diff --git a/include/openmc/constants.h b/include/openmc/constants.h
index 9c8c391e18..5a099f9562 100644
--- a/include/openmc/constants.h
+++ b/include/openmc/constants.h
@@ -360,7 +360,7 @@ enum class GeometryType { CSG, DAG };
 
 //==============================================================================
 // Variance Reduction constants
-constexpr double WEIGHT_CUTOFF {1.0e-38}; // default low weight cutoff
+constexpr double DEFAULT_WEIGHT_CUTOFF {1.0e-38}; // default low weight cutoff
 
 } // namespace openmc
 
diff --git a/include/openmc/weight_windows.h b/include/openmc/weight_windows.h
index 12059f1cb2..12113d528f 100644
--- a/include/openmc/weight_windows.h
+++ b/include/openmc/weight_windows.h
@@ -44,14 +44,14 @@ extern vector<unique_ptr<WeightWindows>> weight_windows;
 //==============================================================================
 
 struct WeightWindow {
-  double lower_weight {-1}; // -1 indicates not valid state
+  double lower_weight {-1}; // -1 indicates invalid state
   double upper_weight {1};
   double survival_weight {0.5};
-  double weight_cutoff {WEIGHT_CUTOFF};
+  double weight_cutoff {DEFAULT_WEIGHT_CUTOFF};
   int max_split {1};
 
   //! Whether the weight window is in a valid state
-  operator bool() const { return lower_weight >= 0.0; }
+  bool is_valid() const { return lower_weight >= 0.0; }
 };
 
 //==============================================================================
@@ -74,7 +74,7 @@ public:
   //! \param[in] group  HDF5 group to write to
   void to_hdf5(hid_t group) const;
 
-  //! Return a weight window at the specified index
+  //! Retrieve the weight window for a particle
   //! \param[in] p  Particle to get weight window for
   WeightWindow get_weight_window(const Particle& p) const;
 
@@ -90,7 +90,7 @@ private:
   vector<double> lower_ww_;        //!< Lower weight window bounds
   vector<double> upper_ww_;        //!< Upper weight window bounds
   double survival_ratio_ {3.0};    //!< Survival weight ratio
-  double weight_cutoff_ {1.0e-38}; //!< Weight cutoff
+  double weight_cutoff_ {DEFAULT_WEIGHT_CUTOFF}; //!< Weight cutoff
   int max_split_ {10};             //!< Maximum value for particle splitting
   int32_t mesh_idx_;               //!< index in meshes vector
 };
diff --git a/src/weight_windows.cpp b/src/weight_windows.cpp
index 885e2733bd..ebdc2d32e4 100644
--- a/src/weight_windows.cpp
+++ b/src/weight_windows.cpp
@@ -39,11 +39,11 @@ void apply_weight_windows(Particle& p)
   WeightWindow weight_window;
   for (const auto& ww : variance_reduction::weight_windows) {
     weight_window = ww->get_weight_window(p);
-    if (weight_window)
+    if (weight_window.is_valid())
       break;
   }
   // particle is not in any of the ww domains, do nothing
-  if (!weight_window)
+  if (!weight_window.is_valid())
     return;
 
   // get the paramters
@@ -74,7 +74,7 @@ void apply_weight_windows(Particle& p)
     for (int l = 0; l < i_split - 1; l++) {
       p.create_secondary(weight / n_split, p.u(), p.E(), p.type());
     }
-    // TODO: maybe weight should be weight - sum of child weight
+    // remaining weight is applied to current particle
     p.wgt() = weight / n_split;
 
   } else if (weight <= weight_window.lower_weight) {
@@ -104,7 +104,7 @@ void free_memory_weight_windows()
 WeightWindows::WeightWindows(pugi::xml_node node)
 {
   // Make sure required elements are present
-  vector<std::string> required_elems {
+  const vector<std::string> required_elems {
     "id", "particle_type", "energy_bins", "lower_ww_bounds", "upper_ww_bounds"};
   for (const auto& elem : required_elems) {
     if (!check_for_node(node, elem.c_str())) {