842,7 +842,7 @@ class Integrator(ABC):
         k = ufloat(res.k[0, 0], res.k[0, 1])
 
         # Scale reaction rates by ratio of source rates
-        rates *= source_rate / res.source_rate[0]
+        rates *= source_rate / res.source_rate
         return bos_conc, OperatorResult(k, rates)
 
     def _get_start_data(self):
diff --git a/openmc/deplete/results.py b/openmc/deplete/results.py
index 3916fb4d7..9ff07b049 100644
--- a/openmc/deplete/results.py
+++ b/openmc/deplete/results.py
@@ -69,6 +69,11 @@ class Results:
 
         self.data = None
 
+    def __repr__(self):
+        t = self.time[0]
+        dt = self.time[1] - self.time[0]
+        return f"<Results: t={t}, dt={dt}, source={self.source_rate}>"
+
     def __getitem__(self, pos):
         """Retrieves an item from results.
 
@@ -406,7 +411,7 @@ class Results:
         results.data = number_dset[step, :, :, :]
         results.k = eigenvalues_dset[step, :]
         results.time = time_dset[step, :]
-        results.source_rate = source_rate_dset[step, :]
+        results.source_rate = source_rate_dset[step, 0]
 
         if "depletion time" in handle:
             proc_time_dset = handle["/depletion time"]
diff --git a/openmc/deplete/results_list.py b/openmc/deplete/results_list.py
index f2f2be0ab..843e3aec6 100644
--- a/openmc/deplete/results_list.py
+++ b/openmc/deplete/results_list.py
@@ -29,9 +29,24 @@ def _get_time_as(seconds, units):
 class ResultsList(list):
     """A list of openmc.deplete.Results objects
 
-    It is recommended to use :meth:`from_hdf5` over
-    direct creation.
+    Parameters
+    ----------
+    filename : str
+        Path to depletion result file
+
     """
+    def __init__(self, filename):
+        with h5py.File(str(filename), "r") as fh:
+            cv.check_filetype_version(fh, 'depletion results', VERSION_RESULTS[0])
+            data = []
+
+            # Get number of results stored
+            n = fh["number"][...].shape[0]
+
+            for i in range(n):
+                data.append(Results.from_hdf5(fh, i))
+        super().__init__(data)
+
 
     @classmethod
     def from_hdf5(cls, filename):
@@ -46,17 +61,14 @@ class ResultsList(list):
         -------
         new : ResultsList
             New instance of depletion results
+
         """
-        with h5py.File(str(filename), "r") as fh:
-            cv.check_filetype_version(fh, 'depletion results', VERSION_RESULTS[0])
-            new = cls()
-
-            # Get number of results stored
-            n = fh["number"][...].shape[0]
-
-            for i in range(n):
-                new.append(Results.from_hdf5(fh, i))
-        return new
+        warn(
+            "The from_hdf5(...) method is no longer necessary and will be removed "
+            "in a future version of OpenMC. Use ResultsList(...) instead.",
+            FutureWarning
+        )
+        return cls(filename)
 
     def get_atoms(self, mat, nuc, nuc_units="atoms", time_units="s"):
         """Get number of nuclides over time from a single material
diff --git a/tests/regression_tests/deplete/test.py b/tests/regression_tests/deplete/test.py
index 4f0e738a3..91f18667e 100644
--- a/tests/regression_tests/deplete/test.py
+++ b/tests/regression_tests/deplete/test.py
@@ -77,8 +77,8 @@ def test_full(run_in_tmpdir, problem, multiproc):
         return
 
     # Load the reference/test results
-    res_test = openmc.deplete.ResultsList.from_hdf5(path_test)
-    res_ref = openmc.deplete.ResultsList.from_hdf5(path_reference)
+    res_test = openmc.deplete.ResultsList(path_test)
+    res_ref = openmc.deplete.ResultsList(path_reference)
 
     # Assert same mats
     for mat in res_ref[0].mat_to_ind:
@@ -139,7 +139,7 @@ def test_depletion_results_to_material(run_in_tmpdir, problem):
     """Checks openmc.Materials objects can be created from depletion results"""
     # Load the reference/test results
     path_reference = Path(__file__).with_name('test_reference.h5')
-    res_ref = openmc.deplete.ResultsList.from_hdf5(path_reference)
+    res_ref = openmc.deplete.ResultsList(path_reference)
 
     # Firstly need to export materials.xml file for the initial simulation state
     geometry, lower_left, upper_right = problem
diff --git a/tests/unit_tests/test_deplete_activation.py b/tests/unit_tests/test_deplete_activation.py
index 2f02ec4b8..2c3e0c053 100644
--- a/tests/unit_tests/test_deplete_activation.py
+++ b/tests/unit_tests/test_deplete_activation.py
@@ -107,7 +107,7 @@ def test_activation(run_in_tmpdir, model, reaction_rate_mode, reaction_rate_opts
     integrator.integrate()
 
     # Get resulting number of atoms
-    results = openmc.deplete.ResultsList.from_hdf5('depletion_results.h5')
+    results = openmc.deplete.ResultsList('depletion_results.h5')
     _, atoms = results.get_atoms(w, "W186")
 
     assert atoms[0] == pytest.approx(n0)
@@ -155,7 +155,7 @@ def test_decay(run_in_tmpdir):
     integrator.integrate()
 
     # Get resulting number of atoms
-    results = openmc.deplete.ResultsList.from_hdf5('depletion_results.h5')
+    results = openmc.deplete.ResultsList('depletion_results.h5')
     _, atoms = results.get_atoms(mat, "Sr89")
 
     # Ensure density goes down by a factor of 2 after each half-life
diff --git a/tests/unit_tests/test_deplete_integrator.py b/tests/unit_tests/test_deplete_integrator.py
index a08d8738c..9c53ad7e2 100644
--- a/tests/unit_tests/test_deplete_integrator.py
+++ b/tests/unit_tests/test_deplete_integrator.py
@@ -103,7 +103,7 @@ def test_results_save(run_in_tmpdir):
     Results.save(op, x2, op_result2, t2, 0, 1)
 
