Physical Properties Of Helium-Xenon Cooling Space Nuclear Reactor Coolant

The helium-xenon mixture can reduce the compressor and turbine levels while maintaining the heat transfer capacity,making it the preferred type of high-power space nuclear reactor.However,there are few industrial applications of helium-xenon mixture.The commonly used calculation methods have errors and lack experimental verification.Therefore,it is necessary to measure the physical properties of helium-xenon mixture。In this study,the dynamic viscosity of two kinds of helium-xenon mixture(Xe-8.64%、28.28%)was measured by dual-capillary method.RELAP5 was modified according to the obtained physical properties to model and calculate space nuclear reactor.In order to study the properties of helium-xenon mixture under space reactor conditions,a set of experimental equipment for measuring the viscosity of helium and xenon at high temperature and high pressure was designed and built based on the dual capillary method.The combined standard uncertainty of the experimental measurement is 3.7%.Argon gas was used to calibrate the experimental apparatus,and the reliability of the apparatus was verified.The viscosity of the two helium-xenon mixtures at 0.1-2.5MPa and 298.15-548.15 K was obtained.The experimental results are in good agreement with the existing literature values.In order to extend the viscosity to a higher temperature,results were fitted to obtain the model of viscosity varying with temperature and pressure.The model was extended to 1273 K.By comparing the model with the experimental and calculated values in the literature,the error is small,which verifies the reliability of the model.On the basis of the investigation results,other thermal parameters of helium-xenon mixture are given.On the basis of obtaining the properties of helium-xenon mixture,RELAP5 was modified by modifying four subroutines.The simulation data and experimental data are compared by using single tube modeling,and the error is small,which verifies the correctness of the property modification.Then,the space reactor was modeled.Considering the power distribution and cosine distribution,the temperature,pressure,flow rate of the coolant and clad temperature distribution of the space reactor were given.The analysis results show that overall temperature and pressure distribution are more consistent with the space reactor design than that without modification.Because of the low thermal conductivity of heliumxenon,the temperature of clad are higher than before modification,so the requirements for the reactor materials are higher.