Xiaoyu Zhang,Jianxing Dai,Qi Liu,Zirui Wang,Qiang Dou,Yuan Qian,Haiying Fu
NaF-BeF 2 molten salt has been proposed as one of the potential solvents and coolants for molten salt reactor due to its pertinent properties and satisfactory neutron capture cross-section. The experimental measurements combined theoretical simulations were employed to investigate comprehensive information on the structures and thermophysical properties of molten NaF-BeF 2 . Specifically, the specific heat capacity, density, and viscosity of NaF-BeF 2 systems were determined using custom devices. Using the fitting relationships and simulations, the extrapolative data were also successfully obtained under the critical temperatures. The local structure including bond lengths, coordination structures and the potential of mean force, was further simulated by ab initio molecular dynamics in the temperature range of 673–1123 K. The coordination of Na and Be is predominantly characterized by six-fold and four-fold, respectively. Moreover, of Be-F bond is 7 times than Na-F bond, which suggests the stronger stability of Be-F bond in molten NaF-BeF 2 .
A comprehensive study by integrating first principles molecular dynamic (FPMD) simulations and differential scanning calorimetry (DSC) experiments on the physicochemical properties of multiple halophilic fission products ( M F n = RbF, SrF 2 , YF 3 , and ZrF 4 ) and molten NaF-BeF 2 (FNaBe) mixed salts is reported. The effect mechanism of product type on density and specific heat capacity has been discussed from the interionic distance and its stability, coordination number and its distribution, as well as the neighbor cluster structure and its orientation. It is concluded that volume increments of molten FNaBe+ M F n are primarily caused by Na-Na and M -F interactions, while the highest specific heat capacities ( c p ) of molten FNaBe+ZrF 4 is closely related to the stability of Zr-F bonds and its coordination structures. Furthermore, the DSC results assisted by quantitative analysis of elements indicate that the additive concentration of YF 3 is positively correlated with c p of molten FNaBe+YF 3 in a certain range.
危险品化学品经营许可证（带存储）