Analysis of transient fission gas behaviour in oxide fuel using BISON and TRANSURANUS

• Published in: Journal of nuclear materials Vol. 486; no. C; pp. 96 - 110
• Main Authors: Barani, T., Bruschi, E., Pizzocri, D., Pastore, G., Van Uffelen, P., Williamson, R.L., Luzzi, L.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01-04-2017; Elsevier BV; Elsevier
• Subjects: BISON code; Burst release; Bursting; Computer simulation; Data processing; Diffusion; Finite element method; Fission gas; Fission gas behavior; Fuel modelling; Integrals; Irradiation; Kinetics; Light water; Mathematical models; Mechanical properties; Nuclear fission; NUCLEAR FUEL CYCLE AND FUEL MATERIALS; Nuclear fuel elements; Nuclear fuel modeling; Nuclear fuels; Parameter sensitivity; Radiation; Reaction kinetics; Reactors; Sensitivity analysis; Solid oxide fuel cells; Studies; TRANSURANUS code; Xenon; Burst release; Fuel modelling; Fission gas; TRANSURANUS code; BISON code
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/j.jnucmat.2016.10.051

The modelling of fission gas behaviour is a crucial aspect of nuclear fuel performance analysis in view of the related effects on the thermo-mechanical performance of the fuel rod, which can be particularly significant during transients. In particular, experimental observations indicate that substantial fission gas release (FGR) can occur on a small time scale during transients (burst release). To accurately reproduce the rapid kinetics of the burst release process in fuel performance calculations, a model that accounts for non-diffusional mechanisms such as fuel micro-cracking is needed. In this work, we present and assess a model for transient fission gas behaviour in oxide fuel, which is applied as an extension of conventional diffusion-based models to introduce the burst release effect. The concept and governing equations of the model are presented, and the sensitivity of results to the newly introduced parameters is evaluated through an analytic sensitivity analysis. The model is assessed for application to integral fuel rod analysis by implementation in two structurally different fuel performance codes: BISON (multi-dimensional finite element code) and TRANSURANUS (1.5D code). Model assessment is based on the analysis of 19 light water reactor fuel rod irradiation experiments from the OECD/NEA IFPE (International Fuel Performance Experiments) database, all of which are simulated with both codes. The results point out an improvement in both the quantitative predictions of integral fuel rod FGR and the qualitative representation of the FGR kinetics with the transient model relative to the canonical, purely diffusion-based models of the codes. The overall quantitative improvement of the integral FGR predictions in the two codes is comparable. Moreover, calculated radial profiles of xenon concentration after irradiation are investigated and compared to experimental data, illustrating the underlying representation of the physical mechanisms of burst release.
•A model for transient fission gas behaviour including burst release is presented and assessed for fuel rod analysis.•Analytic sensitivity analysis is performed to evaluate the effect of model parameters on a physical figure of merit.•The same model is implemented in two fuel performance codes and assessed against 19 LWR fuel rod experiments.•Results with the transient model are more accurate than with the canonical models, for both codes.•Application in two structurally different codes isolates the effect of the specific model from the global analysis.