Past Seminars and Events 2017

McLaren Center for Ceramic Research, CCR-101

SR IMMOBILIZATION IN IRRADIATED PORTLAND CEMENT PASTE EXPOSED TO CARBONATION

Dr. Gabriela Bar-Nes

Department Head

Department of Applied Chemistry,

Nuclear Research Center, Negev

Negev, Israel.

Abstract

Cement based materials are widely used as binding matrices for radionuclides in low and intermediate level waste management applications. We studied the effect of irradiation and carbonation under atmospheric condition on the leaching of Sr from Portland cement paste. Samples were exposed to gamma irradiation or subjected to thermal treatment under either inert or atmospheric conditions. Leaching tests were performed and supplemented by post-leaching characterization including local chemical analysis (LA-ICPMS) crystallographic analysis (XRD), and EPMA imaging. The combination of these methods enabled us to link between the microstructure and composition of the treated samples and their ability to retain Sr ions. Results show that carbonation was the main factor determining the retention of Sr ions, whereas irradiation did not have a significant effect. Moreover, carbonation has a positive effect on the retention of Sr ions in the matrix with the formation of a carbonated zone.

Biosketch

Dr. Bar-Nes is the Head of waste treatment group in the Chemistry Department at NRCN.  Her main research activities are waste immobilization in cementitious pastes and geopolymers. Her scientific focus is on mechanisms of ion transport, the effect of the matrix composition on the microstructure and transport properties, and degradation mechanisms: (microbial, radiation, carbonation, thermal). Dr. Bar-Nes received her B.Sc from the Department of Chemistry,  at the  Ben-Gurion  University of the Negev, Israel. She received her M.Sc. in Chemical Engineering Department, from the same university studying “Copolymers of Polyisoprene: Synthesis and Product Characterization'', under the supervision of Prof. Moshe Gottlieb. Following that, she received her PhD: from the Department of Materials and Performance, at the Technion, Haifa, Israel. Her thesis focused on: “Strontium and Cesium Immobilization in Cementitious Materials” under the supervision of Prof. Amnon Katz, Prof. Arnon Bentur and Prof. Yehuda Zeiri.

Hosted by Prof. Richard Riman