Development of the sodium pool and floor concrete module for the integrated SFR safety analysis code, SPECTRA

高速炉統合安全性評価解析コードSPECTRAのナトリウムプール・床コンクリートモジュールの開発

青柳 光裕 ; 内堀 昭寛 ; 高田 孝  

Aoyagi, Mitsuhiro; Uchibori, Akihiro; Takata, Takashi

The SPECTRA code has been developed as an integrated safety analysis tool for sodium-cooled fast reactors (SFRs). In this study, the capability of SPECTRA is enhanced by establishing a sodium pool and floor concrete module commonly used in individual physical modules. This paper describes the framework of modelling for the mass and heat transfer in the sodium pool and the floor concrete. Considering concrete ablation due to sodium and debris, bottom of the sodium pool changes during event progression. This change in material composition in certain position is modeled by volume and mass fraction of each component. A simple convection model for the pool is implemented to ensure the conservation of heat and mass. This model is tested through the verification analysis in comparison with the existing model. As the result, it is confirmed the behavior of pool spreading and concrete ablation can be simulated by this module correctly.