The development of solid-state materials for the sequestration of nuclear waste

点击翻译按钮获取中文摘要

INTRODUCTION: Nuclear power has lower greenhouse gas emissions compared to fossil fuels. However, a consequence of nuclear power is radioactive waste. The objective of this research program is the development of nuclear waste form materials. OBJECTIVE 1: LOW TEMPERATURE SYNTHESIS AND RADIATION RESISTANCE OF WASTE FORMS: Proposed nuclear waste forms are often synthesized using high-temperature methods; however, these methods are not practical when synthesizing these materials on large scales. Solution-based methods can form materials at lower temperatures. This study will determine if the synthesis method affects the radiation resistance of these materials. The transformation of a material from crystalline to amorphous because of radiation-induced damage could affect its properties. Single- and multi-phase ceramics will be synthesized using sol-gel and coprecipitation methods. The conditions needed to synthesize these materials at low temperatures will be determined along with the effect the synthesis method has on the radiation resistance of these materials. Radiation-induced structural damage will be simulated by ion implantation and studied using XRD and X-ray absorption spectroscopy (XAS). OBJECTIVE 2: MULTI-PHASE GLASS-CERAMIC COMPOSITES: Spent nuclear fuel pellets contain a variety of fission products and actinides. It is essential to find materials that can sequester elements having different ionic radii and oxidation states. Glass-ceramic composites offer unprecedented flexibility for this application. The objective of this study is to synthesize glass-ceramic composites containing crystallites of several ceramic phases dispersed in a glass matrix so as to increase the number of waste elements that can be sequestered. The glass-ceramic composites will be synthesized using multiple methods and studied using XRD, XAS, and SEM. OBJECTIVE 3: CORROSION RESISTANCE OF NUCLEAR WASTE FORMS: The corrosion resistance of nuclear waste forms must be understood to predict the long-term behaviour of these materials. Changes in the composition and structure of the waste form as well as the properties of the aqueous environment can affect the corrosion of these materials. The objective of this study is to understand how the corrosion resistance of proposed waste forms changes depending on composition and structure. Waste form materials will be exposed to water under different conditions. The materials will be studied using XAS and XPS, and the concentration of leached ions will be studied using mass spectrometry. SIGNIFICANCE: It is important to investigate strategies to sequester nuclear waste for the long term to support the use of nuclear energy to combat climate change. This unique research program will study the synthesis, radiation resistance, and corrosion resistance of ceramic and glass-ceramic composite materials. This research program will also lead to uniquely trained HQP who are experienced in solid-state chemistry and nuclear materials.