大型放射光施設 SPring-8

Speaker: Dr. Myrtille O.J.Y. Hunault

Language: English

Affiliation: Synchrotron SOLEIL

Title: MARS beamline: a unique facility for the characterization of highly radioactive samples from the nuclear fuel cycle

Abstract:
The MARS beamline ^[1] at the SOLEIL synchrotron source belongs to the exclusive club of the few synchrotron beamlines dedicated to the investigation of highly radioactive materials using hard X-rays in the 3-35 keV energy range. Two experimental end-stations are available: i) a 4-circle high-resolution diffractometer (allowing powder diffraction, surface analyses with combined texture and residual-stress analysis, reflectometry and reciprocal space mapping), and ii) a multimodal end-station for X-ray absorption spectroscopy techniques (XANES, EXAFS) as well as diffraction and scattering measurements (XRD and SAXS/WAXS) using a Pilatus 2M detector. Furthermore, a x-ray emission spectrometer enclosed in a He-filled chamber allows per-forming XES and RIXS measurements and the investigation of the low energy edges of actinides (M-edges) and other fission products with high energy resolution. ^[2] These techniques can be combined with imaging techniques based on X-ray microbeam raster scanning techniques or tomography reconstruction protocols.
Both end-stations are equipped with specific shieldings to allow studying highly radioactive samples. Today, MARS is allowed to receive samples with radioisotope activities up to 2 Million times their isotope specific Euro-pean exemption limits, and complies with all legal requirements and safety precautions to avoid contaminating aerosol dissemination and guarantee the public dose rate outside the beamline.
Thus the safety conditions offered on MARS allows using synchrotron techniques to directly characterize of the chemistry and microstructure of massive spent nuclear fuel ^[3] and high-level waste-glass samples. The applications of MARS beamline in the field of the nuclear fuel cycle are illustrated by selected highlights from recent or ongoing research.

References:
[1] B. Sitaud, et al., Journal of Nuclear Materials (2012) 425 (1-3), 238–243.
[2] I. Llorens, et al. Radiochimica Acta (2014) 102 (11), 957–972.
[3] Klosek, V. et al. Journal of Nuclear Materials (2023) 586, 154660