Ultrasonic technologies offer the potential for high accuracy and resolution in-pile measurement of
a range of parameters, including geometry changes, temperature, crack initiation and growth, gas
pressure and composition, and microstructural changes. Many Department of Energy-Office of
Nuclear Energy (DOE-NE) programs are exploring the use of ultrasonic technologies to provide
enhanced sensors for in-pile instrumentation during irradiation testing. For example, the ability of small diameter ultrasonic thermometers (UTs) to provide a temperature profile in candidate
metallic and oxide fuel would provide much needed data for validating new fuel performance
models. These efforts are limited by the lack of identified ultrasonic transducer materials capable
of long term performance under irradiation test conditions. To address this need, the Pennsylvania
State University (PSU) was awarded an Advanced Test Reactor National Scientific User Facility
(ATR NSUF) project to evaluate the performance of promising magnetostrictive and piezoelectric
transducers in the Massachusetts Institute of Technology Research Reactor (MITR) up to a fast
fluence of at least 1021 n/cm2
. A multi-National Laboratory collaboration funded by the Nuclear
Energy Enabling Technologies Advanced Sensors and Instrumentation (NEET ASI) program also
provided initial support for this effort. This irradiation, which started in February 2014, is an
instrumented lead test and real-time transducer performance data are collected along with
temperature and neutron and gamma flux data. The irradiation is ongoing and will continue to
approximately mid-2015. To date, very encouraging results have been attained as several
transducers continue to operate under irradiation.