Raman spectra of thorium(IV) fluoride complex ions in fluoride melts

Abstract

Synthesis of Bis(tripheny1phosphine)iminium Salts. The bis(tripheny1phosphine)iminium salts were prepared by combination of 5:l molar ratios of the sodium or potassium oxocarbon salt and triphenylphosphineiminium chloride. respectively. These were dissolved separately in boiling water and combined. The product precipitated immediately upon mixing of the two solutions, and was recrystallized from CHzClz and dried under vacuum. (It was necessary in the case of the rhodizonate anion to carry out the reaction and filtration quickly to prevent oxidative decarboxylation to croconate anion.) 2[(c&5)3P]zA~+ C4042-.2Hzo. Electronic spectrum (CHzCl.2): A , , , 275 nm (6 2.8 X lo4), 268 nm (2.9 X lo4).Anal. Calcd for [(Ph3P)zX]zC404.

Investigation of ionic local structure in molten salt fast reactor LiF-ThF4-UF4 fuel by EXAFS experiments and molecular dynamics simulations

“…These results are in agreement with MD computations performed on LiF-ThF 4 structure at 1200 K [20,23,24] and high temperature Raman measurements [14,15]. These works also highlighted the existence of these three complexes and the fact that anionic species [ThF 8 ] 4-were in the majority over a composition range from 5 mol.…”

“…High Temperature Raman spectroscopy was used to describe the local structure of molten thorium fluorides [14]. For example, Toth et al showed the presence of [ThF 8 ] 4and [ThF 7 ] 3species in LiF-NaF-ThF 4 mixture [15]. More recently, Bessada et al [16] followed by Smith et al [17], developed a new set-up and a sample containment cell for measuring local structure of radioactive molten fluorides AF-ThF 4 (A + = K + , Li + ) by extended X-ray absorption fine structure (EXAFS) at the L 3 threshold of the thorium.…”

Experimental and Computational Exploration of the NaF–ThF4 Fuel System: Structure and Thermochemistry

“…Furthermore, the predominance of 8-coordinated complexes and the substantial presence of 7-coordinated complexes, as found in this work, was also observed experimentally with Raman spectroscopy in LiF–NaF–ThF 4 melts. 55 As the temperature increases, the relative fractions of 7- and lower-coordinated complexes increase. The same phenomenon was also observed during investigations on the LiF–ThF 4 system.…”

Impurities in Primary Coolant Salt of FHRs: Chemistry, Impact, and Removal Methods

“…Both Te and Sb are fission products, and if there is any Te and Sb in the primary salt of the FHR, they should be from the leakage of the failed fuel or decay of their precursors such as 132 I. Te and Sb have similar chemical properties, and their fluorides are unstable in the primary salts with respect to their elements. However, Te can exist in the salt in the form of tellurides . On the other hand, Te has a high vapor pressure at the operation temperature of FHR and MSR, and can dissolve into the salt as a dissolved gas .…”

“…However, Te can exist in the salt in the form of tellurides. [42] On the other hand, Te has a high vapor pressure at the operation temperature of FHR and MSR, and can dissolve into the salt as a dissolved gas. [43] According to MSRE, Te and Sb can heavily deposit on metal surface, which provides a method for separating Te and Sb from the salt.…”