Mixing Enthalpy and Structure of the Molten NaCl-DyCl<sub>3</sub> System

Abstract

Mixing enthalpy(Hmix)at1100K was measured in the mo｝ten NaC1-1)yCl3system by calorimetry．The interaction parameter(入l Hmix＝一入301エ2)of this system is given in kJ mo1-1by 入二48．74コ〔23-20．90コ 22-62．92エ2十56，44 whereκ1andエ2are mole fractionsofNaCI and DyC13，respectively，Isothermal molecular dynamics(MD)simulations ofthe molten DyC13and NaC1-DyCI3systems were carried out to calculate the mixing enthalpy，and then the structure in these systems were investigated，In the simulated systems the coordination number ofC1-ions around Dy3＋ ion is6，and Dy2C11115-and Dy3C1167-were observed as well as DyC163一，Although most of these polymers shαre apex C1-ions，an edge sh＆ring polymers were fbund around コ 2ニ0。4，Experimental mixing enthalpy is discussed in terms of polymers in the SimUlated SyStemS． 11NTRODUCTION Spent metallic fuels in fast nuclear reactors contain significant amount of fission lanthanide elements、ln the Integral Fast Reactor(IFR) program1)proposed by Argonne National Laboratory in the United States，fission lanthanide elements as well as other elements are transferred into a molten salt(an eutectic mixture ofLiCI and KCl)by anodic dissolution：a spent metallic fuel is an anode．Depending on standard decomposition potentials，some elements among elements transferred from the anode to the melt may be recovered by electrolysis。As well known，a decomposition po． tentia1(E)isdeterminedby the Nemstequation，