Analysis of selected Phenix EOL tests with the FAST code system - Part I: Control-rod-shift experiments

The end-of-life (EOL) tests recently performed at the Phenix reactor present a unique opportunity to validate computational tools used for Sodium-cooled Fast Reactor (SFR) static and transient analysis. In the first part of the current study, PSI's FAST code system - which includes ERANOS and TRACE/PARCS - has been used to analyze test data from the control-rod-shift (CRS) experiments. The second part of the study, presented in a separate paper, is devoted to an analysis of the unprotected phase of the Natural Convection (NC) Test. Both tests have been studied in the framework of international benchmark exercises organized by the IAEA. A static model of the Phenix core was first developed with ERANOS. This was used (i) for direct comparison with the CRS test data and (ii) to prepare the macroscopic reference cross-sections and their derivatives for use in the 3D neutron kinetics PARCS model. A coupled TRACE/PARCS static model was then developed and verified against ERANOS results. The power deformations resulting from the different control rod (CR) positions calculated with both models have been found to agree very well with the experimental data, showing that the control rods were accurately modeled. This analysis has thus provided valuable additional validation of the SFR modeling capabilities of ERANOS and TRACE/PARCS as implemented within the FAST code system. (C) 2012 Elsevier Ltd. All rights reserved.