Institut für Mineralogie, Mineralogisches Museum (Kristalle und Gesteine)	Tel. (0251) 83-33464 Fax: (0251) 83-38397 e-mail: minsek@nwz.uni-muenster.de www: uni-muenster.de/Mineralogie
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Forschungsschwerpunkte 2003 - 2004    zurück    weiter

Allgemeine und Angewandte Mineralogie Stability of ceramic materials proposed as nuclear waste forms under experimental hydrothermal conditions   Based on present familiarity with production technology, the two best candidate materials for the immobilization of high-level nuclear waste (e.g., 99Tc, 129I, 79Se, 135Cs, 239Pu, and 137Np) are glasses and crystalline ceramics. The main objectives of the research are to understand the fundamental atomic-scale mechanisms at the fluid-ceramic interface and their dependence on self-irradiation damage, the thermodynamics, and kinetics of fluid-ceramic interaction under moderate P-T conditions expected in deep borehole repositories and near-surface environments. Hydrothermal experiments with natural samples under different physicochemical conditions are linked (i) to detailed studies on natural analogues, which have been altered under geological conditions and thus representing real case scenarios, and (ii) to carefully designed hydrothermal experiments with 238Pu- und 239Pu-doped synthetic samples. Experiments with Pu-doped synthetic samples are carried out in collaboration with the V. G. Khlopin Radium Institute in St. Petersburg (Russia) and the Institute of Transuranium Elements (ITU) in Karlsruhe (Germany). Drittmittelgeber: Deutsche Forschungsgemeinschaft Beteiligte Wissenschaftler: Dr. Boris Burakov, Dr. Thorsten Geisler-Wierwille, Dr. Uta Golla-Schindler, Arne Janßen, Dr. Rudy Konings, Philipp Pöml, Dr. Kilian Pollok, Prof. Andrew Putnis Veröffentlichungen: Geisler T., Rashwan A.A., Rahn M., Poller U., Zwingmann H., Pidgeon R.T., and Schleicher H. (2003) Low-temperature hydrothermal alteration of natural metamict zircons from the Eastern Desert, Egypt. Mineral. Mag. 67, 485-508. Geisler T., Zhang M., and Salje E.K.H. (2003) Recrystallization of almost fully amorphous zircon under hydrothermal conditions: An infrared spectroscopic study. J. Nucl. Mater. 320, 280-291. Geisler T., Pidgeon R.T., Kurtz R., van Bronswijk W., and Schleicher H. (2003) Experimental hydrothermal alteration of partially metamict zircon. Amer. Mineral. 86, 1496-1518. Geisler T., Trachenko K., Ríos S., Dove M., and Salje E.K.H. (2003) Impact of self-irradiation damage on the aqueous durability of zircon (ZrSiO4): Implications for its suitability as nuclear waste form. J. Phys: Condens. Matter 15, L597-L605. Trachenko K., Dove M.T., Geisler T., Todorov I., and Smith B. (2004) Radiation damage effects and percolation theory. J. Phys.: Condens. Matter 16, S2623-S2627. Trachenko K., Dove M.T., Pruneda M., Artacho E., Salje E.K.H., Geisler T., Todorov I., and Smith B. (2004) Radiation-induced structural changes, percolation effects, and resistance to amorphization. Mat. Res. Soc. Symp. Proc. 792, R.6.2.1. Geisler T., Berndt J., Meyer H.-W., Pollok K., Putnis A. (2004) Low-temperature aqueous alteration of crystalline pyrochlore: Correspondence between nature and experiment. Mineral. Mag. 68, 905-922. Geisler T., Burakov B.E, Yagovkina M., Garbuzov V., Zamoryanskaya M., Zirlin V., and Nikolaeva L. (2005) Structural recovery of self-irradiated natural and 238Pu-doped zircon in an acidic solution at 175°C. J. Nucl. Mater. 336, 22-30. Geisler T., Seydoux-Guillaume A.-M., Poeml P., Golla-Schindler U., Berndt J., Wirth R., Pollok K., Janssen A., and Putnis A. (2005) Experimental hydrothermal alteration of crystalline and radiation-damaged pyrochlore. J. Nucl. Mater. (in press).