Qualification of HELIOS models for XS preparations to new types of fuel
The introduction of new types of nuclear fuel on Ukrainian NPPs for the improvement of operational characteristics and diversification of nuclear fuel supplier is an on-going process. Significant efforts have been made to license alternative fuel designs for the VVER plants in Ukraine. As a technical support organization of the Ukrainian regulatory authority, SSTC NRS takes part in the licensing process for the introduction of new fuel assembly (FA) types. On first step of the independent analysis of core characteristics, the preparation of cross-section (XS) libraries, the HELIOS code is applied. To ensure this capability, HELIOS models for the actual types of fuel were developed and tested within the framework of BMU/HZDR/SSTC NRS cooperation. The following fuel types are operated now or considered for near perspective for Ukrainian NPPs: TVEL Fuel Company – First and Second Generation and “slim fuel pin (fp)” for VVER-440, TVSA and TVSA-12 for VVER-1000; Westinghouse – TVS-WR (or RWFA) and FA with IFBA fuel for VVER-1000, “ESSANUF” FA for VVER 440.
The result of HELIOS models been developed for new types of fuel and their testing are presented in this paper.