An advanced uranium ore grade estimation method based on photofission driven by an e-LINAC

A method for evaluating the grade of uranium (U) ores through the analysis of β-delayed neutrons following (γ, fission) is discussed. By measuring β-delayed fission neutrons stimulated from 238U, the U-Ra disequilibrium problem, which limits the accuracy of traditional grade estimation methods that rely on measuring radioactivity, is addressed. In this research, 6 MV bremsstrahlung photons, delivered by a 6 MeV electron linear accelerator (e-LINAC), were used to irradiate U ore samples, and a moderator surrounded thermal neutron detector was designed to register the emitted neutrons after each X-ray pulse. Although the prompt fission neutrons were discarded due to the interference caused by the photoneutrons emitted from the matrix nuclides in the analytical environment, an excellent linear relationship was observed between the counts of β-delayed neutrons and U ore grades, demonstrating that this method is promising for the in-situ analysis of U ores.