This article focuses on environmentally assisted cracking (EAC) of structural materials in the boiling water reactor (BWR), reactor pressure vessel, core internals, and ancillary piping. It discusses the effects of water chemistry on materials degradation, mitigation approaches, and their impact on aging management programs. The article reviews the effects of materials, environment, and stress factors on the cracking susceptibility of ferritic and austenitic structural alloys in BWRs. It describes the methods, such as data-based life-prediction approaches and mechanisms-informed life-prediction approaches for predicting the cracking kinetics in BWRs. The article presents several EAC mitigation techniques for BWR components, namely material solutions, stress solutions, and environmental solutions.
This article discusses the principles of corrosion and the basis of the various prevention measures that can be taken for the different corrosion modes. It describes aqueous corrosion phenomena in terms of the electrochemical reactions that occur at the metal-environment interface. The article describes the specific forms of corrosion, including general corrosion, localized attack, and environmentally assisted cracking. It provides a discussion on engineering aspects of design that can, without due care and attention, precipitate unexpected premature failure. The article discusses ways to improve corrosion awareness and to prevent corrosion/degradation. It describes a life prediction method with an example of environmental degradation in light-water nuclear reactors. The article concludes with a discussion on validation of life-prediction algorithms and their application.