Smith Anna L, Verleg Malte N, Vlieland John, de Haas Dick, Ocadiz-Flores Jaen A, Martin Philippe, Rothe Jörg, Dardenne Kathy, Salanne Mathieu, Gheribi Aimen E, Capelli Elisa, van Eijck Lambert, Konings Rudy J M
Delft University of Technology, Faculty of Applied Sciences, Radiation Science and Technology Department, Mekelweg 15, 2629 JB Delft, The Netherlands.
CEA, Nuclear Energy Division, Research Department on Mining and Fuel Recycling Processes, SFMA, LCC, F-30207 Bagnols-sur-Céze, France.
J Synchrotron Radiat. 2019 Jan 1;26(Pt 1):124-136. doi: 10.1107/S160057751801648X.
The development at the Delft University of Technology (TU Delft, The Netherlands) of an experimental set-up dedicated to high-temperature in situ EXAFS measurements of radioactive, air-sensitive and corrosive fluoride salts is reported. A detailed description of the sample containment cell, of the furnace design, and of the measurement geometry allowing simultaneous transmission and fluorescence measurements is given herein. The performance of the equipment is tested with the room-temperature measurement of thorium tetrafluoride, and the Th-F and Th-Th bond distances obtained by fitting of the EXAFS data are compared with the ones extracted from a refinement of neutron diffraction data collected at the PEARL beamline at TU Delft. The adequacy of the sample confinement is checked with a mapping of the thorium concentration profile of molten salt material. Finally, a few selected salt mixtures (LiF:ThF) = (0.9:0.1), (0.75:0.25), (0.5:0.5) and (NaF:ThF) = (0.67:0.33), (0.5:0.5) are measured in the molten state. Qualitative trends along the series are discussed, and the experimental data for the (LiF:ThF) = (0.5:0.5) composition are compared with the EXAFS spectrum generated from molecular dynamics simulations.
据报道，荷兰代尔夫特理工大学（TU Delft）开发了一种实验装置，用于对放射性、对空气敏感且具有腐蚀性的氟化物盐进行高温原位扩展X射线吸收精细结构（EXAFS）测量。本文详细描述了样品容纳池、炉体设计以及允许同时进行透射和荧光测量的测量几何结构。该设备的性能通过在室温下对四氟化钍的测量进行测试，并将通过拟合EXAFS数据获得的Th-F和Th-Th键距与从在代尔夫特理工大学PEARL光束线收集的中子衍射数据精修中提取的键距进行比较。通过绘制熔盐材料的钍浓度分布来检查样品限制的充分性。最后，对几种选定的盐混合物（LiF:ThF）=（0.9:0.1）、（0.75:0.25）、（0.5:0.5）和（NaF:ThF）=（0.67:0.33）、（0.5:0.5）在熔融状态下进行测量。讨论了该系列的定性趋势，并将（LiF:ThF）=（0.5:0.5）组成的实验数据与分子动力学模拟生成的EXAFS光谱进行了比较。
