A Practical Method for Low-temperature Hydrogen Addition Into CANDU Pressure Tube Material

Abstract

A practical method to add hydrogen to zirconium alloys is described that works at low temperatures and short times. Fitness-For-Service predictions to support extended service of CANDU pressure tubes requires mechanical testing of tubes removed from service with end-of-life hydrogen concentrations and representative changes in alloy microstructure caused by irradiation. With the current method, (101 ± 5) wt-ppm hydrogen has been added to Zircaloy at (201.5 ± 4.4) °C within 22.3 h. These times and temperatures are well below values that would change any effects of irradiation in the alloy.