|About this Abstract
||MS&T22: Materials Science & Technology
||Advanced Materials for Harsh Environments
||High Temperature Irradiation Resistant Thermocouples for In-Pile Temperature Sensing
||Scott Riley, Kyle Holloway, Richard Skifton, Brian Jaques
|On-Site Speaker (Planned)
The high temperature and irradiation resistance of niobium, molybdenum, and their alloys make them candidates for applications within nuclear reactors. The INL has developed thermocouples composed of doped niobium and doped molybdenum thermoelements, an alumina insulation, and a sheath made of niobium or its alloys. These thermocouples are projected to be used in GEN IV nuclear reactors. However, to stabilize the generated EMF signal during extended operation and use, the thermocouples undergo a preliminary heat treatment above the maximum service temperature. Herein, a study was conducted to evaluate the impact of the stabilization heat treatment on the microstructure, chemical stability, and electrical properties of the thermoelements to elucidate a mechanistic understanding of the stabilization event. The doped niobium thermoelement recrystallized and a Nb3P phase formed during the stabilization heat treatment. The impact of the stabilization heat treatment on the Seebeck coefficient and resistivity of the thermoelements will also be discussed.