Feasibility study of fissile mass quantification by photofission delayed gamma rays in radioactive waste packages using MCNPX

Eric Simon (1) , Fanny Jallu (2, 1) , Bertrand Perot (2, 1) , Stéphane Plumeri (3)

1 CEA-DES (ex-DEN) - CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire)
2 LMN - Laboratoire de Mesures Nucléaires
3 ANDRA - Agence Nationale pour la Gestion des Déchets Radioactifs

The feasibility of fissile mass quantification in large, long-lived medium activity radioactive waste packages using photofission delayed gamma rays has been assessed with MCNPX. The detection limit achievable is lower than the expected uranium mass in these waste packages, but the important sensibility to the waste matrix density and sample localization imposes to get an accurate measurement of these parameters. An isotope discrimination method based on gamma-ray ratios has been evaluated showing that photofission delayed gamma rays can be used to measure the fissile mass as well as the total uranium mass.

Mots clés: Accurate measurement; Detection limits; MCNPX; Radioactive waste packages; Waste matrices; Uranium; Photofission; Radioactive waste package; Fission reactions; Radioactive wastes; Radioactivity; Gamma rays; Uranium 8; Feasibility studies; Isotope discrimination

Domaines: Physique Nucléaire Expérimentale [nucl-ex]

Eric Simon, Fanny Jallu, Bertrand Perot, Stéphane Plumeri. Feasibility study of fissile mass quantification by photofission delayed gamma rays in radioactive waste packages using MCNPX. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2016, 840, pp.28-35. ⟨10.1016/j.nima.2016.09.047⟩. ⟨cea-01992404⟩