LIST MODE RESPONSE MATRIX FOR ADVANCED CORRELATED NEUTRON ANALYSIS FOR NUCLEAR SAFEGUARDS

Within the current safeguards technology toolkit, there is no existing detection capability to verify loading patterns and partial defects in fresh fuel assemblies for nuclear safeguards applications. To address this need, research is being performed at Oak Ridge National Laboratory to develop an advanced neutron correlation analysis method, the “list mode response matrix”, for implementation in field-deployable software for fuel assay measurements. This method uses list mode data acquisition for each detector in a neutron coincidence collar to extend correlated neutron analysis by extracting a greater number of useful signatures from a neutron assay than are currently generated. In particular, this method may enable the verification of spatial information about the assay item, such as the loading pattern of fuel and poison rods. The goal of this work is to enable nuclear safeguards inspectors to draw stronger conclusions with regard to nuclear material diversion scenarios and partial defect identification for fresh fuel assemblies. In this paper, we present the concept and preliminary spatial analysis simulation results, using particle transport, to demonstrate the viability of this technique.