Radioactive Waste Repackaging Methods Based on Genetic Algorithms and Simulation for Reactor Decommissioning

After going through the lifecycle of design, construction, and operation, nu-clear reactors need go to decommissioning phase according to requirement of nuclear regulator or need of environmental protection. Decommissioning, as the last phase of a nuclear facility's lifecycle, is characterized by its difficulty, long duration, and high cost. During the decommissioning process, various types of waste are generated, such as solid, liquid, gas waste, and mixed waste. In order to protect the surrounding environment from radioactive contamination and prevent excessive radiation exposure to workers and residents, radioactive waste needs to be processed, prepared, transported, stored, and disposed of according to standards. In response to the low space utilization of steel containers due to the irregular shapes of waste when packing decommissioned reactor components, this paper optimizes the process using genetic algorithm to determine the optimal number of cut chunks for reactor components and the best placement of cut chunks in the steel container. First, the complex three-dimensional irregular part packing problem is projected onto a two-dimensional plane for study to simplify the problem's difficulty; second, genetic algorithm is used for individual selection, crossover, and mutation to obtain the optimal layout of individuals; finally, the optimal number of cut chunks in different areas is determined based on the optimization results of individuals, and a global packing solution for all cut chunks is obtained. The results indicate that the proposed method not only provides the optimal cutting solutions for different cutting areas of reactor components and the best placement of cut chunks in the steel container but also satisfies all cutting constraints, potentially providing insights for future reactor decommissioning work