Chapter 18 - Radiation–Matter Interaction and Radiation-Tolerant Oxides

Abstract

Materials play a crucial role in various nuclear technologies. Fission reactor–based technologies involve application of materials such as nuclear fuel, control rod in encapsulating and diluting spent nuclear fuel and as prospective candidates for transmuting/burning long-lived radionuclides in fast reactors and even in futuristic accelerator-driven subcritical systems. Materials used in these applications face an extreme environment of radiation. Thus one of the critical requirements for a material to be used in any of these applications is its ability to resist any kind of structural, chemical, and morphological modifications under the influence of radiation. Interaction of radiation with materials, primarily, causes point defects, which at high temperatures agglomerate into line defects like dislocations and voids. These lead to detrimental effects like phase transformations, including amorphization, segregation of atoms and hence changes in the chemistry, thermal properties (decreased thermal conductivity), swelling, etc. These eventually may cause failure of the structural component in use. The major damage producing radiation in the nuclear environment includes neutrons, primary knock-on atoms created by neutrons, fission fragments (70–120MeV Ga-Gd ions), α-particles, α-recoils, and β-particles. In some applications such as nuclear waste immobilization, accumulation of radiation damage takes place over prolonged timescales. Irradiating materials with accelerated ion beams has been a popular and a favored method of imparting damage selectively and assessing it over practical duration of time. This chapter provides an outline of different sources of radiation and interaction of radiation with materials significant from the point of view of nuclear energy applications. Some specific aspects like effect of structure and powder properties on radiation stability of complex oxides of nuclear relevance are also discussed. Basic understanding of the herein-mentioned factors would aid the development of a new generation of radiation-tolerant materials.