Development, Validation and Application of the TRANSURANUS Code for Westinghouse Fuel Designs

The TRANSURANUS nuclear fuel performance code of the European Commission, Joint Research Centre has been extended with new best-estimate and conservative models to support deterministic and probabilistic safety analyses of Westinghouse's PWR and VVER fuel rod designs. The recent model refinements and code validation analyses have been carried out in the EU-funded project ESSANUF aiming at the development of an alternative nuclear fuel, as well as licensing methods and methodologies for the Russian-designed pressurized water reactor VVER-440. The Westinghouse-specific developments of TRANSURANUS have covered fission gas release, fuel swelling, cladding corrosion and hydrogen uptake, rod growth, cladding creep, rod burst, inner cladding steam oxidation and oxide breakaway. The code validation has been based on two major data sources: (1) an extensive database of Westinghouse consisting of pool-side measurements and postirradiation examinations (PIE) for a large number of commercial and experimental fuel rods and separate-effect tests representing a wide range of conditions and (2) data of on-line measurements in specific test fuel assemblies of the Halden Reactor Project (HRP). A statistical evaluation method has been applied to prove the correct simulation of the different physical phenomena and the adequate bounding of the experimental data.