diff --git a/src/bank.cpp b/src/bank.cpp
index d5d364756..f587197aa 100644
--- a/src/bank.cpp
+++ b/src/bank.cpp
@@ -96,6 +96,10 @@ void sort_fission_bank()
     const auto& site = simulation::fission_bank[i];
     int64_t offset = site.parent_id - 1 - simulation::work_index[mpi::rank];
     int64_t idx = simulation::progeny_per_particle[offset] + site.progeny_id;
+    if (idx >= simulation::fission_bank.size()) {
+      fatal_error("Mismatch detected between sum of all particle progeny and "
+          "shared fission bank size.");
+    }
     sorted_bank[idx] = site;
   }
 
diff --git a/src/physics.cpp b/src/physics.cpp
index 212149694..ea578d7c6 100644
--- a/src/physics.cpp
+++ b/src/physics.cpp
@@ -167,8 +167,7 @@ create_fission_sites(Particle& p, int i_nuclide, const Reaction& rx)
   int nu = static_cast<int>(nu_t);
   if (prn(p.current_seed()) <= (nu_t - nu)) ++nu;
 
-  // Begin banking the source neutrons
-  // First, if our bank is full then don't continue
+  // If no neutrons were produced then don't continue
   if (nu == 0) return;
 
   // Initialize the counter of delayed neutrons encountered for each delayed
@@ -179,13 +178,16 @@ create_fission_sites(Particle& p, int i_nuclide, const Reaction& rx)
   p.nu_bank().clear();
 
   p.fission() = true;
-  int skipped = 0;
 
   // Determine whether to place fission sites into the shared fission bank
   // or the secondary particle bank.
   bool use_fission_bank = (settings::run_mode == RunMode::EIGENVALUE);
 
-  for (int i = 0; i < nu; ++i) {
+  // Counter for the number of fission sites successfully stored to a fission bank
+  // or secondary bank
+  int n_sites_stored;
+
+  for (n_sites_stored = 0; n_sites_stored < nu; n_sites_stored++) {
     // Initialize fission site object with particle data
     SourceSite site;
     site.r = p.r();
@@ -203,8 +205,14 @@ create_fission_sites(Particle& p, int i_nuclide, const Reaction& rx)
       int64_t idx = simulation::fission_bank.thread_safe_append(site);
       if (idx == -1) {
         warning("The shared fission bank is full. Additional fission sites created "
-            "in this generation will not be banked.");
-        skipped++;
+            "in this generation will not be banked. Results may be non-deteministic.");
+
+        // Decrement number of particle progeny as storage was unsuccessful. This
+        // step is needed so that the sum of all progeny is equal to the size
+        // of the shared fission bank.
+        p.n_progeny()--;
+
+        // Break out of loop as no more sites can be added to fission bank
         break;
       }
     } else {
@@ -229,14 +237,14 @@ create_fission_sites(Particle& p, int i_nuclide, const Reaction& rx)
 
   // If shared fission bank was full, and no fissions could be added,
   // set the particle fission flag to false.
-  if (nu == skipped) {
+  if (n_sites_stored == 0) {
     p.fission() = false;
     return;
   }
 
-  // If shared fission bank was full, but some fissions could be added,
-  // reduce nu accordingly
-  nu -= skipped;
+  // Set nu to the number of fission sites successfully stored. If the fission
+  // bank was not found to be full then these values are already equivalent.
+  nu = n_sites_stored;
 
   // Store the total weight banked for analog fission tallies
   p.n_bank() = nu;