Thermotransport of hydrogen in Zr-1.0Nb-1.0Sn-0.1Fe alloy

Hydrogen redistribution caused by thermotransport in the Zr-1.0Nb-1.0Sn-0.1Fe alloy under the temperature gradient which is likely to be encountered between nuclear fuel cladding and primary cooling water (300-340 degrees C) was investigated. The heat of transport (Q*) of hydrogen was determined by using a steady state technique to evaluate the magnitude and direction of thermotransport of hydrogen in the alloy. The values of (Q)* were 23.1, 23.7 and 27.1 KJ/mol for the hydrogen concentration of 73.4, 75.8 and 94.3 ppm by weight respectively. In other words, hydrogen was transported from hot region to cold region and the value of (Q)* increased with increasing overall hydrogen concentration. The Zr-1.0Nb-1.0Sn-0.1Fe alloy had the smaller (Q)* value than that of Zircaloy-4 when compared with same overall hydrogen concentration. Thus, Zr-1.0Nb-1.0Sn-0.1Fe alloy has better resistance to the formation of hydride due to thermotransport than Zircaloy-4 does.