This document is intended to provide regulators, their technical support organisations and industry with a concise review of existing fuel experimental data at reactivity-initiated accident (RIA) and loss-of-coolant accident (LOCA) conditions and considerations on how these data affect fuel safety criteria at increasing burn-up. It mostly addresses experimental results relevant to BWR and PWR fuel and it encompasses several contributions from the various experts that participated in the Committee on the Safety of Nuclear Installations (CSNI) Special Expert Group on Fuel Safety Margins (SEGFSM) activities. It also covers the information presented at the joint CSNI/CNRA Topical Discussion on high burn-up fuel issues that took place on this subject in December 2004.