Study on Thermal Hydraulic Characteristics of Rod-Type Fuel Irradiation Test Section

Irradiation test is the crucial segments to develop new type of nuclear fuel. In order to guide the irradiation test of rod-type fuel from the perspective of design and operation, the thermal hydraulic characteristics of the irradiation device test section were numerically simulated. In this paper, the simulated results are compared with the hydraulic test data to verify the reliability of the numerical simulation method. The thermal hydraulic characteristics of the test section under different linear heat rates (LHR) of fuel and mass flow rates of coolant were analyzed. It was verified whether the temperature, mass flow rate and other parameters met the design requirements and irradiation test criteria. The results show that the numerical simulation method has certain reliability. The LHR that makes the temperature of fuel test rod meet the criteria is 47.9–71.8 kW/m. Due to the outside narrow channel has less shunting, the flow channel design of fuel section is reasonable. When the average LHR of fuel is 60 kW/m, the temperature of the fuel test rod at different mass flow rates can meet the irradiation test criteria and leave a safety margin. The pressure drop of test section is mainly concentrated in the resistance section and fuel section. With the decrease of mass flow rate, the proportion of pressure drop in resistance section significantly increases, and the shunt ratio of outside narrow channel decreases. In summary, the irradiation test is reasonably designed to achieve the expected irradiation goals.