Halides of the Actinides and Fission Products Relevant for Molten Salt Reactors

Thermodynamic Description of the ACl-ThCl4 (A = Li, Na, K) Systems

“…Using an adiabatic calorimeter, Chiotti et al [35] measured an enthalpy of transition equal to (5.0˘1.5) kJ¨mol´1 at (679˘2) K. Taking the heat capacity of ThCl 4 -α (the low-temperature phase) to be equal to that recommended for ThCl 4 -β (the high-temperature phase), the standard enthalpy of formation and standard entropy of ThCl 4 -α were optimised in this work, such that the transition between both phases matched the values reported by Chiotti et al [35]. The enthalpy of fusion (61.5˘5.0) kJ¨mol´1, melting temperature (T = 1042 K), and heat capacity recommended by Capelli and Konings [34] were used to describe ThCl 4 (l). The thermodynamic functions of the intermediate compounds were optimised in this work to match the experimentally determined phase diagrams as closely as possible.…”

“…Considering the average of the four studies, van Oudenaren et al recommend (68˘1) kJ¨mol´1 in the 1074 to 2500 K range. In the case of ThCl 4 (cr,l), the data used were recommended by Fuger et al [5] and Capelli and Konings [34]. As mentioned in the introduction, ThCl 4 crystallises in two phases.…”

Synthesis, Covalency Sequence, and Crystal Features of Pentagonal Uranyl Acylpyrazolone Complexes along with DFT Calculation and Hirshfeld Analysis

“…1 H NMR spectra of all representative uranyl complexes were recorded in DMSOd 6 , and the spectra of their phenyl and methyl protons exhibit sharp lines because uranyl ions have a slower relaxation time than other ions. 37 In all complexes, one multiplet for the OCH 2 group and a triplet for CH 3 2.503 ppm. In all of the complexes, there are several multiplets that correlate to aromatic protons in the 6.8−8.6 ppm range.…”

“…The application of actinides in the fields of nuclear weapons, defense operations, and energy production has been increasing in the last few decades. − As a part of their application in the nuclear fuel cycle and weapon synthesis, uranium and plutonium speciation is necessary to understand their migration methods . Uranium and Thorium are the most important of the many elements of the actinide series as enduring elements to understand their properties by building complexes.…”

A Promising Fuel for Fast Neutron Spectrum Molten Salt Reactor Nacl-Thcl4-Pucl3

“…In this work, the thermodynamic data for NaCl(cr,l) were taken from the IVTAN database [24] with an exception for the heat capacity of the liquid phase, which was recently revised by van Oudenaren et al [25]. The ThCl 4 (cr,l) functions were taken from the recommendations by Rand et al [26] and by Capelli and Konings [27]. The occurrence of a polymorphic transition between an 𝛼-ThCl 4 , lowtemperature metastable tetragonal phase (space group I4 1 /a), and a high temperature form 𝛽-ThCl 4 (tetragonal, space group I4 1 /amd) was observed by Chiotti et al at 679 K [27,28].…”