Abstract: The report performs the preliminary transient analyses of principal designbasis accidents for HTR-Module test reactor of thermal power 10 MW. Theaccidents concerned can be grouped into four categories: depressurization, loss ofmain heat sink, rupture of one steam generator tube and reactivity insertion. The results of the transient analyses show that the reactor is possessed ofinherent accident safety. The reactor afterheat under conditions of depressuriza-tion and loss of main heat sink would be removed away through mechanism ofpassive heat transfer by conduction, radiation and natural convection. If theaccidents of reactivity insertion or ATWS occur, the reactor can automaticallyshutdown due to the negative reactivity temperature coefficient of the reactor.The maximal fuel element temperatures for all accidents involved do not exceed970℃ that is far below HTR's fuel temperature limit.