| The recent Fukushima disaster has again demonstrated the need for improvements in nuclear power technology. The Fukushima disaster was essentially unstoppable once initiated, however the research herein has the potential to help prevent such disasters. The inflection point in the course of events which lead to the numerous explosions began with the generation of hydrogen from the zirconium alloy cladding. This hydrogen is generated when the cladding temperature exceeds specified limits, in this case due to the inability to pump coolant, and occurs with all metal cladding materials (Pool, 2011).;The objective of this dissertation is the development sensors that will greatly facilitate the design of improved nuclear materials, and as such has the potential to eliminating the danger of hydrogen release from the cladding, which represents only one of many potential benefits of in-core ultrasonic sensors. In addition to utilizing the sensors in material test reactors, their use for structural health monitoring of operating nuclear power plants is very feasible.;The research herein begins with testing of new high temperature piezoelectric materials, namely the rare earth oxyborates and bulk single crystal aluminum nitride. An extensive review of the radiation effects on piezoelectric materials is then presented and candidate materials are selected based on the knowledge obtained therein. The most promising material, aluminum nitride, is then tested in a reactor core for three months confirming its viability. Optimization of an ultrasonic phased array composed of radiation hard materials is then performed by way of diffraction beam and finite element analyses. |
