SENSITIVITY ANALYSIS OF PWR SPENT FUEL DUE TO MODELLING PARAMETER UNCERTAINTIES USING SURROGATE MODELS

In the BEPU (Best Estimate Plus Uncertainty) framework, uncertainty quantification (UQ) is a requirement to improve confidence and reliability of code predictions. Over years, lot works have been done quantify uncertainties in predictions spent nuclear fuel (SNF) characteristics due data uncertainties. The purpose this study pressurized water reactor (PWR) assembly radiation source terms (isotopic inventory, activity, decay heat, neutron gamma source) modeling parameters. deterministic STREAM used predict typical PWR following realistic detailed irradiation history. For sensitivity analysis (SA) UQ, surrogate models are developed based on polynomial chaos expansion (PCE) variance-based global indices ( i.e. , Sobol’ indices) employed. SA identifies less important uncertain parameters, showing that number input parameters can be reduced. model offers significantly reduced computational burden even with large samples required for SA/UQ response.