Understanding cesium(Cs)transport in TRistructural ISOtropic(TRISO)particle fuel is crucial for predicting fission product release in high-temperature reactors.However,current challenges include significant scatter in...Understanding cesium(Cs)transport in TRistructural ISOtropic(TRISO)particle fuel is crucial for predicting fission product release in high-temperature reactors.However,current challenges include significant scatter in diffusivity data and unexplained temperature-dependent diffusion regimes in the silicon carbide layer.This study addresses these challenges by developing a multiscale,mechanistic Cs transport model integrating atomistic simulations and phase field modeling.Our model quantifies temperature and grain size effects on Cs diffusivity,attributing experimentally observed regimes to a transition from bulk-dominated diffusivity at high temperatures to grain boundary-dominated diffusivity at lower temperatures.The model,validated against diffusion measurements and advanced gas reactor(AGR)-1 and AGR-2 post-irradiation fission product release data,enhances the predictive capability of the BISON fuel performance code.This study advances our understanding of Cs release from TRISO particles and its dependence on temperature and silicon carbide grain size,with implications for the safety and efficiency of high-temperature nuclear reactors.展开更多
基金provided by the Nuclear Energy Advanced Modeling and Simulation(NEAMS)program.This report was authored by a contractor of the U.S.Government under contract DE-AC07-05ID14517the U.S.Government retains a non-exclusive,royalty-free license to publish or reproduce the published form of this report,or allow others to do so,for U.S.Government purposes.This research made use of the resources of the High Performance Computing Center at Idaho National Laboratory(INL),which is supported by the DOE Office of Nuclear Energy and the Nuclear Science User Facilities under contract no.DE-AC07-05ID14517.The authors would like to recognize Paul Demkowicz at INL for the fruitful discussions and invaluable feedback he provided to improve the manuscript.
文摘Understanding cesium(Cs)transport in TRistructural ISOtropic(TRISO)particle fuel is crucial for predicting fission product release in high-temperature reactors.However,current challenges include significant scatter in diffusivity data and unexplained temperature-dependent diffusion regimes in the silicon carbide layer.This study addresses these challenges by developing a multiscale,mechanistic Cs transport model integrating atomistic simulations and phase field modeling.Our model quantifies temperature and grain size effects on Cs diffusivity,attributing experimentally observed regimes to a transition from bulk-dominated diffusivity at high temperatures to grain boundary-dominated diffusivity at lower temperatures.The model,validated against diffusion measurements and advanced gas reactor(AGR)-1 and AGR-2 post-irradiation fission product release data,enhances the predictive capability of the BISON fuel performance code.This study advances our understanding of Cs release from TRISO particles and its dependence on temperature and silicon carbide grain size,with implications for the safety and efficiency of high-temperature nuclear reactors.
