b'Mechanistic Understanding of Radiolytically AssistedHydrothermal Corrosion of Silicon Carbide in Light WaterReactor Coolant EnvironmentsPrincipal Investigator: Dr. Peng Wang, University of MichiganTeam Members/ Collaborators: Dr. Gary S. Was, University of Michigan; Dr. Izabela Szlufarska, University of Wisconsin-Madison; Dr. Keyou Mao, Oak Ridge National Laboratory; Dr. Luke Czerniak, Westinghouse Electric Company LLCT his project will provide aradiolysis products. This research fundamental understandingcan transfer knowledge to other of the hydrothermal corrosionapplications involving SiC in a water mechanisms of Silicon Carbide (SiC)environment at high temperatures. in light water reactors (LWRs) underCorrosion kinetics of SiC in reactor the condition where displacementoperation is critical to constructing damage and radiolysis products area corrosion model for SiC cladding present. This project also addressesin fuel performance codes. This work the need for ongoing accidentwill directly impact the application tolerant fuel (ATF) program researchof SiC as LWR fuel cladding in and development (R&D) on SiC/ commercial reactors.SiC composite cladding. The key feasibility issue of hydrothermalProject Description:corrosion of SiC was assessed inThis project aims to apply ion beam this project, which is critical forirradiation with in-situ pressurized designing a reliable fuel cladding.water reactor water corrosion in Currently, radiolytically assistedcombination with modeling and dissolution of SiC in the LWR simulation to develop a mechanistic environment is still unknownunderstanding of the hydrothermal territory. The in-situ ion irradiation- corrosion behavior for SiC. A corrosion experiments in this studyseries of ion beam irradiation was offer a rapid and cost-effective meansperformed on the chemical vapor to evaluate materials and studydeposition (CVD) SiC sample, and the corrosion mechanisms underlong-term autoclave exposure and irradiation conditions comparablein-situ proton irradiation-corrosion to test reactor conditions. It will experiments were conducted. The also extend our knowledge of themodeling team studied the dynamic degradation mode of SiC-basedcorrosion processes of the water/SiC materials under the influence ofsystem by using ab initio molecular irradiation, especially at high doses,dynamics (AIMD) within the density which is critically important tofunctional theory (DFT) framework. the durability of the cladding. ByThe modeling results indicate coupling with the model study, thisthat the initial hydrogen scission research also provides a broaderreactions play an essential role in picture of the long-term corrosionthe surface corrosion processes, and dissolution behavior of SiCregardless of the surface orientation. with and without irradiation andIn addition, kinetic studies identified that the soluble silicic acid would be 60 2022|AFC ACCOMPLISHMENTS'