Book excerpt: The limitation of 235U enrichment is a current concern among IAEA Member States. In response, work has been undertaken to provide a platform to facilitate a comprehensive review of the current status, prospects and challenges associated with the use of fuels having enrichments higher than 5 % 235U in light water reactors. This publication is the outcome of two technical meetings and compiles the results and conclusions in terms of benefits to be obtained from the use of high assay low enriched uranium (HALEU) fuel, with due consideration of safety issues that arise from its use. It details technological options and corresponding issues regarding fuel and core design, safety analysis and assessments relevant to manufacturing, handling, transportation, storage, irradiation, and performance in normal and accident conditions.