1<?xml version="1.0"?>
2<materials>
3
4  <material id="1">
5    <density value="0.1" units="atom/b-cm" />
6    <nuclide name="U235" ao="1.0" />
7  </material>
8
9  <material id="2">
10    <density value="4.5e22" units="atom/cm3" />
11    <nuclide name="U235" ao="1.0" />
12  </material>
13
14  <material id="3">
15    <density value="12.3e3" units="kg/m3" />
16    <nuclide name="U235" ao="1.0" />
17  </material>
18
19  <material id="4">
20    <density units="sum" />
21    <nuclide name="U235" ao="0.3e-2" />
22    <nuclide name="U238" ao="0.5e-1" />
23    <nuclide name="H1" ao="0.1e-2" />
24  </material>
25
26</materials>
27