Corrosion and hydrogen pickup (HPU) mechanisms of Zr alloys remain a top priority of the nuclear industry. Commercial Zr alloys have today adequate in-reactor corrosion properties. However, hydrogen in fuel components limits the fuel performance today during normal operation and accident conditions as well as during transport of spent fuel.
The intent of this report is to discuss the corrosion mechanisms and the various forms of corrosion features (uniform, nodular and shadow corrosion) in BWRs and PWRs/VVERs. This knowledge will give the possibility to implement actions to reduce corrosion..
This report reviews the experience of the impact of Zn-injection (in PWRs and BWRs) and Nobel Metal Chemical Addition (NMCA) in BWRs on fuel integrity. The report also discusses fundamentals in crud formation related to Zn-injection and NMCA.
The report gives an overview of the development of the Zr-Nb alloys in the nuclear industry, as well as the basic metallurgy and manufacturing of the Zr-Nb alloys. The report focuses on the out-of-reactor as well as in-reactor corrosion and hydrogen pickup performance.
The purpose of the report is to describe the fundamentals in crud formation, transport, and deposition, in order to provide a solid basis for evaluating and analysing any fuel operational problem due to crud deposits. The ultimate purpose is to provide knowledge and insight for staff involved in the operation and materials selection in nuclear power plants, in order to prevent the occurrence of any crud-related fuel problems.
The microstructure in the Zr-Nb alloys have crucial impact on the material performance in-reactor. The microstructure is a function of material chemistry and the manufacturing process. This report provides an overview of Zr alloy manufacturing process and relationship between fabrication, microstructure and in-pile performance.