Quantitative comparison between PGNAA measurements and MCNP

Radioactive waste storages must guarantee the non-toxicity of the waste for long time, not only regarding radioactivity, but also all other possible environmental contamination such as toxic chemicals. Waste management agencies and governments have defined acceptability limits concerning these elements for future geological repositories [1]. Collaboration between the CEA Cadarache (France) and the FZJ (Germany) was initiated to gather their experiences in Prompt Gamma Neutron Activation Analysis (PGNAA), a non-destructive method able to characterize non-radiative elements such as toxic chemicals in radioactive waste [2] [3]. A facility called MEDINA (Multi Element Detection based on Instrumental Neutron Activation) allowing the characterization of 225 L drums is operated at FZJ [3]. In order to study the capability of PGNAA to meet the detection sensitivities required for waste repository, a MCNP model of MEDINA cell was built to support experimental studies. To validate this model, small samples of different elements are irradiated and experimental spectrums are compared to simulation results. After a preliminary comparison with a chlorine sample [4], this paper reports a validation with a larger series of toxic element signatures