The Treatment of Low-Level Radioactive Wastewater by the Nuclear Weapons Using Ultrasonic Standing Wave Methods

The radiation hazards of radionuclide arising from the storage of nuclear weapons can not be ignored to the operators. Ultrasonic standing wave methods can be considered as the green cleaning separation techniques with high efficiency, and it allows the elimination of many chemical flocculants to reduce radioactive contamination. The application of ultrasonic standing wave methods for liquid radioactive wastes treatment requires solving many problems connected with the proper selection of the frequency and power of ultrasonic transducers, and the processing time, etc. Based on the model of one single suspended radioactive particle subjected to in the field of ultrasonic standing wave, the principle of the treatment of low-level radioactive wastewater by ultrasound was analyzed. The mathematic equation representing the change of the number of the suspended particles was built and calculated. The theoretical results show that under the action of ultrasonic standing wave, the particle will move toward the wave node plane, and the time of particle reaching the plane become shorter when the radius particle and the frequency and power of ultrasound was enlarged. The experimental apparatus for liquid low-level radioactive wastes treatment was designed according to the results of theoretical analysis. The experimental results show that the radioactive concentration of wastewater could be reduced from 400Bq · L⁻¹ to 9.3Bq · L⁻¹ and the decontamination efficiency was 97.68%. The decontamination efficiency could not be obviously improved by further increasing the treating time.