[en] The reprocessing of Th-based spent fuel will generate high level radioactive liquid waste (HLW) containing Th as one of the main constituents. Borosilicate glass matrix which is generally adopted for the immobilization of HLW will be used for the immobilization of Th containing HLW. Because of the various problems associated with conventional glass melting in the multi-zone induction heating systems, steps are now being taken to switch over to advanced technologies like Joule heated ceramic melter (JHCM) and cold crucible melter (CCM) for the vitrification HLW, which will facilitate higher waste loading at higher temperature. One of the parameters to be used with these melters is glass resistivity, which dictates the power supply parameters like voltage and current etc. To optimize the process parameter the conductivity data of the molten glass as a function of composition is required. In the absence of the conductivity of the glass melt, the knowledge of the ionic conductivity below melting point, as a function of composition, will provide an insight for the development of suitable process parameter. The conductivity data will also be helpful to understand the ion transport mechanism in the glass matrix. In addition, the electrical conductivity measurement will allow determining the diffusion coefficient of alkali ions in the glass. Barium borosilicate (BBS) glass has been explored to incorporate thoria containing waste and it has been shown that 5 mol% of ThO₂ can be incorporated in BBS without any phase separation. In the present paper the electrical behavior of barium borosilicate glasses with varying concentrations of ThO₂, has been studied