After some accidents like TMI and Fukushima Daiichi, the belief that nuclear fuels can safely and reliably be used up to 65 MW.d/kgU was revised. Different short to long term concepts started to be assessed more seriously. Among these concepts, Cr-coated Zr cladding tubes were taken into consideration as a promising remedy for the short term perspectives. Various efforts to evaluate important aspects of such designs (including coating methodologies, full size coating of cladding tubes, performance analysis, licensing features and so on) have been implemented and some activities are yet under accomplishment. In this study, an optimized cathodic arc PVD coating condition, from the defect density point of view, for applying Cr and CrN coating layers up 10 microns on typical VVER-1000 cladding tubes (Zr-1%Nb alloy) have been obtained. SEM results approved improvements, and furthur modification has been postponed till the finalizing the performance examinations in normal operational and accidental conditions (specifically, LB LOCA condition). Additionally, the list of required test, from characterizations to mechanical and performance experiments, in order to qualify the applicability of such coated samples are suggested.
- Advanced Technology and Accident Tolerant Fuels.
- Arc-PVD Coating condition.
- Coating defects (macro-particles and pin-holes).
- Fuel design evaluation tests.