The basis examination for the processing of the salt waste

Terunuma, Hitoshi*; Arai, Osamu*

For a purpose of glassification processing of the salt waste generated from the fused salt electrolysis method, one of the nuclear fuel reprocessing methods, a processing method to convert chloride to oxide which has an ability of high solubility to the glass was examined. Chloride, the main ingredient of the salt waste, was fused and reacted with water steam. Then the chlorine was separated as a form of hydrogen chloride. The examination was proceeded by an equipment consists of the following compositions. Water steam is generated from the moisture gas generator by the vapor pressure method. The steam is passed through the processing container where the imitation salt is fused and oxidized. Hydrogen chloride generated from the oxidation conversion of chloride is recovered in wet process by the gas scrubber. This examination was implemented under different conditions of imitation salt, processing temperature, water addition amount and presence of boron oxide addition for the stimulation of the oxidation. Volatilized salt steam switched over from the fused salt to the exhaust system, and it caused the plumbing blockade. This phenomenon exerted a big influence on the examination running. By adding boron oxide, percentage of the oxidation conversion increased from a few % to 50%. The oxide generated from processed salt by conversion could be confirmed. It showed that the addition of boron oxide is effective for oxidation conversion of chloride. However, boron oxide was added as the same amount as a commensurate mole of chloride in the imitation salt, and it causes to decline the processing quantity and to increase the amount of the waste evolution. An investigation of the optimal quantity of boron oxide addition will be a next problem to be solved in the future.