Design of nuclear fuel cells for new assemblies in BWR reactors

Preliminary results are presented for the design of nuclear fuel cells, used in the design of new fuel assemblies. To obtain these results, heuristic techniques known as neural networks and a hybrid between scattered search and trajectory re-chaining were implemented. Because the computational requirements are large, it was necessary to implement parallel computing tools to reduce response times. The objective function implemented includes the local peak power factor of the cell throughout its life, as well as the infinite neutron multiplication factor. The enrichment of ²³⁵U pills increased, beyond the usual, allowing pills with up to 5.9% enrichment. The designed cells were used to propose new fuel assemblies for BWR reactors. To test our designs, the fuel assemblies were used in an optimization process to generate the refills and the respective control bar patterns. Our results show that it is possible to increase the bank of pills available for the design of cells and design refills that comply with the security restrictions and the requested energy requirements. (Author)