Neutron flux determination in the lower region of a natural uranium-light water sub-critical assembly

The natural uranium-light water subcritical reactor is classified as a heterogeneous reactor. Reactors are classified according to their neutron energy or relative arrangement of fuel and generator. In a reactor classified as heterogeneous, the fuel is distributed in a fairly definite geometrical lattice or pattern within the mass of the moderator. The reactor housing is a stainless steel cylinder with a diameter of four feet and a height of five feet. This reactor is a subcritical assembly, or, in other words, it is not self sustaining.