The thermohydraulic system code CATHARE, developed in CEA with EDF, Framatome and ASNR, permits to simulate normal and accidental behaviours of the hydraulic circuit of a Pressured Water Reactor (PWR). This code is used as a reference in France for transient simulation in nuclear reactor, and is especially used as a support for licensing by EDF and Framatome.
Former studies show the need to improve the validity of the interfacial friction modelling for rod bundle geometry at low pressure or for high hydraulic diameter conditions. Moreover, the current interfacial friction modelling for rod bundle geometry is based on numerous simplifications and a calibration against some steam-water at high temperature experimental data. A new interfacial friction model for Cathare could nowadays be developed using more comprehensive models found in the literature and be calibrated against a larger experimental database
This doctorate aims to improve the interfacial friction modelling for rod bundle geometry by studying the physical phenomena associated with this problem. This work will help implement a more comprehensive model in the CATHARE code following the thesis, thus extending the code's validity conditions to new applications.