     # Load the files
-    res = ResultsList.from_hdf5("depletion_results.h5")
+    res = ResultsList("depletion_results.h5")
 
     for i in range(stages):
         for mat_i, mat in enumerate(burn_list):
@@ -176,8 +176,7 @@ def test_integrator(run_in_tmpdir, scheme):
 
     # get expected results
 
-    res = ResultsList.from_hdf5(
-        operator.output_dir / "depletion_results.h5")
+    res = ResultsList(operator.output_dir / "depletion_results.h5")
 
     t1, y1 = res.get_atoms("1", "1")
     t2, y2 = res.get_atoms("1", "2")
diff --git a/tests/unit_tests/test_deplete_restart.py b/tests/unit_tests/test_deplete_restart.py
index 82ef05ac7..2bfcfea7d 100644
--- a/tests/unit_tests/test_deplete_restart.py
+++ b/tests/unit_tests/test_deplete_restart.py
@@ -24,8 +24,7 @@ def test_restart_predictor_cecm(run_in_tmpdir):
     openmc.deplete.PredictorIntegrator(op, dt, power).integrate()
 
     # Load the files
-    prev_res = openmc.deplete.ResultsList.from_hdf5(
-        op.output_dir / "depletion_results.h5")
+    prev_res = openmc.deplete.ResultsList(op.output_dir / "depletion_results.h5")
 
     # Re-create depletion operator and load previous results
     op = dummy_operator.DummyOperator(prev_res)
@@ -51,8 +50,7 @@ def test_restart_cecm_predictor(run_in_tmpdir):
     cecm.integrate()
 
     # Load the files
-    prev_res = openmc.deplete.ResultsList.from_hdf5(
-        op.output_dir / "depletion_results.h5")
+    prev_res = openmc.deplete.ResultsList(op.output_dir / "depletion_results.h5")
 
     # Re-create depletion operator and load previous results
     op = dummy_operator.DummyOperator(prev_res)
@@ -75,7 +73,7 @@ def test_restart(run_in_tmpdir, scheme):
     bundle.solver(operator, [0.75], 1.0).integrate()
 
     # restart
-    prev_res = openmc.deplete.ResultsList.from_hdf5(
+    prev_res = openmc.deplete.ResultsList(
         operator.output_dir / "depletion_results.h5")
     operator = dummy_operator.DummyOperator(prev_res)
 
@@ -84,7 +82,7 @@ def test_restart(run_in_tmpdir, scheme):
 
     # compare results
 
-    results = openmc.deplete.ResultsList.from_hdf5(
+    results = openmc.deplete.ResultsList(
         operator.output_dir / "depletion_results.h5")
 
     _t, y1 = results.get_atoms("1", "1")
diff --git a/tests/unit_tests/test_deplete_resultslist.py b/tests/unit_tests/test_deplete_resultslist.py
index 03e7c3eb0..2554d2188 100644
--- a/tests/unit_tests/test_deplete_resultslist.py
+++ b/tests/unit_tests/test_deplete_resultslist.py
@@ -13,7 +13,7 @@ def res():
     """Load the reference results"""
     filename = (Path(__file__).parents[1] / 'regression_tests' / 'deplete'
                 / 'test_reference.h5')
-    return openmc.deplete.ResultsList.from_hdf5(filename)
+    return openmc.deplete.ResultsList(filename)
 
 
 def test_get_atoms(res):
diff --git a/tests/unit_tests/test_transfer_volumes.py b/tests/unit_tests/test_transfer_volumes.py
index e1f3c1053..50e222b95 100644
--- a/tests/unit_tests/test_transfer_volumes.py
+++ b/tests/unit_tests/test_transfer_volumes.py
@@ -19,7 +19,7 @@ def test_transfer_volumes(run_in_tmpdir):
     PredictorIntegrator(op, dt, power).integrate()
 
     # Load the files
-    res = openmc.deplete.ResultsList.from_hdf5(op.output_dir / "depletion_results.h5")
+    res = openmc.deplete.ResultsList(op.output_dir / "depletion_results.h5")
 
     # Create a dictionary of volumes to transfer
     res[0].volume['1'] = 1.5

From aacf3c4938f2ce04ec9b75794f4a73f6bb162442 Mon Sep 17 00:00:00 2001
From: Paul Romano <paul.k.romano@gmail.com>
Date: Thu, 28 Apr 2022 17:18:00 -0500
Subject: [PATCH 2/9] Rename deplete.Results -> deplete.StepResult

---
 docs/source/pythonapi/deplete.rst            |  2 +-
 openmc/deplete/abc.py                        | 10 +++++-----
 openmc/deplete/results.py                    | 14 +++++++-------
 openmc/deplete/results_list.py               | 12 ++++++++----
 tests/unit_tests/test_deplete_integrator.py  |  6 +++---
 tests/unit_tests/test_deplete_resultslist.py |  2 +-
 6 files changed, 25 insertions(+), 21 deletions(-)

diff --git a/docs/source/pythonapi/deplete.rst b/docs/source/pythonapi/deplete.rst
index 383268f8b..41be2d88a 100644
--- a/docs/source/pythonapi/deplete.rst
+++ b/docs/source/pythonapi/deplete.rst
@@ -133,8 +133,8 @@ data, such as number densities and reaction rates for each material.
    AtomNumber
    OperatorResult
    ReactionRates
-   Results
    ResultsList
+   StepResult
 
 The following class and functions are used to solve the depletion equations,
 with :func:`cram.CRAM48` being the default.
diff --git a/openmc/deplete/abc.py b/openmc/deplete/abc.py
index 7c3fc42f7..7d6e33924 100644
--- a/openmc/deplete/abc.py
+++ b/openmc/deplete/abc.py
@@ -22,7 +22,7 @@ from uncertainties import ufloat
 from openmc.lib import MaterialFilter, Tally
 from openmc.checkvalue import check_type, check_greater_than
 from openmc.mpi import comm
-from .results import Results
+from .results import StepResult
 from .chain import Chain
 from .results_list import ResultsList
 from .pool import deplete
@@ -889,7 +889,7 @@ class Integrator(ABC):
                 # Remove actual EOS concentration for next step
                 conc = conc_list.pop()
 
