National programmes for radioactive waste management require very large amounts of data and information across multiple and disparate disciplines. These programmes tend to run over a period of many decades resulting in a serious risk of data and information loss, which in turn can threaten the production and maintenance of robust safety cases.

Metadata and associated tools and techniques play a crucial role in modern data and information management. The Radioactive Waste Repository Metadata Management (RepMet) initiative has prepared the first international study on the application of metadata to the field of radioactive waste management. This report introduces the concept of metadata, explains how metadata can help to facilitate data management, and gives advice on the issues arising when developing metadata within radioactive waste management programmes. It is aimed at readers looking to obtain a highlevel overview of metadata, and associated tools and techniques, and the strategic importance they can play in Radioactive Waste Management Organisations (RWMOs).