Determining local thermal transport in a composite uranium-nitride/silicide nuclear fuel using square-pulse transient thermoreflectance technique

Square-wave pulse thermoreflectance (SPTR) measurements taken from a fine polished and gold coated uranium nitride (70wt%) / uranium silicide (30%) composite fuel sample. SPTR uses a train of square-wave pulses in the time-domain from an excitation laser (OBIS 660 nm CW) to create a periodic heat flux on the coated sample surface. Surface adsorption results in transient film temperatures and hence rapid fluctuations in thermoreflectance that can be measured via detection laser (OBIS 532 nm CW) coupled with a digital oscilloscope (Agilent DSO6014A). In this study, we use the SPTR technique to measure the local thermal diffusivities of UN/U3Si2, an accident-tolerant fuel with a multi-phase microstructure. The data shown is raw data taken exported from the oscilloscope in the form of .csv files.