Design of Vacuum Evaporator for Optimization of Corrosive Liquid Radioactive Waste Treatment

Abstract

The design of a bench-scale vacuum evaporator for corrosive liquid radioactive waste treatment has been developed. The corrosive properties of liquid waste do not meet the waste acceptance criteria of the existing evaporator in the radioactive waste treatment installation of BRIN. The existing evaporator facility was designed to treat liquid waste with a neutral pH. On the other hand, there is huge potential for liquid radioactive waste to come, both have acidic and alkaline properties, which if neutralized, the volume will be even greater. This is certainly contrary to the principle of waste treatment, namely volume reduction. The method used in developing the bench-scale design of vacuum evaporator is to perform a desktop analysis by considering the value of the decontamination factor, the stage of evaporation cycle, the level of practical ability, and the safety of its operation. The vacuum evaporator method allows liquid radioactive waste to be evaporated below its boiling point value. Thus, the use of electrical energy is much more efficient than an ordinary evaporator. In addition, the vacuum system in the processing stage can confine the radionuclide concentrate in the module so that safety is better. The vacuum evaporator design developed is a compact module that consists of an evaporator tank with a capacity of 40 liters, equipped with a refrigerant compressor and heating element (jacket heating), and it is connected to a condensate tank through a venturi vacuum system and vacuum pump. The evaporation process is in batch mode with a loading capacity of 20 liters per hour and the operation is carried out through the control panel instrumentation. Other safety features are a pollution detection system, an interlock system (automatic shutdown by the temperature sensor and/or level control), an emergency stop button, indicator gauges (such as flowmeter, pressure, and temperature), and a visible alarm light.