Abstract
Current light water reactors (LWR) designs have been optimized over decades, and required improvements cannot be based on mere redesign but will require novel technologies. The introduction of an advance fuel in the form of coated micro-fuel particles under Helium atmosphere in the cladding tubes of light water reactor fuel assemblies is a novel technology proposed in this study. This will ensure retention of radioactive fission products by the fuel making LWR attain a passive safety status and among other advantages, higher fuel enrichment in the proposed nuclear fuel will provide higher burn-up. A slender geometrical model with tube-to-particle diameter ratio N = 2.503 and porosity ε = 0.546 mimicking the proposed nuclear fuel in the cladding was numerically simulated using hydrogen as the working fluid. A commercial code, Star CCM+ is used to investigate the heat transfer characteristics and flow distribution under buoyancy driven force expected in the cladding tube of the proposed nuclear fuel. Random packing of the particles is achieved by Discrete Element Method (DEM) simulation. The temperature contour and velocity vector profile obtained can be said to be good illustration of anticipated heat transfer and transport phenomenon to occur in the proposed design. Simulated results for particle-to-fluid heat transfer coefficient, Nusselt number, and Rayleigh number which are of prime importance when analyzing heat transfer performance in fixed bed reactors were validated. Simulated results show close agreement with results obtained in high temperature reactor HTR such as the PBMR.
