A parametric study of graphite dust deposition on high-temperature gas-cooled reactor (HTGR) steam generator tube bundles

2019 ◽  
Vol 123 ◽  
pp. 135-144 ◽  
Author(s):  
Mingzhe Wei ◽  
Yiyang Zhang ◽  
Xinxin Wu ◽  
Libin Sun
Keyword(s):  
High Temperature ◽  
Steam Generator ◽  
Parametric Study ◽  
Dust Deposition ◽  
Steam Generator Tube ◽  
Tube Bundles ◽  
High Temperature Gas

A Numerical Analysis on Graphite Dust Deposition and Resuspension in HTR-10 Steam Generator

2014 ◽  
Author(s):  
Wei Peng ◽  
Tian-qi Zhang ◽  
Ya-nan Zhen ◽  
Su-yuan Yu
Keyword(s):  
High Temperature ◽  
Steam Generator ◽  
Load Capacity ◽  
Fission Products ◽  
Dust Deposition ◽  
Preliminary Calculation ◽  
Transfer Tube ◽  
High Load Capacity ◽  
Fuel Elements ◽  
High Temperature Gas

The behavior of graphite dust is important to the safety analysis of High-Temperature Gas-cooled Reactor (HTGR). The fission products released by fuel elements would enter the primary loop and combine with dust, resulting in that the dust has a high load capacity of cesium, strontium, iodine and tritium. It would bring difficulty and inconvenience to the maintenance and repair of steam generator. Therefore, the behavior of graphite dust in the steam generator is essential to the safety of High Temperature Gas-cooled Reactors. The present study focused on the deposition and resuspension of graphite dust in steam generator of HTR by numerical method. The results show that the graphite dust in steam generator deposits on the surface of heat transfer tube through turbulent deposition, thermophoretic deposition, and other depositional mechanisms, of which thermophoretic deposition is the main mechanism for the particles with the diameter of 2.2μm in the present study. The preliminary calculation result shows that about 6760mg/m2 of graphite dust tends to load on the tube surface.

A Numerical Study on Graphite Dust Deposition on Steam Generator Tubes in the High-Temperature Gas-Cooled Reactor (HTGR)

2018 ◽  
Author(s):  
Mingzhe Wei ◽  
Yiyang Zhang ◽  
Zhu Fang ◽  
Xinxin Wu ◽  
Libin Sun
Keyword(s):  
High Temperature ◽  
Steam Generator ◽  
Deposition Rate ◽  
Numerical Study ◽  
Fem Simulation ◽  
Dust Deposition ◽  
Lagrangian Simulation ◽  
Large Particles ◽  
Steam Generator Tubes ◽  
High Temperature Gas

Graphite dust is an important issue for the operation and maintenance of high-temperature gas-cooled reactor (HTGR), because the transport of fission product (FP) is coupled closely with graphite dusts. For instance, vapor phase FP could condense as flowing through the steam generator (SG) and deposit on the surface of graphite dusts that are either air-borne or already deposited on SG tubes. In water ingress or loss-of-coolant accidents, these dusts may re-suspend and contribute to the source term. Despite the importance of graphite dusts in HTGRs, the transport and deposition of dust particle are far from being fully understood, neither particle-fluid nor particle-wall interactions. In this work we present a numerical study on the particle transport through upper 5 layers of SG tubes. Particularly, the particle impaction process is simulated by Finite Element Method (FEM) with adhesion and dissipation specially accounted. The FEM simulation predicts the critical adhesion velocity and restitution coefficient when rebound occurs. Then we substitute the particle impaction model into Eulerian-Lagrangian simulation of flow field and extract the deposition rate statistically. The result shows that for small particles (< 5 μm), the deposition rate is controlled by the collision rate, which is mainly determined by the interaction between turbulence and thermophoresis. The particle-vortex interaction is essentially important for the distribution of particles near wall and thus influences the deposition rate. For large particles the deposition rate is more affected by the sticking efficiency, which is simultaneously controlled by both the critical adhesion velocity and normal impaction velocity. Therefore, the deposition rate first increases then decreases with particle size and reaches maximum at about 5 μm.

Simulation of Fluid Flow Using Reduced-Order Modeling by POD Approach Applied to a Fixed Tube Bundle System

2010 ◽  
Author(s):  
Marie Pomarede ◽  
Erwan Liberge ◽  
Aziz Hamdouni ◽  
Elisabeth Longatte ◽  
Jean-Franc¸ois Sigrist
Keyword(s):  
Dynamic Analysis ◽  
Steam Generator ◽  
Tube Bundle ◽  
Fluid Structure Interaction ◽  
Reduced Model ◽  
Steam Generator Tube ◽  
Fluid Structure ◽  
Reduced Order ◽  
Structure Interaction ◽  
Tube Bundles

