Procedure and device for measuring resistance to hydriding of tubes and tubular claddings

Method of measuring the resistance to hydriding of tubes and tubular claddings, meaning hydriding the formation of hydrides, characterized by the following steps:

• inserting a tube to be tested through a chamber of ultra-high vacuum equipment, said chamber containing a mass spectrometer and a total pressure gauge;
• passing hydrogen gas or a gas mixture of hydrogen and inert gas(es) into the interior of the tube, the permeation of hydrogen through the tube wall causing hydriding of the material thereof;
• heating said tube by Joule effect heating means;
• detecting hydrogen which has permeated through the wall of the tube at the exterior of the tube
• by measuring H2 and H partial pressures in the chamber or
• by measuring the total pressure in the chamber and determining a permeation time on the basis of a permeation curve, i.e. a curve of quantity of hydrogen detected
• by measuring H2 and H partial pressures in the chamber against time, or
• total pressure detected against time, said permeation time being a time obtained from said permeation curve and representing the first appearance of hydrogen exterior of the tube, and;
• detecting a sudden rise in the total pressure, as an indication of the time of appearance of a first micro crack in the tube.