b'In-pile Pyrometry for Transient Testing ApplicationsPrincipal Investigator: Austin Fleming, INLTeam Members/ Collaborators: Colby Jensen, INLP roviding accurate in-piledifferent challenges for each case. cladding surface temperatureBoth require high-temperature measurements is a technicallymeasurements in extremely challenging problem fromharsh environments. For LOCA a metrology standpoint. Theexperiments the non-contact conventional technique is to usenature has the ability to enable thermocouples which are weldedballoon temperature measurement to the cladding surface. Usingunder prototypic conditions (not thermocouples for transient in-pilepossible with thermocouples). RIA applications can result in severalexperiments require a high speed hundred degrees of error due tomeasurement capability to resolve the fin effect, the heat capacity, andthe temperature history and peak the thermal resistance between thecladding temperatures reached cladding and thermocouple. Fiber- during the event. Pyrometry has optic based in-pile pyrometry canthe potential to satisfy all of these provide high-speed, non-contact,requirements which would provide temperature measurements.valuable data to researchers for fuel/Pyrometry provides high temperaturecladding development, testing, measurement capability, well beyondand qualification. While pyrometry other convection techniques, andsystems are commercially available, the non-contact nature of thethere are unique requirements measurement eliminates the heatand challenges associated with transfer challenges that are associatedin-pile applications. Some of these with thermocouples. include: radiation-induced emission, Project Description: radiation-induced attenuation, The objective of this research isthe harsh environment optical to develop a fiber-optic based,components need to survive, viewing high-speed pyrometer for in-pilethrough participating media (water temperature measurement& steam), oxidizing surfaces, high-applications. One of the mainpressure/high-temperature feed applications of the sensor is forthroughs, and unique alignment cladding surface temperaturechallenges. Many of these challenges measurements during accidentare unique to the nuclear industry, conditions. The data objectives forbut the research can leverage the Reactivity Initiated Accidents (RIA)experience from industries such as and Loss of Coolant Accidentsoil & gas to help solve some of the (LOCA) have similar but slightlycommon challenges.118 2019|AFC ACCOMPLISHMENTS'