Uncertainty quantification of fuel pebble model and its effect on the uncertainty propagation of nuclear data in pebble bed HTR

Abstract In order to give a clear picture of key parameters uncertainties introduced from fuel pebble model in HTR and its effect on the uncertainty propagation, herein different methods of sampling the position of a random dispersed TRISO particle in the fuel region were studied. And total ten different fuel pebble models including high-fidelity models with random dispersed fuel particles and homogenized models were built to quantify the uncertainty of eigenvalue introduced by fuel pebble models. Meanwhile, the effect of fuel pebble model on the uncertainty propagation of nuclear data was also investigated. The numerical results indicate that the fuel pebble models introduce a great model uncertainty to the calculated multiplication factor and also have a significant effect on the uncertainty propagation of nuclear data. However, the uncertainty of the multiplication factors due to the random distribution of TRISO particles is relatively small compared with the uncertainty propagated from nuclear data.