A novel method of neptunium-237 detection in its separated form and advanced fuel based on photonuclear reactions

This paper presents a novel method for the detection of Np-237 in its separated form and advanced fuel by applying the principle of the photofission reaction ratio (PFRR). In this method, Np-237 was identified using the photon-induced multiple neutron generation reaction rate ratio (PMNRR) with multiple high-energy gamma rays. The feasibility of the discrimination between the separated Np-237 and uranium (U-235, U-238) and the detection of the Np-237 above a certain composition ratio in UO2 was examined by numerical analysis simulation. The proposed method has a wide range of incident photon energy selectivity because it utilizes the (*, 2n) reaction, which is considered an inevitable measurement obstacle in the PFRR method. The results show the detectability of Np-237 even with a 10% uncertainty in the nuclear data of the (c, fission/2n) reaction, and the robustness of the PMNRR method to the energy distribution of incident pho-tons. In the future, the proposed method is expected to be applied for detection and verification in the field of nuclear non-proliferation and security. (c) 2022 Elsevier Ltd. All rights reserved.