Actinide immobilisation by incorporation into solid phasEs relevant for final disposal

  AcE Copyright: © AcE

One of the central tasks of nuclear waste disposal is the immobilisation of actinides (U, Th, etc.) from spent fuel elements. Among others, phosphate ceramics with monazite-type structure are well-suited for immobilisation: They are able to incorporate large amounts of actinides at regular sites of their crystal structures and to bind them there permanently. Natural monazite, with an age of up to 3.2 billion years, contains up to 27 weight-percent by UO2 and ThO2, without showing any significant radiation damage. For this and other reasons, ceramic monazite phases are potential candidates for future disposal strategies.

  Monazite Copyright: © IfK Schematic drawing of a monazite-type unit cell viewed parallel to [010].

[Incorporation of trivalent actinides into the monazite-type structure was investigated in the previous project "Conditioning“.]

We are responsible for part "B" of the BMBF- funded joint project “AcE”.

The aim of the project “AcE” is to understand the incorporation and immobilisation of tetravalent actinides (An) in crystalline solid phases relevant to final disposal (including monazite, pyrochlore, uraninite / zirconia, zircone) at the atomic level. For this purpose, complementary experiments and calculations are carried out to study the average and the local structure of the matrix-material, as well as the direct environment of the incorporated An-species (or their surrogates) on an atomic scale.

 

Team:

PD Dr. Lars Peters (Project Manager)
Theresa Lender, M. Sc. (PhD)

Publications:

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.

H. Loesch, A. Hirsch, J. Holthausen, L. Peters, B. Xiao, S. Neumeier, M. Schmidt, N. Huittinen: A Spectroscopic Investigation of Eu3+ Incorporation in LnPO4 (Ln = Tb, Gd1-xLux, X = 0.3, 0.5, 0.7, 1) Ceramics. Frontiers in Chemistry 7 (2019) Seiten/Artikel-Nr: 94. DOI: 10.3389/fchem.2019.00094.

Antje Hirsch: Monazite solid solutions - characterisation of structural, thermal and physical properties. PhD thesis RWTH Aachen, 2018, xviii + 169 Seiten.

  BMBF Copyright: © BMBF

Funding:

Bundesministerium für Bildung und Forschung, Projektträger Karlsruher Institut für Technologie (KIT)
Title of the project: Fundamental investigations of Actinide immobilisation by incorporation into solid phasEs relevant for final disposal
Grant Nr.: 02NUK060B
Project period: 01.01.2021 - 31.12.2023