Development of an integrated non-destructive analysis system, Active-N

An integrated active neutron non-destructive analysis (NDA) system, Active-N, was developed to gain knowledge of active neutron NDA techniques that are applicable to measurements of nuclear materials in highly radioactive nuclear fuels. Active-N, equipped with a D-T neutron generator, combines three complementary active neutron NDA techniques: Differential Die-away Analysis (DDA), Prompt Gamma-ray Analysis (PGA), and Neutron Resonance Transmission Analysis (NRTA). In this paper, we provide an overview of Active-N and then demonstrate that the compact NRTA system in Active-N can quantify nuclear materials. Monte Carlo simulations were conducted to determine the design of the compact NRTA system including a moderator, flight tubes, and a detector shield. To investigate how accurately the compact NRTA system determines areal number densities in a sample, measurements were performed with a Pu pellet-type sample as well as metallic plate samples of In and Ag. The experimental areal number densities of 240 Pu, 115 In and 109 Ag were consistent with those calculated for the individual nuclei. These results show that it is feasible to develop a compact NRTA system capable of determining the contents of nuclear materials in nuclear fuels.