KIT SCIENTIFIC REPORTS 7625 Reihentitel der Instituts-Schriftenreihe und Zählung XY Proceedings of the International Workshops ABC-Salt (II) and HiTAC 2011 Marcus Altmaier, Christiane Bube, Bernhard Kienzler, Volker Metz, Donald T. Reed (Eds.) ISBN 978-3-86644-912-1 ISSN 1869-9669 ISBN 978-3-86644-912-1 9 783866 449121 Cover_KIT-SR_7625_Proc-ABC-HiTAC_v3.indd 1-3 08.10.2012 12:52:07 Marcus Altmaier, Christiane Bube, Bernhard Kienzler, Volker Metz, Donald T. Reed (Eds.) Proceedings of the International Workshops ABC-Salt (II) and HiTAC 2011 Karlsruhe Institute of Technology KIT SCIENTIFIC REPORTS 7625 Proceedings of the International Workshops ABC-Salt (II) and HiTAC 2011 edited by Marcus Altmaier Christiane Bube Bernhard Kienzler Volker Metz Donald T. Reed Report-Nr. KIT-SR 7625 Impressum Karlsruher Institut für Technologie (KIT) KIT Scientific Publishing Straße am Forum 2 D-76131 Karlsruhe www.ksp.kit.edu KIT – Universität des Landes Baden-Württemberg und nationales Forschungszentrum in der Helmholtz-Gemeinschaft Diese Veröffentlichung ist im Internet unter folgender Creative Commons-Lizenz publiziert: http://creativecommons.org/licenses/by-nc-nd/3.0/de/ KIT Scientific Publishing 2012 Print on Demand ISSN 1869-9669 ISBN 978-3-86644-912-1 In November 2011 the Institute for Nuclear Waste Disposal at the Karlsruhe Institute of Technology organized two workshops on topics of high importance to the safe disposal of nuclear waste, ABC-Salt(II) and HiTAC. The safe disposal of long-lived nuclear waste is one of the main challenges associated with nuclear energy production today. A thorough understanding of actinide geochemical processes and their quantification are required as building blocks of the nuclear waste disposal safety case. As a consequence of many dedicated research activities, a detailed scientific understanding of fundamental proces­ ses controlling the behavior of radionuclides in aqueous systems has been established. The performance and safety of a repository based on analysis of pertinent scenarios can thus be assessed based upon scientific evidence and laws of nature. The need for international exchange and scientific discussions on actinide chemistry, in the context of nuclear waste disposal, has long been realized and is reflected in interna­ tional research activities, multilateral cooperation agreements and well-established scientific conferences like Migration, Actinides or Plutonium-Futures. As these large international conferences serve as a general forum to present new scientific results and trends, only very few workshops so far have specifically targeted actinide brine chemistry or high temperature aqueous chemistry. KIT-INE organized ABC-Salt (II) together with LANL-CO and also took the initiative to organize the HiTAC workshop. The proceedings of the ABC-Salt (II) and HiTAC workshops summarize recent research on actinide and brine chemistry relevant to waste disposal in rock-salt formations and the aqueous chemistry at the elevated temperature conditions expected in high level waste scenarios. The two successful workshops highlighted new scientific studies, offered room to discuss specific research activities and finally strengthened ties within the international scientific research community. I would like to express my thanks to the respective organizing committees and especially acknowledge the financial support for the workshops. ABC-Salt (II) was supported by the Federal Ministry of Economics and Technology (BMWi, Germany), the Department of Energy Waste Isolation Pilot Plant (DOE/WIPP, USA). HiTAC was supported by the Federal Ministry of Economics and Technology (BMWi, Germany). Prof. Horst Geckeis, head of KIT-INE Table of Contents PART I..............................................................................................................................................3 OVERVIEW OF THE ABC‐SALT (II) WORKSHOP.................................................5 SUMMARY OF THE ABC‐SALT (II) WORKSHOP ..................................................7 PROGRAM..........................................................................................................................13 Oral contributions ........................................................................................................... 13 Poster presentation......................................................................................................... 15 ABSTRACTS OF ORAL CONTRIBUTIONS.............................................................17 List of contributions........................................................................................................ 19 POSTER ABSTRACTS....................................................................................................63 List of poster contributions ......................................................................................... 