IRSN funded and CEA oversaw a major 12-year refurbishment of the facility (2003-2015), which included a safety upgrade (for seismic and fire risk) and numerous improvements to functionalities, including refurbishment of the reactor core cooling and waste systems, refurbishment of the core block and fast valves of the transient rods, and replacement of nuclear ventilation and equipment and facility control/command.
Several equipment were replaced (test device handling cask and transport shell) or renovated (IRIS nondestructive station, seismic reinforcement, and the hodoscope).
In terms of experiments, the most significant modification is the replacement of the sodium test loop with a pressurized water loop in order to reproduce the thermal hydraulic conditions of a pressurized water reactor (280°C, 155 bar, speed of water at test rod 4 m/s), which is the type of reactor found in nuclear power plants in France.
Introduction of the out of pile containment vessel in the reactor hall (c) Michel Thurin / Médiathèque IRSN