Development Of An Integrated Active Neutron Non-destructive Analysis System: Active-N

Since neutrons have exceptional ability to penetrate high-density materials and can induce fission, they are used in non-destructive analysis such as, Differential Die-Away Analysis (DDA), Prompt Gamma-ray Analysis (PGA), Neutron Resonance Capture Analysis (NRCA), Neutron Resonance Transmission Analysis (NRTA) and Delayed Gamma-ray Analysis (DGA). The different analytical methods give us complementary information, which are particularly useful for the quantification of Special Nuclear Materials (SNM) and Minor Actinides (MA) in highly radioactive nuclear materials, including spent fuel and MA transmutation fuel. The Japan Atomic Energy Agency (JAEA) and the Joint Research Centre (JRC) of the European Commission are collaborating to develop an active neutron NDA system for nuclear non-proliferation and nuclear security. In the second phase of the project, an integrated active neutron NDA system: Active-N which enables the simultaneous measurements of DDA, PGA and NRTA (and NRCA) has been developed at NUclear fuel Cycle safety Engineering research Facility (NUCEF) in the JAEA. The DDA detects fission neutrons, and it can determine very small amounts of the fissile mass, such as U-235 and Pu-239. PGA is well acknowledged to be especially valuable for the measurement of light elements such as H, B, N, S, and Cl, as well as Cd, Gd, Sm, and Hg which have large neutron capture cross sections. Therefore, PGA is utilized for the quantification of neutron absorber and particularly useful for the detection of explosives because the most typical high explosive materials contain nitrogen. NRTA can determine isotopic composition by relating neutron resonance absorption and/or scattering. Therefore, it can be used to quantify almost all medium and high-Z elements and considered as one of the most accurate NDA to quantify the amount of SNM and MA. In this presentation, we will provide an overview of Active-N and report the recent experimental results at NUCEF. This research was implemented under the subsidy for nuclear security promotion of MEXT: Ministry of Education, Culture, Sports, Science and Technology.