<?xml version='1.0' encoding='utf-8'?>
<model>
  <materials>
    <material id="1">
      <density units="g/cc" value="1.0"/>
      <nuclide ao="2.0" name="H1"/>
      <nuclide ao="1.0" name="O16"/>
      <sab name="c_H_in_H2O"/>
    </material>
    <material depletable="true" id="2">
      <density units="g/cc" value="4.5"/>
      <nuclide ao="1.0" name="U235"/>
    </material>
  </materials>
  <geometry>
    <cell id="1" material="1" region="1 2 -3 4" universe="0"/>
    <cell id="2" material="2" region="1 2 -4" universe="0"/>
    <surface boundary="periodic" coeffs="0.4999999999999999 0.8660254037844387 0.0 0.0" id="1" type="plane"/>
    <surface boundary="periodic" coeffs="0.4999999999999999 -0.8660254037844387 0.0 0.0" id="2" type="plane"/>
    <surface boundary="reflective" coeffs="5.0" id="3" type="x-plane"/>
    <surface coeffs="2.598076211353316 1.4999999999999998 2.0" id="4" type="z-cylinder"/>
  </geometry>
  <settings>
    <run_mode>eigenvalue</run_mode>
    <particles>1000</particles>
    <batches>4</batches>
    <inactive>0</inactive>
    <source particle="neutron" strength="1.0" type="independent">
      <space type="box">
        <parameters>0 0 0 5 5 0</parameters>
      </space>
    </source>
  </settings>
  </model>
