Towards coupling conventional with high-fidelity fuel behavior analysis tools

Multi-dimensional fuel performance codes have the potential to enhance the understanding of complex phenomena affecting fuel integrity, but their application is often limited by the high computational cost. Recognizing that many multi-dimensional aspects such as the ballooning of the cladding during a loss of coolant accident or the pellet-cladding mechanical interaction (PCMI) during power ramps are of interest mainly for operational and accidental transients, we have developed a coupling methodology between conventional and high-fidelity fuel behavior analysis. This consists in using a well-validated 1.5-D code to rapidly simulate the base irradiation and set the initial and boundary conditions for the 2-D or 3-D transient model, leading to an optimized use of computational resources. In this paper we present the coupling methodology, and we apply it to link the TRANSURANUS code and the multi-dimensional code OFFBEAT. To demonstrate the capabilities of the coupling tool, we study the PCMI during the end-of-life power ramp of the AN3 segment from the Riso-3 experiment and we compare the predicted cladding deformation and bamboo structure against the experimental profilometry provided by the Post Irradiation Examination (PIE). In the conclusions, we also outline further potential applications of the coupling methodology.