Safety demonstration test (S1C-2/S2C-1) plan using the HTTR (Contract research)

Sakaba, Nariaki ; Nakagawa, Shigeaki  ; Takada, Eiji*; Tachibana, Yukio ; Saito, Kenji ; Furusawa, Takayuki ; Takamatsu, Kuniyoshi  ; Tochio, Daisuke ; Iyoku, Tatsuo

Safety demonstration tests using HTTR are now underway in order to verify the inherent safety features and to improve the safety design and evaluation technologies for HTGRs, as well as to contribute to research and development for the VHTR, which is one of the Generation IV reactors. The first phase of the safety demonstration tests includes reactivity insertion tests by means of control-rod withdrawal and coolant flow reduction tests by tripping the gas circulators. In the second phase, accident simulation tests will be conducted. This paper describes the plan of coolant flow reduction tests by tripping of gas circulators planned in August 2003 with detailed test method, procedure and results of pre-test analysis. The analysis results of the steady state and transient behaviours of the reactor and the plant of the HTTR show that in the case of a rapid decrease of the coolant flow rate, the negative reactivity feedback effect of the core brings the reactor power safely to certain stable level without a reactor scram, and that the temperature transient of the reactor core is slow.