“…[3,8,[11][12][13]. The mitigation of undesirable LMC effects in HLM-cooled nuclear reactors, such as the accelerator-driven system (ADS) system MYRRHA (multi-purpose hybrid research reactor for high-tech applications [14]), relies on the judicious combination of moderate operation temperatures, active oxygen control, in-depth understanding of the LMC mechanisms and, whenever needed, possible implementation of steel surface protection approaches (e.g., PLD-deposited alumina [15][16][17][18][19], GESA surface modification [20]). Active oxygen control aims at steel passivation (i.e., covering the steel surface with thin, protective oxide scales) by maintaining the dissolved oxygen concentration in the HLM coolant, CO, within appropriate, system-specific limits (these limits depend on the ΔT of the reactor system, the steels used for its construction, the specific HLM coolant, etc.)…”