Enhancements to High Temperature In-Pile Thermocouple Performance

J. C. Crepeau ; J. L. Rempe ; J. E. Daw ; D. L. Knudson ; K. G. Condie ; S. C. Wilkins

关键词: ALLOYS;    DESIGN;    DUCTILITY;    EVALUATION;    FABRICATION;    HEAT TREATMENTS;    IRRADIATION;    MOLYBDENUM;    MOLYBDENUM ALLOYS;    NIOBIUM ALLOYS;    PERFORMANCE;    RECOMMENDATIONS;    RELIABILITY;    STABILITY;    TESTING;    THERMOCOUPLES high temperature in-pile;    thermocouple;   

DOI  :  10.2172/935460
RP-ID  :  INL/EXT-08-14042
PID  :  OSTI ID: 935460
Others  :  TRN: US200816%%891

学科分类：社会科学、人文和艺术（综合）

美国|英语

来源: SciTech Connect

【 摘 要 】

A joint University of Idaho (UI) and Idaho National Laboratory (INL) University Nuclear Research Initiative (UNERI) was to initiated to extend initial INL efforts to develop doped lybdenum/niobium alloy High Temperature Irradiation Resistant Thermocouples (HTIR-TCs). The overall objective of this UNERI was to develop recommendations for an optimized thermocouple design for high temperature, long duration, in-pile testing by expanding upon results from initial INL efforts. Tasks to quantify the impact of candidate enhancements, such as alternate alloys, alternate geometries, and alternate thermocouple fabrication techniques, on thermocouple performance were completed at INL's High Temperature Test Laboratory (HTTL), a state of the art facility equipped with specialized equipment and trained staff in the area of high temperature instrumentation development and evaluation. Key results of these evaluations, which are documented in this report, are as follows. The doped molybdenum and Nb-1%Zr, which were proposed in the initial INL HTIR-TC design, were found to retain ductility better than the developmental molybdenum-low niobium alloys and the niobium-low molybdenum alloys evaluated. Hence, the performance and lower cost of the commercially available KW-Mo makes a thermocouple containing KW-Mo and Nb-1%Zr the best option at this time. HTIR-TCs containing larger diameter wires offer the potential to increase HTIR-TC stability and reliability at higher temperatures. HTIR-TC heat treatment temperatures and times should be limited to not more than 100 °C above the proposed operating temperatures and to durations of at least 4 to 5 hours. Preliminary investigations suggest that the performance of swaged and loose assembly HTIR-TC designs is similar. However, the swaged designs are less expensive and easier to construct. In addition to optimizing HTIR-TC performance, This UNERI project provided unique opportunities to several University of Idaho students, allowing them to become familiar with the techniques and equipment used for specialized high temperature instrumentation fabrication and evaluation and to author/coauthor several key conference papers and journal articles.