-                Results.save(self.operator, conc_list, res_list, [t, t + dt],
+                StepResult.save(self.operator, conc_list, res_list, [t, t + dt],
                              source_rate, self._i_res + i, proc_time)
 
                 t += dt
@@ -901,7 +901,7 @@ class Integrator(ABC):
             if output and final_step:
                 print(f"[openmc.deplete] t={t} (final operator evaluation)")
             res_list = [self.operator(conc, source_rate if final_step else 0.0)]
-            Results.save(self.operator, [conc], res_list, [t, t],
+            StepResult.save(self.operator, [conc], res_list, [t, t],
                          source_rate, self._i_res + len(self), proc_time)
             self.operator.write_bos_data(len(self) + self._i_res)
 
@@ -1048,13 +1048,13 @@ class SIIntegrator(Integrator):
                 # Remove actual EOS concentration for next step
                 conc = conc_list.pop()
 
-                Results.save(self.operator, conc_list, res_list, [t, t + dt],
+                StepResult.save(self.operator, conc_list, res_list, [t, t + dt],
                              p, self._i_res + i, proc_time)
 
                 t += dt
 
             # No final simulation for SIE, use last iteration results
-            Results.save(self.operator, [conc], [res_list[-1]], [t, t],
+            StepResult.save(self.operator, [conc], [res_list[-1]], [t, t],
                          p, self._i_res + len(self), proc_time)
             self.operator.write_bos_data(self._i_res + len(self))
 
diff --git a/openmc/deplete/results.py b/openmc/deplete/results.py
index 9ff07b049..bfd165481 100644
--- a/openmc/deplete/results.py
+++ b/openmc/deplete/results.py
@@ -16,10 +16,10 @@ from .reaction_rates import ReactionRates
 VERSION_RESULTS = (1, 1)
 
 
-__all__ = ["Results"]
+__all__ = ["StepResult"]
 
 
-class Results:
+class StepResult:
     """Output of a depletion run
 
     Attributes
@@ -72,7 +72,7 @@ class Results:
     def __repr__(self):
         t = self.time[0]
         dt = self.time[1] - self.time[0]
-        return f"<Results: t={t}, dt={dt}, source={self.source_rate}>"
+        return f"<StepResult: t={t}, dt={dt}, source={self.source_rate}>"
 
     def __getitem__(self, pos):
         """Retrieves an item from results.
@@ -139,7 +139,7 @@ class Results:
         return self.data.shape[0]
 
     def allocate(self, volume, nuc_list, burn_list, full_burn_list, stages):
-        """Allocates memory of Results.
+        """Allocate memory for depletion step data
 
         Parameters
         ----------
@@ -177,10 +177,10 @@ class Results:
 
         Returns
         -------
-        Results
+        StepResult
             New results object
         """
-        new = Results()
+        new = StepResult()
         new.volume = {lm: self.volume[lm] for lm in local_materials}
         new.mat_to_ind = {mat: idx for (idx, mat) in enumerate(local_materials)}
 
@@ -485,7 +485,7 @@ class Results:
         stages = len(x)
 
         # Create results
-        results = Results()
+        results = StepResult()
         results.allocate(vol_dict, nuc_list, burn_list, full_burn_list, stages)
 
         n_mat = len(burn_list)
diff --git a/openmc/deplete/results_list.py b/openmc/deplete/results_list.py
index 843e3aec6..97170f226 100644
--- a/openmc/deplete/results_list.py
+++ b/openmc/deplete/results_list.py
@@ -6,7 +6,7 @@ from warnings import warn
 import h5py
 import numpy as np
 
-from .results import Results, VERSION_RESULTS
+from .results import StepResult, VERSION_RESULTS
 import openmc.checkvalue as cv
 from openmc.data.library import DataLibrary
 from openmc.material import Material, Materials
@@ -27,7 +27,11 @@ def _get_time_as(seconds, units):
 
 
 class ResultsList(list):
-    """A list of openmc.deplete.Results objects
+    """Results from a depletion simulation
+
+    The :class:`ResultsList` class acts as a list that stores the results from
+    each depletion step and provides extra methods for interrogating these
+    results.
 
     Parameters
     ----------
@@ -44,7 +48,7 @@ class ResultsList(list):
             n = fh["number"][...].shape[0]
 
             for i in range(n):
-                data.append(Results.from_hdf5(fh, i))
+                data.append(StepResult.from_hdf5(fh, i))
         super().__init__(data)
 
 
@@ -59,7 +63,7 @@ class ResultsList(list):
 
         Returns
         -------
-        new : ResultsList
+        ResultsList
             New instance of depletion results
 
         """
diff --git a/tests/unit_tests/test_deplete_integrator.py b/tests/unit_tests/test_deplete_integrator.py
index 9c53ad7e2..4348b8c34 100644
--- a/tests/unit_tests/test_deplete_integrator.py
+++ b/tests/unit_tests/test_deplete_integrator.py
@@ -16,7 +16,7 @@ import pytest
 
 from openmc.mpi import comm
 from openmc.deplete import (
-    ReactionRates, Results, ResultsList, OperatorResult, PredictorIntegrator,
+    ReactionRates, StepResult, ResultsList, OperatorResult, PredictorIntegrator,
     CECMIntegrator, CF4Integrator, CELIIntegrator, EPCRK4Integrator,
     LEQIIntegrator, SICELIIntegrator, SILEQIIntegrator, cram)
 
@@ -99,8 +99,8 @@ def test_results_save(run_in_tmpdir):
                   for k, rates in zip(eigvl1, rate1)]
     op_result2 = [OperatorResult(ufloat(*k), rates)
                   for k, rates in zip(eigvl2, rate2)]
-    Results.save(op, x1, op_result1, t1, 0, 0)
-    Results.save(op, x2, op_result2, t2, 0, 1)
+    StepResult.save(op, x1, op_result1, t1, 0, 0)
+    StepResult.save(op, x2, op_result2, t2, 0, 1)
 
