• Validation
• System code
• Severe Accident
• Natural circulation
• In Vessel Retention
• CATHARE

This work shows the result of a six months internship at the Commissariat pour l'energie atomique (CEA) of Saclay in the framework of the CALO project in collaboration with Electricité de France (EDF).

CALO is a facility designed to study the hydraulic phenomena during the In Vessel Retention (IVR) scenario, that is, the management strategy of a Severe Accident chosen for the AP1000 reactor. The facility simulates the heat production with Air injections in order to create a two-phase natural circulation loop.The aim of this work is to validate CATHARE code on CALO tests made on 23 January 2013.

In the first chapters there is an introduction of the IVR phenomenon and a description of the main features of CATHARE code.
The following part deals with the code simulation with a mono-dimensional approach, both with Air injection and with heat production.
In the last part, the calculation was done with a three-dimensional simulation of the loop in order to compare the two different approaches in the Air injection situation.