Contact
Prof. Dr. Nina Maria Huittinen
Head Solid State Chemistry of Radionuclides
n.huittinen
hzdr.de
Phone: +49 351 260 2148
Solid State Chemistry of Radionuclides Department
Research
As the name implies, the Solid State Chemistry of Radionuclides department focuses on research related to the structure and properties of solid phases containing radioactive elements. We are especially interested in crystalline inorganic solid phases such as zircon (ZrSiO4), zirconia (ZrO2), and pyrochlore (Ln2Zr2O7), as well as lanthanide (Ln-)orthophosphates of the monazite type (LnPO4). These solid phases are of relevance in the corrosion of the Zircaloy cladding surrounding spent nuclear fuels rods, or they are envisioned as ceramic hosts for the immobilization and safe disposal of specific actinide-bearing waste streams generated in the late stages of the nuclear fuel cycle. We produce polycrystalline powders or single crystals doped with actinide elements using hydrothermal, flux growth, and solid-state synthesis routes. Combining X-ray diffraction and various microscopic and spectroscopic techniques, we explore the microstructure, redox chemistry, and local structural order/disorder phenomena in the doped solid phases. With this, we aim to develop a detailed understanding of actinide immobilization in crystalline matrices on an atomic basis and to make reliable statements with regard to the performance of the host materials under repository conditions.
Latest Publication
Relationship between Mineralogically Complex Iron (Oxyhydr)oxides and Plutonium Sorption and Reduction: A High-Energy Resolution X‑ray Absorption Spectroscopy Perspective
Vejar, M. R.; Zengotita, F. E.; Weiß, S.; Shams Aldin Azzam, S.; Huittinen, N. M.; Beutner, S.; Bazarkina, E.; Amidani, L.; Kvashnina, K.; Hixon, A. E.
Abstract
o facilitate the continued use of commercial nuclear power and
address environmental contamination, it is essential to understand the fate and
transport of plutonium (Pu) in (sub)surface environments. Current geochemical
models do not account for complexity in mineral assemblages, such as metal
substitution or the role of nanoscale crystallite sizes. In this work, we studied
mineralogically complex systems where Pu(V) was the sorbate and Al-substituted
or nanoscale iron (oxyhydr)oxides were the sorbents. Using M4-edge and L3-edge
high-energy resolution fluorescence detection X-ray absorption near-edge structure
(HERFD-XANES) spectroscopy, we probed the electronic configuration of Pu,
quantified the extent of Pu surface-mediated reduction, and explored Pu speciation.
Our results indicate that nanoscale iron oxides exert a greater degree of control
over the redox behavior of Pu than Al-substituted iron (oxyhydr)oxides under
circumneutral pH and oxic conditions. This is due to the dependence of Pu surface-mediated reduction on an initial sorption step,
which is greater with the increased specific surface area and reactivity of nanoscale crystallites.
Keywords: plutonium; redox; iron (oxyhydr)oxide minerals; HERFD-XANES; sorption
Involved research facilities
- Rossendorf Beamline at ESRF DOI: 10.1107/S1600577520014265
Related publications
- DOI: 10.1107/S1600577520014265 is cited by this (Id 41430) publication
-
ACS ES&T Engineering 59(2025)23, 11756-11766
DOI: 10.1021/acs.est.4c13899
Permalink: https://www.hzdr.de/publications/Publ-41430
Latest publication
Relationship between Mineralogically Complex Iron (Oxyhydr)oxides and Plutonium Sorption and Reduction: A High-Energy Resolution X‑ray Absorption Spectroscopy Perspective
Vejar, M. R.; Zengotita, F. E.; Weiß, S.; Shams Aldin Azzam, S.; Huittinen, N. M.; Beutner, S.; Bazarkina, E.; Amidani, L.; Kvashnina, K.; Hixon, A. E.
Abstract
o facilitate the continued use of commercial nuclear power and
address environmental contamination, it is essential to understand the fate and
transport of plutonium (Pu) in (sub)surface environments. Current geochemical
models do not account for complexity in mineral assemblages, such as metal
substitution or the role of nanoscale crystallite sizes. In this work, we studied
mineralogically complex systems where Pu(V) was the sorbate and Al-substituted
or nanoscale iron (oxyhydr)oxides were the sorbents. Using M4-edge and L3-edge
high-energy resolution fluorescence detection X-ray absorption near-edge structure
(HERFD-XANES) spectroscopy, we probed the electronic configuration of Pu,
quantified the extent of Pu surface-mediated reduction, and explored Pu speciation.
Our results indicate that nanoscale iron oxides exert a greater degree of control
over the redox behavior of Pu than Al-substituted iron (oxyhydr)oxides under
circumneutral pH and oxic conditions. This is due to the dependence of Pu surface-mediated reduction on an initial sorption step,
which is greater with the increased specific surface area and reactivity of nanoscale crystallites.
Keywords: plutonium; redox; iron (oxyhydr)oxide minerals; HERFD-XANES; sorption
Involved research facilities
- Rossendorf Beamline at ESRF DOI: 10.1107/S1600577520014265
Related publications
- DOI: 10.1107/S1600577520014265 is cited by this (Id 41430) publication
-
ACS ES&T Engineering 59(2025)23, 11756-11766
DOI: 10.1021/acs.est.4c13899
Permalink: https://www.hzdr.de/publications/Publ-41430
