Development of detailed temperature analysis model for a scale model of HTGR vessel cooling system

Teramachi, Yuhei*; Sawa, Kazuhiro*; Ishitsuka, Etsuo   ; Ho, H. Q.   

The reactor vessel cooling system is a static cooling system that removes decay heat from the core by convection and radiation heat transfer without using dynamic components and it is one of the safety systems that constitute the inherent safety features of High-Temperature Gas-cooled Reactor (HTGR). However, the natural convection of the gas may cause hot spots on important structures such as the pressure vessel during the cooling using this system. For this reason, a three-dimensional numerical model simulating the 1/6 scale model of HTGR vessel cooling system was developed and numerically analyzed.