Overview of CFD Round Robin Benchmark of the High Fidelity Fuel Rod Bundle NESTOR Experimental Data

Computational fluid dynamics (CFD) is becoming a vital tool to analyze the complex fluid flow and heat transfer phenomena in pressurized water reactor (PWR) cores, and its use has been increasing although only limited information is currently provided to the industry as to how the CFD analysis should be applied. In addition significant discrepancies have been observed between the CFD predictions and experimental data from rod bundle tests. This is largely due to the fact that most CFD codes have not been benchmarked against high-fidelity rod bundle data nor optimized for fuel assembly analyses. To address such industry concerns related to the benchmarking of CFD analysis and Best Practices for applying CFD to PWR cores, EPRI convened a CFD round robin (RR) Group in 2009. This group included participants from fuel suppliers, CFD software developers, universities, research organizations, and utilities. The RR Participants volunteered to apply their process to the evaluation of the data from the NESTOR (New Experimental Studies of Thermal-Hydraulics of Rod Bundles) program collected on two 5x5 rod bundle configurations. In addition to evaluating the current status of applying CFD analysis to a PWR fuel bundle, the ultimate goal of this project is development of a Best Practices document for CFD analyses to ultimately streamline fuel risk assessment as defined in the Fuel Reliability Guideline: PWR Fuel Cladding Corrosion and Crud. This paper describes the dataset from the NESTOR experimental program that was used in the EPRI RR activities, outlines the efforts of the EPRI CFD RR Group, and highlights the significant observations. Many of the RR Participants have related papers on their volunteered CFD analyses in this special session of NURETH-16.