     # Load the files
     res = ResultsList("depletion_results.h5")
diff --git a/tests/unit_tests/test_deplete_resultslist.py b/tests/unit_tests/test_deplete_resultslist.py
index 2554d2188..2a2669920 100644
--- a/tests/unit_tests/test_deplete_resultslist.py
+++ b/tests/unit_tests/test_deplete_resultslist.py
@@ -87,7 +87,7 @@ def test_get_steps(unit):
         conversion_to_seconds = 1
 
     for ix in range(times.size):
-        res = openmc.deplete.Results()
+        res = openmc.deplete.StepResult()
         res.time = times[ix:ix + 1] * conversion_to_seconds
         results.append(res)
 

From 8bfb1889b972ed31ab48da6b5c88810c8ddc38c2 Mon Sep 17 00:00:00 2001
From: Paul Romano <paul.k.romano@gmail.com>
Date: Thu, 28 Apr 2022 17:20:55 -0500
Subject: [PATCH 3/9] Rename deplete.ResultsList -> deplete.Results

---
 docs/source/pythonapi/deplete.rst               |  2 +-
 docs/source/usersguide/depletion.rst            |  4 ++--
 examples/pincell_depletion/restart_depletion.py |  4 ++--
 examples/pincell_depletion/run_depletion.py     |  2 +-
 openmc/deplete/abc.py                           |  8 ++++----
 openmc/deplete/operator.py                      | 12 ++++++------
 openmc/deplete/results_list.py                  | 10 +++++-----
 tests/regression_tests/deplete/test.py          |  6 +++---
 tests/unit_tests/test_deplete_activation.py     |  4 ++--
 tests/unit_tests/test_deplete_integrator.py     |  6 +++---
 tests/unit_tests/test_deplete_restart.py        |  8 ++++----
 tests/unit_tests/test_deplete_resultslist.py    |  8 ++++----
 tests/unit_tests/test_transfer_volumes.py       |  4 ++--
 13 files changed, 39 insertions(+), 39 deletions(-)

diff --git a/docs/source/pythonapi/deplete.rst b/docs/source/pythonapi/deplete.rst
index 41be2d88a..9f7d8c447 100644
--- a/docs/source/pythonapi/deplete.rst
+++ b/docs/source/pythonapi/deplete.rst
@@ -133,7 +133,7 @@ data, such as number densities and reaction rates for each material.
    AtomNumber
    OperatorResult
    ReactionRates
-   ResultsList
+   Results
    StepResult
 
 The following class and functions are used to solve the depletion equations,
diff --git a/docs/source/usersguide/depletion.rst b/docs/source/usersguide/depletion.rst
index e3f4017f2..57619611f 100644
--- a/docs/source/usersguide/depletion.rst
+++ b/docs/source/usersguide/depletion.rst
@@ -49,11 +49,11 @@ one of these functions along with the timesteps and power level::
 
 The coupled transport-depletion problem is executed, and once it is done a
 ``depletion_results.h5`` file is written. The results can be analyzed using the
-:class:`openmc.deplete.ResultsList` class. This class has methods that allow for
+:class:`openmc.deplete.Results` class. This class has methods that allow for
 easy retrieval of k-effective, nuclide concentrations, and reaction rates over
 time::
 
-    results = openmc.deplete.ResultsList("depletion_results.h5")
+    results = openmc.deplete.Results("depletion_results.h5")
     time, keff = results.get_keff()
 
 Note that the coupling between the transport solver and the transmutation solver
diff --git a/examples/pincell_depletion/restart_depletion.py b/examples/pincell_depletion/restart_depletion.py
index 45bb4343d..95bbb9954 100644
--- a/examples/pincell_depletion/restart_depletion.py
+++ b/examples/pincell_depletion/restart_depletion.py
@@ -12,7 +12,7 @@ with openmc.StatePoint(statepoint) as sp:
     geometry = sp.summary.geometry
 
 # Load previous depletion results
-previous_results = openmc.deplete.ResultsList("depletion_results.h5")
+previous_results = openmc.deplete.Results("depletion_results.h5")
 
 ###############################################################################
 #                      Transport calculation settings
@@ -56,7 +56,7 @@ integrator.integrate()
 ###############################################################################
 
 # Open results file
-results = openmc.deplete.ResultsList("depletion_results.h5")
+results = openmc.deplete.Results("depletion_results.h5")
 
 # Obtain K_eff as a function of time
 time, keff = results.get_keff(time_units='d')
diff --git a/examples/pincell_depletion/run_depletion.py b/examples/pincell_depletion/run_depletion.py
index 727039a29..ae069334e 100644
--- a/examples/pincell_depletion/run_depletion.py
+++ b/examples/pincell_depletion/run_depletion.py
@@ -101,7 +101,7 @@ integrator.integrate()
 ###############################################################################
 
 # Open results file
-results = openmc.deplete.ResultsList("depletion_results.h5")
+results = openmc.deplete.Results("depletion_results.h5")
 
 # Obtain K_eff as a function of time
 time, keff = results.get_keff(time_units='d')
diff --git a/openmc/deplete/abc.py b/openmc/deplete/abc.py
index 7d6e33924..9ba70af37 100644
--- a/openmc/deplete/abc.py
+++ b/openmc/deplete/abc.py
@@ -24,7 +24,7 @@ from openmc.checkvalue import check_type, check_greater_than
 from openmc.mpi import comm
 from .results import StepResult
 from .chain import Chain
-from .results_list import ResultsList
+from .results_list import Results
 from .pool import deplete
 
 
@@ -79,7 +79,7 @@ class TransportOperator(ABC):
         in initial condition to ensure they exist in the decay chain.
         Only done for nuclides with reaction rates.
         Defaults to 1.0e3.
-    prev_results : ResultsList, optional
+    prev_results : Results, optional
         Results from a previous depletion calculation.
 
