Abstract: Heat pipe reactor is a new type of reactor which uses heat pipe to cool the core. Due to the advantages of mobility, safety and universality, the megawatt-class heat pipe reactors have great competitiveness in many applications such as strategic defense locations, remote communities and space exploration programs. While the study on megawatt-class heat pipe reactor is still in the stage of concept design and thermal analysis. There are many neutronics and thermal-hydraulics behavior needed to be pointed out and discussed. In this paper, the neutron physics of the megawatt-class heat pipe reactor core was calculated on the open source Monte Carlo code OpenMC. The reactive control methods such as the control drum design were analyzed. The power distribution of the core was used as the boundary condition to analyze the steadystate thermal characteristics in the normal condition and accident conditions by means of finite element analysis software COMSOL. The neutron calculation results show that the maximum radial and axial power factors of the core are 1.325 and 1.229. The core axial power distribution presents an increase-decrease trend, and the power level in the lower part of the core is higher than that in the upper part. The power in radial direction decreases with radial distance. There is an increase of power near the radial reflection layer, where the power distribution is obviously affected by the control drum. The distributions are in good agreement with the references which use MCNP or other code. Rotation of control drums is a primary way to control the reactivity in heat pipe reactor. The result reveals that different rotation modes would have diverse reactivity changes. Using different sizes of control drum can reduce the space occupied by the core but is not reliable for reactivity control. In normal condition, the maximum temperature of core is 1 010 K and is located in the fuel rod adjacent to the inner part of core. For accident condition, the heat pipe failure in the boundary region will cause a more dangerous temperature rise in fuel and monolith. The reason for that is because the heat pipes in boundary region have fewer heat pipes adjacent to them. The temperature rise of fuel under the condition of three heat pipes failure is 3.2 times that of two heat pipes failure condition. Even if three heat pipes fail, the maximum temperature of the core is still below the melting point of the fuel rods, which indicates safety performance of heat pipe reactor. This paper also shows a potential solution to safety analysis and conceptual design of heat pipe reactor.