Study of models for high burn behavior of uranium-7% gadolinium fuel rods for pressurized light water reactors

Abstract

The objective of this work is to verify the validity of the results provided by the FRAPCON-3.5 software in the simulation of the behavior of the fuel UO2 - 7% by weight of Gd2O3, in order to evaluate the different models that are being proposed in codes of performance of fuels, in view of the behavior of fuel rods from PWR (Pressurized Water Reactor) under high burning conditions. To perform the analysis of the models that simulate the behavior of fuel pellets, the formation of the microstructure of (UO2-7% Gd2O3), fuel restructuring, temperature in the center of the fuel, comparison of the thermal conductivity between UO2 and the concentration of gadolinium as burnable venom, porosity in the restructured material, release of athermanous fission gases into the restructured material, release of thermally activated fission gases, including gas release models that occur due to grain growth. The results obtained in the computational simulations with the FRAPCON-3.5 program and its comparison with UO2 and UO2-7% Gd2O3, it will be possible to verify that the program has good capacity to predict the operational behavior of PWR fuel rods in permanent regime at high burns under transient condition initialized by reactivity.