熱流動CFD技術の進展; 研究機関におけるCFD技術の進展; 機構論的CFD技術の現状と今後の展開

Progress of CFD in nuclear thermal hydraulics; Progress of CFD in research institute; Current status and future development of mechanistic simulation

山下 晋   

Yamashita, Susumu

原子力熱流動分野において数値流体力学(CFD)技術は、原子炉の最適設計、事故進展時における炉心および格納容器内の熱流動場予測など多方面で活用されている。本報告では、原子力機構が開発している機構論的CFD技術を、過酷事故時の溶融物の機構論的挙動予測、定常運転時の燃料集合体内部における気泡流挙動の機構論的予測といった原子炉熱流動現象に適用した事例について紹介する。事例紹介を通じて、機構論的CFD技術の現状とそれを原子炉熱流動現象に適用する際の課題と今後の展開について述べる。

Computational Fluid Dynamics (CFD) technology is used in many fields in the nuclear thermal hydraulics, including optimal reactor design and prediction of thermal hydraulic behavior in the reactor core and containment vessel during accident progression. In this article, the author will present examples of the application of mechanistic CFD technology developed by JAEA to reactor thermal hydraulics phenomena, such as the prediction of melt behavior during severe accidents and the prediction of bubble flow behavior inside a fuel assembly during steady-state operation. Through case studies, the current state of mechanistic CFD technology and its application to thermal-hydraulic phenomena in nuclear reactors are described, as well as problems and future prospects.