Determinação por ultrassom de constantes elásticas de pastilhas de alumina utilizadas em varetas combustíveis de reatores nucleares.

• Autor(a) principal: Lopes, Alessandra Susanne Viana Ragone
• Data de Publicação: 2014
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/11711
• topic: Mechanic Engineering; Ultrasound; Ultrasonic Wave; Elastic Constants; Alumina; Engenharia Mecânica; Ultrassom; Onda Ultrassônica; Constantes Elásticas; Alumina; CNPQ::ENGENHARIAS::ENGENHARIA MECANICA

Uranium dioxide pellets (UO2) are used as fuel in nuclear power reactors, where operational conditions introduce high thermal gradients in the pellets. High powers cause the fusion in the center of the pellet. The swelling of uranium dioxide pellets (UO2) pellets, resulting from the fission products, causes cracking of the material and it is important to study their behavior. This study evaluated the application of the ultrasonic method in obtaining elastic constants. Due to the difficulties in handling nuclear material, we chose a comparative study in tablets of alumina (Al2O3). Were made and used two sets of pellets 10 Al2O3 with densities of 92% and 96%. Ultrasonic transmission technique was used for obtaining measurements of the travel time of the ultrasonic longitudinal and transverse waves. These are used for determining the elastic constants of the material. Equations relating material density and velocity of the ultrasonic wave to the elasticity, shear and Poisson's modules have led to these elastic constants, which showed excellent agreement with literature available for Al2O3 .