Perforated plates with thin orifices is one of the options under considerations to be used in the debris filtering bottom end pieces for the next generation of fuel assemblies for the Brazilian nuclear plants. The increase in pressure drop can be drastically reduced by optimizing the chamfer geometries. This paper describes the development and validation of a procedure devised to use Computational Fluid Dynamics (CFD) to accurately estimate the pressure drop of water flow through perforated plates with chamfered thin orifices. The procedure comprises a scaled down calculation domain, grid configuration and a set of numerical solution parameters. The validation was performed against experiments with a set of plates with different chamfer geometric features like position (inlet, outlet and both sides), angles and sizes. Three turbulence models were evaluated with the standard k-ε giving the best result. For the range of parameters evaluated here the pressure drop decrease of a two sided chamfer plate can be estimated as a sum of both inlet and outlet chamfers individually. In both cases the pressure drop decreases rapidly for small chamfers and more slowly for larger chamfers. In the flat regions the chamfer angle has little influence at the inlet and is more important at outlet284 7479(2012) CFX Handbook, , ANSYSBarth, T.J., Jespersen, D.C., (1989) The Design and Application of Upwind Schemes on Unstructured Meshes, pp. 89-0366. , AIAA Paper(2008) Evaluation of Measurement Data - Guide to the Expression of Uncertainty in Measurement, , BIPM, IEC, IFCC, ILAC, ISO, IUPAC, IUPAP, OIML, and JCGM 100 BIPM - Bureau International des Poids et Mesures Sevres, FranceBroach, K.D., Norrell, J.L., Conner, M.E., Lunde, C.E., Perforated plate pressure losses with improved inlet and outlet flow hole features (2003) Proceedings of the ASME FEDSM'03, 4th ASME-JSME Joint Fluids Engineering Conference, , Honolulu, HI, USACasey, M., Wintergerste, T., (2000) Special Interest Group on Quality and Trust in Industrial CFD. Best Practice Guidelines, Version 1, ERCOFTAC ReportCelik, I., Li, J., Assessment of numerical uncertainty for the calculations of turbulent flow over a backward facing step (2005) Int. J. Numer. Methods Fluids, 49, pp. 1015-1031Chung, K.M., Song, C.H., Chung, H.J., Won, S.Y., Cho, Y.R., Kim, B.D., (1992) Debris Filtering Effectiveness and Pressure Drop Tests of Debris Resistance Bottom End Pieces, , KAERI/TR/248/92Dominique, B., Martin, A., Menter, F., Boucker, M., Pigny, S., Scheuerer, M., Heitsch, M., Andreani, M., Recommendation on use of CFD codes for nuclear reactor safety analysis, ECORA, European commission (2004) 5th EURATOM Framework Program, , http://www.domino.grs.de/ecora/ecora.nsf, Available fromEca, L., Hoekstra, M., Roache, P., Coleman, H., (2009) Code Verification, Solution Verification and Validation: An Overview, of the 3rd Lisbon Workshop, , AIAA-2009-0047(2003) Use of Computational Fluid Dynamics Codes for Safety Analysis of Nuclear Reactor Systems, , IAEA TECDOC-1379Idelchik, I.E., (2008) Handbook of Hydraulic Resistance, , 3rd ed. Jaico Publishing House MumbaiLockard, D.P., In search of grid converged solutions (2010) Procedia Eng., 0, pp. 1-10Mahaffy, J., Chung, B., Dubois, F., Ducros, F., Graffard, E., Heitsch, M., Henriksson, M., Zigh, G., (2007) Best Practice Guidelines for the Use of CFD in Nuclear Reactor Safety Applications, , OECD Nuclear Energy Agency Issy-les-Moulineaux, France NEA/CSNI/R(2007)5Menter, F., CFD best practice guidelines for CFD code validation for reactor-safety applications, European commission (2002) 5th EURATOM Framework Programme, Report, EVOLECORA D1Oberkampf, W.L., Roy, C.J., (2010) Verification and Validation in Scientific Computing, , Cambridge University PressRoache, P.J., (2009) Fundamentals of Verification and Validation, , Hermosa Publishers SocorroSantos, A.A.C., Barros Filho, J.A., Navarro, M.A., Verification and validation of a numeric procedure for flow simulation of a 2 × 2 Pwr Rod Bundle (2011) International Nuclear Atlantic Conference - INAC 2011, , Belo Horizonte, BrazilShyy, W., Garbey, M., Appukuttan, A., Wu, J., Evaluation of Richardson extrapolation in computational fluid dynamics (2002) Numer. Heat Transf. B, 41, pp. 139-164Whelan, B.P., Robinson, A.J., Effect of nozzle geometry on pressure drop and heat transfer to both free-surface and submerged liquid jet arrays (2008) 5th European Thermal-Sciences Conference, , The NetherlandsYogesh, J., Challenges in the accurate numerical simulation of practical thermal processes and systems (2013) Int. J. Numer. Methods Heat Fluid Flow, 23 (1), pp. 158-175