     Attributes
@@ -88,7 +88,7 @@ class TransportOperator(ABC):
         Initial atom density [atoms/cm^3] to add for nuclides that are zero
         in initial condition to ensure they exist in the decay chain.
         Only done for nuclides with reaction rates.
-    prev_res : ResultsList or None
+    prev_res : Results or None
         Results from a previous depletion calculation. ``None`` if no
         results are to be used.
     """
@@ -102,7 +102,7 @@ class TransportOperator(ABC):
         if prev_results is None:
             self.prev_res = None
         else:
-            check_type("previous results", prev_results, ResultsList)
+            check_type("previous results", prev_results, Results)
             self.prev_res = prev_results
 
     @property
diff --git a/openmc/deplete/operator.py b/openmc/deplete/operator.py
index 1f31a22b6..da9588b87 100644
--- a/openmc/deplete/operator.py
+++ b/openmc/deplete/operator.py
@@ -25,7 +25,7 @@ from .abc import TransportOperator, OperatorResult
 from .atom_number import AtomNumber
 from .chain import _find_chain_file
 from .reaction_rates import ReactionRates
-from .results_list import ResultsList
+from .results_list import Results
 from .helpers import (
     DirectReactionRateHelper, ChainFissionHelper, ConstantFissionYieldHelper,
     FissionYieldCutoffHelper, AveragedFissionYieldHelper, EnergyScoreHelper,
@@ -94,7 +94,7 @@ class Operator(TransportOperator):
         Path to the depletion chain XML file.  Defaults to the file
         listed under ``depletion_chain`` in
         :envvar:`OPENMC_CROSS_SECTIONS` environment variable.
-    prev_results : ResultsList, optional
+    prev_results : Results, optional
         Results from a previous depletion calculation. If this argument is
         specified, the depletion calculation will start from the latest state
         in the previous results.
@@ -192,7 +192,7 @@ class Operator(TransportOperator):
         Initial heavy metal inventory [g]
     local_mats : list of str
         All burnable material IDs being managed by a single process
-    prev_res : ResultsList or None
+    prev_res : Results or None
         Results from a previous depletion calculation. ``None`` if no
         results are to be used.
     cleanup_when_done : bool
@@ -284,7 +284,7 @@ class Operator(TransportOperator):
             if comm.size == 1:
                 self.prev_res = prev_results
             else:
-                self.prev_res = ResultsList()
+                self.prev_res = Results()
                 mat_indexes = _distribute(range(len(self.burnable_mats)))
                 for res_obj in prev_results:
                     new_res = res_obj.distribute(self.local_mats, mat_indexes)
@@ -494,7 +494,7 @@ class Operator(TransportOperator):
             Volumes for the above materials in [cm^3]
         nuclides : list of str
             Nuclides to be used in the simulation.
-        prev_res : ResultsList, optional
+        prev_res : Results, optional
             Results from a previous depletion calculation
 
         """
@@ -543,7 +543,7 @@ class Operator(TransportOperator):
         ----------
         mat : openmc.Material
             The material to read from
-        prev_res : ResultsList
+        prev_res : Results
             Results from a previous depletion calculation
 
         """
diff --git a/openmc/deplete/results_list.py b/openmc/deplete/results_list.py
index 97170f226..fb45792f6 100644
--- a/openmc/deplete/results_list.py
+++ b/openmc/deplete/results_list.py
@@ -12,7 +12,7 @@ from openmc.data.library import DataLibrary
 from openmc.material import Material, Materials
 from openmc.exceptions import DataError, InvalidArgumentError
 
-__all__ = ["ResultsList"]
+__all__ = ["Results"]
 
 
 def _get_time_as(seconds, units):
@@ -26,10 +26,10 @@ def _get_time_as(seconds, units):
         return seconds
 
 
-class ResultsList(list):
+class Results(list):
     """Results from a depletion simulation
 
-    The :class:`ResultsList` class acts as a list that stores the results from
+    The :class:`Results` class acts as a list that stores the results from
     each depletion step and provides extra methods for interrogating these
     results.
 
@@ -63,13 +63,13 @@ class ResultsList(list):
 
         Returns
         -------
-        ResultsList
+        Results
             New instance of depletion results
 
         """
         warn(
             "The from_hdf5(...) method is no longer necessary and will be removed "
-            "in a future version of OpenMC. Use ResultsList(...) instead.",
+            "in a future version of OpenMC. Use Results(...) instead.",
             FutureWarning
         )
         return cls(filename)
diff --git a/tests/regression_tests/deplete/test.py b/tests/regression_tests/deplete/test.py
index 91f18667e..6c431fb33 100644
--- a/tests/regression_tests/deplete/test.py
+++ b/tests/regression_tests/deplete/test.py
@@ -77,8 +77,8 @@ def test_full(run_in_tmpdir, problem, multiproc):
         return
 
     # Load the reference/test results
-    res_test = openmc.deplete.ResultsList(path_test)
-    res_ref = openmc.deplete.ResultsList(path_reference)
+    res_test = openmc.deplete.Results(path_test)
+    res_ref = openmc.deplete.Results(path_reference)
 
     # Assert same mats
     for mat in res_ref[0].mat_to_ind:
@@ -139,7 +139,7 @@ def test_depletion_results_to_material(run_in_tmpdir, problem):
     """Checks openmc.Materials objects can be created from depletion results"""
     # Load the reference/test results
     path_reference = Path(__file__).with_name('test_reference.h5')
-    res_ref = openmc.deplete.ResultsList(path_reference)
+    res_ref = openmc.deplete.Results(path_reference)
 
     # Firstly need to export materials.xml file for the initial simulation state
     geometry, lower_left, upper_right = problem
diff --git a/tests/unit_tests/test_deplete_activation.py b/tests/unit_tests/test_deplete_activation.py
index 2c3e0c053..0b82a5fbc 100644
--- a/tests/unit_tests/test_deplete_activation.py
+++ b/tests/unit_tests/test_deplete_activation.py
@@ -107,7 +107,7 @@ def test_activation(run_in_tmpdir, model, reaction_rate_mode, reaction_rate_opts
     integrator.integrate()
 
     # Get resulting number of atoms
-    results = openmc.deplete.ResultsList('depletion_results.h5')
+    results = openmc.deplete.Results('depletion_results.h5')
     _, atoms = results.get_atoms(w, "W186")
 
     assert atoms[0] == pytest.approx(n0)
@@ -155,7 +155,7 @@ def test_decay(run_in_tmpdir):
     integrator.integrate()
 
