Following the accident at the Fukushima Daiichi Nuclear Power Plant, many countries began funding research and development on nuclear fuel designs with enhanced accident tolerance (ATFs). ATFs have improved designs, materials and performance features compared with those of the current generation of slightly enriched UO2 ceramic pellets within cylindrical zirconium alloy cladding. This report evaluates the applicability of existing fuel design and performance requirements to some of the new ATF designs (coated zirconium alloy fuel rod cladding, FeCrAl fuel rod cladding, silicon carbide fuel rod cladding, doped uranium dioxide ceramic fuel pellets, uranium silicide ceramic fuel pellets),identifies new phenomena which create the need for new or different performance metrics and design requirements, identifies data gaps and discusses opportunities for international collaborative research to fill them. A variety of new phenomena were identified for the examined ATF designs which challenged the applicability of existing performance metrics and analytical limits or created the need for new criteria. Recommendations to address these challenges are provided with the intention to inform future international research programmes and support ATF licensing.