THERMAL DIFFUSIVITY OF URANIUM DIOXIDE FUEL PELLETS WITH ADDITION OF BERYLLIUM OXIDE BY THE LASER FLASH METHOD

摘要

A research program is in progress at CDTN - Centro de Desenvolvimento da Tecnologia Nuclear, aiming the development of fuel pellets made from a mixture of uranium dioxide microspheres or powder and beryllium oxide powder for increasing the thermal conductivity of the nuclear fuel. This type of fuel promises to be safer than current fuels, improving the performance of the reactor. In previous studies conducted at CDTN, fuel pellets were manufactured and tested considering the following weight percentages: 1, 2, 3, 5, 7 and 14wt.% of beryllium oxide (BeO) in mixture with microspheres of UO_2. Continuing this project, new uranium dioxide fuel pellets with addition of 2wt.% of BeO were manufactured and tested. The Laser Flash Method was employed to investigate the variation of thermal diffusivity at room temperature on those new pellets. The results obtained showed an increase of 12% in the thermal diffusivity with addition of 2wt.% of BeO in the uranium dioxide fuel pellets.