     # Get resulting number of atoms
-    results = openmc.deplete.ResultsList('depletion_results.h5')
+    results = openmc.deplete.Results('depletion_results.h5')
     _, atoms = results.get_atoms(mat, "Sr89")
 
     # Ensure density goes down by a factor of 2 after each half-life
diff --git a/tests/unit_tests/test_deplete_integrator.py b/tests/unit_tests/test_deplete_integrator.py
index 4348b8c34..cb6374152 100644
--- a/tests/unit_tests/test_deplete_integrator.py
+++ b/tests/unit_tests/test_deplete_integrator.py
@@ -16,7 +16,7 @@ import pytest
 
 from openmc.mpi import comm
 from openmc.deplete import (
-    ReactionRates, StepResult, ResultsList, OperatorResult, PredictorIntegrator,
+    ReactionRates, StepResult, Results, OperatorResult, PredictorIntegrator,
     CECMIntegrator, CF4Integrator, CELIIntegrator, EPCRK4Integrator,
     LEQIIntegrator, SICELIIntegrator, SILEQIIntegrator, cram)
 
@@ -103,7 +103,7 @@ def test_results_save(run_in_tmpdir):
     StepResult.save(op, x2, op_result2, t2, 0, 1)
 
     # Load the files
-    res = ResultsList("depletion_results.h5")
+    res = Results("depletion_results.h5")
 
     for i in range(stages):
         for mat_i, mat in enumerate(burn_list):
@@ -176,7 +176,7 @@ def test_integrator(run_in_tmpdir, scheme):
 
     # get expected results
 
-    res = ResultsList(operator.output_dir / "depletion_results.h5")
+    res = Results(operator.output_dir / "depletion_results.h5")
 
     t1, y1 = res.get_atoms("1", "1")
     t2, y2 = res.get_atoms("1", "2")
diff --git a/tests/unit_tests/test_deplete_restart.py b/tests/unit_tests/test_deplete_restart.py
index 2bfcfea7d..e8bfc062a 100644
--- a/tests/unit_tests/test_deplete_restart.py
+++ b/tests/unit_tests/test_deplete_restart.py
@@ -24,7 +24,7 @@ def test_restart_predictor_cecm(run_in_tmpdir):
     openmc.deplete.PredictorIntegrator(op, dt, power).integrate()
 
     # Load the files
-    prev_res = openmc.deplete.ResultsList(op.output_dir / "depletion_results.h5")
+    prev_res = openmc.deplete.Results(op.output_dir / "depletion_results.h5")
 
     # Re-create depletion operator and load previous results
     op = dummy_operator.DummyOperator(prev_res)
@@ -50,7 +50,7 @@ def test_restart_cecm_predictor(run_in_tmpdir):
     cecm.integrate()
 
     # Load the files
-    prev_res = openmc.deplete.ResultsList(op.output_dir / "depletion_results.h5")
+    prev_res = openmc.deplete.Results(op.output_dir / "depletion_results.h5")
 
     # Re-create depletion operator and load previous results
     op = dummy_operator.DummyOperator(prev_res)
@@ -73,7 +73,7 @@ def test_restart(run_in_tmpdir, scheme):
     bundle.solver(operator, [0.75], 1.0).integrate()
 
     # restart
-    prev_res = openmc.deplete.ResultsList(
+    prev_res = openmc.deplete.Results(
         operator.output_dir / "depletion_results.h5")
     operator = dummy_operator.DummyOperator(prev_res)
 
@@ -82,7 +82,7 @@ def test_restart(run_in_tmpdir, scheme):
 
     # compare results
 
-    results = openmc.deplete.ResultsList(
+    results = openmc.deplete.Results(
         operator.output_dir / "depletion_results.h5")
 
     _t, y1 = results.get_atoms("1", "1")
diff --git a/tests/unit_tests/test_deplete_resultslist.py b/tests/unit_tests/test_deplete_resultslist.py
index 2a2669920..6ce15601f 100644
--- a/tests/unit_tests/test_deplete_resultslist.py
+++ b/tests/unit_tests/test_deplete_resultslist.py
@@ -1,4 +1,4 @@
-"""Tests the ResultsList class"""
+"""Tests the Results class"""
 
 from pathlib import Path
 from math import inf
@@ -13,7 +13,7 @@ def res():
     """Load the reference results"""
     filename = (Path(__file__).parents[1] / 'regression_tests' / 'deplete'
                 / 'test_reference.h5')
-    return openmc.deplete.ResultsList(filename)
+    return openmc.deplete.Results(filename)
 
 
 def test_get_atoms(res):
@@ -72,9 +72,9 @@ def test_get_keff(res):
 
 @pytest.mark.parametrize("unit", ("s", "d", "min", "h"))
 def test_get_steps(unit):
-    # Make a ResultsList full of near-empty Result instances
+    # Make a Results full of near-empty Result instances
     # Just fill out a time schedule
-    results = openmc.deplete.ResultsList()
+    results = openmc.deplete.Results()
     # Time in units of unit
     times = np.linspace(0, 100, num=5)
     if unit == "d":
diff --git a/tests/unit_tests/test_transfer_volumes.py b/tests/unit_tests/test_transfer_volumes.py
index 50e222b95..b768bc88a 100644
--- a/tests/unit_tests/test_transfer_volumes.py
+++ b/tests/unit_tests/test_transfer_volumes.py
@@ -2,7 +2,7 @@
 
 from pytest import approx
 import openmc
-from openmc.deplete import PredictorIntegrator, ResultsList
+from openmc.deplete import PredictorIntegrator, Results
 
 from tests import dummy_operator
 
@@ -19,7 +19,7 @@ def test_transfer_volumes(run_in_tmpdir):
     PredictorIntegrator(op, dt, power).integrate()
 
     # Load the files
-    res = openmc.deplete.ResultsList(op.output_dir / "depletion_results.h5")
+    res = openmc.deplete.Results(op.output_dir / "depletion_results.h5")
 
