Numerical investigation of high-temperature heat pipe bundle failure scenario for heat pipe cooled reactor

The heat pipe reactor is an innovative nuclear reactor technology that employs alkali-metal heat pipes to transfer heat efficiently. However, during operation, heat pipes face significant thermo-mechanical loads, which can lead to failures and reduced cooling performance. While numerous studies have conducted numerical simulations to investigate potential failure scenarios and assess the safety of heat pipe reactors, there remains a lack of validation against experimental data. This study evaluates the feasibility of using the thermal resistance network method for simulating accident scenarios based on experimental data from high-temperature heat pipe bundle failure tests. Results show that individual performance differences among heat pipes must be included in simulations; neglecting this can underestimate the maximum matrix temperature. Additionally, modeling failed heat pipes should not assume adiabatic boundary conditions but rather increase thermal resistance appropriately to preserve partial heat transfer capability. Using adiabatic conditions results in a higher maximum matrix temperature compared to applying increased thermal resistance. When the performance differences among individual heat pipes and the corresponding thermal resistance variations of failed heat pipes are taken into account, this approach yields a more accurate representation of the temperature distribution.