Evaluating Precise Quantity of Decommissioning Waste by Cutting Virtual 3D Models of Large Equipment

Abstract

Equipment and piping components contaminated by radioactive materials and/or containing low-level irradiated waste must be cut, segmented, and packed into waste containers. Workers need to avoid overexposure to radiation in dismantling environments, and the number of waste containers for the pieces of equipment and piping components needs to be minimized. Thus, we developed an automatic planning method for virtually cutting 3D equipment with limitations on container size, radioactivity, weight, and dose rate. Cutting sequence data was used to formulate different cutting-work procedures, generate cut objects, and calculate the exposure during disassembling work. By calculating the required cutting length and dose-rate distribution in working environments for various cutting sequences of large equipment, the developed system is expected to aid in the planning of decommissioning. To utilize systems engineering in conjunction with elemental technologies, the following problems need to be solved; both weight and volume of the waste need to be controlled so that radioactive waste for decommissioning nuclear power plants is traceable. Identifying segmented equipment from a 3D model is key to calculating the number of volumetric segmented fragments and required number of containers. To evaluate exposure and amount of waste, we developed an automatic planning method for virtually cutting 3D equipment objects given constraints. Cutting sequence data was used to formulate different cutting workflows, generate cut objects, and calculate the exposure dose from disassembling work.