     # Create a dictionary of volumes to transfer
     res[0].volume['1'] = 1.5

From bd7b33c636628cd4826dd4507fc01a9fc628896d Mon Sep 17 00:00:00 2001
From: Paul Romano <paul.k.romano@gmail.com>
Date: Thu, 28 Apr 2022 17:23:37 -0500
Subject: [PATCH 4/9] Rename results.py stepresult.py

---
 openmc/deplete/__init__.py                   | 2 +-
 openmc/deplete/abc.py                        | 2 +-
 openmc/deplete/results_list.py               | 2 +-
 openmc/deplete/{results.py => stepresult.py} | 0
 4 files changed, 3 insertions(+), 3 deletions(-)
 rename openmc/deplete/{results.py => stepresult.py} (100%)

diff --git a/openmc/deplete/__init__.py b/openmc/deplete/__init__.py
index b8c1cdfff..e15a368de 100644
--- a/openmc/deplete/__init__.py
+++ b/openmc/deplete/__init__.py
@@ -10,7 +10,7 @@ from .chain import *
 from .operator import *
 from .reaction_rates import *
 from .atom_number import *
-from .results import *
+from .stepresult import *
 from .results_list import *
 from .integrators import *
 from . import abc
diff --git a/openmc/deplete/abc.py b/openmc/deplete/abc.py
index 9ba70af37..3d8d08c76 100644
--- a/openmc/deplete/abc.py
+++ b/openmc/deplete/abc.py
@@ -22,7 +22,7 @@ from uncertainties import ufloat
 from openmc.lib import MaterialFilter, Tally
 from openmc.checkvalue import check_type, check_greater_than
 from openmc.mpi import comm
-from .results import StepResult
+from .stepresult import StepResult
 from .chain import Chain
 from .results_list import Results
 from .pool import deplete
diff --git a/openmc/deplete/results_list.py b/openmc/deplete/results_list.py
index fb45792f6..952fb37f7 100644
--- a/openmc/deplete/results_list.py
+++ b/openmc/deplete/results_list.py
@@ -6,7 +6,7 @@ from warnings import warn
 import h5py
 import numpy as np
 
-from .results import StepResult, VERSION_RESULTS
+from .stepresult import StepResult, VERSION_RESULTS
 import openmc.checkvalue as cv
 from openmc.data.library import DataLibrary
 from openmc.material import Material, Materials
diff --git a/openmc/deplete/results.py b/openmc/deplete/stepresult.py
similarity index 100%
rename from openmc/deplete/results.py
rename to openmc/deplete/stepresult.py

From 5421bf0b1f0a3186aa033be915d5d120c5b084cf Mon Sep 17 00:00:00 2001
From: Paul Romano <paul.k.romano@gmail.com>
Date: Thu, 28 Apr 2022 17:25:10 -0500
Subject: [PATCH 5/9] Rename results_list.py -> results.py

---
 openmc/deplete/__init__.py                     | 2 +-
 openmc/deplete/abc.py                          | 2 +-
 openmc/deplete/operator.py                     | 2 +-
 openmc/deplete/{results_list.py => results.py} | 0
 4 files changed, 3 insertions(+), 3 deletions(-)
 rename openmc/deplete/{results_list.py => results.py} (100%)

diff --git a/openmc/deplete/__init__.py b/openmc/deplete/__init__.py
index e15a368de..5891555a2 100644
--- a/openmc/deplete/__init__.py
+++ b/openmc/deplete/__init__.py
@@ -11,7 +11,7 @@ from .operator import *
 from .reaction_rates import *
 from .atom_number import *
 from .stepresult import *
-from .results_list import *
+from .results import *
 from .integrators import *
 from . import abc
 from . import cram
diff --git a/openmc/deplete/abc.py b/openmc/deplete/abc.py
index 3d8d08c76..df30579e5 100644
--- a/openmc/deplete/abc.py
+++ b/openmc/deplete/abc.py
@@ -24,7 +24,7 @@ from openmc.checkvalue import check_type, check_greater_than
 from openmc.mpi import comm
 from .stepresult import StepResult
 from .chain import Chain
-from .results_list import Results
+from .results import Results
 from .pool import deplete
 
 
diff --git a/openmc/deplete/operator.py b/openmc/deplete/operator.py
index da9588b87..327c762e0 100644
--- a/openmc/deplete/operator.py
+++ b/openmc/deplete/operator.py
@@ -25,7 +25,7 @@ from .abc import TransportOperator, OperatorResult
 from .atom_number import AtomNumber
 from .chain import _find_chain_file
 from .reaction_rates import ReactionRates
-from .results_list import Results
+from .results import Results
 from .helpers import (
     DirectReactionRateHelper, ChainFissionHelper, ConstantFissionYieldHelper,
     FissionYieldCutoffHelper, AveragedFissionYieldHelper, EnergyScoreHelper,
diff --git a/openmc/deplete/results_list.py b/openmc/deplete/results.py
similarity index 100%
rename from openmc/deplete/results_list.py
rename to openmc/deplete/results.py

From 8a4fd95b9bea56d83a9ded8467cb2da41be66605 Mon Sep 17 00:00:00 2001
From: Paul Romano <paul.k.romano@gmail.com>
Date: Mon, 2 May 2022 12:27:28 -0500
Subject: [PATCH 6/9] Retain ResultsList name for backwards compatibility

---
 openmc/deplete/results.py | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/openmc/deplete/results.py b/openmc/deplete/results.py
index 952fb37f7..fd6d72fba 100644
--- a/openmc/deplete/results.py
+++ b/openmc/deplete/results.py
@@ -10,9 +10,9 @@ from .stepresult import StepResult, VERSION_RESULTS
 import openmc.checkvalue as cv
 from openmc.data.library import DataLibrary
 from openmc.material import Material, Materials
-from openmc.exceptions import DataError, InvalidArgumentError
+from openmc.exceptions import DataError
 
-__all__ = ["Results"]
+__all__ = ["Results", "ResultsList"]
 
 
 def _get_time_as(seconds, units):
@@ -68,8 +68,8 @@ class Results(list):
 
