Joint project Conditioning:

 

Basic investigations of the immobilization of long-lasting radionuclides by means of installation in ceramics relevant to repository

Ceramic materials have been discussed for decades as a promising alternative to borosilicate glass as a matrix for the final storage of radioactive waste due to their physical and chemical properties. Due to their crystallinity, they have a few orders of magnitude higher corrosion resistance under final storage conditions compared to glass. The phosphates with a monazite structure and the zirconates with a pyrochlore structure, which are investigated in this project, are characterized by their particularly pronounced resistance to radiation. Radiation damage does not cause amorphization with these materials. In the case of the monazites, this effect is due to recrystallization processes at low temperatures and in the case of the pyrochlore-zirconates to the structural flexibility. However, to date no models have been developed that can adequately describe the highly complex relationships between structure and stability with regard to the behavior of monazites and zirconate-pyrochlores under repository-relevant conditions.

As part of this project, experimental investigations (structure elucidation, corrosion tests, radiation resistance) were combined with complementary model calculations to determine thermodynamic and kinetic data relevant to repositories. In this way, contributions were made to the development of models based on structure/property relationships, with which the processes of the repository processes can be described on an atomic basis and reliable statements can be made with regard to long-term stability and retention capacity.

Team:

Prof. Dirk Bosbach (FZ Jülich, IEK6)
PD Dr. Thorsten Stumpf (Karlsruher Institut für Technologie, INE)
Dr. Andreas C. Scheinost (Helmholtz-Zentrum Dresden-Rossendorf, IRO)
Prof. Georg Roth, Dr. Lars Peters, M. Sc. Antje Hirsch (RWTH Aachen, IFK)
Prof. Rainer Telle (RWTH Aachen, GHI)
Prof. Clemens Walther (Leibnitz-Universität Hannover, IRS)
Prof. Björn Winkler (Goethe-Universität Frankfurt, IFG)
Dr. Guido Deissmann (Brenk Systemplanung GmbH, Aachen)
Projektkoordinator: Dr. Stefan Neumeier (FZ Jülich, IEK6)

Publications:

  • J. D. Bauer, A. Hirsch, L. Bayarjagal, L. Peters, G. Roth, B. Winkler: Schottky contribution to the heat capacity of monazite type (La,Pr)PO4 from low temperature calorimetry and fluorescence measurements. Chemical Physics Letters 654 (2016), 97-102.
  • J. Ruiz-Fuertes, A. Hirsch, A. Friedrich, B. Winkler, L. Bayarjagal, W. Morgenroth, L. Peters, G. Roth, V. Milman: High-pressure phase of LaPO4 studied by x-ray diffraction and second harmonic generation. Physical Review B 94 (2016), 134109.
  • A. Hirsch, P. Kegler, I. Alencar, J. Ruiz-Fuertes, L. Peters, C. Schreinemachers, A. Shelyug, A. Neumann, S. Neumeier, H.-P. Liermann, A. Navrotsky, G. Roth: Structural, vibrational, and thermodynamical properties of the monazite-type solid solution La1-xPrxPO4. Journal of Solid State Chemistry 245 (2017), 82-88.
  • A. Thust, A. Hirsch, L. Peters, G. Roth, E. Haussühl, N. Schrodt, B. Winkler: Physical properties and microstructures of La1-xPrxPO4 monazite-ceramics. Phys. Chem. Minerals (2017), DOI: 10.1007/s00269-017-0921-2.
  • H. Schlenz, S. Neumeier, A. Hirsch, L. Peters, G. Roth: Phosphates as safe containers for radionuclides. In: Highlights in Applied Mineralogy. Herausgeber: Soraya Heuss-Aßbichler, Georg Amthauer, Melanie John. De Gruyter, Berlin/Boston 2018. Kap. 8, S. 171-195. ISBN: 978-3-11-049122-7, e-ISBN (pdf): 978-3-11-049734-2,
    DOI: 10.1515/9783110497342-009.
  • D. Errandonea, O. Gomis, S. N. Achary, G. Roth, J. Ruiz-Fuertes, A. Hirsch, L. Peters, P. Rodriguez-Hernandez, M. Bettinelli, M. Gupta, F. J. Manjon, A. Munoz, A. K. Tyagi: High-pressure structural and vibrational properties of monazite-type BiPO4, LaPO4, CePO4 and PrPO4. Journal of Physics/Condensed Matter 30 (2018), 065401.

  Copyright: © Bundesministerium für Bildung und Forschung

Funding:

Bundesministerium für Bildung und Forschung
Project executing organization: Karlsruhe im Karlsruher Institut für Technologie (PTKA-WTE)
Grant Nr.: 02NUK021E
Project period: 01.10.2012 – 31.03.2016