EFFECT OF HYDROGEN ON THERMAL EMF OF Zr-1% Nb ALLOY

This work deals with determining the effect of hydrogen (up to 400 ppm (ppm - part per million)) and hydride reorientation (from tangential to radial orientation) on the thermal emf of Zr-1% Nb cladding tubes. There was plotted the dependence of thermal emf of initial and hydrogenated (200 ppm) Zr-1% Nb (cladding tubes) relative to copper on the temperature gradient between the hot and cold junctions (T-1 = 20 degrees C, Delta T - up to 80 degrees C). The dependence of the absolute thermal emf coefficient Zr-1% Nb on the hydrogen content (T-1 = 20 degrees C,.T = 40 degrees C) in the investigated interval of concentrations (up to 400 ppm), the absolute thermal emf coefficient of Zr-1% Nb (cladding tubes) in the longitudinal direction (S) decreases with increasing hydrogen content: S = 7.263-0.0012x+ 10(-6)x(2), where x - is the hydrogen content in the samples under investigation in ppm. The resulting pattern is recommended for evaluation of the hydrogen content in reactor products made of Zr-1% Nb (measurement of the thermal emf is recommended as a method of non-destructive evaluation of hydrogen content in zirconium and zirconium alloys).