diff --git a/smr/build-core-short.py b/smr/build-core-short.py
new file mode 100644
index 0000000..5ed19b9
--- /dev/null
+++ b/smr/build-core-short.py
@@ -0,0 +1,118 @@
+#!/usr/bin/env python3
+
+import os
+import shutil
+import copy
+import argparse
+from math import pi
+from pathlib import Path
+
+import numpy as np
+
+import openmc
+from smr.materials import materials
+from smr.plots import core_plots
+from smr.surfaces import lattice_pitch, bottom_fuel_stack, top_active_core, \
+    pellet_OR, surfs, pin_pitch
+import smr.surfaces
+import smr.pins
+from smr.core import core_geometry
+from smr import inlet_temperature
+
+
+# Define command-line options
+parser = argparse.ArgumentParser()
+parser.add_argument('--multipole', action='store_true',
+                    help='Use multipole cross sections')
+parser.add_argument('--no-multipole', action='store_false',
+                    help='Do not use multipole cross sections')
+parser.add_argument('-a', '--axial', type=int, default=3,
+                    help='Number of axial subdivisions in fuel')
+parser.add_argument('-d', '--depleted', action='store_true',
+                    help='Whether UO2 compositions should represent depleted fuel')
+parser.add_argument('-o', '--output-dir', type=Path, default=None)
+parser.set_defaults(multipole=True)
+args = parser.parse_args()
+
+# Make directory for inputs
+if args.output_dir is None:
+    if args.depleted:
+        directory = Path('core-short-depleted')
+    else:
+        directory = Path('core-short-fresh')
+else:
+    directory = args.output_dir
+directory.mkdir(exist_ok=True)
+
+# Modify fuel length
+length = 3. * pin_pitch
+smr.surfaces.active_fuel_length = length
+smr.pins.top_active_core = length
+surfs['top active core'].z0 = length
+
+# Change top and bottom of model to contain only fuel
+surfs['lower bound'].z0 = 0.0
+surfs['lower bound'].boundary_type = 'reflective'
+surfs['upper bound'].z0 = length
+surfs['upper bound'].boundary_type = 'reflective'
+
+ring_radii = [0.1*pin_pitch, 0.2*pin_pitch]
+
+geometry = core_geometry(ring_radii, args.axial, args.depleted)
+
+h = length / args.axial
+fuel_mats = {}
+
+fuel_volume = pi * pellet_OR**2 * h / (len(ring_radii) + 1)
+for cell in geometry.get_all_cells().values():
+    if cell.fill in materials:
+        # Determine volume of each fuel material
+        if 'UO2 Fuel' in cell.fill.name:
+            r_o = cell.region.bounding_box[1][0]
+            if r_o not in fuel_mats:
+                cell.fill = cell.fill.clone()
+                cell.fill.volume = fuel_volume
+                fuel_mats[r_o] = cell.fill
+            else:
+                cell.fill = fuel_mats[r_o]
+        else:
+            cell.fill.volume = 1.0
+
+
+#### Create OpenMC "materials.xml" file
+all_materials = geometry.get_all_materials()
+materials = openmc.Materials(all_materials.values())
+materials.export_to_xml(str(directory / 'materials.xml'))
+
+
+#### Create OpenMC "geometry.xml" file
+geometry.export_to_xml(str(directory / 'geometry.xml'))
+
+
+#### Create OpenMC "settings.xml" file
+
+# Construct uniform initial source distribution over fissionable zones
+lower_left = [-7.*lattice_pitch/2., -7.*lattice_pitch/2., bottom_fuel_stack]
+upper_right = [+7.*lattice_pitch/2., +7.*lattice_pitch/2., top_active_core]
+source = openmc.source.Source(space=openmc.stats.Box(lower_left, upper_right))
+source.space.only_fissionable = True
+
+settings = openmc.Settings()
+settings.batches = 200
+settings.inactive = 100
+settings.particles = 10000
+settings.output = {'tallies': False, 'summary': False}
+settings.source = source
+settings.sourcepoint_write = False
+
+settings.temperature = {
+    'default': inlet_temperature,
+    'method': 'interpolation',
+    'range': (300.0, 1500.0),
+}
+if args.multipole:
+    settings.temperature['multipole'] = True
+    settings.temperature['tolerance'] = 1000
+
+settings.export_to_xml(str(directory / 'settings.xml'))
+
diff --git a/smr/smr/surfaces.py b/smr/smr/surfaces.py
index b454c61..d91ec92 100644
--- a/smr/smr/surfaces.py
+++ b/smr/smr/surfaces.py
@@ -69,7 +69,8 @@ spacer_height = 1.750*INCHES  # ML17013A274, Figure 4.2-7
 # assembly parameters
 assembly_length   = 95.89*INCHES  # ML17013A274, Table 4.1-2
 pin_pitch         = 0.496*INCHES  # ML17013A274, Table 4.1-2
-lattice_pitch     = 8.466*INCHES  # ML17013A274, Table 4.1-2
+#lattice_pitch     = 8.466*INCHES  # ML17013A274, Table 4.1-2
+lattice_pitch     = 17*pin_pitch
 grid_strap_side   = 21.47270
 top_nozzle_height = 3.551*INCHES  # ML17013A274, Figure 4.2-2
 top_nozzle_width  = 8.406*INCHES  # ML17013A274, Figure 4.2-2