Investigation of neutronic characteristics of a partially damaged reactor model

Nguyen, H. H.

In this study, a model of a partially damaged reactor, that simulates a possible scenario of a nuclear accident, was proposed. In this model, the fuel assemblies at the core center have melted into fuel debris of various shapes, while the fuel assemblies at the core edge remain unaffected. The effects of various parameters, including debris shape, the volume of debris, and the moderator-to-debris volume ratio, on the neutronic characteristics of the system were investigated using the Serpent 2 code and the JENDL-5 nuclear data library. The results indicated that for a small moderator-to-debris volume ratio, the neutronic characteristics of the system were divided into two groups according to the shape of the fuel debris. However, when this ratio became large, the difference between these two groups became insignificant.