Mapping the Zirconium-Hydrogen Phase System

There are economic incentives to extend service of CANDU nuclear reactors in Ontario because of their reputation for safety and reliability. Ageing pressure tubes made of zirconium alloys are vulnerable to failure by Delayed Hydride Cracking, which limits the amount of hydrogen, stress, and temperature history permitted during operation. Recreating reactor end-of-life conditions for testing purposes requires a method of adding hydrogen quantitatively into zirconium alloys without modifying irradiation damage. The thesis demonstrates a promising mechanical hydriding technique that is suitable for adding hydrogen beyond the solubility limit into irradiated zirconium alloys at 200 °C within hours. Predictions are 99 % accurate with a precision of 3 % based on mass-balance. The technique can be used to map the Zirconium-Hydride phase system. Results attributed to the delta solvus have been measured and agree with reported values.