Thermal hydraulic analysis of water cooled blanket under transient condition

Nuclear fusion is known as the most effective way in the future to solve energy problems. And blanket is the key component to achieve the function of energy transfer. In a fusion reactor, the fusion reaction produces high energy neutrons, and the blanket is designed to slow and absorb neutrons in a reliable and efficient manner. Energy absorbed from the fast neutrons is extracted and passed into the primary coolant in the blanket. Hence, the design of the blanket will strongly affect the operating power and the safety of fusion reactors. It is significant to analyze the hydraulic properties and heat transfer properties of the blanket. The object of this study is a water cooled blanket within conceptual design. In the first place, the original complicated design of the blanket is simplified reasonably. Then, RELAP5 is adopted to analyze the thermal hydraulic properties in steady state of the blanket under 100% power level. The system pressure drop along the flow and the temperatures of water, channel wall and blanket structure were discussed. After that, this study analyzed the transient response characteristics of the blanket under transient condition. The results of this study turn out that, under transient condition, the blanket of current design cannot keep safety. To ensure the normal operation of fusion reactors in the future, the current design should be improved.