Development and validation of a coupled PARCS/RELAP5 model of the Ringhals-3 PWR

Paper in proceeding, 2007

This paper deals with the development of a coupled PARCS/RELAP5 model of the Swedish Ringhals-3 pressurized water reactor. The stand-alone PARCS and RELAP5 models are first presented. On the neutronic side, the dependence of the material constants on history effects, burnup, and instantaneous conditions is accounted for, and the full heterogeneity of the core is thus taken into account. The reflectors are also explicitly represented. On the thermal-hydraulic side, each of the 157 fuel assemblies is modelled. The model is furthermore able to handle possible asymmetrical conditions of the flow velocity and temperature fields between the loops. The coupling between the two codes is touched upon, with emphasis on the mapping between the hydrodynamic/heat structures and the neutronic nodes. Validation of the model against measured plant data at steady-state conditions is then summarized. Comparisons between calculated/measured parameters demonstrate that the model is able to correctly represent steady-state conditions of the plant. Finally, the validation of the model against measured transient plant data is described. The transient chosen for this validation task was a load rejection (“house-load”) transient, which occurred on January 8, 2005.