The pebble bed high temperature gas-cooled reactor is a promising generation-IV reactor, which uses large fuel pebbles and helium gas as coolant. The pebble bed flow is a fundamental issue for both academic investigation and engineering application, e.g., reactor core design and safety analysis. This work performed a review of recent progress on pebble flow study, focusing on the important issues like pebble flow, gas phase hydrodynamics, and inter-phase heat transfer (thermal hydraulics). Our group’s researches on pebble flow have also been reviewed through the aspects of phenomenological observation and measurement, voidage distribution, geometric and parameter optimization, pebble flow mechanisms, flow regime categorization, and fundamentals of modelings of pebble flow and radiation. Finally, the major problems or possible directions of research are concluded which would be some of our focuses on the pebble bed flow study.

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A review of pebble flow study for pebble bed high temperature gas-cooled reactor

Experimental simulation study on start-up of the 5 MW nuclear heating reactor

Review of the nuclear reactor thermal hydraulic research in ocean motions

Analysis of fuel element matrix graphite corrosion in HTR-PM for normal operating conditions

The goal of the present study is to demonstrate that direct numerical simulations (DNS) coupled with interface tracking methods can be used to estimate interfacial forces in two-phase flows. Curren...

Estimation of Shear-Induced Lift Force in Laminar and Turbulent Flows

Numerical investigation on lateral migration and lift force of single bubble in simple shear flow in low viscosity fluid using volume of fluid method

Falling films are used as a safety measure in the safety systems of current advanced pressurized water reactor(PWR) nuclear power plant(e.g.,the AP1000).Falling films are also widely used in various industrial devices and technological processes.The flow instability in falling films,one of its significant features,was studied by shadowgraphy at different inclination angles to explore the relationship between inclination angle β and other parameters,as well as the effects on the film instabilities.The experimental results indicate that the inclination angle has a stronger influence on the falling flow instability than the Reynolds number;wave coalescence and wave interference play important roles in falling film instabilities.The results also show that different wave patterns occur in different regions with Re having a strong effect on the pattern.

Experimental study of flow instabilities of falling films

The HTR-10 built at Tsinghua University is an advanced pebble bed reactor because of its inherent safety and economic efficiency. It is fundamental to explore the voidage of the pebble bed. The existing experimental bed is limited in depth and contains mono-size pebbles. The effects of pebble size and bed dimension of voidage distribution are still not well known. In this work, the discrete element method is used to simulate the static packing of pebbles of three sizes in 2D and 3D pebble beds under the same load. The effects of bed dimension and pebble size on voidage distribution are analyzed. The results are useful for better understanding of the voidage distribution of pebble bed reactor and the effects of bed dimension and particle size as well as the wall effects.

https://journals.sagepub.com/doi/pdf/10.1177/1757482X17716046

Effect of pebble size and bed dimension on the distribution of voidages in pebble bed reactor

Cognitive model research of nuclear power plant operators

The low temperature nuclear heating reactor(NHR),developed by Institute of Nuclear and New Energy Technology of Tsinghua University,is highly safe because of its natural circulation at full power level.The driving force of natural circulation is very low,so the flow rate is highly affected by the resistance of the reactor coolant loop.As a result,reducing the flow resistance is a key technology of NHR design.A experiment equipment,which simulated the natural circulation of the reactor coolant loop,was constructed to validate the design.The pressure drop was measured by differential pressure transmitters.The temperature difference of the water in different impulse tubes introduced density difference,which led to large measurement error.Considering the high precision of IAPWS-97,an ActiveX control was developed based on IAPWS-97 to calculate the density of water at deferent pressures and temperatures.The control was used in the data acquisition system based on configuration software platform and the online correction of differential pressure measurement was realized.The testing data analysis shows that the precision of the corrected differential pressure measurement results is highly improved.

Jiang Shengyao

Papers

Numerical investigation on lateral migration and lift force of single bubble in simple shear flow in low viscosity fluid using volume of fluid method

Experimental study of flow instabilities of falling films

Effect of pebble size and bed dimension on the distribution of voidages in pebble bed reactor

Cognitive model research of nuclear power plant operators

Natural Circulation Differential Pressure Measurement Correction Technology Based on IAPWS-IF97