|제목(국문)||사용후핵연료의 운송 및 저장을 위한 연료 장전 최적화 프로그램 개발|
|제목(영문)||Development of Fuel Loading Optimizer for Transportation and Storage of Spent Nuclear Fuel|
In June 2017, Kori Unit 1 was permanently shutdown, there is a growing interest in transporting and storing spent nuclear fuel. In the fourth quarter of 2018, the number of spent nuclear fuel stored in the spent fuel pool per site is about 2000 bundles at most. The purpose of this study is to develop a module that more efficiently loads nuclear fuels into all transportation and storage casks, when the entire bunch of 2000 spent nuclear fuel assemblies are loaded into transport and storage casks. ORNL and PNNL suggested that criticality, radiation dose, and maximum temperature of the cladding material could be reduced according to the loading pattern of the transportation and storage casks. EPRI developed the Cask Loader program and is currently distributing it. The Cask Loader sorts and groups the spent nuclear fuel according to the criteria selected by users. Subsequently, the fuel is sequentially selected for each group according to the number of the designated containers, and the fuels are loaded into each container. However, when fuel is selected and loaded at the cask by the above method, the later loaded containers have a smaller safety margin than the earlier loaded containers. To overcome this problem, we tried to solve the group optimization method using the simulated annealing optimization algorithm. In addition, the Ordering grouping method is the same as the Cask Loader for grouping according to the priority, but the group-by-group arrangement is sequentially arranged in each group as in the case of the half-placement test. The fuel loading optimization module is performed according to a two-step strategy consisting of first step fuel group optimization and second step loading pattern optimization for each group. In the case of the second step loading pattern, since there is no significant difference between the loading pattern derived from optimization algorithm and the empirical loading pattern, a fixed empirical loading pattern similar to that of Cask Loader was used. The first step fuel group optimization takes into account the pros and cons of Ordering grouping method and simulation annealing algorithm, allowing users to choose one based on time and optimization ratio. By using this module to simulate the loading of thousands of assemblies of fuel at a single site on transport and storage casks, group optimization is done to have a similar safety margin as a whole. This means that even if all groups of spent fuel are loaded into the transport and storage cask, the same efficiency is achieved. Therefore, it contributes to the efficient disposal and management of spent nuclear fuel.
|keyword||Optimization , Trasnportation and Storage Cask , Spent Nuclear Fuel|