Current generation light water reactors (LWRs), sodium cooled fast reactors (SFRs), small
modular reactors (SMRs), and next generation nuclear plants (NGNPs) produce harsh environments in and
near the reactor core that can severely tax material performance and limit component operational life. To
address this issue, several Department of Energy Office of Nuclear Energy (DOE-NE) research programs
are evaluating the long duration irradiation performance of fuel and structural materials used in existing
and new reactors. In order to maximize the amount of information obtained from Material Testing
Reactor (MTR) irradiations, DOE is also funding development of enhanced instrumentation that will be
able to obtain in-situ, real-time data on key material characteristics and properties, with unprecedented
accuracy and resolution. Such data are required to validate new multi-scale, multi-physics modeling tools
under development as part of a science-based, engineering driven approach to reactor development. It is
not feasible to obtain high resolution/microscale data with the current state of instrumentation technology.
However, ultrasound-based sensors offer the ability to obtain such data if it is demonstrated that these
sensors and their associated transducers are resistant to high neutron flux, high gamma radiation, and high
temperature. To address this need, the Advanced Test Reactor National Scientific User Facility (ATRNSUF)
is funding an irradiation, led by PSU, at the Massachusetts Institute of Technology Research
Reactor to test the survivability of ultrasound transducers. As part of this effort, PSU and collaborators
have designed, fabricated, and provided piezoelectric and magnetostrictive transducers that are optimized
to perform in harsh, high flux, environments. Four piezoelectric transducers were fabricated with either
aluminum nitride, zinc oxide, or bismuth titanate as the active element that were coupled to either Kovar
or aluminum waveguides and two magnetostrictive transducers were fabricated with Remendur or
Galfenol as the active elements. Pulse-echo ultrasonic measurements of these transducers are made insitu.
This paper will present an overview of the test design including selection criteria for candidate
materials and optimization of test assembly parameters, data obtained from both out-of-pile and in-pile
testing at elevated temperatures, and an assessment based on initial data of the expected performance of
ultrasonic devices in irradiation conditions.
