Implementation of burnup effects in the multiphysics fuel behavior module FINIX

Abstract

The FINIX fuel behavior module and interface for multiphysics applications has been developed at VTT since 2012. The module is designed to be implemented in other reactor safety analysis tools, such as neutronics and reactor dynamics codes. A new reactor analysis framework, Kraken, is currently under development at VTT, where FINIX would serve as the main fuel model.The first versions of FINIX were mostly capable of simulating transients. Recently, FINIX modeling capabilities under long irradiation periods have been improved by the implentation of several models for fuel and cladding behavior under irradiation.The inclusion of these models has improved the accuracy of FINIX in prediction fuel temperatures compared to experimental data from integral tests performed at the Halden reactor. At the current development stage, FINIX predictions are on average within 6 % of experimentally determined temperatures.