Preparatory experimental campaign for the Primary Heat eXchanger of the MYRRHA reactor

SCK•CEN Mentor

Mirelli Fabio,, +32 (0)14 33 80 14

Expert group

Primary System Design

SCK•CEN Co-mentor

Marino Alessandro , , +32 (0)14 33 80 11


MYRRHA is a flexible fast spectrum research reactor cooled by Lead-Bismuth. Conceived as an Accelerator Driven System prototype, it is able to operate in sub-critical mode. Operating in critical mode, MYRRHA serves as demonstrator for the Lead Cooled Fast Reactor (LFR) which is one of the Generation IV reactor concepts. This kind of nuclear system is highly economical, has enhanced safety, produces minimal waste and is proliferation friendly. In addition, such systems can be used to transmute transuranic elements in shorter-lived waste, thus lowering the burden on deep geological storage.

One of the key components of the reactor is the Primary Heat eXchanger: for improved safety, designers have opted for a double walled PHX, where the gap between the two walls is filled with a fluid that can be coupled to a leak monitoring system.

This solution must be extensively investigated for what concerns its thermal, mechanical properties and behaviour: preparatory tests are foreseen to take place in 2018, while full-scale experiments will be performed as of January 2019.


The main goal of this activity is to perform experiments on a small test facility: the one key parameter that the design team needs to establish is the heat transfer coefficient of the double wall structure, all along its active length and in representative conditions; a table-top experiment is being constructed in order to obtain its first-order estimate.

The base configuration of this facility foresees the heat exchanger tube to be heated up directly with electrical resistors. In a later stage, the facility will be equipped with an outer shell in which a natural circulation LBE flow will take place: the conceptual design of this device must be proposed by means of CFD (Computational Fluid Dynamics); this model will be therefore coupled to the available STH (System Thermal Hydraulics) model of the water/steam side.

Familiarity with CAD and/or CFD is appreciated.


The minimum diploma level of the candidate needs to be

Academic bachelor