<p>High Temperature Gas-cooled Reactor (HTGR), one of the promising advanced nuclear reactors, has such characteristics as inherent safety, high power conversion efficiency and satisfactory application prospect. In HTGR, tri-structural isotropic (TRISO) fuel particles usage helps to achieve high operating temperature and high fuel burnup. TRISO fuel performance is crucial for the safety of HTGR. The Institute of Nuclear and New Energy Technology (INET) adopted PANAMA code in evaluating mechanical performance and TRISO coated particle fuels failure probability in engineering design of HTR-PM. However, PANAMA only used simple theoretical models, such as the ideal gas law and pressure vessel mechanical model. Compared with the recent HTR-PM fuel irradiation experiment, PANAMA’s results are quite conservative. INET further developed FRAT, a new TRISO fuel performance code. FRAT employs more delicate models involving gas pressure buildup, mechanical stress analysis and the temperature and burnup effects. For example, based on the pressure vessel model, FRAT introduced irradiation-induced PyC shrinkage, creep and thermal expansion. Furthermore, mechanical stress and failure probability are influenced by complex factors, such as geometrical, material and irradiation parameters. In addition, these parameters are affected by temperature, fast neutron fluence, material density and anisotropic factor. In this paper, we use FRAT code to perform a comprehensive sensitivity investigation on effects of particle stress and failure probability from geometric, material and irradiation parameters of particle coating layers. Results show that the calculated TRISO fuel failure probability is greatly influenced by models and input parameters used in gas production, gas pressure and mechanical stress calculations. This work lays a ground for uncertainty quantification of FRAT code.</p>

Sensitivity Study on TRISO Fuel Failure Probability Evaluation for HTGR

Paper Proceedings: https://asmedigitalcollection.asme.org/ICONE/ICONE28/volume/85246

2021 28th International Conference on Nuclear Engineering (ICONE28)

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