Short Lived Species Produced in Pulse Irradiated Melts of LiF-KF and LiF-NaF-KF Eutectic Mixtures.

Abstract

For a long time, coloration in alkali halide melts containing the alkali metals (such as Li, Na) has received much attention in the study of the properties of excess electrons in ionic solutions(1). Today, there are evidences that the coloration is due to the formation of the solvated electron es- in the melts, whose existence is well known as a primary product of radiolysis of polar liquids such as water(2). Of more recent attention(3), alkali halide melts are a prospective stable material in molten salt nuclear reactor engineering in which melts are subjected to heavy irradiation by high energy nuclear radiation of different LET. Recently, a pulse radiolysis method has been applied to study the radiation-induced decomposition of the melts of alkali halides and their mixtures(4)(6). The proposed mechanism of decomposition has shown that ionization of halogen ion (X-) by radiation initiates the radiolysis of the melt, which is followed by the formation of a solvated electron as well as a molecular halogen ion in the melt: Among alkali halide melts, a pulse radiolytic study of fluoride systems has not been carried out yet, though they are important melts in the nuclear engineering because a fluorine atom has a small neutron absorption cross section. In our research, we attempt to observe the absorption spectrum of primary products formed in irradiated melts of fluoride systems, especially, LiF-KF and LiF-NaF-KF eutectic mixtures.