Study of a zirconia based inert matrix fuel under irradiation

Yttria-stabilised zirconia doped with erbia and plutonia has been selected as inert matrix fuel (IMF) at PSI, Switzerland. The results of experimental irradiation experiments on yttria-stabilised zirconia doped with erbia and thoria samples utilising accelerators, tests with yttria-stabilised zirconia doped with plutonia and erbia or urania pellets within research reactors, and a study of natural zirconia contacted to actinide rich rock are evaluated and compared. The results obtained for zirconia implantation with xenon as a representative fission product are analysed in term of swelling and inertness of the material. The reactor tests preformed in the material test Boiling Water Reactor, Halden and in the High Flux Reactor, Petten are also described, with emphasis on the IMF properties under in-pile irradiation. The natural analogue study of baddeleyite from Jacupiranga, southern Brazil, provides additional information. Baddeleyite crystals enclosed within uranpyrochlore grains and received intense irradiation, which did not affect either the structural integrity or the durability of the mineral. The results of these case studies, with accelerator, use in-pile and contacted with natural radioactive sources, provide useful information on the outstanding of the behaviour of zirconia under irradiation.