Low Cross-Section Mo-Nb Thermocouples for Nuclear Application: The State-of-the-Art.

摘要

Long-term high-temperature measurements in nuclear environments have long posed difficult problems. The tungsten-rhenium alloy thermocouples typically used in such applications undergo large decalibrations resulting from nuclear transmutation of the component materials. An alternative thermocouple, comprising pure molybdenum and niobium thermoelements, is virtually immune to transmutation effects, but is limited in utility by other properties. Thermocouples composed of molybdenum-niobium alloys show promise of significant improvement over the pure-metal combination. The W-Re decalibration problem is detailed and the status of Mo-Nb thermocouple development reviewed, including recent efforts at the Idaho National Engineering Laboratory. 18 refs., 4 figs.