In this work a physical analysis of the pebble bed nuclear reactor's fluid dynamics is undertaken using Computational Fluid Dynamics software. However, efficiency of the reactor does not solely depend on the number of kernels of fuel within each graphite sphere, but also depends on the type and motion of the coolant within the voids between the spheres and the reactor itself. In pebble bed reactors, the typical pebble diameter used is 6cm, and within each pebble is are thousands of nuclear fuel kernels. Jones, Andrew Enriquez, Christian Spangler, Julian Yee, Tein Park, Jungkyu Farfan, Eduardo
Preliminary CFD study of Pebble Size and its Effect on Heat Transfer in a Pebble Bed Reactor Especially near the wall large variations in local packing fractions exists, with a higher probability for both clusters of pebbles with low (0.65) packing fraction, which could significantly affect flow rates and, together with higher power densities, could result in hotspots. Next, variations in the local packing density are investigated by comparing probability density functions of the packing fraction of small clusters of pebbles throughout the bed. Results also show the packing structure is different near the wall than in the bulk of the bed, with pebbles near the wall forming ordered layers similar to hexagonal close packing.
Especially for the bulk of the bed, properties of the computed bed show good comparison with the scanned bed and with literature, giving confidence our method generates beds with realistic packing microstructure. We first compare various properties of the local packing structure of a computed bed with those of an image made using computer aided X-ray tomography, looking at properties in the bulk of the bedmore » and near the wall separately. To analyse local density variations computational methods are needed that can generate randomly stacked pebble beds with a realistic packing structure on a pebble-to-pebble level. These variations can influence local coolant flow and power density and are a possible cause of hotspots. In pebble bed type nuclear reactors the fuel is contained in graphite pebbles, which form a randomly stacked bed with a non-uniform packing density. Packing microstructure and local density variations of experimental and computational pebble bedsĪuwerda, G. Results of this study might become an importance guidance for design optimization of OTTO fuel scheme PBR. Results of this study show that diameter and H/D effectsare stronger compare to the power density and nominal core power. The parameters include its core diameter, height-per-diameter (H/D), power density, and core nominal power.
Latin hypercube sampling san antonio wake garg code#
PEBBED code is utilized in this study to perform the equilibrium PBR core analysis for different design parameter and fuel scheme. Parametric survey is perform in this study to investigate the contribution of different design parameters to power peaking effect of OTTO cycle PBR. Important challenge in the OTTO fuel scheme is the power peaking effect which limit the maximum nominal power or burnup of the design. Effort to introduce the PBR design to the market can be strengthen by simplifying its system with the Once-through-then-out (OTTO) cycle PBR in which the pebble fuel only pass the core once. Pebble Bed Reactor (PBR) type of Hight Temperature Gas-cooled Reactor ( HTGR) is a very interesting nuclear reactor design to fulfill the growing electricity and heat demand with a superior passive safety features. Power Peaking Effect of OTTO Fuel Scheme Pebble Bed Reactor
0 kommentar(er)
