In order to verify the feasibility of small heat pipe reactor,an experimental device of high temperature heat pipe bundle is designed in this study.The experimental device simulates the failure of heat pipe by pulling out the heat pipe,and simulates the core fuel rod by electric heating rod to explore the influence of heat pipe failure on heat pipe bundle,fuel rod and core matrix.It is found that the most direct impact of heat pipe failure is a sudden local temperature rise in the nearby matrix.Under the power of 4.2 kW,the average increase of matrix temperature in the vicinity of single heat pipe failure is about 70℃,and the average increase of matrix temperature in the vicinity of double heat pipe failure is about 120℃.The failure of a single heat pipe has a minor impact on the remaining normal heat pipes,with an average temperature rise of 15℃in the evaporation section of the normal heat pipes.The average temperature increase of fuel element in the vicinity of double heat pipe failure is about 66℃.The experimental data of high temperature heat pipe bundle under heat pipe failure obtained in this study can provide data support for the modeling and simulation of heat pipe reactor.