65 WORKSHOP PARTICIPANTS.................................................................................. 109 PART II...................................................................................................................................... 115 OVERVIEW OF THE HITAC WORKSHOP........................................................... 117 SUMMARY OF THE HITAC WORKSHOP............................................................ 119 PROGRAM....................................................................................................................... 125 Oral contributions .........................................................................................................125 Poster presentation.......................................................................................................127 ABSTRACTS OF ORAL CONTRIBUTIONS.......................................................... 129 List of contributions......................................................................................................131 POSTER ABSTRACTS................................................................................................. 149 List of contributions......................................................................................................151 WORKSHOP PARTICIPANTS.................................................................................. 181 PART I 2nd International workshop on Actinide Brine Chemistry in a Salt‐Based Repository ‐ ABC‐Salt (II) ‐ Karlsruhe, Germany November 7 ‐ 8, 2011 2nd International workshop on Actinide Brine Chemistry in a Salt-Based Repository 7th – 8th Nov 2011 Organisation Organizers Karlsruhe Institute of Technology (KIT) Institute for Nuclear Waste Disposal (INE) Karlsruhe, Germany Los Alamos National Laboratory (LANL) Earth and Environmental Sciences Division (EES12) Carlsbad Operations Carlsbad, New Mexico, United States of America Sponsors Federal Ministry of Economics and Technology (BMWi), Germany Department of Energy Waste Isolation Pilot Plant (DOE/WIPP), United States of America Organizing Committee Marcus Altmaier, Christiane Bube, Volker Metz Karlsruhe Institute of Technology (KIT), Institute for Nuclear Waste Disposal (INE) PO-Box 3640, 76021 Karlsruhe, Germany Donald T. Reed Los Alamos National Laboratory (LANL), Earth and Environmental Sciences Division (EES12), Carlsbad Operations, 1400 University Drive, Carlsbad, NM 88220, United States of America Contact, e-mail: [email protected], [email protected], [email protected] Acknowledgements We gratefully acknowledge Angelika Aurich, Elke Bohnert, Elke Lukas, Bernhard Kienzler, Stefanie Krieger, Andrej Skerencak, Hieronymus Sobiesiak and Denise Wedemeyer for their administrative and technical sup­ port. 4 2nd International workshop on Actinide Brine Chemistry in a Salt-Based Repository 7th – 8th Nov 2011 OVERVIEW OF THE ABC­SALT (II) WORKSHOP Among the geological formations discussed as suitable hosts for nuclear waste disposal – crystalline rocks, clay and rock salt - salt offers several unique features. Most importantly, it is known that salt, due to its self­ sealing properties, leads to conditions that clearly favor the complete isolation of waste for the long-term dis­ posal of radioactive waste in dry conditions. In the huge majority of scenarios, the nuclear waste will be imbedded in a dry salt matrix without any significant mobilization of radioactivity. This situation is a markedly different than waste disposal in crystalline or clay rocks, where groundwater saturation is expected. The actinide and brine chemistry discussed within the ABC-Salt workshop is relevant for low probability repository failure scenarios, when water intrusion into a salt-based repository cannot be excluded. The poten­ tial for radionuclide mobilization in the unlikely event of water intrusion and the subsequent interaction of concentrated salt brine solutions with the waste needs to be understood and predicted in detail as this would be a key mobilization pathway of radionuclides into the environment. Performance assessment calculations that account for this low-probability scenario will require input from geochemistry and actinide chemistry to support reliable model calculations and long-term safety predictions. The behavior of radionuclides in salt brines is not only relevant for salt-based repositories but also for potential nuclear waste repositories in some other deep geological formations. At a depth of several hundred meters, argillaceous and crystalline formation waters are Na+/Cl- type solutions. Formation waters with elevated ionic strength occur for instance in Ordovician shales