Grant: Alliance Grants

The purpose of this project is to develop an understanding of the delayed hydride cracking behaviour of the key mechanical component 'pressure tube' in Canada Deuterium Uranium (CANDU) nuclear power reactors. The overarching objective is to correlate the microstructures and deformation mechanism of bulk hydrided samples as a function of temperature. Several experimental approaches will be used to provide this insight. Since fracture toughness of Zr-Nb pressure tube material may be affected by hydride reorientation and test temperature, the information on the mechanical property and deformation behavior of the irradiated bulk hydrides with different orientation and their interaction with surrounding matrix at different temperatures is critical for the development of the cohesive-zone fracture toughness model. This project proposes an experimental program of multiscale testing, including both in-situ Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) experiments to obtain such information, which will complement other work packages with similar objective. The proposed experiments include using existing in-situ SEM and TEM loading as well as the in-situ synchrotron x-ray loading. Given the criticality of the information to model development, and the potential technical challenges to obtain relevant and valuable information, in particular when performing high temperature in-situ experiments under SEM or TEM, there will be a high value to benefit the industry needs. In addition, this project will also provide HQP training opportunities for the new generation of nuclear engineers. The proposed work will ensure safe running of existing reactors for as long as possible, providing economic and environmental benefits for Canada.