[en] A key topic in international safeguards is the work in preventing the further spread of nuclear weapon technology and nuclear materials. High performance analyses play an important role in enabling the detection of undeclared nuclear activities. Such analyses require comparison between different producers of analytical results. Within the European Commission Support Programme, the JRC Karlsruhe has been demonstrating that the technical competences in safeguards laboratories are to the benefit to IAEA. It will be shown that direct contact between inspectors and applied nuclear scientists brings scientific excellence at the working level. Furthermore, frequent and informal contacts between inspectors and R&D staff are essential to enhance scientific/technical capabilities for the IAEA and the safeguards community. Specific examples include:  Participation in inter-laboratory exercises, provided by the IAEA, allowing the safeguards community to gain confidence in the results produced by different laboratories.  Reference materials produced by the IAEA, known as Large Size Dried (LSD) spikes, are verified by JRC Karlsruhe and other laboratories to offer assurance for U and Pu content analyses.  The experience gained from operating the Euratom safeguards on-site laboratories OSL/LSS since 1999. This activity has provided sustainable information and experience, which fed into the on-site laboratory at the Rokkasho Reprocessing Plant in Japan.  The COMPUCEA technique, which was developed in Karlsruhe for in-field measurement in support of inspections, was transferred to the IAEA and is now a Class A method used in international safeguards. Furthermore, such collaborations facilitate non-conventional combinations of measurement techniques, used in safeguards and nuclear forensics to obtain more comprehensive safeguards information. (author)

[en] The combined procedure for uranium concentration and enrichment assay (COMPUCEA 2nd generation) is a transportable analytical system that combines L-edge transmission and γ-ray spectrometry for high-accuracy, on-site uranium concentration and enrichment assays of uranium bearing materials. This paper presents: (i) a summary of the establishment of an integrated measurement system, consisting of specialized hardware and software; (ii) the results of the continued evaluation of the system's analytical performance against primary analytical methods; (iii) the build-up of expertise in performing COMPUCEA analysis in the field, and (iv) recent extensions of the system's analytical capabilities addressing new safeguards verification challenges. (author)