diff --git a/src/criticality.F90 b/src/criticality.F90
index 92f3c95b04..e2492cbf82 100644
--- a/src/criticality.F90
+++ b/src/criticality.F90
@@ -47,29 +47,20 @@ contains
     ! LOOP OVER BATCHES
     BATCH_LOOP: do current_batch = 1, n_batches
 
-       message = "Simulating batch " // trim(to_str(current_batch)) // "..."
-       call write_message(8)
-
-       ! Reset total starting weight
-       total_weight = ZERO
+       call initialize_batch()
 
        ! =======================================================================
        ! LOOP OVER GENERATIONS
        GENERATION_LOOP: do current_gen = 1, gen_per_batch
 
-          ! Set all tallies to zero
-          n_bank = 0
-
-          ! Count source sites if using uniform fission source weighting
-          if (ufs) call count_source_for_ufs()
-
-          ! ====================================================================
-          ! LOOP OVER HISTORIES
+          call initialize_generation()
 
           ! Start timer for transport
           call timer_start(time_transport)
 
-          HISTORY_LOOP: do i = 1, work
+          ! ====================================================================
+          ! LOOP OVER PARTICLES
+          PARTICLE_LOOP: do i = 1, work
 
              ! grab source particle from bank
              call get_source_particle(i)
@@ -77,44 +68,19 @@ contains
              ! transport particle
              call transport()
 
-          end do HISTORY_LOOP
+          end do PARTICLE_LOOP
 
           ! Accumulate time for transport
           call timer_stop(time_transport)
 
-          ! ====================================================================
-          ! WRAP UP FISSION BANK AND COMPUTE TALLIES, KEFF, ETC
-
-          ! Start timer for inter-cycle synchronization
-          call timer_start(time_intercycle)
-
           ! Distribute fission bank across processors evenly
+          call timer_start(time_intercycle)
           call synchronize_bank()
-
-          ! Stop timer for inter-cycle synchronization
           call timer_stop(time_intercycle)
           
        end do GENERATION_LOOP
 
-       ! Collect tallies
-       if (tallies_on) then
-          call timer_start(time_ic_tallies)
-          call synchronize_tallies()
-          call timer_stop(time_ic_tallies)
-       end if
-
-       ! Calculate shannon entropy
-       if (entropy_on) call shannon_entropy()
-
-       ! Collect results and statistics
-       call calculate_keff()
-
-       ! Turn tallies on once inactive cycles are complete
-       if (current_batch == n_inactive) then
-          tallies_on = .true.
-          call timer_stop(time_inactive)
-          call timer_start(time_active)
-       end if
+       call finalize_batch()
 
     end do BATCH_LOOP
 
@@ -127,4 +93,62 @@ contains
 
   end subroutine run_criticality
 
+!===============================================================================
+! INITIALIZE_BATCH
+!===============================================================================
+
+  subroutine initialize_batch()
+
+       message = "Simulating batch " // trim(to_str(current_batch)) // "..."
+       call write_message(8)
+
+       ! Reset total starting particle weight used for normalizing tallies
+       total_weight = ZERO
+
+  end subroutine initialize_batch
+
+!===============================================================================
+! INITIALIZE_GENERATION
+!===============================================================================
+
+  subroutine initialize_generation()
+
+    ! Reset number of fission bank sites
+    n_bank = 0
+
+    ! Count source sites if using uniform fission source weighting
+    if (ufs) call count_source_for_ufs()
+
+  end subroutine initialize_generation
+
+!===============================================================================
+! FINALIZE_BATCH handles synchronization and accumulation of tallies,
+! calculation of Shannon entropy, getting single-batch estimate of keff, and
+! turning on tallies when appropriate
+!===============================================================================
+
+  subroutine finalize_batch()
+
+    ! Collect tallies
+    if (tallies_on) then
+       call timer_start(time_ic_tallies)
+       call synchronize_tallies()
+       call timer_stop(time_ic_tallies)
+    end if
+
+    ! Calculate shannon entropy
+    if (entropy_on) call shannon_entropy()
+
+    ! Collect results and statistics
+    call calculate_keff()
+
+    ! Turn tallies on once inactive cycles are complete
+    if (current_batch == n_inactive) then
+       tallies_on = .true.
+       call timer_stop(time_inactive)
+       call timer_start(time_active)
+    end if
+
+  end subroutine finalize_batch
+
 end module criticality