[en] In 2005 six (6) Westinghouse WWER-1000 Lead Test Assemblies (LTAs) were loaded in the South Ukraine Unit 3. This design has demonstrated full compatibility with resident fuel designs and all associated fuel handling and reactor components. Operations have further demonstrated adequacy of performance margins and the reliability requirements for multiple cycles of operation. The LTA's have now been discharged after completing the planned four cycles of operation and having reached an average assembly burnup in excess of 43 MWd/kgU. Post Irradiation Examinations were performed after completion of each cycle. The final LTA inspection program at end of Cycle 20 in 2010 yielded satisfactory results on all counts, and it was concluded that the 6 Westinghouse LTA's performed as expected during their operational regimes. Very good performance was demonstrated in the WWER-1000 reactor environment for the Zr-1%Nb as grid material, and ZIRLO fuel cladding and structural components. Control Rod Assemblies drop times and drag forces were all within the accepted values. The LTA program demonstrated that this fuel design is suitable for full core applications. However, the topic of fuel assembly distortion resistance was re-visited and Westinghouse therefore considered operational experience and design features from multiple development programs to enhance the basic Westinghouse WWER-1000 fuel design for Ukrainian reactors. The design now includes features that further mitigate assembly bow while at the same time improving the fuel cycle economy. This paper describes briefly the development of the Westinghouse WWER-1000 fuel design and how test results and operational experiences from multiple sources have been utilized to produce a most suitable fuel design. Early in 2011 a full region of the Westinghouse WWER-1000 design completed another full cycle of operation at South Ukraine Unit 3, all with excellent results. All 42 fuel assemblies were examined for visible damage or non-standard position of fuel assembly components during unloading from the core. In addition all 42 assemblies were subject to the standard leak testing process with all found to be hermetically sealed. Six fuel assemblies of this Westinghouse reload batch were then subjected to a more extensive inspection program similar to what was done during the LTA program. Detailed results and concluding remarks from the post irradiation examination is provided in this paper. Westinghouse has now completed manufacturing and delivery of three regions of the Westinghouse WWER-1000 design to the South Ukraine NPP. Manufacturing of these fuel campaigns has gone very well without major issues, and the production of the WWER-1000 design has been integrated successfully with the other product lines in Sweden. In the second half of 2012 the first region of fuel to the Zaporizhzhya NPP will be delivered. (authors)