Towards grain-scale modelling of the release of radioactive fission gas from oxide fuel. Part I: SCIANTIX

When assessing the radiological consequences of postulated accident scenarios, it is primary interest to determine amount radioactive fission gas accumulated in fuel rod free volume. The state-of-the-art semi-empirical approach (ANS 5.4–2010) reviewed and compared with a mechanistic evaluate release gases. At intra-granular level, diffusion-decay equation handled by spectral diffusion algorithm. inter-granular description grain boundary considered: bubble growth coalescence are treated as interrelated phenomena, resulting grain-boundary venting onset for from pellets. outcome kinetic gases, when normal off-normal conditions. We implement model SCIANTIX reproduce short-lived during CONTACT 1 experiments. results show satisfactory agreement measurement methodology, demonstrating soundness. A second work will follow, providing integral analysis coupling code thermo-mechanical TRANSURANUS.