The Primary Heat eXchanger (PHX) of MYRRHA constitutes the most important interface between the nuclear island and the secondary system. In fact, it is placed inside in the reactor pool allowing to operate a compact reactor without an intermediate loop. Its safe operation is thus of primary importance and should be properly guaranteed even in case of design basis accident scenarios.
One of the most promising option for the PHX is based on the double wall coextruded tube technology with gas leakage monitoring system placed between the double wall. This innovative heat exchanger has never been used in the nuclear technology. Extensive experimental R&D is therefore necessary to investigate the behavior of this component. To fulfill this purpose, an experimental facility is under construction at SCK•CEN: the Heat EXchAnger at COMplot (HEXACOM) facility. HEXACOM is an up-grade of the already in operation COMponent Loop Test (COMPLOT) facility and it is aimed to test a single double wall coextruded bayonet tube in full scale (to MYRRHA PHX tubes).
The aim of this work is to develop a qualified TH system code model of the facility on the basis of an initial nodalization. The model will be used to support the design of the experimental campaigns of HEXACOM by performing extensive pre-test analyses.