<?xml version='1.0' encoding='utf-8'?>
<geometry>
  <cell id="1" material="1" region="-1" universe="1" />
  <cell id="2" material="2" region="1 -2" universe="1" />
  <cell id="3" material="3" region="2" universe="1" />
  <cell fill="2" id="4" region="3 -4 5 -6" universe="3" />
  <lattice id="2">
    <pitch>4.0 4.0</pitch>
    <dimension>2 2</dimension>
    <lower_left>-4.0 -4.0</lower_left>
    <universes>
1 1 
1 1 </universes>
  </lattice>
  <surface coeffs="0.0 0.0 1.5" id="1" type="z-cylinder" />
  <surface coeffs="0.0 0.0 1.7" id="2" type="z-cylinder" />
  <surface boundary="reflective" coeffs="-4.0" id="3" name="minimum x" type="x-plane" />
  <surface boundary="reflective" coeffs="4.0" id="4" name="maximum x" type="x-plane" />
  <surface boundary="reflective" coeffs="-4.0" id="5" name="minimum y" type="y-plane" />
  <surface boundary="reflective" coeffs="4.0" id="6" name="maximum y" type="y-plane" />
</geometry>
<?xml version='1.0' encoding='utf-8'?>
<materials>
  <material depletable="true" id="1" name="fuel">
    <density units="g/cc" value="11" />
    <nuclide ao="1.0" name="U235" />
  </material>
  <material id="2" name="cladding">
    <density units="g/cc" value="6.44" />
    <nuclide ao="1.0" name="Zr90" />
  </material>
  <material id="3" name="water">
    <density units="g/cc" value="1.0" />
    <nuclide ao="2.0" name="H1" />
    <nuclide ao="1.0" name="O16" />
  </material>
</materials>
<?xml version='1.0' encoding='utf-8'?>
<settings>
  <run_mode>eigenvalue</run_mode>
  <particles>100</particles>
  <batches>10</batches>
  <inactive>1</inactive>
</settings>
