Topic: Radiation-Induced Corrosion of Nuclear Reactor Materials

Speaker: Prof. Dr. Jngsook Clara Wren

　　　　　Western University, London, Ontario, Canada N6A 5B7

Time: 9:00-10:30 AM., Tue., Apr. 23, 2013

Venue: Lecture Hall, South Campus, IMR

ABSTRACT

Many nuclear power safety and operational issues concern the effects of ionizing radiation on water chemistry and materials degradation. A key mechanism by which radiation influences chemical and materials processes is via water radiolysis. Ionizing radiationdecomposes water to chemically reactive species, ranging from oxidizing (e.g., •OH, H₂O₂) to reducing (e.g., •e_aq–, •O₂-). Due to their high reactivity, these species, even at low concentrations, can effectively control the aqueous redox (or electrochemical) potential of the water phase and strongly influence surface and interfacial reaction kinetics.

My groupis studying various aspects of radiation-induced chemistry as it affects nuclear reactor materials performance. Corrosionrelated studiesinclude:

1. Corrosion kinetics of in-reactor materials (steels, Co-based alloys and Ni-based alloys) in nuclear reactor environments and

2. Radiation-induced formation of metal oxide colloids from dissolved metal ions (important for activity transport in the reactor coolant circuit).

In these studies, we combine experimentswith computational model calculations. For the experimental studies, we have used a wide range of chemical, electrochemical and surface analysis techniques, including gas chromatography (GC), UV-Vis, Raman and FTIR spectroscopy, electrochemical impedance spectroscopy (EIS), x-ray photoelectron spectroscopy (XPS), Raman spectroscopy, Auger electron spectroscopy (AES), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and focussed ion beam (FIB) cross-section analysis. For the modeling studies we have used commercially available software (FACSIMILE) to solve complex radiolysis kinetics, and COMSOL MultiPhysics to model interfacial charge and mass transfer. By comparing experimentalresults withcomputational model simulations we are developing a coherent understanding of corrosion processes.Our studies have not only shown how steady-state radiolysis can influence on corrosion behaviour, but also have provided new insights into the competing corrosion mechanisms.

In this presentation, I willprovide a brief overview of the research at Western and discuss key results from ourcorrosion studies.

Welcome to attend!