Book excerpt: There is high interest in new fuel types with increased accident tolerance. These range from using an oxidation resistant coating on zirconium based cladding to alternate fuel and cladding materials. These new fuels/claddings under development must be licensed before being deployed industrially and therefore research is being undertaken to assess their behaviour in various conditions. This publication arises from an IAEA coordinated research project (CRP) dealing with the acquisition of data through experiments on new fuel types and cladding materials and the development of modelling capacity to predict the behaviour of the components and the integral performance of accident tolerant fuel designs under normal and transient conditions. Demonstrations of improvements under severe accident conditions were documented. Several coated cladding materials were produced, tested, characterized and analysed in round robin tests carried out within the CRP. For improvement and validation of fuel performance codes, several benchmarks were organized to compare and analyse predictions of the extended codes. The findings and conclusions of the CRP are summarized in this publication.