Towards simulations of fuel rod behaviour during severe accidents by coupling TRANSURANUS with SCIANTIX and MFPR-F

•The coupling of the TRANSURANUS fuel rod code and the mechanistic modules for fission product behaviour SCIANTIX and MFPR-F has been completed.•The coupled-code show that mesoscale models can be developed independently, in either modern fortran or c++ programming language.•The coupling applied here paves the way for further code couplings.•Simulating irradiation in a commercial plant, followed by a re-irradiation in a research reactor revealed no convergence or cliff-edge effects. Among the applications of the multiscale modelling approach in nuclear fuel rod performance, the coupling of integral thermo-mechanical fuel performance codes with lower-length meso-scale modules is of great interest. This strategy allows to overcome correlation-based approaches with mechanistic ones and test their application in accidental conditions. In this work, we explore the coupling between the TRANSURANUS fuel performance code and two meso-scale modules for fission gas/product behaviour: MFPR-F and SCIANTIX. These modules, coupled within TRANSURANUS, are assessed against the IFA-650.10 loss-of-coolant accident test to analyse their overall impact and highlight future developments toward mechanistic modelling of fission gas during accident scenarios.