Mechanical Characterization of Irradiated Fuel Materials with Local Utrasonic Methods

Abstract

Since 1996, our research has been focused on the local assessment of mechanical properties of non-irradiated and irradiated fuels with micro-acoustic and micro-indentation [1] methods. In 1999, a study by acoustic microscopy concerning the influence of volume fraction porosity (in the range 1 to 7 %) on the elastic properties of non-irradiated fuel has been performed [2]. Other measurements on non-stochiometric samples containing Erbium and Cerium, and on irradiated pellets have proved all the potentiality of micro-acoustic approach [3]. This paper first deals with the improvement of the experimental ultrasonic device recently introduced in a hot cell in the Institute Für Transurane of Karlsruhe in order to get more local characterization or to operate on tiny samples. Secondly, measurements on very porous samples, Simfuel, and irradiated UO₂ pellets are presented and discussed.