Intermediate Level Liquid Radwaste Tank Decommissioning Technological Plan Disign

This article expounds the characteristics of large-scale ILW liquid storage tanks and the difficulties of decommission them.Combining with relevant foreign experience,design considerations and solutions to various problems,a preliminary feasible project of ILW liquid storage tank decommissioning is obtained.And suggestions for follow-up work and scientific research are provided.The overall process route for the decommissioning of the ILW liquid storage tank is mainly divided into two stages.The first stage is the engineering verification of the main technical methods and devices,mainly to explore the processing parameters and verify the processing equipment.The second stage is the implementation of decommissioning project,on the basis of the processing and equipment parameters obtained in the first stage.The implementation is mainly divided into four steps: pre-decommissioning preparation,residue pouring,slurry treatment and tank decontamination.The preparations before decommissioning are mainly the remediation of the factory,including:repairing and rectifying the infrastructure and auxiliary service systems such as water supply,air pressure,power supply and ventilation,and addingtemporary measures for using in subsequent projects;Check the system equipment,pipelines,valves,instruments,etc.for the necessary replacement and maintenance,to ensure that the flushing water and decontamination liquid can be smoothly poured out in the subsequent decommissioning stage;Set up the air account and set up the temporary exhaust system;Set up work platform and build the necessary decommissioning auxiliary facilities.The residue is mainly poured out of the waste liquid and mud remaining in the tank.The main route is to use the hydraulic jet mixing technology to suspend the tank bottom mud,and then transport it with a diaphragm pump,equipped with a power robot to pour the bottom of the tank bottom.The mud is sent to the mud filtration and drying treatment facilities for treatment,and the intermediate waste liquid is sent to the intermediate discharge waste treatment facility.Slurry treatment is mainly the treatment and disposal of the retrievable slurry.The residual slurry in the tank is poured out to the newly built ? mud filtration facility.The filtrate is returned to the tank and finally sent to the ILW treatment facility.The filtered slurry is then transported to ? mud drying facility.The dried ? waste is temporarily stored in barrel.The decontamination is decontaminated by high-pressure water,laser and dry ice.By comparing the decontamination effects,the optimal decontamination scheme is selected and applying to other large tanks.The secondary waste liquid generated by the decontamination is sent to the corresponding waste liquid treatment facility,and the gaseous waste is collected and purified and sent to the chimney fordischarge.Dismantling only dismantled the carbon steel cladding of the top,bottom and side walls of the large tank,and used multi-functional dismantling robot with different tool heads to cut and remove the inner surface of the tank,then cut into small pieces and put them into 200 L barrels,and the barrels will be temporarily stored in the repository.After that,the waste will sent to the radioactive solid waste preparation center for unified treatment and conditioning.