Current generation light water reactors (LWRs), sodium cooled fast reactors (SFRs), small modular reactors (SMRs), of various types, and potentially next generation nuclear plants (NGNPs) all provide harsh environments in and near the core that can severely test material performance, and limit their operational life. As a result of this several Department of Energy Office of Nuclear Energy (DOE-NE) research programs require that the long duration radiation performance of fuels and materials be demonstrated. Such demonstrations in a Material and Test Reactor (MTR) require enhanced instrumentation to detect microstructural changes under the irradiation conditions with unprecedented accuracy and resolution. Recent work supported by DOE?s Advanced Reactor Concepts (ARC) program has been investigating ultrasonic transducers for both under sodium viewing and in-service inspection measurements near the core for fast spectrum reactors. In DOE-NE?s Fuel Cycle Research and Development (FCR&D) program, ultrasonics-based technology was identified as a key approach that should be pursued to obtain the high-fidelity, high-accuracy data required to characterize the behavior and performance of new candidate fuels and structural materials during irradiation testing. Several DOE-NE programs are in the design phase for ultrasonic sensors for in-pile applications; however, these programs are severely limited by the lack of existing knowledge of ultrasonic transducer durability under irradiation conditions. It is therefore proposed that PSU and collaborators assess the performance of common ultrasonic transducer materials (i.e., piezoelectric and magnetostrictive materials) exposed to the high radiation fields for long durations. This test would include both instrumented lead testing to assess the dynamic and transient behavior of the transducer while in-situ as well as post irradiation evaluation to determine sensor material property changes after extended exposures.The proposed research will be completed in five stages: (1) Selection of candidate sensor materials as well as optimization of test assembly parameters. PSU has had longstanding experience in transducer design for harsh environments and is currently designing high temperature transducers for the Intermediate Heat Exchanger in the gas reactor proposed for the next generation nuclear power plant and has had experience testing at the PSU Breazeale Nuclear Reactor. (2) High temperature benchmark testing: will assess the temperature dependent behavior of the sensor materials as a benchmark for the ATR testing. (3) ATR Testing: will be performed to assess sensor degradation by pulse-echo and impedance measurements. (4) Post-Irradiation Evaluation: system components will be inspected at the MFC hot cells to access sensor material property changes. (5) Synthesis: acquired data will be synthesized to assess sensor behavior.The proposed real-time instrumented lead test performed in this ATR NSUF irradiation will provide real-time data related to magnetostrictive and piezoelectric transducer survivability during irradiation testing. This data facilitate the development of transducers for a variety of in-pile measurements in MTRs, including sensors to perform temperature measurements and characterize the properties of fuels and structural materials of interest to several DOE-NE programs. This work is a necessary step for DOE-NE programs to design in-pile sensors necessary for evaluating the long duration performance of fuel and structural materials.