SUMMARYSeveral programs funded by the Department of Energy Office of Nuclear Energy (DOE-NE), such as the Fuel Cycle Research and Development, Advanced Reactor Concepts, Light Water Reactor Sustainability, and Next Generation Nuclear Plant programs, are investigating new fuels and materials for advanced and existing reactors. A key objective of such programs is to understand the performance of these fuels and materials when irradiated. The Nuclear Energy Enabling Technology (NEET) Advanced Sensors and Instrumentation (ASI) in-pile instrumentation development activities are focused upon addressing cross-cutting needs for DOE-NE irradiation testing by providing higher fidelity, real-time data, with increased accuracy and resolution from smaller, compact sensors that are less intrusive.Ultrasonic technologies offer the potential to measure a range of parameters, including geometry changes, temperature, crack initiation and growth, gas pressure and composition, and microstructural changes under harsh irradiation test conditions. There are two primary issues that currently limit in-pile deployment of ultrasonic sensors. The first is transducer survivability. The ability of ultrasonic transducer materials to maintain their useful properties during an irradiation must be demonstrated. The second issue is signal processing. Ultrasonic testing is typically performed in a lab or field environment, where the sensor and sample are accessible. The harsh nature of in-pile testing and the variety of measurements that are desired demand that an enhanced signal processing capability be developed to make in-pile ultrasonic sensors viable. To address these issues, the NEET ASI program is funding the Ultrasonic Transducer Irradiation and Signal Processing Enhancements project, which is a collaborative effort between the Idaho National Laboratory, the Pacific Northwest National Laboratory, the Argonne National Laboratory, and the Pennsylvania State University (PSU). As summarized within this document, significant work has been accomplished during the first two years of this three year project:• Transducer Irradiation Test -The first task of this project supports efforts to develop a test capsule design and define irradiation conditions for evaluating most promising candidate piezoelectric and magnetostrictive transducer materials and designs. In July FY-2012, the ATR NSUF announced that a proposal led by PSU for irradiating ultrasonic transducers was selected, and the irradiation would occur in the Massachusetts Institute of Technology Nuclear Research Reactor (MITR). Subsequent project efforts have focused on developing a capsule design and on identifying appropriate test conditions, identifying transducers for inclusion in the capsule, appropriate post-irradiation examinations, and performing out-of-pile laboratory tests needed to support the irradiation. As documented in this report, the irradiation test builds on prior research and exceeds previous tests in terms of the number of materials tested and accumulated fluence. The pur...