Results of post-irradiation examinations of inert matrices fuels irradiated in BOR-60 reactor up to 19 at% of burn-up in frame of Russian-French BORA-BORA experiment

Full text: Within the framework of agreement between CEA (France) and Minatom (Russia) on fast sodium-cooled reactors the experiment BORA-BORA has been carried out on irradiation behavior study of different fuels with high plutonium content in the BOR-60 reactor. For the period of 1996 - 2007 the experiment covered fabrication, irradiation in BOR-60 and post-irradiation examination (PIE) of the experimental pins with oxides, nitrides and inert matrices fuels. The dismountable assembly design used for the fuel irradiation allows the intermediate unloading of some fuel pins for PIE and prolongation of other pins irradiation up the higher burn-ups. The first irradiation stage has been completed on October 2002, the second - on May 2005. The post-irradiation examinations of fuels after the second irradiation stage have been completed on 2007. The results of non-destructive and destructive PIE of fuel pins with 40%PuN+60%ZrN and 40%PuO2+60%MgO after the second irradiation stage are presented in the paper. The non-destructive investigations did not show any anomalies in fuels condition. The distributions profiles of Co-58 and Mn-54 cladding activation products for all pins have been corresponded to the neutron flux distribution. The Zr-95 and Ru-106 activation product distributions testified the absence of some anomalies for fissile components axial distribution, of fuel column disruptions and of big metallic fission products inclusions. The Cs-137 distributions confirmed the absence of its migration from the core to the axial blankets. The results of fuels microstructure study, of fuels density measurements, of fuels crystal lattice parameters measurements and fission products distributions study are presented. (author)