Actinide Nanoparticle Research . Stepan N. Kalmykov l Melissa A. Denecke Editors Actinide Nanoparticle Research Editors Prof.Dr. Stepan N. Kalmykov Dr. Melissa A. Denecke Lomonosov Moscow State University Forschungszentrum Karlsruhe Dept. Chemistry Inst. Nukleare Leninskie Gory 1/3 Entsorgungstechnik 119991 Moscow Postfach 36 40 Russia 76021 Karlsruhe [email protected] Germany [email protected] ISBN 978-3-642-11431-1 e-ISBN 978-3-642-11432-8 DOI 10.1007/978-3-642-11432-8 Springer Heidelberg Dordrecht London New York Library of Congress Control Number: 2011924898 # Springer-Verlag Berlin Heidelberg 2011 This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilm or in any other way, and storage in data banks. Duplication of this publication or parts thereof is permitted only under the provisions of the German Copyright Law of September 9, 1965, in its current version, and permission for use must always be obtained from Springer. Violations are liable to prosecution under the German Copyright Law. The use of general descriptive names, registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. Cover design: eStudio Calamar S.L. Printed on acid-free paper Springer is part of Springer ScienceþBusiness Media (www.springer.com) Foreword A challenge for most of the countries that developed nuclear fuel cycles is the problem of safe and economically reasonable methods for management of spent nuclear fuel (SNF) and radioactive wastes. In Russia, the government plans to increase the share of nuclear power from 15% up to 25% by 2030. This would increase the volume of SNF that have to be processed and nuclear wastes that have to be disposed into the geological repositories. On these grounds, research in different fields including behavior of SNF and vitrified nuclear wastes under repository conditions, interaction of radionuclides with engineered and natural barriers, migration and speciation of radionuclides in the environment, and so on, is highly appreciated. Another challenging problem that many countries face is the remedia- tion of contaminated sites as a legacy of such diverse activities as weapon programs, SNF reprocessing, or uranium mining and milling. No effective remediation strate- gies could be developed without knowledge on the speciation of radionuclides. It was demonstrated by research groups in many countries that actinides, as well as other radionuclides, tend to form colloid particles of different nature that are responsible for their environmental behavior. Structurally, most of these colloids are hierarchic particles that consist of agglomerated nanoparticles. In order to understand and predict their environmental behavior, their characterization at nano- and subnano scale is required. This is the first book that covers different aspects of actinide nanoresearch: formation, structure, and properties of actinide nanoparticles and thin layers, environmental behavior of actinide colloids including modeling approaches. Several chapters are devoted to the new innovative spectroscopic and microscopic techniques of actinide nanoparticle characterization. This book is of interest both for fundamental research into chemistry and physics of actinides and for applied researchers. The chapters are written and reviewed by top-level specialists in the field of actinide chemistry, allowing one to recommend this book to broad audience including scientists, engineers, and students who study nuclear chemistry. Moscow, Russia Boris F. Myasoedov February 2011 Academician, Professor, Honorary chairman of Russian-German Symposium on Actinide Nanoparticles v . Preface The idea for this book on actinide nanoparticle research was born during the “Russian–German Symposium on Actinide Nanoparticles” held in May 2009 in Moscow and organized by the institutes Department of Chemistry of the Lomonosov Moscow State University (MSU) and the Institute of Nuclear Waste Disposal at the Karlsruhe Institute of Technology (KIT-INE). The symposium itself is a milestone in a cooperation between MSU and KIT-INE, the Helmholtz-Russian Joint Re- search Group entitled “Actinide Nanoparticles: Formation, Stability, and Properties Relevant to the Safety of Nuclear Waste Disposal” funded by the German Helm- holtz Society and the Russian Foundation for Basic Research. The research interest in actinide nanoparticles is multifaceted. An obvious interest lies in their importance for safety research related to nuclear waste disposal and assessment of actinide-contaminated sites, as the formation and transport of actinide nanoparticles is an environmental concern that is vital not only to our generation but also to future generations. There are other aspects of more basic character, which are a driving force behind actinide nanoparticle research. This research belongs to a distinct realm of nanoscience, but with a history longer than other areas of today’s conventional nanoscience. Modern nanoscience, as a pres- ently well-funded, “sexy” research area, has actually joined the ranks of the area of nanoscience referred to for decades as colloid chemistry or colloid research, including macro- and supramolecular chemistry. Our endeavors in actinide nanoparticle research entail much more than being simply classified as a sector of nanoscience, however. We are clearly tackling the grand challenge of understanding the behavior of these heavy elements as nanoclusters and nanoparticles with inherent special behavior, reactivity, and structure. Part of this challenge lies in the radioactivity of actinide-containing systems investigated, requiring specialized expertise and infrastructure. It is not always a trivial task equipping instrumentation for nanoparticle characterization to make safe studies of radioactive systems possible and only a limited number of laboratories worldwide have the capability and licensing for working with trans- uranium actinide elements. Certainly an exceptionally challenging aspect is the vii viii Preface theoretical description of heavy actinide elements. Experimental observation and interpretation on the nanoscale is driving instrumentation and method develop- ment and the thrust to couple experiments on actinide systems with quantum chemical calculations is promoting advances in theory. Theoretical, computational description of 5f element systems must deal with numerous electrons in (5f, 6d, 7s, and 6p) orbitals close in energy, requiring scalar and often spin-orbit relativistic effects or electron correlation effects. Many chapters of this book, but not all, are an extension or overview of presentations given at the Russian–German Symposium on Actinide Nanoparticles. The first chapter Actinide Nanoparticles – Generation, Stability, and Mobility is a summary of the presentation given by Professor Horst Geckeis at the symposium and is an excellent discourse on the state of knowledge and the importance of environmental actinide nanoparticle behavior. The remaining chapters of this book are divided into four sections dealing with different aspects of actinide nanoparticle research, in a manner similar to the structure of the symposium: Methods, Model- ing, Surface Reactivity and Environmental Behavior. In the Methods section, we have included imaging, spectroscopic and separation techniques covering over- views of previous studies (STXM, FFF, and MS), newer results (STEM), and a chapter on a newer spectroscopy offering great potential for direct characterization of actinide nanoparticle bulk electronic structure (RIXS). The Modeling section includes not only a treatise on modeling of colloid-mediated actinide transport in the environment but also a chapter on the outlook of quantum chemical strategies for computing actinide nanoparticle structures. This is followed by a section on Interfacial Phenomena and Formation of Actinide Nanoparticles. The interfacial phenomena are addressed in three separate chapters, one reporting new results from an investigation of actinide ion interaction with silica nanoparticles, the second chapter on well-defined thin films produced under controlled sputtering conditions as models for reactive surfaces, especially spent fuel but potentially applicable for advancing our understanding of actinide nanoparticles with inherent large surface to bulk ratios. The third chapter in this section deals with novel structures of uranium selenate clusters, which can serve as models for formation and reactivity of certain classes of actinide nanoparticles. The last section presents results from previous and new investigations of actinide nanoparticle environmental behavior. Four of this section’s chapters deal with anthropogenic actinide contamination legacies; the last chapter reports new results of X-ray tomography investigations with nanoscale resolution and techniques offering a potentially encouraging out- look for future research activities. Ultimate goal in actinide nanoparticle research of attaining a level of under- standing, which permits us to predict and ultimately control actinide behavior in systems covering the entire size-scale range – from ion, to nanoclusters, to nano- particles and microparticles, up to bulk, condensed systems – is not only a noble ambition necessary