Review of Irradiation Programs to Study Long-Term Behaviour of In-Core Components in CANDU Reactors

During the life of a nuclear reactor, there are changes to the in-core components that are a function of operating environment and time. It is important to know how the properties of critical core components change, which can be assessed through materials surveillance programs. It is also desirable to characterize materials behaviour long before the end of the reactor design life. Therefore, experiments to characterize materials for in-core applications are performed in test reactors that typically have higher total neutron fluxes than power reactors. The extensive in-core materials irradiation programs that supported the validation of long-term material behaviour in CANDU (CANada Deuterium Uranium) reactors used various irradiation facilities, both domestic and international, are summarized in this paper. However, these test reactor facilities are aging and in some cases are closing, including NRU, which ceased operations in 2018. As Canada contemplates a new domestic high-flux test reactor to support both existing and potential new power reactors, this paper provides a review of the facilities and approaches that were implemented to successfully research CANDU reactor materials and can serve as a basis to define future facility requirements.