On The Study Of Cleaning System In Nuclear Waste Solidification Barrel

Using the manual decontamination method to clean different types of radioactive pollutants on the surface of the nuclear waste solidification barrel,which has the disadvantages of low work efficiency and unfavorable health.Combined with the above engineering background,the high-efficiency,non-secondary dry ice cleaning method is used to carry out the design of the nuclear waste solidification barrel cleaning system,and the flow field of the core component of the cleaning system is numerically simulated.The following research work was carried out:According to the nuclear waste solidification barrel structure and cleaning requirements,the overall cleaning plan and the specific structural design were determined.On the one hand,using a single-axis nozzle walking clamping device and a rotating platform to achieve the cleaning of the nuclear waste curing barrel top cover and the barrel body;On the other hand,using a two-axis linkage nozzle walking clamping device and the electromagnetic lifting device to clean the bottom of the nuclear waste curing barrel;Using FLUENT software,the gas flow field of the nozzle and the trajectory of dry ice particles were simulated by S-A gas phase model and DPM model respectively.The influence of working parameters on gas-solid two-phase flow field was obtained.The study found that the pressure is proportional to the maximum value of the Mach number,which is proportional to the distance from the nozzle exit corresponding to the maximum Mach number;As the diameter of dry ice particles increases,the better the degree of aggregation of dry ice particles,the smaller the influence of air resistance,the farther the position of dry ice particles reaches the maximum;The plate shock wave is the key to the influence of the cleaning target distance on the flow field,and the closer the plate is to the center position corresponding to the Mach disk,the larger the range of the plate shock wave;Using orthogonal test method combined with numerical simulation method to study the combination of inlet pressure,dry ice particle diameter and cleaning target distance;The optimal working parameters of the dry ice cleaning system are obtained as the inlet pressure 1MPa,the dry ice particle diameter 3mm,and the target distance 50mm;At the same time,the reliability of the simulation is illustrated by the dry ice cleaning experiment;The reasons for the difference in acceleration performance of different nozzle structures for dry ice particles were analyzed.It was decided to optimize the original nozzle from the expansion angle and nozzle length.It was found that the original nozzle outlet could be changed to 6° expansion angle and the length increased by 50 mm.The speed of dry ice pellets increased by 18.9%;Through the design and research of the nuclear waste solidification barrel dry ice cleaning system,the cleaning and decontamination efficiency of the nuclear waste solidification barrel can be improved,thereby promoting the development of the safety and environmental protection level of nuclear waste in China.