Tube bundles in steam boilers of nuclear power plants and nuclear on-board stokehold are known to be exposed to high levels of vibrations. This coupled fluid-structure problem is very complex to numerically set up, because of its three-dimensional characteristics and because of the large number of degrees of freedom involved. A complete numerical resolution of such a problem is currently not viable, all the more so as a precise understanding of this system behaviour needs a large amount of data, obtained by very expensive calculations. We propose here to apply the now classical reduced order method called Proper Orthogonal Decomposition to a case of 2D flow around a tube bundle. Such a case is simpler than a complete steam generator tube bundle; however, it allows observing the POD projection behaviour in order to project its application on a more realistic case. The choice of POD leads to reduced calculation times and could eventually allow parametrical investigations thanks to a low data quantity. But, it implies several challenges inherent to the fluid-structure characteristic of the problem. Previous works on the dynamic analysis of steam generator tube bundles already provided interesting results in the case of quiescent fluid [J.F. Sigrist, D. Broc; Dynamic Analysis of a Steam Generator Tube Bundle with Fluid-Structure Interaction; Pressure Vessel and Piping, July 27–31, 2008, Chicago]. Within the framework of the present study, the implementation of POD in academic cases (one-dimensional equations, 2D-single tube configuration) is presented. Then, firsts POD modes for a 2D tube bundle configuration is considered; the corresponding reduced model obtained thanks to a Galerkin projection on POD modes is finally presented. The fixed case is first studied; future work will concern the fluid-structure interaction problem. Present study recalls the efficiency of the reduced model to reproduce similar problems from a unique data set for various configurations as well as the efficiency of the reduction for simple cases. Results on the velocity flow-field obtained thanks to the reduced-order model computation are encouraging for future works of fluid-structure interaction and 3D cases.

The Water Ingress Mass Analysis on Steam Generator Heat-Exchange Tube Rupture Accident of High Temperature Gas-Cooled Reactor

2009 ◽  
Author(s):  
Yan Wang ◽  
Yanhua Zheng ◽  
Fu Li ◽  
Lei Shi ◽  
Zhiwei Zhou
Keyword(s):  
High Temperature ◽  
Heat Exchange ◽  
Steam Generator ◽  
Mechanical Load ◽  
Radioactive Isotopes ◽  
Primary Circuit ◽  
Secondary Circuit ◽  
Water Ingress ◽  
Heat Exchange Tube ◽  
High Temperature Gas

The module high temperature gas-cooled reactor (HTGR) is an advanced reactor with high safety level. The steam generator heat-exchange tube rupture (SGTR) accident (or water ingress accident) is an important and particular accident which will result in water ingress to the primary circuit of reactor. Water ingress may, in turn, result in chemical reaction of graphite fuel and structure with water, causing release of radioactive isotopes and generation of explosive gaseous in large quantity. The analysis of SGTR is significant for verifying the inherent safety characteristics of HTGR. One of the key factors is to estimate the amount of water ingress mass which is used to evaluate the severity of the accident consequence. The 200MWe high temperature gas-cooled reactor, which is designed by the Institute of Nuclear and New Energy Technology of Tsinghua University, is selected as an example to analyze. The accident scenarios of double-ended rupture of both single and two heat-exchange tubes at the inlet and outlet of steam generator are simulated respectively by RETRAN-02. The results show that the amount of water ingress mass is related to the break location, the number of ruptured tubes (or the break size). The greater the number of ruptured tubes or the break size, the larger the amount of water ingress mass. It is important to design the draining pipe line with reasonable diameter, which should be optimized based on economy and safety considerations for preventing large water ingress to the reactor primary circuit, restricting the change rate of mechanical load on SG, and reducing the radioactive isotopes release to the secondary circuit.

Simulation of a Once-Through, Helical-Coiled Steam Generator of High Temperature Gas-Cooled Reactor

2009 ◽  
Author(s):  
Jinliang Ye ◽  
Yangping Zhou ◽  
Xiaoming Chen ◽  
Yuanle Ma ◽  
Fu Li ◽  
...  
Keyword(s):  
High Temperature ◽  
Steam Generator ◽  
Static Model ◽  
Mass Energy ◽  
Design Data ◽  
The Difference ◽  
Steady State Simulation ◽  
Energy And Momentum ◽  
Blast Program ◽  
High Temperature Gas

A quasi-static model of a helical coiled Once-Through Steam Generator of High Temperature gas-cooled Reactor-Pebble Bed Module (HTR-PM) is developed based on the fundamental conservation of fluid mass, energy and momentum. The steam generator is handled with single tube concept and is divided into three regions as subcooled region, boiling region and superheated region. The equations are solved by Rung-Kutta method. The steady-state simulation results agree well with the design data. Furthermore, the results are compared with the results gotten from THERMIX/BLAST program, and the difference between them is small which shows the model and the methodology are reasonable.

scholarly journals The Fouling Behavior of Steam Generator Tube at Different Positions in the High-Temperature Water

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 684
Author(s):  
Tong Zhang ◽  
Guihui Qiu ◽  
Hongying Yu ◽  
Peng Zhou ◽  
Shicheng Wang ◽  
...  
Keyword(s):  
Stainless Steel ◽  
High Temperature ◽  
Steam Generator ◽  
Outer Layer ◽  
Layer Structure ◽  
Steam Generator Tube ◽  
Support Plate ◽  
High Temperature Water ◽  
Triple Layer ◽  
Temperature Water

The fouling behavior of a steam generator (SG) tube was investigated at different positions after 500 h of immersion in high-temperature water. A triple-layer structure of fouling appeared at both the crevice position and the free span position, namely, the large, dispersedly distributed deposition layer on the top; the small and faceted outer layer; and the relatively continuous inner layer. There was no obvious positional effect on the thickness of the inner layer. However, in the crevice position, the density of the deposited particle and the thickness of the outer layer was much higher than those of the free span position. The tube support plate (TSP) made of 410 stainless steel contributed significantly to the fouling behavior of the SG tube in the crevice between the SG tube and the TSP.

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