Shielding thickness evaluation for melter cell in a vitrification plant

Vitrification is the process for immobilizing the liquid high level waste generated from the reprocessing of the spent fuel from PHWR's in India. Vitirfication facility in a reprocessing plant contains Joule melter for liquefying the spent fuel. Since the Joule melter exists in the vitrification plant, it is important to check the shielding adequacy of the cell walls of the plant. This paper presents the results for estimation of dose rates outside the walls of various thicknesses of the plant, to meet the regulatory criteria. The methodology, in brief, involves estimation of the inventory of radioactivity in the melter, followed by calculation of the gamma dose rate at the given representative locations on the outer surface of the shield walls due to activity present in the melter