b'Real-time Transient HeatingDemonstrated proof-of-principle blazes trail for ultrasonic thermometer Measurements for Advancedtype instruments to measure time-dependent nuclear heating in transient Experiment Design andreactorenvironments.Model Validation D evelopment, demonstration, and licensing of nuclear fuels requires irradiation testing of specimens. The magnitude of nuclear heating is one of the most crucial attributes in irradiation test design, analysis, and data interpretation. This project demonstrated a novel nuclear heating sensor technology that directly measures this crucial parameter using spatially resolved real-time ultrasonic thermometry. This sensor was demonstrated by irradiation in the Transient Reactor Test facility (TREAT). This instrument measures nuclear heating TOTAL APPROVED AMOUNT:via temperature-based calorimetry made in real-time based on acoustic time-of-$723,651 over 3 years flight shift arising from temperature dependent changes the material properties of PROJECT NUMBER:nuclear-heated wires. The proof-of-principle for this sensor was performed with an 18A12-020 electrically heated waveguide wire arranged as a classical ultrasonic thermometer. Since the sensor was used to measure self-heating, rather than environmental PRINCIPAL INVESTIGATOR:temperature, it was referred to as an ultrasonic thermometer calorimeter. Successful Nicolas Woolstenhulme construction and irradiation of the ultrasonic thermometer calorimeter was CO-INVESTIGATORS: performed on a non-uranium version using prompt gamma heating to heat the Colby Jensen, INL waveguide wire.James Parry, INL PRESENTATION:Joshua Daw, INL Fathi, N., P. McDaniel, N. Woolstenhulme, L. Hone, J. Daw, E. Larsen, K. Tsai, J. Parry, Lance Hone, INL and C. Jensen, Evaluation of a self-heated ultrasonic calorimeter for in-reactor application, International Conference Nuclear Energy for New Europe, 2020.Example ultrasonic thermometer calorimeter data during irradiation where the prompt temperature rise can be seen in the first few seconds.14'