diff --git a/src/DEPENDENCIES b/src/DEPENDENCIES
index 08f362792e..5fd957902c 100644
--- a/src/DEPENDENCIES
+++ b/src/DEPENDENCIES
@@ -61,6 +61,15 @@ fission.o: global.o
 fission.o: interpolation.o
 fission.o: search.o
 
+fixed_source.o: constants.o
+fixed_source.o: global.o
+fixed_source.o: output.o
+fixed_source.o: physics.o
+fixed_source.o: source.o
+fixed_source.o: string.o
+fixed_source.o: tally.o
+fixed_source.o: timing.o
+
 geometry.o: constants.o
 geometry.o: datatypes.o
 geometry.o: error.o
diff --git a/src/OBJECTS b/src/OBJECTS
index 69229e1819..0daf0f16fe 100644
--- a/src/OBJECTS
+++ b/src/OBJECTS
@@ -13,6 +13,7 @@ energy_grid.o \
 error.o \
 finalize.o \
 fission.o \
+fixed_source.o \
 geometry.o \
 geometry_header.o \
 global.o \
diff --git a/src/fixed_source.F90 b/src/fixed_source.F90
new file mode 100644
index 0000000000..d58c44f7bd
--- /dev/null
+++ b/src/fixed_source.F90
@@ -0,0 +1,79 @@
+module fixed_source
+
+  use constants,  only: ZERO
+  use global
+  use output,     only: write_message, header
+  use physics,    only: transport
+  use source,     only: get_source_particle
+  use string,     only: to_str
+  use tally,      only: synchronize_tallies
+  use timing,     only: timer_start, timer_stop
+
+contains
+
+  subroutine run_fixedsource()
+
+    integer(8) :: i  ! index over histories in single cycle
+
+    if (master) call header("BEGIN SIMULATION", level=1)
+
+    tallies_on = .true.
+    call timer_start(time_inactive)
+
+    ! Allocate particle
+    allocate(p)
+
+    ! ==========================================================================
+    ! LOOP OVER BATCHES
+    BATCH_LOOP: do current_batch = 1, n_batches
+
+       call initialize_batch()
+
+       ! Start timer for transport
+       call timer_start(time_transport)
+
+       ! =======================================================================
+       ! LOOP OVER PARTICLES
+       PARTICLE_LOOP: do i = 1, work
+
+          ! grab source particle from bank
+          call get_source_particle(i)
+
+          ! transport particle
+          call transport()
+
+       end do PARTICLE_LOOP
+
+       ! Accumulate time for transport
+       call timer_stop(time_transport)
+
+       call timer_start(time_ic_tallies)
+       call synchronize_tallies()
+       call timer_stop(time_ic_tallies)
+
+    end do BATCH_LOOP
+
+    call timer_stop(time_active)
+
+    ! ==========================================================================
+    ! END OF RUN WRAPUP
+
+    if (master) call header("SIMULATION FINISHED", level=1)
+
+  end subroutine run_fixedsource
+
+!===============================================================================
+! INITIALIZE_BATCH
+!===============================================================================
+
+  subroutine initialize_batch()
+
+       message = "Simulating batch " // trim(to_str(current_batch)) // "..."
+       call write_message()
+
+       ! Reset total starting particle weight used for normalizing tallies
+       total_weight = ZERO
+
+  end subroutine initialize_batch
+
+end module fixed_source
diff --git a/src/initialize.F90 b/src/initialize.F90
index 6de01f6153..d6e3162d08 100644
--- a/src/initialize.F90
+++ b/src/initialize.F90
@@ -116,7 +116,7 @@ contains
        call create_tally_map()
 
        ! allocate banks and create source particles
-       call allocate_banks()
+       if (run_mode == MODE_CRITICALITY) call allocate_banks()
        call initialize_source()
     end if
 
diff --git a/src/main.F90 b/src/main.F90
index 5de70d8f5d..9aae913461 100644
--- a/src/main.F90
+++ b/src/main.F90
@@ -1,11 +1,12 @@
 program main
 
-  use constants,   only: MODE_CRITICALITY, MODE_PLOTTING
-  use criticality, only: run_criticality
-  use finalize,    only: finalize_run
-  use global,      only: run_mode
-  use initialize,  only: initialize_run
-  use plotter,     only: run_plot
+  use constants,    only: MODE_CRITICALITY, MODE_PLOTTING, MODE_FIXEDSOURCE
+  use criticality,  only: run_criticality
+  use finalize,     only: finalize_run
+  use fixed_source, only: run_fixedsource
+  use global,       only: run_mode
+  use initialize,   only: initialize_run
+  use plotter,      only: run_plot
 
   implicit none
 
@@ -14,6 +15,8 @@ program main
 
   ! start problem based on mode
   select case (run_mode)
+  case (MODE_FIXEDSOURCE)
+     call run_fixedsource()
   case (MODE_CRITICALITY)
      call run_criticality()
   case (MODE_PLOTTING)