The INE Beamlines  (INE-Beamline and the ACT station at the CAT-ACT Beamline) at the KIT-synchrotron are dedicated to actinide research with X-ray spectroscopic techniques. Both are operated by the Institute for Nuclear Waste Disposal (INE).

Schematic sketch visualizing some of the actinide mobilization / retention processes possibly following actinide release from corroded HAW.

Research and development at INE are largely aimed at long term safety assessment of proposed deep geological repositories for high-level, heat producing nuclear waste (HAW) disposal. To ensure sound safety assessment, a molecular understanding of processes determinant in the fate of radionuclides, notably the actinides, and thermodynamic quantification is essential. Of central importance in such investigations is determination of actinide speciation (i.e., their chemical and physical form). X-ray spectroscopic methods have proved to be valuable tools for actinide speciation research. Investigations on non-fissile radioisotopes up to 106 times the legal exemption limit and fissile radioisotopes (Pu-239, U-235) up to 200mg, contained within two layers of protection, are possible. The synchrotron-based activities at the INE-Beamline are embedded in INE’s in-house research, thereby allowing a combination of analytical and instrumental methods, notably laser techniques and microscopic methods.

In situ X-ray spectroscopic investigations on radioactive samples are routinely performed at the INE Beamlines for studying, e.g., actinide containing solid-water interface chemical reactions, not possible at other facilities. A special protocol for working with radioactive samples at both INE beamlines exists and is supervised by INE’s own radiation protection officers. The unique aspect of the INE Beamlines is its close proximity to INE’s active laboratories on-site KIT north campus. The design is for a multi-purpose beamline, where a number of methods are possible on one and the same sample.

Layout of the CAT-ACT facility with optic hutch adjacent to the storage ring wall, two in-line experimental stations and separate control cabin in the ANKA east hall extension.

Schematic beam path (not to scale) from the source (left) to the experiments (right)

CAT-ACT optical components designed and manufactured by FMB Oxford (Oxford, United Kingdom). From right to left: frontend components (intensity absorber, X-ray beam position monitor, white beam slit), collimating mirror, double crystal monochromator, diagnostics module, toroidal focusing mirror, beam shutter separating ACT hutch from optics section. Inset: focusing mirror coating scheme.

Detectors

Sample holder (HUBER stage, combined with HRXES spectrometer):

                   
                   Experimental setup for XAFS and XES measurements at the ACT station. The photo shows the high energy detection setup without He containment.

Sample environment

• Standard holder for transmission and fluorescence measurements of radioactive and non-radioactive samples, e.g., 400 µl and 2 ml PE-tubes, pellets.

• Liquid sample cell for the investigation of redox labile systems under electrochemically controlled conditions

• Environment: atmosphere, inert gas (existing supplies: He, N₂, Ar)

Further detailed information is available in:

Zimina, A.; Dardenne, K.; Denecke, M. A.; Doronkin, D. E.; Huttel, E.; Lichtenberg, H.; Mangold, S.; Pruessmann, T.; Rothe, J.; Spangenberg, Th.; Steininger, R.; Vitova, T.; Geckeis, H.; Grunwaldt, J.-D.; CAT-ACT—A new highly versatile x-ray spectroscopy beamline for catalysis and radionuclide science at the KIT synchrotron light facility ANKA, Review of Scientific Instruments 2017, 88, 113113.

doi:10.1063/1.4999928