         """
         warn(
-            "The from_hdf5(...) method is no longer necessary and will be removed "
-            "in a future version of OpenMC. Use Results(...) instead.",
+            "The ResultsList.from_hdf5(...) method is no longer necessary and will "
+            "be removed in a future version of OpenMC. Use Results(...) instead.",
             FutureWarning
         )
         return cls(filename)
@@ -410,3 +410,7 @@ class Results(list):
                         mat.add_nuclide(nuc, atoms_per_barn_cm)
 
         return mat_file
+
+
+# Retain deprecated name for the time being
+ResultsList = Results

From 355ecd374751c5d773d5d97278c7d88e6cabf5f4 Mon Sep 17 00:00:00 2001
From: Paul Romano <paul.k.romano@gmail.com>
Date: Thu, 5 May 2022 22:05:33 -0500
Subject: [PATCH 7/9] Allow deplete.Results() to be instantiated empty

---
 openmc/deplete/results.py | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/openmc/deplete/results.py b/openmc/deplete/results.py
index fd6d72fba..514c04820 100644
--- a/openmc/deplete/results.py
+++ b/openmc/deplete/results.py
@@ -39,16 +39,17 @@ class Results(list):
         Path to depletion result file
 
     """
-    def __init__(self, filename):
-        with h5py.File(str(filename), "r") as fh:
-            cv.check_filetype_version(fh, 'depletion results', VERSION_RESULTS[0])
-            data = []
+    def __init__(self, filename=None):
+        data = []
+        if filename is not None:
+            with h5py.File(str(filename), "r") as fh:
+                cv.check_filetype_version(fh, 'depletion results', VERSION_RESULTS[0])
 
-            # Get number of results stored
-            n = fh["number"][...].shape[0]
+                # Get number of results stored
+                n = fh["number"][...].shape[0]
 
-            for i in range(n):
-                data.append(StepResult.from_hdf5(fh, i))
+                for i in range(n):
+                    data.append(StepResult.from_hdf5(fh, i))
         super().__init__(data)
 
 

From bc1ab31746518ab420f01695ab91da4390134cd4 Mon Sep 17 00:00:00 2001
From: Paul Romano <paul.k.romano@gmail.com>
Date: Fri, 3 Jun 2022 09:09:52 -0500
Subject: [PATCH 8/9] Raise exception if timestep in [MWd/kg] is given with
 zero power

---
 openmc/deplete/abc.py        | 3 +++
 openmc/deplete/stepresult.py | 2 +-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/openmc/deplete/abc.py b/openmc/deplete/abc.py
index df30579e5..457c51a8a 100644
--- a/openmc/deplete/abc.py
+++ b/openmc/deplete/abc.py
@@ -719,6 +719,9 @@ class Integrator(ABC):
             elif unit.lower() == 'mwd/kg':
                 watt_days_per_kg = 1e6*timestep
                 kilograms = 1e-3*operator.heavy_metal
+                if rate == 0.0:
+                    raise ValueError("Cannot specify a timestep in [MWd/kg] when"
+                                     " the power is zero.")
                 days = watt_days_per_kg * kilograms / rate
                 seconds.append(days*_SECONDS_PER_DAY)
             else:
diff --git a/openmc/deplete/stepresult.py b/openmc/deplete/stepresult.py
index bfd165481..6f30e934d 100644
--- a/openmc/deplete/stepresult.py
+++ b/openmc/deplete/stepresult.py
@@ -20,7 +20,7 @@ __all__ = ["StepResult"]
 
 
 class StepResult:
-    """Output of a depletion run
+    """Result of a single depletion timestep
 
     Attributes
     ----------

From 382867db7feed2cd10223afe8397659edca1695b Mon Sep 17 00:00:00 2001
From: Paul Romano <paul.k.romano@gmail.com>
Date: Mon, 13 Jun 2022 12:32:09 -0500
Subject: [PATCH 9/9] Address @drewejohnson comments on #2077

---
 openmc/deplete/results.py    | 11 +++++------
 openmc/deplete/stepresult.py |  5 +++--
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/openmc/deplete/results.py b/openmc/deplete/results.py
index 514c04820..c238002fe 100644
--- a/openmc/deplete/results.py
+++ b/openmc/deplete/results.py
@@ -81,9 +81,9 @@ class Results(list):
         .. note::
             Initial values for some isotopes that do not appear in
             initial concentrations may be non-zero, depending on the
-            value of :class:`openmc.deplete.Operator` ``dilute_initial``.
-            The :class:`openmc.deplete.Operator` adds isotopes according
-            to this setting, which can be set to zero.
+            value of the :attr:`openmc.deplete.Operator.dilute_initial`
+            attribute. The :class:`openmc.deplete.Operator` class adds isotopes
+            according to this setting, which can be set to zero.
 
         Parameters
         ----------
@@ -186,6 +186,8 @@ class Results(list):
     def get_keff(self, time_units='s'):
         """Evaluates the eigenvalue from a results list.
 
+        .. versionadded:: 0.13.1
+
         Parameters
         ----------
         time_units : {"s", "d", "h", "min"}, optional
@@ -220,7 +222,6 @@ class Results(list):
              "will be removed in a future version of OpenMC.", FutureWarning)
         return self.get_keff(time_units)
 
-
     def get_depletion_time(self):
         """Return an array of the average time to deplete a material
 
@@ -252,7 +253,6 @@ class Results(list):
     def get_times(self, time_units="d") -> np.ndarray:
         """Return the points in time that define the depletion schedule
 
-
         .. versionadded:: 0.12.1
 
         Parameters
@@ -290,7 +290,6 @@ class Results(list):
         Passing ``atol=math.inf`` and ``rtol=math.inf`` will return
         the closest index to the requested point.
 
-
         .. versionadded:: 0.12.1
 
         Parameters
diff --git a/openmc/deplete/stepresult.py b/openmc/deplete/stepresult.py
index 6f30e934d..6e2373c45 100644
--- a/openmc/deplete/stepresult.py
+++ b/openmc/deplete/stepresult.py
@@ -1,6 +1,7 @@
-"""The results module.
+"""The stepresult module.
 
-Contains results generation and saving capabilities.
+Contains capabilities for generating and saving results of a single depletion
+timestep.
 """
 
 from collections import OrderedDict