NUCLEAR CROSS SECTIONS AND NEUTRON FLUX
Reactor Theory (Neutron Characteristics)
In some locations within the reactor, the flux level may be significantly lower than in other areas
due to a phenomenon referred to as neutron shadowing or self-shielding. For example, the
interior of a fuel pin or pellet will "see" a lower average flux level than the outer surfaces since
an appreciable fraction of the neutrons will have been absorbed and therefore cannot reach the
interior of the fuel pin. This is especially important at resonance energies, where the absorption
cross sections are large.
The important information in this chapter is summarized below.