Effect of a flow-corrective insert on the flow pattern in a pebble bed reactor

A flow-corrective insert is adopted in the pebble-bed high temperature gas-cooled reactor (HTGR) to improve flow performance of the pebble flow for the first time. 3D discrete element method (DEM) modeling is employed to study this slow and dense granular flow. It is verified that locating a properly designed insert in the bed can help transform unsatisfactory flow field to the preferred flow pattern for pebble bed reactors. Three characteristic values on the stagnant zone, radial uniformity and flow sequence of pebble flow are defined to evaluate uniformity of the overall flow field quantitatively. The results demonstrate that the pebble bed equipped with an insert performs better than normal beds from all these three aspects. Moreover, based on numerical experiments, several universal tips for insert design on height, location and outlet diameter are suggested.

[1]  Michael Thompson,et al.  Modelling the solids inflow and solids conveying of single-screw extruders using the discrete element method , 2005 .

[2]  Jacek Tejchman,et al.  Confined granular flow in silos with inserts — Full-scale experiments , 2012 .

[3]  J. Tu,et al.  Mechanism analysis of quasi-static dense pebble flow in pebble bed reactor using phenomenological approach , 2012 .

[4]  Jiyuan Tu,et al.  Experimental and numerical validation of a two-region-designed pebble bed reactor with dynamic core , 2012 .

[5]  Edwin A. Harvego,et al.  Next Generation Nuclear Plant: High-Level Functions and Requirements , 2004 .

[6]  Charles S. Campbell,et al.  Granular material flows – An overview , 2006 .

[7]  Evangelos Tsotsas,et al.  Mixing of particles in rotary drums: A comparison of discrete element simulations with experimental results and penetration models for thermal processes , 2006 .

[8]  W. K. Terry,et al.  Direct Deterministic Method for Neutronics Analysis and Computation of Asymptotic Burnup Distribution in a Recirculating Pebble-Bed Reactor , 2002 .

[9]  Shu-San Hsiau,et al.  The simulation and experimental study of granular materials discharged from a silo with the placement of inserts , 2001 .

[10]  R. Pruschek,et al.  The Modular High-Temperature Reactor , 1985 .

[11]  Troy Shinbrot,et al.  Experimentally validated computations of flow, mixing and segregation of non-cohesive grains in 3D tumbling blenders , 2000 .

[12]  Charles S. Campbell,et al.  Granular shear flows at the elastic limit , 2002, Journal of Fluid Mechanics.

[13]  H. Saxén,et al.  Discrete element method simulation of properties of a 3D conical hopper with mono-sized spheres , 2011 .

[14]  Yu Li,et al.  Experimental Research and DEM Simulations on Stagnant Region in Pebble Bed Reactor , 2013 .

[15]  Zenon Mróz,et al.  Analysis and DEM simulation of granular material flow patterns in hopper models of different shapes , 2011 .

[16]  P. Cundall,et al.  A discrete numerical model for granular assemblies , 1979 .

[17]  Marc Vincent Berte.  Modularity in design of the MIT Pebble Bed Reactor , 2004 .

[18]  C. González-Montellano,et al.  Three dimensional discrete element models for simulating the filling and emptying of silos: Analysis of numerical results , 2012, Comput. Chem. Eng..

[19]  Istvan Oldal,et al.  Outflow properties of silos: The effect of arching , 2012 .

[20]  Hayley H. Shen,et al.  The stress tensor in granular shear flows of uniform, deformable disks at high solids concentrations , 1990, Journal of Fluid Mechanics.

[22]  Christopher E. Brennen,et al.  Computer simulation of granular shear flows , 1985, Journal of Fluid Mechanics.

[23]  A. Koster,et al.  PBMR design for the future , 2003 .

[24]  H. Reutler,et al.  The modular HTR ― a new design of high-temperature pebble-bed reactor , 1983 .

[25]  Wang Dazhong,et al.  Roles and prospect of nuclear power in China's energy supply strategy , 2002 .

[26]  C. González-Montellano,et al.  Discrete element modelling of grain flow in a planar silo: influence of simulation parameters , 2011 .

[27]  C. Thornton,et al.  Distinct element simulation of impact breakage of lactose agglomerates , 1997 .

[28]  J. Tu,et al.  Effect of bed configuration on pebble flow uniformity and stagnation in the pebble bed reactor , 2014 .

[29]  Pebble bed HTRs , 1978 .

[30]  Jiang Binbo,et al.  Multi-scale study of particle flow in silos , 2009 .

[31]  C. González-Montellano,et al.  Validation and experimental calibration of 3D discrete element models for the simulation of the discharge flow in silos , 2011 .

[32]  H. Shen,et al.  Comparisons of physical experiment and discrete element simulations of sheared granular materials in an annular shear cell , 2009 .