Evaluation of Spent Fuel Cask Condition using Emission Source Tomography

The objective of this research project is to investigate the feasibility of imaging the spent fuel assemblies and the feasibility of evaluating the conditions of the cask’s inner structure and the fuel assemblies using the emission source tomography method. This doc- ument gives the coarse outline of this project. In order to better understand the effect of shielding of the cask on neutron transmission and guide the design of the detector systems, we have created a geometry model of a TN-32 cask and simulated transmission of neutrons emitted by spontaneous fission sources using MCNP. Neutron density distributions at the inner basket and at the last cm of air are shown. The energy spectra scored at tallies are given. Primary results indicate that the energy spectra shift due to cask attenuation does not depend heavily on the source position inside the cask, and a neutron source can be better imaged with a position dependent flux difference as a function of emission position, even in the presence of a considerable amount of scattering and energy reduction.