Distinct Effects of Irradiation on the Structure and Chemical Reactivity of Silicates and Carbonates
Abstract
Concrete in nuclear power plants (NPP) is subject to sustained exposure to neutron irradiation. The interaction of neutrons with crystalline components of concrete, e.g.., the mineral aggregates, may result in its premature degradation by, for example, alkali-silica reaction leading to cracking. In this collection of studies, we investigated the effects of irradiation on the structure and reactivity of a wide variety of minerals typical of concrete aggregates. The silicates quartz (SiO2), albite (NaAlSi3O8), and almandine (Fe3Al2(SiO4)3), and the carbonates calcite (CaCO3) and dolomite (CaMg(CO3)2) were irradiated using Ar+ ions at 400 keV. Molecular dynamics simulations enabled the characterization of network rigidity of pristine and irradiated samples from the magnitudes of radial and angular bond excursions. Dissolution rates quantified using vertical scanning interferometry showed that the minerals underwent various degrees of enhancement in reactivity upon irradiation, ranging from nearly unchanged (i.e., calcite and dolomite) to a factor of 1000 (i.e., quartz). The observed increase in dissolution rates for a variety of aqueous environments depended on the nature and magnitude of the relative decrease in network rigidity upon irradiation, as well on the specific dissolution mechanism of the phase. The dominance of ionic bonding in carbonates rendered the phase resilient to irradiation, whereas the breakage of Si—O bonds in the percolated silicates albite and quartz resulted in structural disorder. In addition, the trends in reactivity alterations are consistent with the corresponding changes in density. These findings can help guide assessments of susceptibility of concrete to irradiation-induced damage and inform selections of durable aggregates.
Recommended Citation
E. C. la Plante et al., "Distinct Effects of Irradiation on the Structure and Chemical Reactivity of Silicates and Carbonates," Proceedings of the 19th International Conference on Environmental Degradation of Materials in Nuclear Power Systems - Water Reactors (2019, Boston, MA), pp. 582 - 586, American Nuclear Society (ANS), Aug 2019.
Meeting Name
19th International Conference on Environmental Degradation of Materials in Nuclear Power Systems - Water Reactors, EnvDeg 2019 (2019: Aug. 18-22, Boston, MA)
Department(s)
Materials Science and Engineering
Keywords and Phrases
Calcite; Calcium Carbonate; Chemical Bonds; Concrete Aggregates; Concretes; Damage Detection; Dissolution; Feldspar; Magnesium Compounds; Molecular Dynamics; Nanocrystalline Materials; Nuclear Energy; Nuclear Fuels; Nuclear Power Plants; Quartz; Radiation; Reaction Kinetics; Rigidity; Silicates; Silicon, Alkali-Silica Reaction; Aqueous Environment; Crystalline Components; Dissolution Mechanism; Irradiated Samples; Molecular Dynamics Simulations; Structural Disorders; Vertical Scanning Interferometries, Neutron Irradiation
Document Type
Article - Conference proceedings
Document Version
Citation
File Type
text
Language(s)
English
Rights
© 2019 19th International Conference on Environmental Degradation of Materials in Nuclear Power Systems - Water Reactors, EnvDeg., All rights reserved.
Publication Date
01 Aug 2019
Comments
The authors acknowledge financial support for this research provided by: The Oak Ridge National Laboratory (ORNL) operated for the U.S. Department of Energy by UT-Battelle (LDRD Award Number: 4000132990), National Science Foundation (CMMI: 1066583 and 1235269), Department of Energy€™s Nuclear Energy University Program (DOE-NEUP: DENE0008398), National Science Foundation (CAREER award: 1253269), the U.S. Department of Transportation (U.S. DOT) through the Federal Highway Administration (DTFH61-13-H-00011), and University of California, Los Angeles (UCLA).