Investigation of dominant factors for evaluation of sodium leak and fire accident consequences by sensitivity analyses

ナトリウム漏えい火災事故評価における支配因子の感度解析と検討

大野 修司  ; 浜瀬 枝里菜 ; 上出 英樹 

Ohno, Shuji; Hamase, Erina; Kamide, Hideki

ナトリウム漏えい燃焼事故影響に関する支配因子を同定するために、多セル解析コードSPHINCSを用いて大規模2セル体系でのスプレイ・プール同時燃焼の感度解析を行った。ガス圧力上昇及びプール下の鋼板温度上昇を注目すべき評価指標とした解析の結果、重要な事象構成因子が定量的に明らかになり、解析コード妥当性確認や安全評価結果の不確かさ評価に反映できる知見を得ることができた。

Sensitivity analyses of sodium leak and fire are performed to identify the dominant factors for the accident consequences. The analyses with a multi-cell zone model code SPHINCS treat sodium spray and pool simultaneous combustion and heat-mass transfer behaviors in a large-scale two-cell geometry. Atmospheric gas pressure increase and temperature increase of floor steel plate below the sodium pool are analyzed as the figures of merit to be directly focused on. The analyses clarify the important and dominant factors of the phenomena in the accident sequence quantitatively, resulting in the acquirement of the knowledge to conduct the appropriate code validation activity and to discuss the uncertainty in the safety evaluation results.