Preparation of 240Pu and 242Pu targets to improve cross-section measurements for advanced reactors and fuel cycles

Abstract

240Pu and 242Pu targets were prepared by the so-called “molecular plating” on an Al backing for cross-section measurements. The total activity of the actinide layer was determined by low-geometry alpha-particle counting. The atomic abundances of the two Pu materials were determined via thermal ionization mass spectrometry. A radiochemical separation was performed by anion exchange prior to the preparation of the layers to prevent interferences with the ingrown daughter nuclide during the characterization and cross-section measurements. The targets were prepared to be used in the project “Metrology for New Generation Nuclear Power Plants” (MetroFission), within the frame of the European Metrology Research Programme, directed to improve the knowledge on neutron cross sections through metrological approaches. For measurements of the 240Pu(n,f) and 242Pu(n,f) cross sections 240Pu and 242Pu targets were produced and mounted in fission chambers. In parallel, 240Pu and 242Pu targets were prepared for the ANDES project (Accurate Nuclear Data for Nuclear Energy Sustainability) for cross-section measurements at the CERN neutron time-of-flight facility n_TOF, and the Van de Graaff laboratories of IRMM and CNRS/CENBG.