Neutron Resonance Densitometry (NRD), a non-destructive analysis method, was presented. The method has been developed to quantify special nuclear material (SNM) in debris of melted fuel that will be produced during the decommissioning of the Fukushima Daiichi nuclear power plants. The method is based on Neutron Resonance Transmission Analysis (NRTA) and Neutron Resonance Capture Analysis combined with Prompt Gamma–ray analysis (NRCA/PGA). The quantification of SNM relies on the NRTA results. The basic principles of NRD, which are based on well-established methodologies for neutron resonance spectroscopy, have been explained.
To develop NRD for the characterization of rock- and particle like heterogeneous samples a JAEA/JRC collaboration has been established. As part of this collaboration a NRD demonstration workshop was organized at the time-of-flight facility GELINA of the JRC-IRMM in Geel (B). The potential of NRD was demonstrated by measurements on a complex mixture of different elements. It was demonstrated that the elemental composition of an unknown sample predicted by NRTA deviated on average by less than 2% from the declared value. In addition the potential to identify the presence of light elements by NRCA/PGA was shown.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard
